Eagle 05 Alternator Charging Problem

[busman96]

Hello. I have a '69 Eagle Model 05. I am having problems with the electrical system. When the bus is running, the voltage pulses. It goes from 13 volts to 15.5 volts non stop. The voltage gauge goes up and down and up and down. You can even hear the engine drag down when it pushes the higher voltage. I replaced the voltage regulator thinking that was it, but it still does it. Has anyone ever had this problem? Is there a quick fix, or is the problem in the Alternator?
Thanks for any comments!

[littlehouse]

i don't know but this sounds more like a short some were drawing all the power it can then letting go then drawing again, you might
want to check out the things that are running on the same system, lights, fans, instruments, horn relay, starter relay. well you know
what i mean. i don't know if this is any help, you probably already thought of these. so i wish you luck. 
ray with the littlehouse on wheels

[Stan]

It is normal for the Delco DN50 alternator and its original style regulator to hunt when the batteries are fully charged and there is no load.  Try it with a load (headlites, heater motor, etc.), and see if it still hunts. If it does, the likely possibility is a bad diode in the alternator. The alterntor is three phase and if one phase is missing the regiulator  will try to correct when no voltage is coming from the missing phase. If this is the problem the pulse rate will vary with engine speed. Comments have been made on the BBS that a starter/alternator shop can replace the dilode plate on some models without removing the alternator from the bus. If it is a gear driven alternator, specail care is needed when mounting the alternator on the engine. Check out these suggestions and report back.

[FloridaCliff]

I would also verify that the gauge is correct against a VOM.

Maybe the movement went bad.

Just throwing out ideas!!!

Cliff

[DrivingMissLazy]

If he hears the engine slow down when the voltage goes up, this would be an indication that the voltmeter is correct and he is slamming a lot of amps into the battery system. A clamp on DC ammeter would really be a help here. I suspect this is very hard on the batteries also.
Richard

I would also verify that the gauge is correct against a VOM.

Maybe the movement went bad.

Just throwing out ideas!!!

Cliff

[FloridaCliff]

Richard,

I am reading to fast.

I thought he said cannot hear the engine raise

I stand corrected!

Cliff

[Brian Diehl]

Something else to consider..

On my 96A3 I had the same problem.  I replaced the regulator with a brand new electronic regulator and STILL had the same problem.  I did some investigating and found out that the "sense" line from the battery to the regulator had enough resistance that when the regulator was trying to get a lot of current out of the altenator at lower RPMs the current draw on the "sense" line was enough to artificially change the real battery voltage.  I solved this problem by running a new wire directly from the battery to the regulator and used the "sense" line to drive a relay so that power to the regulator was removed when the ignition was shut off.  I would recommend at least a 10 gauge wire and definitely use a relay 'cause if you don't the regulator will drain the batteries in less than 48 hours.

[TomC]

I had the same problem that you could see the lights going up and down.  When I had to replace the DN50, I also replaced the big black box transistorized regulator with a digital regulator that is about 1 1/2 times the size of a deck of cards.  While it still pulses a bit, it is no where near what it was before, and if you have the lights on (I usually run with my lights on), it is not noticeable.  Good Luck, TomC