how to determine what battery is best

[Smelly_Cat]

I've got a collection of batteries .  3 to be exact, plus an iffy one in the Rx7. I live on a hill and a weak morning battery is not an issue with stick shifts.   They all work to some degree.   I also have a $9 core receipt  that I need to give up a battery for.  I have a multimeter and battery charger,    How do I test then to ensure that I trade in the most worn out  battery and not the  goodest one. SC

[Bignick]

Take them to Autozone or Advance and have them check them all. They have the machines to do it. The weakest one loses. My experience is that Autozone just uses the harbor freight "load tester" battery tester. Adcance hooks them up to a computerized machine and runs them through for about 30 minutes trying to charge and what not. Not sure which one is better, but I've had one say it was good and the other say it wasn't, just don't remember which one...

I have saved a few batteries that the chargers wouldn't charge by hooking the weak battery to a good battery with jumper cables and then charging the two together. It tricks the charger into believing the one with 8v really has 12+ and brings it back. Did that with an optima a week or so ago.

[Smelly_Cat]

Thx Big Nick

Awesome Idea with the 2 battery trick the charger idea.   I just get a lawn chair and a 6 pack and keep turning the charger on.off  untill it decides to juice my dead battery.  Your method is better to my liver and lack of spare time


  I always try to get batteries my friends plan to trade in.  I give them one of my stone cold dead ones as a core .  and 50% of the time the battery they think is weak is good for a few years.  SC