Can solar charge controller control power

MikeMl said:

You need a solar panel with an Open-Circuit voltage of at least 17V in order to charge a 12V battery. The typical panel that would be used with your charge-controller would have an OC Voltage of ~21V.

Your Charge-controller is not designed to charge a Li-Po anyway. It is designed to charge only 6-cell Lead-Acid Sealed batteries which has a very different V vs state-of-charge property compared to a Li-Po. Replacing the panel with one that has a higher OC voltage could cause the Li-Po to explode/catch fire. You really need a charger designed specifically for Li-Po.

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N11778 said:

I agree with Mike.
The charge controller thinks the battery is already low at 11.1 v so it keeps the load turned off.

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N11778 said:

look in your solar charge controller instructions some of them you can adjust the voltages.

thought.... you can add one extra cell to a 12v nicad pack and end up with a battery pack that mite work with the controller.

nicads are 1.2 volts full so an extra cell will increase the voltage to 13.2 volts which is real close to a led acid battery I have done it and it has worked for me give it try with your nicads.

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moehao said:

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So, is solar charge controller can only work with Lead-Acid Sealed battery?

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MikeMl said:

Yes, for the model you have chosen. Perhaps, there is a model specifically for charging LiPo, but it would be quite different from the one you bought.

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MikeMl said:

Solar chargers of the type you bought are exclusively for use with Lead-Acid storage batteries.

One idea might be a proper solar panel (20Voc) and a small Sealed Lead Acid battery tied to your existing controller. Then buy a LiPo charger specifically made to start from 12Vdc to charge your specific LiPo. Connect that to the Load output on your existing solar charger.

Look on EBay or other FarEast Importers...

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MikeMl said:

Go back and look at the picture you attached to post #4. It shows where to connect the panel, the battery, and the "load"

The panel you have will not work with this controller; you need one that outputs ~20V in bright sun!

The only battery you can connect to your controller is a 12V SLA; not a LiPo!

The "load" connection is for what ever you want to power with 12Vdc, in your case this is where you would connect a LiPo charger (not the LiPo battery).

Now read the following which comes right from the maker of your controller:

Product Description

Color:5A 12V/24V
Function:
. Always keep the battery on fill voltage condition.
. Prevent the battery from over-charging.
. Prevent the battery from over-discharging.
. Prevent the battery from reverse charging to solar panels during nights.
. Reverse Polarity Protection for Battery
. Reverse Polarity Protection for Solar Panels
. When the battery voltage is low, the controller will automatically cut off the load from the system. If the voltage of battery is back to normal and the load will restart working.
. Thunder protection
. According to the battery voltage grade, the controller can automatically set charge-off voltage, the load-off voltage, the load- restore voltage. (The parameter is default under 25¡æ condition, locked by the CPU procedure, cannot adjust.)
. The controller will automatically compensate the temperature of the charging voltage according to the changes of ambient temperature.

Warning:
Before connecting to the solar panel, please connect the controller to the battery; do not use solar panel supply power to the loads directly.
Notes:
Do not use lamplight to charge the solar panel (lamplight is too weak to charge)
DC power source to replace the solar panel will cause troubles to controller.
Choose the suitable wire which diameter should not be too small, please refer to the parameter.

Note the two Functions in the list above that I underlined.

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MikeMl said:

Solar panels deliver their rated current only when their terminal voltage is about 75% of their open circuit voltage. It takes ~14.5V to fully charge a 6-cell SLA, so the panel must deliver an Amp or two at a minimum of 14.5V. This requires that the unloaded, open-circuit panel voltage be at least 14.5/0.75 = 19.33V. Most panels rated for this service would have an open-circuit voltage of 20V to 22V. Your existing panel will deliver zero current @12V (its open-circuit rating).

If you do not use the LiPo, and instead connect a 12V Sealed Lead Acid Battery to the solar controller, and connect you motor and its remote control circuit to the "load" terminals of the solar controller, then you can start the motor while the SLA battery voltage is >11.5V (almost fully discharged). The motor will run for a few minutes until the battery discharges below 11.5V. If the panel is in bright sun, after about 30min, the solar controller will have recharged the SLA until it is at 12.5V, at which point the motor may start.

It is my impression that the motor will draw more current than the solar panel can provide, so you will be able to run the motor for much less time than it takes to recharge the battery. The more current the solar panel can produce, the shorter the recharge times.

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moehao said:

Hi Mike,
the solar panel i can get is just 12v only, because my surface area to locate the solar panel is not big .
...
My solar panel spec is 12V and 0.1A. Is this solar panel really cannot use at my system?...

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MikeMl said:

You really cannot use it. If you look at the specs, you will find that your panel puts out 100mA when its output voltage is ~8V, even though it may put out ~12V when unloaded. You can not charge a 12V battery with less than ~14V!

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moehao said:

Hi Mike,
Thank you very much, i changed the battery to SLA battery and the motor can run already.
The solar panel is so happen to have 14V under the sun also.
Furthermore, I have another question. Will the solar charge controller cut down to a lower voltage for the load automatically? Or I need to add a resistor or regulator between it?
Bcos my speed controller can handle until 8.4V only.

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MikeMl said:

No. The switch inside your solar controller is either on or off. When on, it supplies the battery voltage to your speed controller, somewhere between 14V when fully charged, and 11.5V when the battery is discharged. When off, it just disconnects your speed controller from the battery (zero volts).

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