Cold morning starts...
Thread Starter
TECH Apprentice
Joined: Jul 2006
Posts: 368
Likes: 0
From: Houston, TX
Cold morning starts... Battery only puts out 10V in cold weather (~40 F in Houston), but 15V when it's warmer.
Brand new Duralast battery... alternator was replaced 2 months ago.
If i rev it up to 4-5k for a few seconds, the battery voltage will jump up to 15V.
Not sure what the heck is going on, but I guess I'll go to Autozone and get the new battery tested just to be sure it's holding a charge properly.
Brand new Duralast battery... alternator was replaced 2 months ago.
If i rev it up to 4-5k for a few seconds, the battery voltage will jump up to 15V.
Not sure what the heck is going on, but I guess I'll go to Autozone and get the new battery tested just to be sure it's holding a charge properly.
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
You mean 10V while running on the gauge when it first starts? Sounds too low, sounds too low even with the engine off reading off the terminals too. Think you're doing the right thing by getting it load tested, if for no other reason just to eliminate it. Is it a reman alt from a parts store? My buddy went through a couple before springing for a new GM unit to solve a similar issue.
Thread Starter
TECH Apprentice
Joined: Jul 2006
Posts: 368
Likes: 0
From: Houston, TX
well the alternator was working just fine with the old battery, but then one of the cells died, so I had to replace it. This battery is acting strangely for a new battery. I would expect odd charging behaviour to disappear after a few days.
And yes, I mean it's only showing 10V in cold weather, the lights are dim, etc. It won't rise until i nail the gas for a few seconds... which is relatively dangerous if you are driving in the wet haha
And yes, I mean it's only showing 10V in cold weather, the lights are dim, etc. It won't rise until i nail the gas for a few seconds... which is relatively dangerous if you are driving in the wet haha
what type alternator did you put on? I know I had a high output one on my Tahoe and due to it being a "1" wire harness, I had to give it a touch of gas for the stater to work and then it would charge fine (all this was when it was cold as well)
Thread Starter
TECH Apprentice
Joined: Jul 2006
Posts: 368
Likes: 0
From: Houston, TX
Ok... battery checked out fine.
Alternator on the first run on the machine performed poorly. The battery sat at 11v and would not charge past that (running at 2k rpms while test is going on).
Second test (1 minute later), battery suddenly starts getting charged and runs up to 14.5v while running car at 2k rpms.
Soooooo first run alternator was crap, second run it worked great. Only problem I've had with alternators was total failure (0 output current) and low output current. I've never heard of one having low current, then high current. Loose wire somewhere???
Alternator on the first run on the machine performed poorly. The battery sat at 11v and would not charge past that (running at 2k rpms while test is going on).
Second test (1 minute later), battery suddenly starts getting charged and runs up to 14.5v while running car at 2k rpms.
Soooooo first run alternator was crap, second run it worked great. Only problem I've had with alternators was total failure (0 output current) and low output current. I've never heard of one having low current, then high current. Loose wire somewhere???
