femailyetti wrote:
given volts times amps is watts, then 15 be a trickle at around 1.4 amps, I vote for the 100 watts my self, with a controller. Most solar cells are not 12 volts exactly, so my math may be a little off. but you get the idea I hope.
If you're trying to charge up dead batteries a 15 watt panel won't be much good. If you just want to maintain a charge 15 watts may be all you need. Most small battery maintainers are 1.5 to 2 amps and do the job quite well. We have a small factory installed panel on the roof, not sure of wattage but due to size it can't be much. I use disconnect on house batteries, solar panel still charges batteries when they are disconnected. I then jumper the positive post of house to chassis battery. Solar panel keeps them charged up just fine as long as there is no load on them. We live in Michigan so it's not like the panel is bathed in sun all the time.
