i like the idea and setup show you are thinking ,i see a weak point in your system tho .its easy enough to add more batteries, go to local garage or store where you purchase automotive batteries from and behind store there will be some used batteries there ,ask someone if you can just have them ,most people return batteries with lots of life in them . please click my referral link and sign up i will return the favour,thank you :) www.coinstarter.com?ref=x37jndqdt