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tgf
Novice
Apr 24, 2008, 8:42 PM
Post #1 of 11
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battery light comes on
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Hi, we've got a 1991 Honda Civic formerly 4WD wagon (wobbly universal joint removed, now 2WD) with 220,000 miles (just got that mark yesterday).
The battery light comes on sometimes.
The battery is brand new. The battery light came on sometimes with the old battery, too.
When the battery light is on, and it's nighttime, the lights appear brighter when the light is on, then dim back to their normal level when the light goes off. When the battery light is on and it's raining, the windshield wipers go faster than their speed when the battery light goes off.
Two years ago we replaced the alternator. The alternator belt is fine.
We brought it in a month ago to be checked and everything looked fine at that point (to the mechanic who checked it by hooking it up to a machine and looking at the shape of the wave forms). But of course the battery light wasn't on when we had it in.
What's it sound like to you? A short?
There's no pattern to when the light comes on, except maybe when the car is cold. It's never on for more than a couple of minutes.
Thanks for any help!
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Charlesmac
User
Apr 25, 2008, 3:30 AM
Post #2 of 11
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Re: battery light comes on
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Have alternator repair shop check trio diod in the alternator, or all neg and pos diods in alternator, possible heating up when car hot and opening up. also check real good for a loose or disconnected ground wire. good luck
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DanD
Veteran
/ Moderator
Apr 25, 2008, 4:45 AM
Post #3 of 11
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Re: battery light comes on
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This alternator uses and internal voltage regulator; the regulator controls/limits system voltage.
In other words the regulator turns the alternator on & off in an attempt to keep the system voltage between 12.5 to 15.5 volts.
What’s likely happening is the regulator for whatever reason is keeping the alternator on and taking the system voltage above its higher end limits of 15.5.
This is something that needs to be attended to right away, as in possibly replacing the alternator again.
All of the electrical is designed to operate within the range of 12.5 to 15.5, if the alternator is allowed to push the voltage above this, you will see things like what you’ve mentioned; brighter lights, faster wipers; that is until this high voltage starts burning things out.
Plus every time that this happens; the battery is taking a bad beating, as in it overheating.
The regulator is a serviceable part but usually not worth the time & energy to open up the alternator to replace; there will likely be other issues with the alternator due to the overcharging.
Dan.
Canadian "EH"
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tgf
Novice
Apr 25, 2008, 8:21 AM
Post #4 of 11
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Re: battery light comes on
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Thank you for your replies!
If we replace the alternator again, and save the old one,
is there a chance that it can be repaired, given that it's an intermittent problem? (i.e. is the voltage regulation problem likely to be not intermittent and the battery light coming on just when it gets above a certain voltage?) I expect it'd be difficult to get it to misbehave...
I should note that two years ago when we replaced the alternator, we got a cheap rebuilt one that lasted only a couple of months. We'd assumed at that point that it was a low quality alternator, and got a factory rebuilt (?) one I think. Could it have been something else wrong with the car that is causing it to eat alternators?
Like I mentioned, we just replaced the battery (it was over 5 years old).
Also, is this a job for an automotive electrical specialist, or can any mechanic take care of it?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 25, 2008, 10:32 AM
Post #5 of 11
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Re: battery light comes on
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Store:    Online:     Duralast / Voltage Regulator
Warranty - 3 MO VR833 $141.99 Application: With Mitsubishi alternator
Ouch! Just the regulator for that alt if that's correct is big bucks! The whole unit wasn't much more so that's a stopper. Perhaps you could get a used one cheap enough to take the working parts of each to cut costs and do it yourself. They can be fussy to take apart if you are unfamiliar with the idea with brushes etc.
My guess is the rebuilts don't have new regulators if the core returned one worked at this price and you might have one that was intermittent from before but tested fine at the time??
T
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tgf
Novice
Apr 29, 2008, 11:46 PM
Post #6 of 11
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Re: battery light comes on
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OK, so we brought it to the local mechanic, who verified the voltage regulator was bad, then the alternator we had got a new VR from the local alternator and starter specialists. That was yesterday.
Today the battery light was on again. So we brought the car back
today to the shop. They still have it, we'll hear more tomorrow. Their work is guaranteed.
But does this sound like a loose ground wire? Could it still be something else bad in the alternator? If so, where are the best places to look? And if not, what else should be checked?
Makes me really wonder if this is something else that's causing our
car to eat alternators...
(This post was edited by tgf on Apr 29, 2008, 11:54 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 30, 2008, 6:17 AM
Post #7 of 11
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Re: battery light comes on
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Let the shop figure it now. When alternators work hard they get hot and it hard on the whole thing and that's common to alternators in general,
T
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tgf
Novice
May 3, 2008, 9:26 AM
Post #8 of 11
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Re: battery light comes on
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fixed,... at least the light hasn't come on for two days so far...
just needed two voltage regulators in one week...
second one was free (under warranty)
I hope the alternator repair shop across town reimbursed
the mechanic for some of his labor...
he had to take out and reinstall the alternator twice.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
May 3, 2008, 9:50 AM
Post #9 of 11
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Re: battery light comes on
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The person you paid for a warranty part is the one responsible to deal with where they got the part or sublet work not you the customer. That's the way it works here anyway unless clearly stated otherwise,
T
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tgf
Novice
May 3, 2008, 10:47 AM
Post #10 of 11
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Re: battery light comes on
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yes yes. I didn't have to pay at all.
I'm just hoping that the two of them worked it out, financially,
because it took a lot of extra time for the mechanic to do
his work twice.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
May 3, 2008, 11:15 AM
Post #11 of 11
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Re: battery light comes on
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Ok: Generally the mechanic gets paid either a flat rate if an employee and would be paid by the shop for a part the shop secured. Shops mark up parts to customers as they are the actual sellers to you. When I get a bad part and sell it to you it's my problem - no pay and just eat it if you will. If my suppier or the parts keep coming in defective we have a little discussion about that !
I'm glad you care about the mechanic. We do end up with a lot of no pay redo work when parts fail which make this such a fun profession! Trust me - we look for the best quality parts out there especially for the hard to replace stuff!
T
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