I've used a 12 volt with a 15 gallon tank on my ATV and it worked fine for spot spraying, but was, IMHO, marginal for broadcast spraying. I put a 60 gal on my tractor with a pto driven roller pump. No comparison. I use it for weed control on 18 acres, using both as a broadcast sprayer and as a spot sprayer. Works great. I am told that with the roller pump I need to empty the tank out and run a little oil thru to protect the roller pump when it won't be in use for awhile. That seems to make sense. No such problem for an electric pump. Look over your application, if periodic use on minimal acreage, then the 12 volt may be better. If more acreage and more use, consider the roller driven unit.