low battery indicator light stays on

[ecuke]

After a long winter, I needed to charge my dead battery which was replaced 2 years ago. The battery charged in full in 5 hours. Drove for a few miles; went out the next day for a few miles, and then the light came on. Then shut the car off for 20 minutes and engine would not turn over. Then 1 hour later engine turned over but was weak. I have read some threads that this may be a regulator/alternator. Would another charge do the trick???

[JFP in PA]

Probably not. If your regulator is bad, you can tell by testing the battery voltage with and without the car running with a simple volt meter; or if you have access to a load tester, perform and engine running load test, which should cause the regulator to respond with about 15.5V or so if it is OK..........

[mptoledo]

Yep, get a $10 meter from walmart. located in their automotive department. I used their batter charger/tester all in one. Test your battery with car turned off, then with car on. You should jump from 12 v to 14 v, if it doesn't go up at all its probably your alternator. Thats what Mine did. I got my alt from Orielleys auto. $220 with lifetime warranty. I have a DIY for alt replacement in the DIY section.

[ecuke]

So JFP says to test for faulty regulator? Is this also part of the alternator? I have a voltage meter but now have to recharge the battery in order to get correct readings. I understand the voltage increase while engine running (test of the altenator); not sure about the voltage regulator .

[sd_boxster]

Allowing a "normal" car battery to discharge completely and remain discharged for a significant period of time causes sulfation - a chemical deposit on the plates of the battery - that reduces the capacity or renders it completely useless.

One or two seasons - especially if you have some parasitic drain - is enough to destroy a new battery.

That said, you might have a charging system fault - but if you haul the battery to Autozone and have it tested, I bet they'll tell you the battery is shot. Order a maintainer now, while you're thinking about it, so the battery can be properly conditioned the next time you store it.

[ecuke]

Thats interesting; Would it be OK to charge the battery back to 100% and then do my voltage tests, since yesterday I did have it charged 100%(according to the battery charger) just to be sure my alternator is working>
. Although some other forums suggest the alternator replacement is rare on this car (35k miles 2001)