I have a couple marine deep cycle batteries that I would rotate. Not sure of the exact size but you want a good quality deep cycle battery. I could get 24 hours per battery. I would put the other battery on charge when not in use. I tried a regular car battery but it would only go 8-10 hours and by the end of the season wouldn't hardly work at all because it couldnt handle the charging and discharging.

I think 2 gallons per tap storage is good. Last year I only had 1 gallon per tap and my tank ran over several times during heavy runs. This year Im getting rid of all my buckets and adding more main line. I will have all my 220 taps coming into one location. Unfortunately this will be too many taps for a shurflo so I am adding a vacuum pump and releaser. Shurflo's are good for about a 100 taps max.