Outdoor LED Solar Lights Circuit Schematic form china

Outdoor LED Solar Lights Circuit Schematic form china
This projects uses two Solar Garden Lights.
SOLAR GARDEN LIGHTS cheap price
Last post >> We show circuits of Solar Garden Light the product form chiana

These lights cost less than $3.00 each and come with a 2.5v solar panel capable of charging at up to 35mA, a rechargeable 1.2v NiCd cell and a circuit we will use to convert the 1.2v + 1.2v to a 5v output.
The two lights are dismantled and all the parts taken off one of the PC boards.
We will be using both NiCd cells in series and the solar panels are placed in series to charge the cells.
The circuits for these Solar Garden Lights are different, depending the manufacturer, however they all do the same job.
The type we have used consists of an oscillator running at about 50kHz and produces a square wave with a high of 60%.
The driver transistor receiving this waveform takes one end of a 100uH inductor to the 0v rail. The other end is connected to the positive rail.
The resistance of the choke (inductor) is fairly important and the ones we tested had a DC resistance from 1.7 ohms to 4.2 ohms and all produced the same output. An inductor with a resistance of 13 ohms did not work.
When the transistor turns off, the spike produced by the inductor is passed though a high speed diode to charge a 100u electrolytic. The voltage produced by the inductor is actually about 12v - 18v but this spike is absorbed by the electro and its voltage gradually rises.
When it rises above 5.5v, a voltage divider made up of a 1M and 150k, creates a voltage of 650mV across the 150k and this turns on the PNP transistor to shut off the oscillator.
Normally, the detection-line to the oscillator is used to detect when the cells are producing a voltage and this shuts off the LED, as the Garden Light determines it is daylight.
This sense-line detects less than a few millivolts to turn on the LED and about 300mV it turns the LED off. This is a very wide gap and is designed to prevent "Hunting."
If we connect directly to this sense-line we will get a 300mV pulsing output. This is called Hysteresis - a condition where a circuit does not change state until a higher voltage is reached and then does not change back again until the lower voltage is reached.
To reduce this Hysteresis, we have added a PNP transistor. This reduces the Hysteresis by a factor of about 100.

這些燈的成本低於 3.00美元每拿出一個 2.5V的太陽能電池板的充電能力高達35毫安，一個 1.2V的鎳鎘充電電池和電路，我們將使用轉換為 1.2V + 1.2V至5V的輸出。
這兩個燈拆除，所有的部件之一，起飛 PC板。
我們將同時使用鎳鎘電池串聯和太陽能電池板放置在充電電池系列。
該電路為這些太陽能庭院燈是不同的，這取決於製造商，但他們都做同樣的工作。
我們使用的類型包括一個振盪器運行，並產生約 50kHz的方波高60％。
在收到此波形驅動晶體管的一端需要一個電感 100uH的0V軌道。另一端則連接到正軌。
該電阻的電抗器（電感器）非常重要，我們測試過的直流電阻 1.7歐姆到4.2歐姆，都產生相同的輸出。電感器具有13歐姆的電阻沒有工作。
當晶體管關閉時，所產生的電感穗傳遞雖然高速二極管收取100u電解。產生的電壓由12V的電感是真正關心 - 18V的，但這個峰值是由電子和吸收其電壓逐漸上升。
當它上升到高於 5.5V的，一個分壓器由一個 1M和15萬，創建一個電壓 650mV橫跨 15萬，這開啟了PNP晶體管關閉振盪器。
通常，檢測線到振盪器用於檢測的細胞時產生電壓，這切斷帶領下，花園燈確定是白天。
這個意義上線檢測不到幾毫伏打開約 300mV的LED和原來的LED熄滅。這是一個非常大的差距，旨在防止“狩獵”。
如果我們直接連接到這個意義上說，行，我們將得到一個 300mV的脈衝輸出。這就是所謂的遲滯 - 一種情況：一個電路不改變狀態，直到達到一個更高的電壓，然後再回來不會改變，直到達到較低的電壓。
為了減少這種滯後，我們增加了一個 PNP晶體管。這減少了遲滯的一個因素，共約 100人。

Here IC1 is wired as a medium current inverting line driver, switched by an encapsulated light detector (10mm LDR). Multi-turn trimpot P1 sets the detection sensitivity. When ambient light dims,transistor T1 turns on to drive the white LED string (D1-D8). Now this lamp load at the output of T1 energises. Resistors R1-R8 limits the operating current of the LEDs. When the ambient light level restores, circuit returns to its idle state and light(s) switched off by the circuit.

Solar 5v Supply Circuit Outdoor LED Solar Lights Circuit Schematic form china

The two solar panels, 2 cells and matrix board
with a 1k load resistor. The 1R in series
with the solar cells detects charging current.
Use a multimeter set to mV. Each mV
represent 1mA charging current.


THE CIRCUIT
The circuit is designed around a "flyback Oscillator."  This consists of an oscillator running at a high frequency.
The output drives a transistor that is connected to an inductor. An indicator is a coil of wire wound on a metal or ferrite material. It can also be wound with an air core but it will not have the same output in this circuit.
When an inductor is paced across a battery, it will not allow a high current to flow immediately. A small current flows and this produces magnetic flux and the flex cuts the other turns of the winding to produce a voltage in the opposite direction. This voltage opposes the incoming voltage and the result is only a very small voltage. This small voltage only allows a small current to flow.
The magnetic field is constantly increasing and this is called expanding flux and this expanding flux does not produce quite the same amount of reverse voltage in the winding due to the permeability of the magnetic material. So the effective incoming voltage becomes higher and this produces a higher current.
All this is happening in microseconds but eventually the current is a maximum and core is saturated with flux and it cannot produce a higher density of expanding flux. This is the point at which we need to turn off the transistor as the inductor is FULL of flux. Keeping the transistor turned on for a longer period of time will just waste current.
The transistor is now turned off and you can consider it is removed from the circuit.
The current ceases to flow and the magnetic flux collapses.
This collapsing magnetic flux produces a voltage in the winding that is opposite to the original voltage and because it collapses very quickly, the voltage is very high. It can be 5 times higher or 100 times higher or even 1,000 times higher.
It depends on the magnetic material of the core and a number of other factors. This is called the "Q" factor or Quality factor of the inductor and is one of the amazing things in electronics.
In our case the voltage is over 18v . But we do not want a voltage this high and you will see how we use this voltage in a moment.
We pass it though a diode to charge an electrolytic. The diode prevents the voltage on the electrolytic passing back into the transistor/inductor circuit and discharging.
The electrolytic gets charged with the energy of the spikes and will charge to almost 18v. To prevent this, we detect when the electro is 5v and turn off the oscillator via the "sense" line.
When the voltage drops below 5v, the oscillator is turned on again.
The circuit is called a "flyback" circuit because we use the high voltage developed during turn-off to deliver a voltage to the output.
It can also be called a "boost" circuit.
The other sections of the circuit have already been discussed.

CHARGING THE CELLS
The two solar panels are connected in series to charge the two 1/3 AA Ni-Cd cells.


1/3 AA Ni-Cd cell

The two 1.2v NiCad cells have a voltage across them of about 1.3v +1.3v when charged and this rises to 2.7v when the panel starts to charge them. This is called a "floating charge" and the voltage developed across a cell when it begins to charge. This voltage has to be taken into account when supplying a charging voltage. On top of this we have a diode to prevent the batteries discharging into the solar panels (when no light is present) and this makes the panels need to produce over 3.3v to start the charging process.
With a high level of sunlight, the panels will deliver a charge-current of about 35mA. Depending on the number of hours of sunlight compared to the number of hours the project is required to deliver 5v, the maximum amount of current you can draw is determined by the following:
The cells have a 130mAh capacity and if you charge them at 35mA, it will take 4 hours.
On most days the cells will be fully charged in this time and you can allow the project to draw about 20mA during the charging process and still produce fully-charged cells on a bright day.
This gives 8 hours of daytime use.
The night-time use must come from the cells. If you draw 5mA from the 5v output, the current from the cells will be 13mA to 18mA and they will last a further 8 hours. This gives a total of 16 hours of use per day @5mA.
This is only a very small current but the project is intended for monitoring where it is turned on for a very short period of time to collect data and store it or transmit it via an RF link.
You cannot expect too much from a $10.00 solar project with battery back-up.

