Bnine

Maybe someone can help, I have an aftermarket serpentine belt drive kit installed on a 71 corvette. The kit works great, but my battery isn’t charging from the aftermarket alternator, at least as far as I can tell. Now assuming that the alternator is functional, and that it is not damaged, which connectors need to be connected on the alternators S-F-L-P connector, and which ones can I leave terminated? I have read a lot on this online, but haven’t seen anything simple, I see a lot about one lead is for the battery light inside the car, sense leads, etc, but I don’t have a battery light, I have a gauge that tells me if the battery is charging back up or not, + = charge, - = drain. This gauge is always centered, doesn’t move, so I don’t think its getting a reading.

The alternator has an S-F-L-P connector on it, and I suspect that the leads from the connector are not wired correctly. I think I am correct in assuming that the only thing this plug really needs to do is 1- to sense whether or not to start charging the battery back up, and 2 – to show me that there is either a positive or negative charge (as shown by the battery gauge) I don’t think it is doing either. Does anyone have input? I go through batteries about 1 every 2 or 3 months. this is my weak area, electrical systems, so try not to get too technical, lol. Hehe

jnb5101

durangoboy had an excellent post on how to wire these alternators. do a search and you'll get perfect info.
jeff

Bnine

Update,

When my SPAL fans turn on while the engine is running, i can see a drain on my battery guage, but when the fans turn off while the engine running, the guage goes back to vertical. It never goes over to the right, as ifit is charging the battery back up. Maybe that will help you electrical gurus, and (this is with the S-F-L-P connector disconnected)

Durango_Boy

Assuming the alternator harness is still intact, and guessing you have a newer CS alternator, here is the proper wiring diagram.

I am not familiar with the gauge you speak of, where it just shows charging or not...can you post a pic of it?

Also, it's possible the gauge is not connected properly or may not even be working. Once we get the name for the gauge we can look up a trouble shooting method for determining if it works or not.

Z-man

AFAIK, '71s have a volt meter like my '70. It's behaving as if there is no charging happening (and well...you said you unplugged the connections - no wonder). The proper position for your meter is usually just slightly to the right when the battery is fully charged.

Can you show us some pix of the alternator, or tell us what kind it is? Is the alternator spinning in the right direction with your serpentine setup? (It could be spinning backwards). If its spinning in the right direction, I'd take the alternator down to the nearest parts store and have it checked out. They usually don't charge for this service. Once you determine that the alternator is good, I'd make sure it was wired up like DB shows. I've also got a few photos on my site that show how I wired up my alternator.

Also, you'll want to check all your connections to make sure there are good grounds and that the wires don't have corrosion on them.