I want to use a solar cell to top up a 12 volt 2.3 Ah sealed gel cell and show state of charge with LED. (A bit more than a basic diode and dropper resistor).The solar cell will be connected all the time, so its output varies from 0 volts at night to 18 volts @ 180 mA in bright sunlight. Am I right in thinking that a gel cell has different charging needs to a lead acid battery? I think it needs about 13.8 - 14.0 volts as a maximum. I don't want to overcharge it with 18 volts all day. The battery is used to power a 12 volt fan, switched on by a thermistor circuit at 21 C.
Any ideas? Thanks
Any ideas? Thanks