ASSEMBLY
The parts are placed on a small matrix board 8 holes x 10 holes. The PC board from the Garden Light is cut so that only the chip and surrounding lands are on the board.
This board is then connected to the matrix board via 4 short lengths of tinned copper wire.
All the other components are fitted to the matrix board as shown in the diagram.  It is a simple matter to join each of the components under the board with fine tinned copper wire (included in the kit).


The top of the Matrix Board showing the
placement of the parts


The underside of the board is very messy
and the parts need to be re-laidout so
that no wires cross over. It can then be made
into a PC board.

TESTING
When the power is applied, the output voltage will rise to about 5v. The circuit needs a slight load to prevent hunting and a 1k resistor will draw 5mA.
If the load is removed, the output will hunt and the current consumption will drop to less than 1mA.
There are lots of different Garden Light circuits and you may need to adjust the value of the voltage-divider to get the output voltage you need for the circuit or the chip you are using.
You need to check the voltage on no load to make sure it does not rise above 5.5v if you are using a microcontroller. If it rises above 5.5v and is not stable, you can add a white LED and red LED in series to get a zener voltage of 5v1. Alternatively you can set the voltage to below 5v and prevent over-voltage.

power by http://solar-power-update.blogspot.com/

We show circuits of Solar Garden Light the product form chiana

 We show circuits of Solar Garden Light the product form chiana >>

Solar Garden Light Set

cheap price Solar Garden Light circuits in this article perform 2 functions:
1. They charge a battery and
2. Turn on a high-bright white (or yellow)  LED at dusk and off during daylight hours.

The two circuits are completely different in design and we will see how different designers tackle the same problem.
Firstly we will discuss the circuit above. It is called Circuit 1.

Here's the clever part: The circuit doesn't deliver a DC voltage to the LED but a high-frequency pulse. This creates the same brightness from the LED (as a constant DC voltage) while needing less than 50% of the energy. It also allows a single cell to be used.
Also, the circuit does not have a dropper resistor for the LED and this further increases the efficiency.
The third clever idea is the use of a single rechargeable cell - even though the white LED requires 2.3v.
And the final clever feature is the use of 4 solar cells to charge the rechargeable cell.
By using a single cell, it is only necessary for the solar panel to produce a voltage above 1.2v for charging to occur. This can be achieved with 3 cells, but if an additional cell is included, the voltage from the panel will rise above 1.2v when the day is not very sunny and thus the battery will be charged almost all the time during the day.

                             http://www.youtube.com/watch?v=5iSH7pe8YTE
                                                    Solar Garden Light
On a very dull day the charge current will be as low as 1mA and increase to over 9mA under very bright sunlight.
The solar panel also performs another function. It turns the LED on and off.
As soon as the voltage from the panel rises above 0.7v, the circuit detects this and turns off the oscillator. This means energy from the battery is not used during the day.
The first transistor is called a "cut-off transistor." It turns off the oscillator section by robbing the base of "turn-on voltage."
When the LED is illuminated, the circuit consumes 10mA, and if you work out the number of night-hours to daylight hours, you will see the LED will illuminate for about 6 hours. This is sufficient for most applications.

CURRENT LIMIT RESISTOR
Although a current-limiting resistor between a solar panel and a battery is technically needed, it is not necessary if the battery will not be overcharged. In our case, the solar cells will not overcharge the battery.

THE SOLAR CELL
The SOLAR CELL actually consists of a number of cells as each cell only generates about 0.5v to 0.6v.
The Solar Cell in our model consists of 4 cells and produces approx 2v with bright sunlight.
The short-circuit current produced is about 30mA and although this is not the correct way to determine the current capability of the cell, it has been given to help you select a suitable cell (or set of cells). The current will drop considerably when the solar cell is connected to a 1.2v battery via a diode and our project delivered 8mA.

HOW THE CIRCUIT WORKS
The circuit consists of two stages. The first stage is a "switch" or cut-off device. It detects a voltage above 0.7v from the solar panel and the resistance between its collector-emitter terminals reduces to a very small value.
The 10k resistor allows the voltage on the solar panel to rise above 0.7v during bright sunlight, while the 100k discharges the 100p when the voltage is very low and the capacitor holds a charge to keep the transistor turned on when the voltage is "high".
When the resistance between the collector-emitter terminals of the first transistor is low, it is turned ON, and the second transistor does not get enough voltage on its base for it to operate as an oscillator.


The function of each component

The purpose of the first transistor is to keep the second stage OFF when the solar cell detects sunlight.
This allows the energy from the solar cell to be passed to the rechargeable battery.
The second transistor is an oscillator.
To see how it works we remove the first transistor.
The second transistor works by itself. The components in the circuit are: the transistor, the two chokes, the 6k8 resistor, the 1n2 capacitor and the LED.

An oscillator needs feedback called POSITIVE FEEDBACK. Positive feedback creates noise or "oscillation" in a correctly designed circuit.
An oscillator must be self-starting and the circuit in this project starts to oscillate by detecting a voltage on the base.
The transistor amplifies this and a larger waveform (larger voltage- change) appears on the collector. This is then passed to the base so that oscillation continues.
For oscillation to occur, the feedback signal must be delayed by a small amount of time.
This small amount of time determines the frequency and the feedback signal has another feature (or characteristic). It is presented to the base with an opposite polarity to that on the collector. To be more precise, the voltage must be moving in the opposite direction. This is called "180° out of phase."
This is achieved by the inductor and the 1n2 capacitor. We all know a capacitor creates time to charge, but an inductor also has a delay-factor.
A resistor does not have a delay-factor, as a voltage at one end of it will appear immediately at the other end, so we can explain the delay-time for an inductor by connecting an inductor in series with a resistor.
There have been many technical descriptions on how an inductor delays a signal, but never a simplified description.
Here is a simple way to understand how an inductor creates a delay.
In the following animation, you will see how the signal (the voltage) is delayed:

The main feature of this animation is to show an inductor effectively GROWS when an applied voltage is delivered to it by producing a back-voltage and thus the voltage at its other end does not change until the core is saturated. This understanding is most important in the circuit we are discussing as the top lead of the inductor is taken from a low-voltage to a high voltage by the action of the transistor when it is turning ON and OFF. As the top lead is taken from one voltage-level to the other, the lead connected to the capacitor does not see this rapid change, but continues in the cyclic process of charging and discharging the capacitor. That's why this circuit is so difficult to understand.
Let's look at the characteristic is the inductor in more detail:
The voltage applied to the inductor starts at zero. As it rises, the turns of wire on it produce magnetic flux that cuts the other turns and this action produces a voltage that opposes the incoming voltage, and a surprising thing happens. The resulting forward voltage is very small and this causes very little current to flow. Thus the voltage across the resistor does not change. This is similar to saying the waveform does not appear at the other end of the inductor. As the waveform rises further, (the applied voltage increases) the core of the inductor becomes saturated. At this point it cannot produce any more flux. The opposing voltage (produced by the expanding flux) is reduced and this allows a higher current to flow. This causes an increase in the voltage across the resistor. If the resistor is replaced by a capacitor, the capacitor would see a delay before it starts to charge.  When the inductor is combined with a capacitor, the two components form a circuit that delays the signal to the base by 180° and the circuit oscillates at a frequency of about 500kHz.
The operation of this circuit can be found in text books under the heading Hartley Oscillator.
But it's a bit more complicated than first meets the eye as the inductor in the positive rail assists in the generation of the waveform.

