Battery or Alternator problem? help please?

Question

my moms 98 hyundai accent has a problem. the power from the battery keeps deiing out. i took it to autozone for a test and the guy said there was no problem with it but just a very low charge. so the guy charged it up for about an hour..i put it back in the car and it was working fine. then about 2 days later the power drained form the battery again. so the question is, is it a bad alternator or bad batter? thanks.

Answer 1

First of all, Auto-zone checked the battery, said it was still a good battery, next make sure you clean the terminals on the battery, both of them, use sandpaper etc, look inside both cable connections, NEG and POS, clean also, you should see bare metal. If you have a meter, set the volt switch to DC 25 volts, connect the Black lead to the NEG terminal on the battery, the Red lead to the POS terminal. With the engine running at idle, read the voltage,should be 12.7vdc for a fully charged battery. Increase engine speed slightly, meter should read approx 13.6vdc if your alternator/regulator is working .

Answer 2

If the battery isn't holding power you're going to need a new one.

Using a weak battery is going to cause your alternator to work twice as hard, which could cause them both to fail.

Answer 3

If the battery checked out okay, and it continues to die, it's not getting charged.  It's either the alternator or the voltage regulator.  You can check alternator belt tension if you want, but you'd probably hear a squeal if it was slipping bad enough not to charge at all.  Pull the alternator and take to Auto Zone for a free check.

Answer 4

Could be a dead cell in the battery, but also may need to check to see if your altenator belt is tight, so your are getting the proper amps to your battery to keep it charge, if not buy a new battery.

Answer 5

If the guy at autozone said he checked it, then he checked it wrong. You can test a battery and the alternator at the same time, all he had to do was flip a switch.  The battery could be good or need a charge, but if the alternator is bad all the charging in the world isn't going to make the battery last.  It's called a load test. If the voltage drops when there is a load, such as lights, or the battery light is on in the dash, then the alternator is bad. Try going to a place that will check it for free, other than the guy at autozone. Advanced auto or other types of stores like that.  

Answer 6

check the alternator belt tension.    

Answer 7

Sounds like you have what my husband refers to as a dead short in one of your wires. It will cause your battery to loss charge.

Answer 8

That battery might be old. Replace that one first b/c you did only recharge it and it's cheaper to replace it. If the battery dies after that then it is the alternator which will cost a lot more to fix. Good luck. I hope its just the battery!