Battery or charging malfunction or both?
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
Battery or charging malfunction or both?
I'll try to keep this short. Yesterday while driving I got red light on my voltmeter and the volts were 11.5 (this was at stop light, with A/C running). I shut off the A/C and noticed the volts went to 11.8 and the light went out. During cruising speed the volts went to 12-12.5, but would drop down to 11.5 at idle. After a while (about twenty minutes of driving) rpms had no effect on volts and volts just kept on dropping. At that point I was 1 mile from home, but stuck in traffic. I made it home, but when I shut it off it was reading 9.5 volts.
About a half-hour later I checked the battery with a multi meter and it read 11.0 volts. I tried to start the car, but just got a click. Later that evening I checked the battery again and it read .015 volts.
I know the battery is history (It was in the car when I bought it two years ago, but looked fairly new, also the alt looked new), but did the battery go bad by its self or did a bad alt kill the battery. I should also note that the belt tensioner is slightly out of range, needs replacing. TIA
About a half-hour later I checked the battery with a multi meter and it read 11.0 volts. I tried to start the car, but just got a click. Later that evening I checked the battery again and it read .015 volts.
I know the battery is history (It was in the car when I bought it two years ago, but looked fairly new, also the alt looked new), but did the battery go bad by its self or did a bad alt kill the battery. I should also note that the belt tensioner is slightly out of range, needs replacing. TIA
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery or charging malfunction or both? (Rick86)
Sounds like the alternator is history. I would at least charge the battery back up, but would consider replacing it. Normal volts with the engine running is 14.3 cold and 13.3 hot. With a heavy load (a/c on) and idling, the volts may drop to 12 but without the red light on (red light indicates no charging by the alt). When you get underway the voltage should go back up to 13.3 hot. The alternator cannot deliver its rated current when at idle speed. After charging the battery, check for 12v on the large red wire on the alternator to prove that the fusible link isn't blown which is a heck of a lot cheaper than a new alternator and then finding out that the fusible link was blown.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Battery or charging malfunction or both? (Rick86)
Have the battery tested if any doubt, else just replace it; then if you still notice charging is low you have enough time to replace the alt.
My alt died (I mean no charging at all) and didn't kill the battery. Now my rebuild AC Delco alt puts out 13+ Volts at idle, even with my underdirve pulley set.
My alt died (I mean no charging at all) and didn't kill the battery. Now my rebuild AC Delco alt puts out 13+ Volts at idle, even with my underdirve pulley set.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
Re: Battery or charging malfunction or both? (65Z01)
Thanks for the replies. I couldn't work on the car last night because kids open house at school. I want to check the voltage coming from the alt, but as I stated I couldn't get the car restarted. I'll probably run the alt over to Autozone and have them check it. I plan on replacing the battery, because it self drained to less then 1 volt in only a matter of hours. I think its history.
Any suggestions on brands of batteries. I can't remember where I saw it but here was a write up on AC Delco batterys, that indicated they were one leading batteries. Thanks again
Any suggestions on brands of batteries. I can't remember where I saw it but here was a write up on AC Delco batterys, that indicated they were one leading batteries. Thanks again
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Battery or charging malfunction or both? (Rick86)
Hey Rick,
Thats a good idea to replace both the battery and alt. the same time since you said they both appear bad.Both kinda support each other so you wont go wrong.
A/C delco batteries are fine but sometimes youll get a bad one.I bought a new a/c delco battery for my car before and its holding up considering I havent been driving the car much lately.
Interstate batteries,I also had good experience with them as well.Lasted me 6 years and I sold the other car with it with no problems at all.
If you buy a new a/c delco,dont go to the dealer.Find a a/c declo parts outlet and get it from there.Will save you more money and they can test it before you pay.
Get the strongest battery they have for your car...those last the longest IMO.I found my a/c delco drop down to 9 volts from sitting soooo long but it still fired back up and recharged to 14 volts.
:)
Thats a good idea to replace both the battery and alt. the same time since you said they both appear bad.Both kinda support each other so you wont go wrong.
A/C delco batteries are fine but sometimes youll get a bad one.I bought a new a/c delco battery for my car before and its holding up considering I havent been driving the car much lately.
Interstate batteries,I also had good experience with them as well.Lasted me 6 years and I sold the other car with it with no problems at all.
If you buy a new a/c delco,dont go to the dealer.Find a a/c declo parts outlet and get it from there.Will save you more money and they can test it before you pay.
Get the strongest battery they have for your car...those last the longest IMO.I found my a/c delco drop down to 9 volts from sitting soooo long but it still fired back up and recharged to 14 volts.
:)
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
Re: Battery or charging malfunction or both? (Bill's86Coupe)
Well I had the Alt tested and it produced NO voltage. So now the search for a new Alt and battery. I don't know if the battery is toast, but its at least two years old and this is my daily driver. Thanks
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
Re: Battery or charging malfunction or both? (Rick86)
I plan on replacing the battery, because it self drained to less then 1 volt in only a matter of hours. I think its history.