Thus the circuit is beyond the scope of our discussion.
The only two things you need to understand are:
The in-rush of current for a capacitor and an inductor.
When a capacitor is connected to a voltage-source, the initial in-rush of current is high and it gradually decreases to zero as it charges.
When an inductor is connected to a supply, the initial in-rush of current is small and gradually increases.
The waveforms across the capacitor and LED are shown in the following diagrams:

The other feature we can discuss is the function of the top 0.47mH inductor.
When the transistor turns off, the magnetic flux in collapses and it produces a high voltage.
This voltage is high enough to illuminate the LED and the graph shows that when the LED is removed from the circuit, the voltage produced by the inductor has a peak of about 3.5v. The area under the peak represents energy and this is absorbed by the LED to produce light. The LED also reduces the peak to 2.3v as this is the maximum voltage (or characteristic voltage) of a white, super-bright LED.

Make an effort to buy a Solar Garden Light from a $2 shop and pull it apart, just to see how it works. If you have a CRO, you will be able to view the waveform on the 1n2 capacitor and across the LED. The waveform across the capacitor is an incredible 10v p-p with part of the waveform going negative by 4v. During the negative excursion, the transistor is turned off and the magnetic flux produced by the current-flow in the top inductor collapses very quickly and produces a high voltage that has an opposite polarity to the energising voltage.
This voltage is passed to the LED and light is produced.
The short pulses of energy delivered to the LED occupy about 20% of the total time but the energy they deliver produces a light-output equal to a constant DC voltage.   By delivering short pulses, only about 30% of the energy is needed to produce the same illumination as a constant voltage.

Now we will cover circuit 2:


Circuit 2

Solar Garden Light-2 consists of three transistors. The first two transistors form a positive-feedback amplifier and the third transistor is a common-emitter amplifier.
The circuit only needs the first two transistors to create an oscillator.
The circuit turns on when the photo resistor fails to detect light and its resistance effectively goes very high. This allows the 47k base resistor to turn on the transistor. The voltage rises on the base as the 100n charges and the transistor turns on.
This action turns on the BC 557 transistor and the voltage on the collector rises.
This increases the current into the base of the first transistor via the 100k resistor and the two transistors would stay in this state if it were not for the 330p capacitor.
The 330p also pulls the base of the BC 557 towards the 0v rail and this assists in turning on the BC 557.
This occurs when the the first two transistors turn on as the emitter-follower third transistor is also turned on during this action.
The 330p is pulled low during this action and it quickly charges. When it becomes charged, the "turn-on" current for the BC 557 is reduced and it turns off slightly.
This action reduces the current through the 100k feed-back resistor and the first two transistors begin to turn off.
The third transistor is also turned off and the current flowing through the inductor is reduced. This causes the magnetic flux to collapse and produce a voltage in the opposite direction.
In the first instance, the voltage on the top of the inductor was more-positive than the voltage on the lead connected to the collector.
When the current is reduced, the voltage collapses and produces a voltage that is negative at the top lead and positive at the lead connected to the collector.
This is exactly the same as connecting a battery to the positive rail of the project with its negative on the top rail and positive to the collector.
This produces a very high voltage on the collector of the transistor and is passed to the base of the BC 557 via the 330p. The BC 557 is effectively turned off completely. The result is the first two transistor are fully turned off and the third transistor is also fully tuned off.
This is exactly the same as removing the third transistor from the circuit.
The inductor produces a voltage (in the form of a spike) that is higher than 2.1v to illuminate the high-bright yellow LED - in fact it is much higher but the LED converts this energy to light.
You cannot measure this voltage with a multimeter as the voltage is produced in the form of spikes.
If you remove the LED, a CRO will show the spikes are higher than 40v. 
This makes the circuit ideal for converting to a 5v supply as shown in our other article: Power Supply 5v Solar.

NOTE:
 An email from a reader asks about the inductors:
http://www.prc68.com/I/EOG.shtml

If you have a circuit as shown in the following photo, that is is powered by 3 AA cells, the circuit does not need any inductors as the 4.5v is sufficient to illuminate white LEDs.


CONCLUSION
Both circuits are much more complex than you would expect, in such a simple product. But that's the miracle of electronics.
You will see the same level of sophistication in many products, such as talking birthday cards, toys, LED torches, etc.
There may be other circuits in these Garden Lights as the author has seen at least 10 different types.
The main thing to look for is the size of the solar panel.
The solar panel in Circuit 1 produced a current of 25mA with full sunlight. The current produced by the solar panel in circuit 2 was 50mA. It had twice the amount of active surface.

Solar Garden Light Set

Add caption

This is just another product that costs less than buying the individual parts from an electronics store.
Now you can see why the hobby of electronics is dying, just when electronics is e-x-p-a-n-d-i-n-g!  But that's no reason to give up. There is still an enormous demand for new ideas and gadgets.

12v fluoro inverter 20watt to 40watt fluorescent lamps from a 12v supply

This is another kit in our self-sufficiency range. We also have a 12v fluoro inverter kit for those who need to operate 20watt to 40watt fluorescent lamps from a 12v supply.
We will be introducing a number of kits for those who have opted to live with 12v energy. With nearly everything electronic capable of operating from a 12v supply, there is no reason why anyone opting to live with a low voltage supply cannot enjoy all the electronic pleasures of those who live in the city.
Some products are not yet available for 12v operation but inverters are available from 100watts to 4kw.

這又是一個工具包在我們的自給自足的範圍。我們也有一個 12V逆變氟試劑盒的那些誰需要對經營二十○瓦特四十○瓦特熒光燈從12V電源。
我們將推出一個數字對於那些誰的包都選擇住用12V的能量。與幾乎所有的電子能夠從一個12V電源操作，沒有理由對任何人選擇住在低電壓供應不能享受所有的電子樂的那些誰住在城市。
有些產品還沒有可用於12V的操作，但逆變器可從一零零瓦特到4千瓦

The aim of this project is to cater for the other end of the range. We are looking at charging a 12v battery, using the cheapest set of solar cells and the cheapest inverter. This also means the cheapest 12v battery -  a 1amphr (1AHr) gell cell or 6v cells salvaged from old analogue mobiles!

THE PROBLEM

The problem with charging a battery from a solar panel is the SUN!  It doesn't shine all the time and clouds get in the way! Our eyes adjust to the variations in the strength of the sun but a solar panel behaves differently.
As soon as the sun loses its intensity, the output from a solar panel drops enormously. No only does the output current fall, but the output voltage also decreases.
Many of the solar panels drop to below the 13.6v needed to charge a 12v battery and as soon as this occurs, the charging current drops to ZERO. This means they become useless as soon as the brightness of the sun goes away.
Our project cannot work miracles but it will convert voltages as low as 3.5v into 13.6v and keep delivering a current to the battery. Obviously the current will be much lower than the maximum, when the sun "half-shines" but the inverter will take advantage of all those hours of half-sun.
At least you know it will be doing its best ALL THE TIME.
The other advantage of the inverter is the cost of the panel. You don't have to buy a 12v panel. Almost any panel or set of solar cells will be suitable. You can even use a faulty 12v panel. Sometimes a 12v panel becomes damaged or cracked due to sun, rail, heat or shock. If one or two of the cells do not output a voltage (see below on how to fix faulty panels) the cells can be removed (or unwired) and the gap closed up. This will lower the output voltage (in fact it may increase the voltage  -  the faulty cells may have reduced the output to zero) but the inverter will automatically adjust. 
The aim of this project is to achieve a 13.6v supply at the lowest cost. That's why the project has been released as a kit. The equivalent in made-up form is 3 times more expensive yet doesn't have some of the features we have incorporated in our kit. We have used a more efficient output circuit than the closest rival design and the driver transistor is the latest "low-voltage" type. These two factors increased the efficiency by 20% over the rival.

