I started out that way as well, with a 5 Watt panel from local hardware store. By itself, it kept my spare car battery at around 12.3 volts. Then adding a cheap charge controller brought it's float voltage up to 12.8 VDC. Going to the 85 W panel brought float up again to 13.2 Volts, but this was the controller's limit. I got a great deal on matched deep-cycle batteries which needed 14.4 V rate, so that's where MorningStar came in. The deep cycle bank is maintained at 13.7 VDC, and I can truly tell the difference.
Car battery - 12.8 VDC @ 675 CCA = 20 Inverter minutes / 5 Amp cooling fan.
Deep Cycle - 13.7 VDC @ 80AH = 4.5 hours Inverter / 5 Amp cooling fan.
That's several times longer than what I usually need, so the extra investment was worth it. I run lights, radio, cooling fan, and vent fans for the couple of hours that I need them(not always at the same time). My shed has been converted to a 'shop', and is not unpleasant.
Quote:
Originally Posted by Xringer
I've got three very small panels that are rated at 5 to 10 watts... 
At least that's the way the first one was was described on EBay..
All three of them do a good job of keeping my 12v batteries charged.
So, I really don't care what their wattage is, because they are going
exactly what I need them to do..  |