charging system help (kinda long)

iron_giant

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keep in mind that this a 24volt system (hj60)- different numbers same principles. I have been getting very low (24 volt and sometimes less) charge at idle. The charging seems sporadic, sometimes charging at 28 volts at speed, and then suddenly at 26volts for a while. I don't get a decent charge until 1500-2000 rpms at best. Turn the headlights on and the charge drops a lot (at idle it drops to 24 volts), turn them off and half the time it stays down. What I have:

Rebuilt alternator (brusher,stator, bearing)
voltage regulator passed all resistance tests at the connectors and looks to be recently rebuilt or new.
2 new optima red tops (discharged a few times-recently trickle charged back up)

Voltmeter at "B" terminal of alternator (FSM) large hot wire on alternator and ground shows 39 volts at idle up to 100 at any kind of speed.

Ammeter between same terminal and corresponding wire reads 7 ohms.

I cant figure out where I am losing the charge. Initially thought regullator but it seems ok. It does sometimes charge the full 28 volts.

any help is appreciated,
david
 

iron_giant

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just a thought. if i'm reading the manual correctly then the reading on the voltmeter when connected to terminal B and grounded should be 27-29v. i got 39-100 volts!! Did I do something wrong or perhaps the regulator is not working after all.

I connected the white wire to the B terminal and took some more readings:
engine off 24.57 volts
engine idle 23.75 volts
2000 rpm 25.14 volts
 
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iron_giant

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one more question. To adjust the external regulator the FSM says to bend the tabs thereby increasing voltage. Do I bend the tabs up or down?
 

Waggoner5

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This sounds like a regulator problem being that you have that kind of voltage coming out of the alt. I would not try to adjust the voltage coming out of the regulator. It is set where it needs to be set. I have seen many regulators go bad after losing an alternator. I have also seen a lot of guys not change the regulator out when doing the alt job only to end up doing it at a later date when the system still doesn't work properly.
 
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