HOW THE CIRCUIT WORKS
The circuit is a single transistor oscillator called a feedback oscillator, or more accurately  a BLOCKING OSCILLATOR. It has 45 turns on the primary and 15 turns on the feedback winding. There is no secondary as the primary produces a high voltage during part of the cycle and this voltage is delivered to the output via a high-speed diode to produce the output. The output voltage consists of high voltage spikes and should not be measured without a load connected to the output. In our case, the load is the battery being charged. The spikes feed into the battery and our prototype delivered 30mA as a starting current and as the battery voltage increased, the charging current dropped to 22mA.
The transistor is turned on via the 1 ohm base resistor. This causes current to flow in the primary winding and produce magnetic flux. This flux cuts the turns of the feedback winding and produces a voltage in the winding that turns the transistor ON more. This continues until the transistor is fully turned ON and at this point, the magnetic flux in the core of the transformer is a maximum. But is is not EXPANDING FLUX. It is STATIONARY FLUX  and does not produce a voltage in the feedback winding. Thus the "turn-on" voltage from the feedback winding disappears and the transistor turns off slightly (it has the "turn-on effect of the 1 ohm resistor).
The magnetic flux in the core of the transformer begins to collapse and this produces a voltage in the feedback winding that is opposite to the previous voltage. This has the effect of working against the 1 ohm resistor and turns off the transistor even more.
The transistor continues to turn off until it is fully turned off. At this point the 1 ohm resistor on the base turns the transistor on and the cycle begins.
At the same time, another amazing thing occurs.
The collapsing magnetic flux is producing a voltage in the primary winding. Because the transistor is being turned off during this time, we can consider it to be removed from the circuit and the winding is connected to a high-speed diode. The energy produced by the winding is passed through the diode and appears on the output as a high voltage spike. This high voltage spike also carries current and thus it represents ENERGY. This energy is fed into the load and in our case the load is a battery being charged.
The clever part of the circuit is the high voltage produced. When a magnetic circuit collapses (the primary winding is wound on a ferrite rod and this is called a magnetic circuit), the voltage produced in the winding depends on the QUALITY of the magnetic circuit and the speed at which it collapses. The voltage can be 5, 10 or even 100 times higher than the applied voltage and this is why we have used it.
This is just one of the phenomenon's of a magnetic circuit. The collapsing magnetic flux produces a voltage in each turn of the winding and the actual voltage depends on how much flux is present and the speed of the collapse.
The only other two components are the electrolytics.
The 100u across the solar panel is designed to reduce the impedance of the panel so that the circuit can work as hard as possible.

The circuit is classified as very low impedance. The low impedance comes from the fact the primary of the transformer is connected directly across the input during part of the cycle.
The resistance of the primary is only a fraction of an ohm and its impedance is only a few ohms as proven by the knowledge that it draws 150mA @ 3.2v. If a battery is connected to the circuit, the current is considerably higher. The 150mA is due to the limitation of the solar panel.
Ok, so the circuit is low-impedance, what does the 100u across the panel do?
The circuit requires a very high current for part of the cycle. If the average current is 150mA, the instantaneous current could be as 300mA or more. The panel is not capable of delivering this current and so we have a storage device called an electrolytic to deliver the peaks of current.
The 10u works in a similar manner. When the feedback winding is delivering its peak of current, the voltage (and current) will flow out both ends of the winding. To prevent it flowing out the end near the 1R resistor, an electrolytic is placed at the end of the winding. The current will now only flow out the end connected to the base of the transistor. It tries to flow out the other end but in doing so it has to charge the electrolytic and this take a long period of time.
These two components improve the efficiency of the circuit considerably.
You will notice the battery is receiving its charging voltage from the transformer PLUS the 3.2v from the solar panel. If the battery voltage is 12.8v (the voltage during charging) the energy from the transformer will be equivalent to 9.6v/12.8v and the energy from the solar cell will be equivalent to 3.2v/12.8v. In other words the energy into the battery will be delivered according to the voltage of each source.

THE BLOCKING OSCILLATOR
The operation of the circuit has been covered above but the term BLOCKING OSCILLATOR needs more discussion. By simply looking at the circuit you cannot tell if the oscillator is operating as a sinewave or if it is turning on and off very quickly.
If the circuit operated as a sinewave, it would not produce a high-voltage spike and a secondary winding would be needed, having an appropriate number of turns for the required voltage.
A sinewave design has advantages. It does not produce RF interference and the output is determined by the number of turns on the secondary.
The disadvantage of a sinewave design is the extra winding and the extra losses in the driving transistor, since it is turned on and off fairly slowly, and thus it gets considerably hotter than a blocking oscillator design.
The factor that indicates the circuit is a blocking oscillator is the absence of a timing capacitor. The circuit gets its timing from the inductance of the transformer. It takes time for the current to start to flow in an inductive circuit, once the voltage has been applied. In technical terms CURRENT LAGS IN AN INDUCTIVE CIRCUIT.
The timing feature is hidden in the circuit, but it has nothing to do with the feedback winding or the transistor. If we simply place the 45 turn coil (the transformer) across a voltage source, current will flow in the coil and this will produce magnetic flux. This flux will cut all the turns of the coil and produce a back-voltage in each turn that will OPPOSE the applied voltage and reduce the voltage being applied to the coil. This will cause less current to flow. During the time when the magnetic flux is increasing (expanding) the current is also increasing and the full current does not flow until the magnetic flux is STATIONARY. When this effect is viewed on a set of voltmeters and ammeters, it appears that the current is LAGGING. In other words it is taking time to reach full value.
This is the delay that creates the timing for the oscillator.
The voltage generated across the primary winding at the instant WHEN THE TRANSISTOR IS TURNED OFF, is called a FLYBACK VOLTAGE. The value of this voltage is determined by the inductance of the transformer (coil), the number of turns and the strength of the magnetic flux. In our case we are taking advantage of this energy to charge a battery but if we did not "tap-off" this energy, it would enter the driver transistor as a high-voltage spike and possibly damage it. (A reverse-biased diode can be placed across the winding to absorb this energy).

WHAT?  NO VOLTAGE REGULATION?
Our simple circuit does not employ voltage regulation. This feature is not needed with a trickle charger. The charging current is so low the battery will never suffer from overcharge. To be of any benefit at all, voltage regulation must be accurately set for the type of battery you are charging. For a 12v jell cell, it is 14.6v. For a 12v Nicad battery,  it is 12.85.
This is the way it works: When a battery is charging, its voltage rises a small amount ABOVE the normal voltage of the battery. This is called a "floating charge" or "floating voltage" and is due to the chemical reaction within the cells, including the fact that bubbles are produced. When the battery gets to the stage of NEARLY FULLY CHARGED, the voltage rises even further and this rise is detected by a circuit to shut-down the charger.
A voltage regulated charger is supposed to have the same results. When the voltage across the battery rises to it fully charged state, the output voltage does not rise above this and thus no current is delivered.
Ideal in theory but in practice the voltage must be very accurately maintained. If its not absolutely accurate, the whole concept will not work.
In our case we don't need it as the charging current is below the "14 hour rate" and the battery is capable of withstanding a very small trickle current.

PARALLEL OR SERIES?
One of the questions you will be asking is: Should be solar cells be connected in parallel or series?
Most individual solar cells are made from small pieces of solar material connected together and placed under a light-intensifying plastic cover. The output of the solar cells used in the prototype were 0.5v and 200mA (with bright sunlight). The circuit has a minimum operating voltage of about 1.5v so any voltage above this will produce an output. In our case the cells should be connected in series to get the best efficiency.

REPAIRING FAULTY SOLAR PANELS
You may have a solar panel or individual solar cells and need to know if they are operating correctly.
All you need is bright sunlight and a place where the entire panel can be exposed to uniform sunlight.
The main problem is being able to access each of the cells with the leads of a multimeter while the panel is exposed to sunlight. To measure the efficiency of each cell, the panel must be delivering its energy to a load. You can place a switch on one of the lines and measure across the switch (when it is open) to determine the current being delivered.
The cells in our prototype measure 3cm x 5cm and deliver 150 mA with full sunlight. Smaller cells (2cm x 4cm) deliver 70mA.
When the cells are delivering their full rated output current, the voltage produced by each cell is about 0.4v to 0.45v  Any cell producing less than 0.35v is faulty.
If the output current of your cells or panel is known, (read the specifications on the panel)  you can check the output by measuring across the switch, as mentioned above. If the output is considerably less than this, you can short-circuit each cell in turn to see if the output current of the whole panel increases. The problem is made more difficult if two or more cells are faulty. Checking the voltage produced by each cell will detect two or more faulty cells in an array.
If you cannot get to the wiring between each of the cells, you can sometimes get to the wiring at the opposite end of the panel by cutting into the backing. This way you can check the left and right sections separately and work out if one side is operating better than the other. From there you can cut into one side of the panel and maybe get 75% of the panel operational. 75% of a panel is better than 100% of a dead panel.
This project is especially designed for a low-voltage panel. If you have a panel slightly below par, it is better to buy a few extra cells and increase the voltage so the panel can be connected directly to the battery. This way you will deliver 100% of the output to the battery. Our inverter has a maximum efficiency of 75%, so a panel that produces nearly 13.6v should have a couple of extra cells fitted so it can be connected directly to a battery.

