charging issue?

[dvboth]

alternator went bad so I changed it and put a new voltage regulator on it also, now at an idle the headlights are dim, but if you rev it up the lights get brighter????

what do I need to fix?

 

[67Dart273]

OK the usual questions. You didn't say so I get to guess. You are working on a 1942 Blohm & Voss BV-141, right?



And the alternator you bought is exactly, what?

 

[TrailBeast]

You have fun with that don't you.

Lookin all those pictures up and stuff, you crack me up Del.

 

[TrailBeast]

Start with a relay kit for headlights from crackedback and get some of that load off those old undersized wires, an then go from there if needed.

 

[Charrlie_S]

If you didn't have that problem with the old alternator, You most likely got a rebuilt unit with a poor low rpm output.
That being said many older Mopars had that problem

 

[fastbackmopar]

If you didn't have that problem with the old alternator, You most likely got a rebuilt unit with a poor low rpm output.
That being said many older Mopars had that problem

Charrlie might be right. Most of the older mopars had 60amp alternators on them. Add an electric fan, aftermarket radio, and brighter lights and you'd be pushing it to maintain even 12volts. One thing you can check is use a volt meter on your battery to see if its at 12v before starting the car. If not, start the car and check voltage again. Sometimes a poorly charged/or bad battery will suck down more juice than the charging system can put out while idling thus causing lower power being available. Just my two cents.

 

[nm9stheham]

Lower voltage/current output from alternators at idle RPMS is common and normal. Generators were even worse. Your new alternator just may not be as a good a quality as the old one, 'spcially if from a consumer parts house.

 

[BillGrissom]

The headlamps shouldn't be "dim" running of a charged battery alone. The alternator adds another 1.5 V, which brightens them slightly but barely noticeable. Most likely you are getting excessive drop thru the firewall bulkhead connector. A common problem and the big red & black wire terminals eventually melt if ignored. Not a problem in 63 & 65 cars (why?), but I don't know about your 1942 Blohm & Voss.

 

[robertob]

Also if you got a parts store rebuild who knows what pulley is on it. I got one with a huge pulley compared to the one that was on my car. Swapped pulleys and low RPM output was much better.