High battery voltage
 

So I was leaving my parent's house to go get some gas then head home. Turned out of alley, then saw my gauges glow brighter than normal and thought it was just the street lights 'cause it went back to normal. Then got gas, started heading home, got onto the highway and saw my Temp gauge shoot near the red part and gauge lights were super bright (including headlights). So I went back to parents' house, could not find a flashlight (they're moving so a lot of things were gone). So I use my stupid cell phone light. Checked the alternator belt as best I could, felt to see if it was too tight/loose and it seemed fine. Battery seemed/looked like normal. Coolant was still full. So I headed home and every once in a while when I start to speed up the same thing happens. My logger read up to 18.4v, but COOL was still at 213.1 like usual yet my TEMP gauge was getting near the red mark scarying me. This also happens when I blast the A/C while cruising on the highway home, but it never happens when I blast the A/C at a dead stop. Only seems to happen when I accelerate, then after about 10 nerver wrecking seconds it'll go back to the normal 14.2 or so volts and lights go normal again.
I'm not very good when it comes to electrical stuff, so ideas of what it could be or what I could check let me know asap. I think if my car goes dead again it'll be the last time I drive it/own it :(.

Re: High battery voltage
 

Not sure why the temp gauge would spike like that unless there's a wiring glitch there too, causing the sending unit to send false voltages (I think it reads 0-5 ohms resistance?) anyway, sounds like the capacitors in the alternator are bad. Switch it out with a new one, check your fuses, and that should be ok.

-A. Swift

Re: High battery voltage
 

I would've never figured that one out, that the capacitors in the alternator are bad. You mean to switch out the alternator or just the capacitors? I seem to be going through alternators more than anything else. Will I be ok to drive the car still or will fuses and stuff start blowing? But anyway, thanks for the help.

Re: High battery voltage
 

I wouldn't say the capacitors in the alternator are bad, but the voltage regulator in the alternator is bad. It's the same thing that goes bad when your alternator stops charging. Take it out and have it tested somewhere, or just pay to put a new one in for piece of mind.

Re: High battery voltage
 

I meant voltage regulator. Damnit. With all the lessons in school on alternators and starters, you'd think I could have remembered the CORRECT term.

-A. Swift

Re: High battery voltage
 

guess I'll be having it tested first to see if I really need a new one. It hasnt even been a year since I've put this current alternator in and now it might need a new one already.

Re: High battery voltage
 

Where'd you get it? Napa? if so, that's why. I don't know how many alternators ive put into various customer cars, only to have them come back with a dead battery, or blown fuses due to a poor quality standard the alternators lived up to.

-A. Swift

Re: High battery voltage
 

So where do you suggest going out and getting one at? I think I need to buy 2 new ones.

Re: High battery voltage
 

Bosch or mitsu

Re: High battery voltage
 

I'd get that thing out of the car ASAP. One of my buddy's alternator was going at 18 volts and blew up the battery in the back of his car since it was relocated. Wouldn't be fun cleaning up acid in the engine bay either.

Re: High battery voltage
 

Yeah, the high voltage can burn up other electrical components too. It is likely the regulator, but I have seen a battery short out and cause the same thing. Alternator is just 10 minutes or so to take out, get it tested.

Re: High battery voltage
 

If you end up buying a new one/getting a re-manufactured one, tell them you have a 1991 Galant vr4, then you will get a 90 amp alternator instead of the DSM 65 amp one.

this is good if you have subs/high amp stuff

my 2 cents

Re: High battery voltage
 

If I'm not mistaken, he'll also need a 90 amp fuse for it. We only have 80 amp fuses... I think..

Re: High battery voltage
 

I finally got the alternator out, havent been driving it since Monday when it started to constantly run 18v minutes after starting. I took it into Autozone to get it warrantied and the guy who helped me did a couple quick tests on the machine and he said it passed and tells me it's perfectly fine. Then he says he cant give me a new one 'cause it passed and he'd be losing money if he gave me a new alternator. So I leave and call up the Autozone that I used to work at, talk to the manager and he's like "Yup, you're voltage regulator is going out and they should've warrantied it." And tells me to stop by and they'll give me a new one. Just like that, quick and simple. I sure hope it doesnt turn out to be a shorted battery tho...I'd rather have the alternator go bad than the battery.

Re: High battery voltage
 

Alright, I'm lost again. I got a new alternator, switched it out and took the car for a spin around the block a few times. Now the stereo shuts off and comes back on every couple mins or so and when I park and turn the key into accessories I have no power, besides the usual dash lights, auto-belts dont work, stereo doesnt work. So I take the battery and have it tested at Checker Auto and it's still good. Now I dont know what else to think or check. Any more ideas? I dont wanna go driving and get stuck on the side of the road so I'm gonna recheck everything and hope I find something wrong.

Re: High battery voltage
 

Check your fuses, and etc. You sure the battery is fully charged? Sometimes if it's not fully charged, or the battery cables aren't making good contact with the terminals (fully tight?) then the radio will be in "limp mode" or turn on/shut off constantly.

-A. Swift

Re: High battery voltage
 

I think I found my problem. I found the 80A Alt. fuse blown, so I'm hoping that is it. The battery should be fully charged by now. Got it checked at Checker Auto and it was reading 12v (that should be fully charged, right?). I need to go find an 80a fuse to replace and then I'll see what happens from there.

Re: High battery voltage
 

replace that fuse. Did they test the battery just after it was running? If so, that creates a "peak voltage" that their machine is reading from, and not actually the "real" voltage of the battery. it should be around 12.94v or higher for a healthy battery.

-A. Swift

Re: High battery voltage
 

replaced that fuse and all is good! Woohoo. I think it was that fuse that started it all. I missed it 'cause the part that was blown wasnt really see-able from the plastic window, took the plastic window piece off and it was blown. Guess I had a good alternator in the first place, but now I got a new one free of charge...even better! Ha.
Thanks to all that helped. Much appreciated. This thread can now be deleted if it's gonna be a waste of space.

Re: High battery voltage
 

12.6 is a 100% fully charged battery. Like you said, fresh off a charger it will be higher but a 100% charged and stable batt. is 12.6 volts.


Glad you got it figured out though. Electrical gremlins can be a pain in the ass.