battery condition.

I have mentioned it several times but now that boating season is upon many of us, I thought it would be worth mentioning it again. Getting a voltage reading off your battery is not a good indicator of it's condition. It can only tell you the level of charge. The only real method for condition is to use a battery load device. This is a meter with a bank of resistors in it. It's attached to the battery and then a load is placed on the battery with the resistors. Then, the voltage is monitored. Most auto supplies will have one and are typically happy to test your battery. (BTW, Autozone has a very special meter - it will always tell you you need a new battery!! )

I just got done changing the dual batteries out on my diesel. It's be slow cranking for a couple weeks now. I cleaned the side terminals up but that didn't help. The other day, I got the volt meter out just out of curiosity and got a reading of 13.1 on both. This is what's called a surface charge since the truck had been running charging the batteries. A full resting charge will be 12.6 volts. The batteries BTW were 6 years old.

DFoster wrote: I've seen cheap load testers at harbor freight for like $20, anybody have experience with those? I would tend to trust my own meeter more than any shop that sells batteries. They don't seem to have any incentive to tell you that your battery is fine.

Well, you really get what you pay for it!! Considering a starter draws several times more the the 100 amp load this "tester" can load the battery too, it sure will not tell you the true story. A good tester will have a carbon pile capable of loading to 500 amps or more. Also, think about the CCA of a typical battery. I think some motorcycle batteries have a rating of around 100 amps!