Car needs jump start, but battery tested OK?

batteries

#1

lost a key between my seats but couldn’t move my electric seats so I pushed the push start button without my foot on the break…was able to move the seat and find my key. (I think I pushed the push start again after moving the seat to turn it off but don’t recall). This took 30 minutes max. Than my car wouldn’t start. Don’t think if car was on, 30 minutes would drain the battery?

Had to get a jump start and car worked fine everyday for 4 days. I let engine run 30 minutes after jump start in idle parking lot.

Than yesterday it didn’t turn on and I needed another jump start. My battery takes 10 minutes to charge up, but the dash did read “low battery” after 2 minutes of charging. After the jump start I took it to autozone and they said battery tested good. He tested alternator while car was on and said that’s fine.

Today, again, the car doesn’t start. Lights, radio, etc. turn on and work fine.

Any idea what the issue is?


#2

It sounds like a bad battery. How old is the battery? Do you make a lot of short trips? I wouldn’t trust a battery test from AutoZone unless they tested it on the car and did the complete test that included starting the car with the tester hooked up. Even then an old battery that is marginal can fool the test.


#3

Make, model, year?

When you say “doesn’t start”, what esactly happens? Can you hear the starter running but the engine doesn’t “catch” ? or no starter sound? do you hear a click?


#4

+1 for bloody_knuckles because a battery can light up a car and play the radio and still be bad. A good battery must provide voltage and enough amperage to start the vehicle. A bad battery loses the amperage necessary to operate the starter motor.


#5

Also, are the battery cable connectors clean and tight or corroded and nasty?


#6

How do you know it takes 10 minutes to charge up?


#7

Starting an engine draws 10+ more power then running your lights or moving the electric seats.

Sounds like a bad battery or charging system.


#8

I think you first need to have the battery charged. Letting a car run at idle doesn’t really charge the battery up much. I think you may find though that the battery is no longer taking a full charge and needs to be replaced.