Small Solar Panel Project Help!

System
System Posts: 2,511 admin


I got a radio cooler i built that is powered by a marine deep cycle battery. Everything works and sounds good! I now want to do 2 things to make this a must-have on my river/lake camping trips and then also for the deerlease(no electricity). The radio will be used about 5 hours during the day, and the lights maybe 3 hours at night. can i make this work?
I want to first, hook up a solar panel w/ a controller(to keep from overcharging) so that the battery can recharge or maintain its charge to last for say 3 days. I also want to get a string of maybe five 12v light bulbs rigged up to a cigarette lighter adapter, or just to alligator clips to run off my battery for the party time at night. Our campsights at the lake, river, nor deerlease dont have any electricity.
Any information, hints, or "dont-do's" that can help me will all be appreciated! I also am not sure what kinda solar panel set-up and size to get for this operation. i have found the 12v bulbs at walmart that are for rv's and use around 12-15watts. also, i am not sure what kinda socket to use to screw these 12v bulbs into.

Thanks!

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Small Solar Panel Project Help!

    A bit of basic info for you to work with:

    Loads in Watt hours. If you know how many Watts you'll use over how many hours you'll have a good idea how much battery capacity you need. Once you've got that, figure on supplying 5-13% of the battery's "20 hour" Amp/hr rating for good charging. You may be disappointed with the performance of the Marine/RV 'hybrid" deep cycle especially as loads grow.

    An approximation based on guess work:

    100 Amp/hr battery needs about 10 Amps @ 14.2 Volts = 142 Watts. Typical panel 'nameplate' derating of 80% means 177.5 Watts of panel. That is to say a 175 Watt panel would probably keep the battery charged. 175 Watt panels are nearly always '24 Volt' so for maximum yield you'd need an MPPT controller to down-convert the higher Voltage or you could use two smaller '12 Volt' panels in parallel. Like these:
    http://store.solar-electric.com/kysokc85wa12.html

    However, if you draw the battery down too much it's going to croak. A 100 Amp/hr battery has at best 50 usable Amp/hrs (it's recommended to not exceed 50% discharge) so that adds up to about 600 Watt hours.

    It could work.