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Solar panel and battery charging/discharging Answered


I am trying to power some LED decoration from a small 6v solar panel. However, I would like the LEDs to be also on during the night, so working from batteries during night time.

I have connected in parallel 3 x AA batteries (800mAh each) to my solar panel (6v, 500mAh), with a diode in between to avoid the battery discharging to the panel. Voltage is fine, and LEDs are working, but I am not sure if during the day, the solar panel is powering the LEDs and charging the batteries, or if the batteries are discharging all the time.

If the solar panel is providing more current than required by the LED, does the excess current go to the AA batteries?

Is it harder to charge AA batteries compared to AAA, apart from the capacity (mAh) being higher and therefore taking longer? Do I need more mA to charge AA batteries?




4 years ago

Chances are the panel isn't doing anything for the LED and is only trickle charging the batteries. The batteries are able to supply more current than the panel can. Depending on the power rating of the panel will determine if it's even capable of running the LEDs by itself. I would venture to guess it cannot unless it's a rather large panel.

FYI mAh is Milli Amp Hours. Which is a rating of how much power a set of batteries can consistently output over a 20 hour period before running dead. So Solar panels don't have a mAh rating to them they will be rated in Watts.


Reply 4 years ago

The solar panel is able to run the LEDs fine without the batteries. It's a 3.5w panel.

However, I have read that batteries can't be charged and discharged at the same time, so since they are always connected to the LEDs, I am not sure if they would charge at all