Charging 1 2v Nimh Batteries With A 2 Watt Solar Panel

The batteries are charging in series.

Charging 1 2v nimh batteries with a 2 watt solar panel.

The solar panel is rated at 1 w with a max load voltage of 6 4 v and the product page is here. I am working on a school project involving charging 4 aaa nimh batteries 1 2v each with a small solar panel used for outside lighting. I actually tested the panel myself and found that in the best case with 90 000 lux full sun the max voltage was 5 2 v corresponding to a max current of 157 ma. My circuit to power a red led require 1 8v so i have to connect the batteries in series in order to light the led.

Then run wires from the battery to the charge connector making sure to match the positive and negative poles. I have 2 nimh aa batteries 1 2v 2050mah 1 solar panel at 2v 0 3w generating 150mah. That thing i already understand the problem is that i can t charge the 2 batteries with the solar panel while the batteries are in series as. Divide the wattage of the solar panel by the voltage of the battery to get the number of amps your charge connector needs to handle.

With the standard 0 7v drop of a diode you ll have 1 3v of charge voltage which won t be high enough for a maximum charge but a schottky rectifier diode selected for 0 5v forward voltage drop would get you 1 5v charging. To charge a battery with a solar panel connect a charge connector to the solar panel. Let s eliminate the lithium ion because its nominal voltage is over twice the voltage of aa or aaa batteries. The battery capacity is 2450 mah with a nominal 1 2 v per cell and the datasheet is here.

The solar panel being used is a 12v 40ma solar panel. It varies from 3 2 v to 3 7 v ni mh is 1 2 v and nicd is also 1 2 v.