LEDrock
Enlightened
- Joined
- Apr 20, 2008
- Messages
- 282
USB AA/AAA chargers can work, I have a couple of older 2-cell ones. One downside is efficiency; by the look of these two, 50-60% at best, probably lower. With small solar setup, wasting power needs to be minimized.
Another downside is adding another level of inefficiency. Running from 12v panel, down-converting to 5v you should manage 75-90%. Then there's the charger, and the "charge efficiency" of cells themselves. In the end, overall efficiency could be rather low.
The charger should not allow cells to discharge into it when its input (solar) power goes away. One 12v charger I was using about 15 years ago did this, lighting up some status LEDs in the dark. Sometimes the only thing to do is test it out.
I also solar-charge USB Li-ion battery packs and use them to run small fans, lights, and charge phone battery.
Dave
I just came across something on Amazon that looks perfectly good. It's a 90x90mm panel with a 2AA battery holder attached to the back of it, and there appears to be a diode there to keep discharging from happening. It's about as basic of a setup as one can get. Specs say the output is 250ma at 4 volts. What do ya think?
https://www.amazon.com/dp/B08YJRMS8D/?tag=cpf0b6-20