Batterie Problem I think?

[redeye280z]

Hi guys I need some help maybe someone here can help. I think my battery is toast but I want to be sure before I change it.

When the car is running The alternator is putting out 13.8 volts so I know it!s working ok. When the car is not running the battery reads 12.4 volts.

Here is the weird part when the car has been parked for awhile it starts fine but after driving for a little while and the car is hot I have a hard time starting the car it feels like the battery has barely enough power to turn the engine over.

The battery is 3 years old and the car is stored in the winter. I never let the battery die over the winter I do charge it occasionally to make sure it doesn't run dead. Any thoughts would be appreciated.

[ekam]

n/m.......

[redeye280z]

I know it does seem low to me too I am not sure what the voltage should be when the car is off.

[ekam]

Most garages should have a battery tester (instead of a simple voltmeter) to test for weak/dead cells. What make is the battery? Perhaps you just need to top it up with distilled water? If it's still in warranty you can try to claim it.

EDIT - actually 12.4v sounds about right...

http://www.buchanan1.net/lead_acid.shtml
http://www.aa1car.com/library/battery_runs_down.htm

[mikehkang]

Sorry to potentially confuse you but my voltage reading from the cigarette socket reads 12.2 volts. (It is around 88 degrees now.)
The battery is about 18 months old.
I have no issue with the battery.

To me, your situation is a puzzle indeed because you can cold start but have an issue AFTER driving for a while. One would think that you would be net charging whiling driving.

Good luck.

[redeye280z]

That's what is weird about it after driving the battery should be well charged because the alternator is working fine.

[mikehkang]

If you suspect the battery, have it checked out.
Here in my area, I can go to an Autozone and they will check it for free.

I will tell you later what the voltage reading from the cigarette lighter is when I am driving.
You can compare it against your figure.

[jb92563]

The 13.8v charging and the 12.4v engine off is right on the mark.

Sounds like the starter is not working well.

Sometimes the starter connection or battery terminals can corrode and cause weak starts even though the voltage is right.

Check for corrosion and clean the battery contacts if there is some.

Heat is also the enemy for things electrical so perhaps your starter is becomming marginal and it gets worse when its hot.

I had another car that the ignition and interior lights would come on but when I tried to start, it could not turn the engine over.
I cleaned the battery terminals since I noticed some of that greenish corrosion and amazingly it started right up and the problem was gone.

I had one car that continually had the corrosion problem so one day I vaselined it all after a good cleaning and that kept the moisture/battery acid off the terminals for good, but that was in the days of maintenance batteries. Should not see any acid corrosion anymore these days.

[particlewave]

+1

That's almost certainly a starter issue that gets worse as the engine heat passes to it. Could be the solenoid coil, a coil in the starter motor itself, or the contacts inside the starter.

[particlewave]

Duplicate...

[redeye280z]

Thanks I will look further into it this weekend as I am afraid to get stranded. Is there a way to check the starter to see if it is defective?