solar panel system for cabin

So many things should be taken into consideration; how many hours a day the module(s) will see full sunlight, how many watt hours of light will be used, budget, but one good thing about PV modules is that they are moduler. If you know the amp hour rating of your battery (at the 20 hr rate) find 20% of that. Example 220 amphrs.x 20%= 44 amphrs. Ideally you would want to keep the battery in this top 20% of charge. To replace that 20% the next (sunny) day lets pick a panels rated amperage output at random, 6 amps and divide the 44 amphrs. 44 / 6 = 7 So with that panel and battery you would need 7 hours of full sunlight on the module(s)something we dont have even here in NC. but I think AZ. comes close. But if you divide 7 hrs. by 3 modules you will only need about 2.5 hrs. of full sunlight. Find your batteries amp hour rating and start from there. Staying in that top 20% percent of charge will give your battery a longer life and better performance (brighter light) and a faster rate of recharge from the PV modules.