One last electrical Gremlin to solve

[BronzeOnSteelies]

I had all the usual problems. Dim lights, dimmer at idle, battery was not charging as it should. Battery was getting 12.5 volts tops. Turns out it was a connection at the bulkhead connector most likely because all these problems were solved by bypassing the bulkhead connectors and the ammeter by putting a large gauge wire and fusible link from the alt output to the starter relay (As recommended in many threads on this board). There is a rig job on an alt wire female terminal in the bulkhead connector  After adding the bypass the battery was getting 14.5 volts, a load test on the system showed the alt was putting out 50 amps and it is a 1966 round-back that was in the car when I bought it. I had the bearings repaired in the alt when I had the engine bay apart a couple years ago. As far as electrical needs the car is basically stock. No new loads added.


Anyway one problem persists. When I hit the brakes the dash/gauge lights dim. Any thoughts? Bad ground? Eliminate alt gauge by putting red and black wires together?               

Mark

[Plumcrazy]

Mark

The dash lights are grounded through the cluster housing so make sure the attaching screws are tight.

The fact that you can get 50 amps out of the alternator tells me there is nothing wrong with the charging system. One difference between the old Mopar alternators and the modern alternators is that even though they may have the same rating, the new alternators are more efficient at idle speeds

At idle with the lights on I doubt the old style alternator will be able to keep up with the electrical demands without the dash lights dimming a little.

One thing you could try is putting a double belt pulley on the alternator, they're a little smaller so the alternator will spin a little faster at idle.

[2Gunz]

I would say the dimming thing is a "feature".
I think all chargers do it to some extent.

The question is how much does it do it?

If it gets really dim.....

I would start the process by sticking the brake lights to on.

Let it sit with the brake lights on for a bit then go hunting for warm wires.

That should be your problem.


Make sure the car is off and not on a charger. The lower voltage will increase the
amp draw and heat the wires up faster.

Dont let the car sit like that for extended periods of time.

[BronzeOnSteelies]

PlumC and 2Gunz

Thanks for the help once again.

It is not that bad, gauges are still readable, but it just annoys me.

I did order a smaller double pulley 2.7 inch vs 3 inch for 8 bucks thinking more rpm would help.
I for sure will check the grounding and wiring as suggested by both of you. I plan to do that first before putting the new pulley on.

I will let you know.

Mark

[craigandlynda]

are you using a group 24 battery? try a group 27....?

[BronzeOnSteelies]

Thanks C & L,

I do have that one covered.

It is a brand new Mopar Group 27 with 770 CCA's so I am good to go on that score.
I was suprised some of the places that sold batteries had no idea what the Group designation was.
Batteries Plus and the Mopar Dealer knew.

Mark

[Bobs69]

Could you tell me?  I've never heard of those 2 groupings either.  Thanks.

[BronzeOnSteelies]

Bob the group numbers are called "BCI Battery Group Numbers" and I don't know a lot except different groups have different physical dimensions and basic configuration. For example a Group 24 is 10 inches long while a Group 27 is 12 inches long. Both are 12 volt 6 cell configurations. I just know the Chargers came with Group 27 Batteries.

You can go to the following webpage for a list. I do not know what BCI stands for.

www.rtpnet.org/~teaa/bcigroup.html or just Google search BCI Battery Group Numbers

Mark