Battery not charging properly
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Battery not charging properly
Today I drove for about 50 minutes to a car show, let the car sit for 6 hours, then it started right up and I began to drive home.
On the way home I ran into terrible traffic, there was a point where it took about 45 minutes to go 3 miles. It was hot out so the dual Spal fans were running most of the time.
I finally got home and parked the car for about 1 hour. I tried to start it agian, but it wouldn't turn over.
I have had the charging system tested and it tests out ok.
I have a 90 amp alt.
When the car is idling and the fans are on I noticed that the volt meter is reading negative values.
My guess is that on this particular drive I was using that battery faster than it was charging.
The other time this happens is at the drag strip, where the car idles for 20 minutes, runs like heck for 13 seconds, then I turn it off for a bit and then start the cycle again.
How do I make the alt charge more durring idle? It is a '68 style alt with an external regulator.
thanks,
~Jay
On the way home I ran into terrible traffic, there was a point where it took about 45 minutes to go 3 miles. It was hot out so the dual Spal fans were running most of the time.
I finally got home and parked the car for about 1 hour. I tried to start it agian, but it wouldn't turn over.
I have had the charging system tested and it tests out ok.
I have a 90 amp alt.
When the car is idling and the fans are on I noticed that the volt meter is reading negative values.
My guess is that on this particular drive I was using that battery faster than it was charging.
The other time this happens is at the drag strip, where the car idles for 20 minutes, runs like heck for 13 seconds, then I turn it off for a bit and then start the cycle again.
How do I make the alt charge more durring idle? It is a '68 style alt with an external regulator.
thanks,
~Jay
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
Even though it's rated at 90 amps. Idle speeds aren't enough to keep the alt spinning fast enough to charge the batt, especially with a couple hungry Spal's spinning up front.
A smaller pulley on the alternator will make it spin faster and probably get it charging.
A smaller pulley on the alternator will make it spin faster and probably get it charging.
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
That thought crossed my mind, but the pully is already quite small.... I'm affraid that it will be spinning at too many rpms when the engine is near 6000rpms
Are there any alternators that make good power at idle?
~Jay
Are there any alternators that make good power at idle?
~Jay
Instructor
Joined: Sep 2005
Posts: 194
Likes: 0
From: Hamilton Ontario
Test the alternator and battery with a voltmeter to make sure neither are going south on you, before you fork out cash on an upgrade. They do make high output alternators but they cost 'mucho doneros' compared to a standard. They are usually used on police/fire/ambulance vehicles which are running lots of radios, sirens, etc. or on tuners who draw stupid amounts of power with their stereos, lights and videogames. In those uses they may also be storing power in extra batteries. Usually when a cars voltmeter is reading in the negative while driving it means bad alternator, bad battery, wrong battery for the vehicle, or all of the above. In your case the external regulator may even be the culprit. The whole system needs to run in balance. A topline standard alternator, with functioning regulator, mated with the proper battery, should be more than enough for just about anything you can throw at it. Hope this helps.
Last edited by Mark PittPayne; Sep 26, 2005 at 11:18 PM.