9v to 12v OUTPUT
If you require 9v to 12v output, you will need to add the four voltage-regulating components shown in the diagram below.

With the voltage-regulation components added, the circuit produces a 9v or 12v output. This arrangement is only suitable if you have a constant, reliable, source of sun as any clouds will reduce the output to below the regulated voltage. (If a 9v1 zener diode is fitted, the output voltage will be 9v.) The BC 547 prevents the ZXT 851 oscillator transistor turning on when the voltage is slightly above 12v (or 9v). The 10u on the output stores the "reference voltage" and keeps the BC 547 turned on during the time when the output voltage is above 12v. This effectively stops the oscillator, but as soon as the output voltage drops below 12v, the circuit comes back into operation, "charge-pumping" the 10u on the output.
The 12v zener works like this: No voltage appears on the anode end (the end connected to the 100R resistor) until 12v is on the cathode. Any voltage above 12v appears on the anode and this voltage passes through the 100R to the base of the BC 547. For instance, if 12.5v is on the cathode, 0.5v will appear on the anode.  When the base sees 0.7v, the transistor turns on, so slightly more than 12.7v is needed to turn on the transistor.
The regulation components are not really necessary as a reliable output will only be present when strong sunlight is seen by the solar panel. For the cost of a rechargeable battery or set of rechargeable cells, you get a much more reliable arrangement by removing the regulation components, using the first circuit in the article, and allowing the battery to deliver the 9v or 12v. The battery appears as a HUGE electrolytic on the output, delivering a constant voltage and is capable of delivering a high current.

OUR PROTOTYPE
Our prototype consisted of 8 solar cells charging two 6v batteries in series. These were obtained from old analogue phones and were purchased for $5.00 each but if you want to spend a lot more, you can get individual AA cells or a 12v jell cell.
The solar cells in our prototype are rated at 0.5v and 200mA
The array produced 3.2v @ 150mA with bright sunlight and the output of the inverter was 12.8v @ 31mA during the initial charging period.  This reduced to 22mA as the battery became charged. As more cells are added, the charging current increased. We also tried 10 cells and 12 cells and the results are shown in the table below:
No of solar cells:     Charging current (for 12v battery):
8 cells     22mA
10 cells     xxmA
12 cells     yymA

WINDING THE TRANSFORMER
The primary winding consists of 45 turns of 0.7mm wire on a 10mm dia ferrite rod. Wind 40 close-wound turns on the rod then 5 spiraling turns to get back to the start.  Twist the two ends together to keep the coil in position.
The feedback winding must also be wound in the same direction if you want to keep track of the start and finish as shown in the circuit diagram. It consists of 15 turns spiral wound so that it takes 8 turns across the rod and 7 turns back to the start. Twist the two ends together to keep the coil in position.
The result is called a transformer. It's a feedback or blocking oscillator transformer with a flyback feature. The output is taken across the primary via a high-speed diode.
The oscillator will only work when the feedback winding is connected around the correct way. The correct way is shown in the diagram, with the start of the primary and secondary as shown in the diagram. For this to work, both windings must be wound in the same direction.
You can keep track of the start and finish of each winding or simply connect the transformer and see if it works. If it doesn't work, reverse the feedback winding  (reverse only one winding  - NOT both).
Nothing can be damaged by trying this method as the solar panel does not deliver enough current to damage the transistor.

THE TRANSISTOR
One of the special features of this design is the driver transistor. It is one of the new style of transistors, having a very low collector-emitter resistance (voltage drop) when saturated. It is also capable of handling a very high current (3 amps) and peaks of 20 amps. When used in a high-speed saturation mode such as this, the losses in the transistor are extremely small and it does not require heat-sinking.  Other transistors will work but the ZTX 851 transistor added 6mA to the output current due to its characteristics.

CONSTRUCTION
Wind the transformer as explained above and have it ready for fitting to the PC board. Fit the other components according to the overlay on the board making sure the transistor and diode are around the correct way. The two electrolytics must also be fitted around the correct way.
Now comes the transformer. As we have already mentioned, the easiest way to fit the transformer is to solder it in position and try the circuit. If it is around the wrong way, the circuit will not produce an output. Reverse one of the windings and the job's done.
PARTS LIST
1 -  220R  1/2 resistor
1 - 470R
1 - 1k

1  -  ZTX 851 transistor or BC 338
1  -  BY 207 or equiv high-speed diode
1  -  10u 16v electrolytic
1  -  100u 25v electrolytic
2m  -  0.25mm enamelled wire
1  -  10mm dia ferrite rod  5cm long
1- Solar Charger PC Board

Regulation components (not in kit)
1  -  100R
1  -  10u electrolytic
1  -  9v or 12v zener diode
1  -  BC 547 transistor

TESTING THE CIRCUIT
The output current of the project can be measured with a multimeter set to milliamps. Place the meter between the battery and output of the circuit as shown in the diagram below. You can add an electrolytic to the output to smooth the pulses to get a more-accurate reading. Select a scale such as 0-100mA (for analogue multimeters) or 0-199mA (for digital multimeters). Note how the multimeter is connected, with the positive lead to the output of the circuit and negative to the battery.
There are many ways to "visualise" how the meter should be connected. The best way to remember is this: think of the meter as going directly across the output, to measure the current. Which way would it be placed? Obviously, the positive of the meter to the output and negative to ground. But you must NEVER place an amp-meter (ammeter) (or milliamp-meter) directly across the output of a supply as this will either damage the supply or the meter. So, include a resistor (or in our case, the battery being charged), and you will measure the "current flowing."
Do not measure the voltage without a load. The output voltage will be as high as the transistor will allow. This will be as high as the rating of the transistor. In other words it will be as high as the "zener voltage" of the transistor (the collector-to-emitter voltage-rating of the transistor).
You may not be able to measure the output of the circuit accurately with a high impedance (digital) multimeter. One constructor got a reading of 1900v from a digital meter. This is obviously incorrect and was due to the high frequency of the circuit interfering with the reading.



 SUMMARY
You can now see how the circuit works. It generates a voltage higher than the battery voltage and that's how it can deliver energy to the battery. The energy comes in the form of "pulses" and we can measure  the "average" or "equivalent to DC value" on a milliamp meter (a multimeter set to milliamps).

A FEW NOTES ON TRANSFORMERS
Transformers are one of the versatile components in electronics. They can be large, small, high-frequency, low-frequency, single winding, multi-winding, step-up or step-down (voltage) high-current, isolating, extremely-high voltage, voltage-reversing or even a combination of any of the above. They can be technically very complex, or very simple to design and you could spend a life-time studying their construction.
On the other hand you can learn how to construct them very quickly. Simply copy a design and maybe modify it a little. By copying a design you "home-in" on the essential features such as wire-size, core size, number of turns etc and you can change any of the features to suit your own requirements.
Before we start, let's point out the two main mis-conceptions of a transformer. Firstly, a transformer only operates on a voltage that turns on and off. This is commonly called AC (it stands for Alternating Current but this also means the voltage is ALTERNATING). The voltage can also be a DC voltage that turns on and off - commonly called chopped DC.
A battery cannot be connected directly to a transformer. It will not work. An oscillator (an oscillator circuit) is needed to convert the DC into pulses.
Secondly, the energy into a transformer (called watts) is equal to the watts output of the transformer (minus some losses). If a transformer on 240v AC (or 110v) produces 240 AMPS output,  the output voltage must be low because the maximum input wattage for 240v is 2400 watts. This means the maximum output voltage is 2400/240 = 10 volts. Even though a transformer performs amazing things, it abides by the laws of physics. In general terms, if an output voltage is higher than the input voltage, the current will be lower.

