Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve