How do you know when to replace your car battery before you car dies?

Answer 1

First is the battery age. After 3 years on places with cold winters, 4 years for place with no winters.
A good shop can test the battery for life expectancy.

A test is done with a battery tester and problems related to the battery can be found earlier.

Answer 2

I always drive, until the day the battery can't turn the motor over anymore, Then I load it up and try again. If it happens one more time after only a couple of days, I get the cheapest battery I can find and exchange it.
One battery I bought for 22 Dollar for a six cylinder held up for 6 years. My BMW has a 32 Dollar battery in, I had to make a new fit for it. The original lasted for 5 years.

Answer 3

The load test the parts store does on a battery is worthless. It only tells you how much current the battery puts out, not how long it lasts. You can test it by leaving the headlights on for two hours. If it doesn't last that long, you need a new one. If you have doubts and it's more than five years old, go ahead and get a new one in any case.

Answer 4

Go to AutoZone or O'Reilly's (or most auto parts stores) and they will do a free check of the battery. They check for the amount of voltage and amperage the battery is putting out. If the amperage is low, it is likely the battery is getting old. Generally though, batteries last about 2-to-4 years.