G24 Solar Innovations Power Curve Portable Charger with Assorted Fittings

G24 Solar Innovations Power Curve Portable Charger with Assorted Fittings (Black) From G24 Solar Innovations List Price: $49.99 Price: $39.09 & eligible for FREE Super Saver Shipping on orders over $25. Details http://www.amazon.com/G24-Solar-Innovations-Portable-Assorted/dp/B002N4OIWC?tag=solarpowerlex-20 Availability: Usually ships in 24 hours Ships from and sold by Amazon.com 2 new or used available from $39.09 Average customer review: (7 customer reviews)

Product Description Solar Innovations Power Curve Portable Charger with Assorted Fittings

 

G24 Power Curve is designed to be an easy to use multi purpose solar charger. The product is designed to function well in the sun and also be pre-charged with a supplied USB connection. The Power Curve comes with many fittings and a Female USB so it is complete solar charging package.

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Product Details Solar Innovations Power Curve Portable Charger with Assorted Fittings

• Color: Black
• Brand: G24 Solar Innovations
• Model: CHG24008BLK
• Released on: 2010-10-09

Features Solar Innovations Power Curve Portable Charger with Assorted Fittings

• The Power Curve Comes Standard With An Assortment Of Adapters For Products From Cell Phones And Ipods, To Digital Cameras, Game Players, And Gps Systems (includes a female usb for additional applications)
• Charge with USB for intitial charge and maintain with Solar power
• Quality Water Resistant screen and high temp capable battery 1200MAH
• The Power Curve Solar Charger Has A Rugged, Durable, Waterproof Casing That Can Attach To Any Outdoor Gear
• This Device Works In Various Light Conditions, Be It Direct Or Indirect Sunlight, Charging Its Internal Battery So You Have Power When You Need It

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Customer Reviews Solar Innovations Power Curve Portable Charger with Assorted Fittings

Most helpful customer reviews
14 of 14 people found the following review helpful.
POWER to spare... Many extras....
By Live Outdoors
G24i Power Curve, charger battery unit.

Comes in the box, the solar unit: it feels quality and the panels are much more durable than some of the first generation solar panels.

Case for fittings: nice holds all the fittings.

Fittings and cables: Included in the pack

LG phone fitting
Blackberry
Mini USB *(lots of the bluetooth headsets)
Nokia
PSP
USB regular to charge the box
DC cable for tips
Wide samsung
Sony ericsson
Thin Samsung
USB for ipod and GPS (this can work for any USB charger)

That will cover most everything, if you have a usb for your product you can charge it!

Here is how it works, you plug it in for the first time and give it a nice 6 hour charge(important) After that you can charge it with solar or even slowly with indoor lighting.

The unit is much more powerful than the first generation of portable solar products, the case is waterproof, I don't think you can swim with it!!

It will power for about 4-6 hours of use after the sun goes down... this is a great camping or hunting product since you can use it so many ways. It also has a led light you can buy to use with it called a Sun Light (of course)

Ideas you may of not thought about: Great for Emergency preparedness, it could run a radio for emergencies or charge any products during a power outage.

It can be used to charge up batteries, AA batteries for a camera or many other things.

will update in the field...UPDATE still great, I always give it a nice AC charge before any trip. I have since bought a Car USB Dc USB Charger This one is about $3.

UPDATE: used this in the rain very water resistant.

UPDATE: they have the sunlight LED light available on Amazon now G24 Solar Innovations Power Curve LED Light to Plug Into (White)


10 of 10 people found the following review helpful.
Be Prepared
By Fishgriller
Watch Video Here: http://www.amazon.com/review/R1GPQYFEXZLOGV It seems like you have a plug in everywhere you go, campsites now have cable tv.

If you were ever to lose power for an extended period of time or be somewhere where no power is available, how would you recharge your devices.

This is a great little device, it works best to charge it up when you have a plug available and use the power as needed.

It also can recharge by the power of the sun, (slower but sometimes your only option)

The biggest problem people have with solar stuff is they expect it to work the same as the 110 wall plug... It will work but patience is the key.

USB female and several other fittings come with this device so you can pretty much power everything from a kindle to a cell phone.
4 of 4 people found the following review helpful.
Great customer service
By Vonelmo
So my first thought at opening this item was how sturdy it felt. This item did not work at first and I was frustrated but on inspection I found That it was a short in the cable. It Took about 4 days after contacting the company to receive my new cable! this unit works Great . having never owned a solar charger it seams that this will do the trick! I do however wish that their was an attachment to charge my Cannon camera batteries. However it did come with plenty adapters and works great on my PSP and cell phone. I imagine that finding the adapter for my camera will be an easy inexpensive Fix.
Overall This product is great and I would recommend this item to all my friends.


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Product OverviewG24 Power Curve is designed to be an easy to use multi purpose solar charger. The.
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25 Apr 2011  G24 Solar Innovations Power Curve Portable Charger with Assorted Fittings (Black) Reviews. Other Picture. G24 Solar Innovations Power Curve
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 G24 Solar Innovations Power Curve Portable Charger

G24 Power Curve is designed to be an easy to use multi purpose solar charger. The product is designed to function well in the sun and also be pre-charged
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This review is from G24 Solar Innovations Power Curve Portable Charger with Assorted Fittings (Sports). G24i Power Curve, charger battery unit.
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 G24 Solar Innovations Power Curve Portable Charger

 G24 Solar Innovations Power Curve Portable Charger with Assorted Fittings.
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Great Value G24 Solar Innovations Power Curve Portable Charger

Sunforce 50048 60Watt Solar Charging Kit

Sunforce 50048 60-Watt Solar Charging Kit From Sunforce List Price: $599.99 Price: $270.51 & eligible for FREE Super Saver Shipping on orders over $25. Details http://astore.amazon.com/solarpowerlex-20/detail/B000CIADLG Availability: Usually ships in 24 hours Ships from and sold by Amazon.com 7 new or used available from $266.99 Average customer review: (91 customer reviews)

Product Description

The Sunforce 50048 60 Watt Solar Charging Kit gives you another reason to love the sun -- it'll help keep your batteries charged. This kit is excellent for cabins, remote power, back-up power, and 12-volt battery charging. The kit includes a PVC mounting frame, 7 Amp charge controller, 200-watt inverter, and wiring/connection cables. And with the built-in blocking diode technology, this charger kit is designed to protect against battery discharge at night. You can also use this kit to maintain the charge on any 12-volt battery for clean, silent operation of various electronics, such as deer feeders and landscaping pumps. The 50048 features a built-in ultra-bright blue LED charging indicator, and is a great choice for automobiles, recreational vehicles (RV), tractors, all terrain vehicles (ATV), boats, electric fences, telemetry and more, and it is even effective on cloudy days. This battery charger kit is made of durable ABS plastic and amorphous solar cells and has a maximum temperature range of -40 to 176-degrees Fahrenheit.

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Product Details

• Amazon Sales Rank: #241 in Automotive
• Color: Black
• Brand: Sunforce
• Model: 50048
• Released on: 2005-11-25
• Dimensions: 42.25" h x 12.00" w x 54.00" l, 59.80 pounds

Features

• Amorphous solar charging kit provides up to 60-Watts of clean, free, renewable power
• Designed for RVs, cabins, homes, boats, back-up and remote power use, and more
• Weatherproof, durable solar panels can withstand impacts from hailstones travelling 50 miles-per-hour
• Includes four 15-Watt solar panels with durable mounting frames, a 200-Watt power inverter, a 7-Amp solar charge controller, and a wiring kit with accessories for easy installation
• Built-in, ultra-bright blue LED charging indicator

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Editorial Reviews

Amazon.com Product Description
The Sunforce 50048 60-Watt Solar Charging Kit gives you several more reasons to love the sun. It provides the power you need, while helping you save money and protect the environment. This kit is ideal for cabins, recreational vehicles, remote power, back-up power, and 12-volt battery charging. It comes with everything you need to start producing up to 60 Watts/4 Amps of clean, free power in all weather conditions.

