[MetroMPG]

You could also accomplish testing with a string of freely gotten 12v starting batteries. We used old worn out golf cart style batteries (from electric floor sweepers, actually) for our "test" pack. I'd say most builders don't even bother with test packs, but I wasn't confident enough to run out and buy a new set of batts for an unfinished project.

Or keep those ones (if they have any capacity) for a photovoltaic solar project!