This weekend I'm going to do round two of de-mouse pooping and begin tinkering with my 73 that has been stored for 18 years. Dumb newbie question: Can I hook-up a larger 12V battery from another car just for the purposes of testing electrical items to see what does and does not work without damaging any of the electrical components? I'm assuming that 12V is 12V and that the larger size has more to do with having more juice available for turning over a larger engine and powering more stuff. I realize that the 914 may not charge a larger battery effectively, but I'm not worried about it charging the battery since I won't be running the engine with it. I won't need a dedicated battery for this car for a long time so it would be unfortunate to have to spend $100 on a battery at this point, but I don't want anything to get fried either.

12V is 12V. You're all clear.

Excellent, thank you!