I have been using an 120VAC electric pump I salvaged from my old washing machine that recently went belly up... It works great as a portable pump for me transferring water but being 120VAC I have to plug it in somewhere...
I always have an inverter around to run it so no big deal... having a 12VDC version pump is probably a better idea however...
Might be better than those cheap portable ones you find at WALMART in their boat section...
Roy Ken