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914World.com _ 914World Garage _ Battery no longer charging.

Posted by: moneysmarts Feb 2 2006, 01:19 PM

Had the local gas station / repair shop check to see if the battery was charging. (just replaced it again for the 3rd time under warrantee from FLAPS)
Stuck at 12 Volts.
Before I replace the alternator, anything else I should check or have tested?
Thanks.

Posted by: Mueller Feb 2 2006, 01:19 PM

QUOTE (moneysmarts @ Feb 2 2006, 12:19 PM)
Before I replace the alternator, anything else I should check or have tested?
Thanks.

the voltage regulator

Posted by: lapuwali Feb 2 2006, 01:34 PM

Does your G light come on with the key? If not, check the bulb and the wiring to it. This MUST work for the charging system to function. Does it go out when the engine is running? If not, either your alternator or your VR is toast.

Posted by: moneysmarts Feb 2 2006, 02:17 PM

Now that I think about it, I'm not sure if the g light actually does come on.
I'll check it tonight when I get home.
Presuming it doesn't come on with the ignition, what do I do about it.
Can just the bulb prevent the alt. from charging the battery.
And how would I check the Voltage Regulator?
Thanks

Posted by: markb Feb 2 2006, 02:39 PM

QUOTE (moneysmarts @ Feb 2 2006, 12:17 PM)
Can just the bulb prevent the alt. from charging the battery.

Yes

Posted by: moneysmarts Feb 2 2006, 03:01 PM

Just checked the car.
G light comes on with key, off when engine starts.
Now what?

Posted by: lapuwali Feb 2 2006, 03:07 PM

If you have a meter, check the voltage at the battery terminals. Engine off, you should see 12.3-12.8v. Engine on, you should see 13.5-14.5v. If you see less than 13v or more than 15v at the battery, engine on, then the VR is history. Low voltage can also be the alternator, but the VR is cheaper to replace, and unless the alternator is making noise, it's more likely to be the VR.

If the starter spins slowly even with a charged battery, then look at the ground strap at the rear of the transmission to the trunk floor.

Posted by: moneysmarts Feb 2 2006, 03:13 PM

Today, with the engine running, it measured just slightly better than 12 volts with the engine running.
Increasing the rpm's had no effect on the volts.

Time to replace the VR?

Posted by: Mueller Feb 2 2006, 03:16 PM

if the VR is the old mechanical type, you can pop off the cover and "manually" activate it to see if the voltage increases...

Posted by: Rand Feb 2 2006, 03:20 PM

QUOTE (moneysmarts @ Feb 2 2006, 01:13 PM)
Today, with the engine running, it measured just slightly better than 12 volts with the engine running.
Increasing the rpm's had no effect on the volts.

Time to replace the VR?

If your "slightly better than 12" is still less than 13.

Posted by: ClayPerrine Feb 2 2006, 03:24 PM

You can also do what is called a "full field" test. Jump the field wire to the battery positive. The voltmeter should show about 15v like this. If that is the case, then replace the voltage regulator.

Posted by: Mueller Feb 2 2006, 03:32 PM

QUOTE (ClayPerrine @ Feb 2 2006, 02:24 PM)
You can also do what is called a "full field" test. Jump the field wire to the battery positive. The voltmeter should show about 15v like this. If that is the case, then replace the voltage regulator.

should be the DF on the picture...this is the top view of the relay board in the engine compartment:

Attached image(s)

Posted by: moneysmarts Feb 2 2006, 04:44 PM

I have an old analog voltmeter.

It appears to read 12.5 V, at the battery terminals, both while the car is running and when it is off.

I pulled the cover off of the V reg.

I don't dare start moving the little points around to see what happens while the car is running, it thats what "manually activating" is.

Posted by: Mueller Feb 2 2006, 07:32 PM

yep, all it'll do if you "activate" the VR manually is charge the battery....this is fine for testing, don't rig it to stay on for long periods of time (like hours with the car running) since it could overcharge the battery..... a few minutes or longer is fine, if you "had" to drive the car with it rigged, just turn on the lights and any other power draining device to limit overcharging the battery while running....

Posted by: racerx7 Feb 2 2006, 07:56 PM

What everybody else said is good.

I would just like to add one little think to check is your wiring. Get a big
wire like from jumper cables. Take it straight from your alt
to the battery B+. Also take the jumper cables straight from the
negative to a good ground. All this does is eliminate all your
wiring in the car. Check it again with your meter with the car running . If it stays at 12 volts, it VR or alt.

Posted by: moneysmarts Feb 2 2006, 08:09 PM

Thanks for the help, guys.
I appreciate it.