Battery test?

What is the battery's rated life? Most are 60 to 72 months and they last about that long. As for testing, read here, about half way down the page

If you trust your mechanic, then you better take his advice. That's because a 5 year old battery is quite old. Only a few last 5 years, and fewer still last to 6. Believe me, it will let you down at the worst possible moment.

The cheap batteries last ~4 years, the expensive ones last ~5 years, but cost nearly twice as much. So it's your call on how much to spend.

A standard load test will usually reveal the problem.

If you don't have a load tester, a simple voltage test will give you a rough idea: When you come home, do a simple voltage test with the engine turned off. You should get ~13.5v give or take. Check the voltage the next morning, preferably after a chilly night. If your voltage didn't change much, it's a good sign. If the voltage drops ~1v or more, it's a bad sign. Keep in mind this is a rough test, but it can be a useful indicator. -

Bob

Mine usually stays between 12.85 and 13.50v. Charging voltage is usually around 14-14.5v. I guess each vehicle will vary by .5v or so.

The real test is not the absolute battery voltage, but the difference between warm and cold battery voltage. -

Bob

JS

If you are seeing above 12.8V from a lead-acid battery that has set for any length of time at all after charging, then you need to have your voltmeter calibrated. :-)

Matt

True! The self-discharge curve is very steep for the first hour or 2 after a full charge. You can actually stand there and watch the voltage drop pretty quickly in .01v increments. -

Bob