Sunforce kits are easy to set up and operate.

Convenient Power That Helps You Save Money and Protect the Environment
The Sunforce 50048 60-Watt Solar Charging Kit lets you harness the power of the sun, the most powerful and plentiful source of energy available to us. This inexhaustible supply of power is freely available wherever the sun shines, and gives users the freedom to power their homes, RVs, boats, batteries, and electronic equipment far from civilization or right in town. Solar power can help cut your energy bills by reducing your dependence on the main electrical grid, and can also provide back-up power during outages. Unlike nuclear and fossil fuels, solar power systems are clean and pollution-free, and they require very little maintenance to operate.

Sunforce Solar Panels are effective in areas of both high and lower sun exposure, making them ideal for use in the United States. View Larger

Everything You Need to Power Up
The Sunforce 50048 60-Watt Solar Charging Kit has everything you need to start generating power. It includes four (4) 15-Watt amorphous solar panels with durable mounting frames, a 200-Watt modified sine wave power inverter, a 7-Amp solar charge controller, and a wiring kit with accessories for easy installation.

With built-in blocking diode technology, this solar charging kit is designed to protect against battery discharge at night. You can also use this kit to maintain the charge on any 12-Volt battery for clean, silent operation of various electronics, such as deer feeders and landscaping pumps. The included charge controller features a built-in ultra-bright blue LED charging indicator, and is a great choice for automobiles, recreational vehicles, tractors, all-terrain vehicles, boats, electric fences, telemetry and more.

About Amorphous Solar Power
Amorphous solar panels are created by spraying silicon on to glass in very thin layers, and are commonly known as thin film solar panels. This process allows them to be better at generating electricity in all lighting conditions, including cloudy or shady environments. Sunforce amorphous solar panels are weatherproof and suitable for outdoor use. They have a maximum operating temperature range of -40 to 176-degrees Fahrenheit, require virtually no maintenance, and are also effective on cloudy days. They can even withstand impacts from one-inch hailstones at 50 miles-per-hour.

Solar panels convert sunlight into an electric current, they do not store power. Sunforce Solar Charging Kits are primarily used to recharge 12-Volt batteries (not included), which store and provide usable power. The included 200-Watt power inverter allows you to use traditional 110-Volt appliances with this system. The included Sunforce 7-Amp Solar Charge Controller must be installed to prevent any connected batteries from overcharging. Once fully charged, it is normal for the charge controller LED to turn off and on as the battery voltage fluctuates from the discharge/recharge cycle.

Product Dimensions
Shipping Box: 41" x 13 1/4" x 16 1/4", 62.4 lbs
Individual Panel: 42.5" x 1.5" x 16", 11 lbs

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Customer Reviews

Most helpful customer reviews
759 of 775 people found the following review helpful.
Innovative design from China, packaging needs help
By HMMWV
*Update* 6-2010, while my original panels are still running strong so long as I hose them down once a month, I've noticed that the PVC pipe provided to hold them in place has become brittle with sun exposure, hence I would now in 20/20 hindsight recommend a coat of Krylon Fusion Dover White Plastic Satin Spray Paint on the PVC parts to prevent UV cracking later in life. I do not think the Krylon Fusion product was available when I first setup my first panels but UV cracking of the support structure could cause panel damage in years 2 and 3.

Meanwhile Amazon got their hands on some obsolete & discontinued Sharp panels (12.5% efficiency vs the new 13.1% efficiency) - if you are serious about needing lots of solar power in a small space, this is a big kit - you can view it here: Sunforce 39126 246-Watt High-Efficiency Polycrystalline Solar Power Kit

My only concern about the kit is that due to the new panels being higher efficiency means it will be difficult to match panels if you find you still need more power later on. The other con on that system is it's price -- $1300+ but you get the wattage, along with a cheap charge controller and inverter, both of which could be upgraded for better system performance. It's just another solar system to consider in the $5/watt or less pricepoint for DIYers.

Update 9-18-2008 - Still going strong. I am very pleased with the summer power output of these panels. I wash them with a hose 1x/mo to keep the output current up. Measured before washing and after washing the panel efficiency is clearly a factor of how much dirt is on them. No problems long term on a roof though!

Update 2-20-2008 - goes with graph "photograph" #3 above - pink line is power and blue line is amps from the panel x 10 to share the graph. The X axis is panel voltage. Data was acquired using an Agilent dummy load with programmable voltage in 1V steps from 1V to 22V (open circuit voltage on the panel) on a partially cloudy day in winter sun. Expectations are for 2-3 times performace in summer sun provided the panels don't get too hot. These are on my house roof laying flat on a 3/12 pitch facing due south which is suboptimal but easy for me to do. Be sure to read the photo notes. Sorry about the colors excel defaulted to!

This is a MPPT chart (maximum power point tracking) - you can see that the panels are optimized for charging a 12V wet cell right out of the box. Charge current turns on when battery voltage drops down to 13.0 VDC and turns off at 14.2 VDC with the supplied charge controller in the kit.

The only other interesting fact in 2 months is to keep your panels clean. My maximum current was 5.0 A on a cold morning with bright sun until it rained hard and washed the panels clean. The current went up to 7.0 A maximum right after the rainstorm. Below is the original review - these panels have been running constant for 2 months now into 3 parallel deep cycle marine cells (315 AH) connected to the prosine inverter below to drain the energy made.

When reading the power/current chart you should keep in mind the amps have been multiplied by 10 so they use the same Y axis (so 20A on the chart corresponds to 2.0 A panel current) Watts are actual volts*amps. This was taken in the winter with partial clouds - expectations are for a X3 improvement during summertime but its still february and I'm in the northern hemisphere so we'll have to wait and see. Basically an MPPT charger won't gain but a few watts with this panel so it's not a good investment unless you already have one laying around.

(Begin original review after buying panels)

I never seem to be overwhelmed by the latest shipment of product from China, but this one seems to show some promise and shows signs of good cost engineering and a complete design that can be set up quickly by one person with very little effort. I'd give it 5 stars if it were well packed, but my purchase turned into a shipping fiasco.

Most ALL solar installations are rated in $/watt much like new homes are rated in $/sq ft. We'll get to the sq ft bit later. Here you are getting 60W for 320 dollars or about 5.33 $/watt. Compared to a similar wattage panel, the BP solar 365U rated at 65W and priced (street) at 399 or 6.13 $/watt the amazon package seems to be a good deal when you consider it comes complete less battery (we'll hit that one later too)

In fact, the amazon package deal includes a xantrex 175 watt inverter with a .15A "idle" current designed for solar systems where current consumption must be minimized. It even includes a simple diode/switch "charge regulator" with 2 leds to indicate panel voltage and battery is full but lacks the ability to tell it what type of battery you are using (full is defined at 14.2 volts give or take so it's for wet/flooded cells). Neither of these are big buck items, but they do set you up for a complete small scale solar kit minus the battery out of the box, which is impressive.

Oh yes, the battery. I also ordered the duracell 480W inverter+28AH battery with this panel so I'd have a battery. Also made by Xantrex, it's a nice piece to complete the system. I made the mistake of ordering it with the solar panels (read on)

So how does China produce a complete kit for a lower $/watt price than professional solar companies like BP solar, GE, Kyocera, etc? Well - it's the sq ft part we forgot about for a while. This uses 4 panels @ 15W each to get up to 60 watts with a simple parallel adapter included in the kit. The BP solar is one panel about the size of 1 of these 15W panels, or put another way, is 1/4 the sq footage. So if you are planning on covering your roof with these, think again because you'd need a really big house and have lots of 7A charge diodes and 175W inverters kicking around when you are done. The reason for the 4:1 size difference is the China panels are made using a silicon deposition on glass technique with a very thin film and correspondingly thin output, while other manufacturers use a silicon wafer production method that is roughly 4x more efficient in area, and somewhat more expensive as a result.

