Battery, alternator, lights surging, oh my.

[kokes_1]

I recently bought a battery for my 1984 944 restoration project. Did a tune up, changed the gas and oil and presto it started and all was good until I noticed that the the lights were surging (bright then dim). Reved the engine to see if the frequency changed and it didn't.

My question is whether this is a charging system issue or a battery issue. I was told that the battery was not the exact specified model but was from the same family group (what ever that means) as the one recommended and had the same specifics that was recommended.

The battery charges fine. So, I don't think it's the alt.

Thanks for any help you can offer.

Dan

[John_AZ]

I doubt if the battery will cause the flickering lights.

1. Clean grounds and wire contacts around the altermator.
2.Change the VR (voltage regulator). Prices range from $20
3. Alternator diodes could be failing.
4. Replace the old battery cable ends with military style.
5. Replace the battery cables with thicker "Ice Shark battery cables"
WTB Ice Shark Battery Cables - Rennlist Discussion Forums
6. Run a second ground cable from the alternator case to the NEG battery body ground.
7. Check your light wiring for crack in insulation.
8. Clean all grounds on engine



????

J_AZ

[Jfrahm]

On an older car I would worry a lot about the starter and alternator wiring, there have been cases where shorts cause the starter to run unexpectedly and if it's in gear the car can roll into the garage door or out into the street or into the neighbor's yard.

Your problem could be a ground or voltage regulator but it could also be a thick unfused positive cable (starter or alternator) welding on something.

-Joel.