Solar Charger Protection Circuit

[nickelflippr]

Brain dead today. My question is what happens when a battery is hooked up backwards to a solar panel? Here is a previous link for a reverse battery to load circuit.https://www.electro-tech-online.com/attachments/reverse_batery_protection-pdf.27203/

Simple enough to just use another schottky diode, but that kills the voltage when used for green, blue leds, which at a minimum would need 3.2-3.4v for full brightness.

So combining a solar charger with a battery protection circuit. The FDC6312P data sheet. Comments on how to improve?

 

[crutschow]

Reversing the battery to a solar panel will simply reverse bias all the cells. Since this reverse bias voltage per cell is likely not larger than the normal forward bias voltage of about 0.5V/cell, I would not expect the reverse bias to damage the solar panel. It could, however, damage any connected electronics.

 

[HarveyH42]

Isn't the diode there to prevent the battery from discharging through the panel at night?

 

[nickelflippr]

Well the battery could be fused, that's one option. I must say that I've never seen a fuse in a solar garden light, which is the intended application.

The rating on the battery is 600 mah, but because of the chemistry it can source at least twice the current (2C), or maybe more. At 1.3A the schottky would be getting warm I would think.

The interaction or effect on the solar panel itself though is still a mystery to me. Depending on the internal resistance, the solar panel itself could get really hot?

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O.K. got some posts while drafting up my own response, Thanks:

HarveyH42: yes the schottky diode is to prevent reverse flow from battery at night "only". I realize that doesn't help or preclude inserting the battery backwards.

crutschow: So yea, the battery voltage would always be less than the open circuit voltage of the panel, hadn't thought of it that way, thanks. The schottky diode should be O.K. I think, may just have to try it out (with safety precautions of course) to see.