Ok - now onto packaging. We need to get this from China to Amazon and finally to the consumer. On the first attempt FEDX carefully placed my fragile glass solar panels on the concrete then put 2ea 60lb batteries on top of them, cracking the glass on all 4 panels. After returning that to amazon, we tried again, this time without the batteries and shipping the system by itself. FEDX again noted shipment damage which wrecked 1 of the 4 panels, but running on 3/4 panels it does work, just not with full output. Amazon has given up because they will only ship and ruin something twice instead of making fedx pay up for piling 120 lbs of batteries on top of the glass panels and poking through the box & styrofoam the second time so I am still in negotiation with them about the shipment, however the product does deserve mention while I have it.

PERFORMANCE:

The design is actually quite well done. You can make (with 4 panels) a 12V (actually 15V) x 4A system, or a 30V x 2A or a 60V x 1A configuration depending on your power inverter and battery collection. For me, this will always be tied into a 12VDC bus so it is fine as shipped, but the flexibility is there if you have other voltages in use. There is no skimping on wire with 16 foot cords on each panel which helps to minimize power lost in the wire since each panel has its own cordset going to the combiner, after which runs are kept short. On a cloudy day I was able to get 2 amps from 3 panels (30 W) - in full sun it peaked at 5.91A with 3 panels, so the Chinese manufacturing has under-rated their output as 90W from a 1/4 dead 60W panel in winter sun is doing very good - I'd like to know how it performs in the summer!

As for mounting, a very clever system was designed to support the panels out of 1" PVC tubing with elbows and T's - all of this is assembled with a singular bolt/wingnut style and the pipes have slots milled into them to ensure that the panels will line up one way or another without breaking after you get them. It has a prop-up leg system for use on the ground or can lay flat if placed on a roof that is already angled towards the sun. There isn't a provision for connecting multiple systems together, however you could make one out of sprinkler pipes you probably have.

All this really needs to be a well designed solar kit is 1) better packaging and 2) a battery. Even with 25% of my panels broken and removed from the system, it still managed to charge a car battery in under 1 cloudy winter day.

I'm impressed with the product, however disappointed with the shipper. I've also run up against Amazon's policy of two strikes and they are out meaning they won't negotiate for repair or replacement as the shipper on my behalf. I can return it alltogether or pay 100% for 75% of a system so it's probably going back tomorrow (monday) - but my testing this weekend has shown that the product warrants consideration for people who

A) Need to keep their starting batteries charged year round (2nd cars, generators, etc) outside where AC power is not convenient.
B) People lacking A/C power somewhere and would like to run a small refrigerator (purchase a Xantrex Technologies Prosine 1,000 to 1,500-Watt Power Inverter #1000 TRUE SINEWAVE power inverter to run any motor load without damage) - for 12V refrigeration needs its best to AVOID both inverters and peltier effect coolers ($40-80) and spend the money ($427 - ouch) to get one of the Danfoss 12VDC real compressor refrigerators. The peltier coolers are just that - coolers - in a car they can keep something from your fridge cool, but the power draw of 8A x 12V (96 watts!) running continuously just to cool a 6 pack is insane. The danfoss iceless iceboxes can MAKE ICE if their compressor runs 80% duty cycle at 3A or about 24 watts. If you just want to keep 3 ea. 12 packs ice-cold and have a 2nd cool box inside for stuff you don't want to freeze they run 20-25% duty cycle on the 3 Amp compressor depending on temperature difference. Because I am on the road alot I keep one of these iceboxes with me attached to its own 80AH battery which will run it 3 days w/o charge. The same battery would run a peltier cooler less than 8 hours till dead. The battery is isolated from my engine but charges when I drive.

C) Or people who have *lots* of roof space and are looking at the lowest cost/watt installation complete with mounting hardware.

Don't forget the battery - and don't have it delivered with your solar panels. As for emergency power, 60 watts won't do much for you but keep your generator battery charged and ready to go when the power fails. My natural gas genset is rated for 12,000 watts or 200 of these 60 watt 4-panel kits (800 panels) which would cost $64,000 and still not provide power at night, like the quiet genset does. With 12,000 watts I can comfortably run my whole house. Considering these natural gas gensets can be had for under $3000 they are clearly a great solution for whole house power backup systems so long as the gas stays on (most do propane or natural gas). I still like my friend's earthquake backup solution - his house is heated by diesel and also has a diesel genset + diesel vehicle, so he is quite well prepared.

My use was to keep my seldom used 12VDC batteries all charged in the back yard. I kept the solar system for long term statistics and measurement and now have 2 of these in parallel. I bought a grid powered battery tender CTEK CTK7002 MULTI US 7002 Battery Charger to best charge my genset starting battery.

One last reliability issue - having seen 5 broken panels now I can see an advantage to the professional panel systems - these use the glass just as a cover & weatherproofing plate. The cells underneath are not damaged if the glass breaks provided the break is superficial. On the amazon system, the cells are deposited on the back of the glass, so if it breaks, by default so does the entire cell. A hailstorm could easily wipe out your backup power if using these monolithic inexpensive panels.
195 of 196 people found the following review helpful.
Permanently installed on roof
By Michael
The panels are installed on my garage roof, wired in to a battery bank and inverter which primarily functions as a very large (4KW) uninterruptible power supply for the house. So far, everything is working fine. They keep the batteries topped off without using power from the grid.
Like most manufacturer's specs, the 60 watt claim is hard to realize. The panels' current output is about 3.2 amps under bright sun, which yields only about 45 watts into a 12 volt gel cell battery at 14.2 volts. The panels can output about 20 volts which would indeed yield 60 watts, but not while connected with the included charge controller. A MPPT controller would achieve 60 watts, however.
The included controller is acceptable in that it works as advertised. One good thing about it is that it does not shunt the panels when the battery is charged, it actually opens the circuit, which means the excess panel output would be available for other uses. I intend to build another device for charging another set of batteries after the primary set is charged.
The included inverter works, but I did not use it in the system. Instead, I'll just keep it around for a portable inverter.
Also, I did not use the PVC pipe stand included with the system, instead mounting the panels directly to the roof.
The kit did include a variety of connectors allowing use with cigarette lighter plugs and jacks, alligator clips, and hardwire, but the charge controller is only usable if hardwired. I strongly recommend the charge controller be used, as the panels can easily overcharge most any 12 volt battery if a charge controller is not wired in.
289 of 295 people found the following review helpful.
Recharges all our stuff
By C. Bayne
We bought this a few months ago. We live in Phoenix, AZ ("Valley of the Sun"), so this has plenty of opportunity to work. We have it plugged into 2 marine batteries (like car batteries, but bigger), and we have an inverter connected to those. The inverter is in the house, and the batteries are outside. The wire goes through the wall. We plug things into the inverter.

This was easy to put together. You have to buy the batteries, but this came with everything else.

I can run my laptop all day, as well as recharge the cell phones and Wii remotes. My husband can also run his laptop. If we only get on the laptops after work, we can run them well into the night. I've had to switch to grid power a couple of times if I've used my laptop all day, but I've never had to switch over if I've only used it during the evening. (This doesn't count the few rainy days we've had. Yes, once in a while it rains in Phoenix.)

This is not the most efficient solar panel set, but it's very good for starting out and learning about solar power. It's inexpensive enough to set up and charge all your rechargeable stuff whenever you need it, as long as you live in a fairly sunny area.

Oh, as an experiment, I plugged the vacuum cleaner into the inverter, which promptly started screaming for help. (The inverter has an alarm, apparently.) This whole set-up CANNOT handle this kind of power draw. You have to unplug everything and turn the inverter off and let it just sit a while and reset before plugging in your lower power things again.

You're not going off the grid with this set-up, but you'll save yourself a few bucks a month. And you get to be smug whenever anyone talks about going green. "Well of course, our solar array has lowered our carbon footprint considerabley. Shall we go for an organic smoothie now?"