24V overcharging? (1 Viewer)

[Mongrel]

I changed my brushes in my alt last night as they were a little short.

Now my truck is 12HT 24V system and the voltage used to read at 28V while at 2000rpm, now its reading 32V! is this too much?

Voltage reg is solid state and is part of the brush assy.

One of the wires did arc while I was reinstalling .

 

[iron_giant]

Per FSM, an externally regulated alternator should charge at 27-29 volts and an internally regulated should charge 27.9-28.5. Are your number from the voltmeter on the dash or from a seperate volt meter tool?

I've only ever adjusted an external regulator by bending the tabs to get a specific voltage.

I'd imagine that you may have an overcharging conditon that will damage your batteries. That's sixteen volts each!!

 

[phoenix60]

I changed my brushes and ic regulator (internal) on my 88 12HT and am now experiencing overcharging as well. only about 28V though on factory dash gauge. reads 24V before stating the engine, engaging alternator. I changed back to original regulator but same result. I had thought the belt was a bit loose and tightened it as well. Maybe I should loosen belt tension a bit?...

 

[Koffer]

28v sounds about right , 13.8v per battery when running is good so I say your fine

 

[bigboss]

some of the denso and hitachi alternators do have a function to send the charge rate upo if a(sense) wire is lost that is a seperate power feed be it ignition or main feed then sends it into over volt it it not good for your batteries obviously could you post a couple of pics or the numbers of the alt and the coulers of the wires . the one other thing it coulde be is bad connection on the battery term or even a sulfated battery this is when you have to tricle charge the batterys for about 24 hours at about 2amps each to solve this issue

 

[123456]

28v at high idle (RPM) is fine for a 24v system you don't want to go much higher .

 

[phoenix60]

Checked it again this morning. Batterys have 24.5V at rest. 27.88 at idle and 27.67 at load. Those voltages seem fine (are they) but the lights stay lit on dash for are turbo green, amber and battery light. Any ideas? Before new brushes, turbo green worked normal, and battery light came on with turbo amber light, intermittently.

I was able to grab a used relay at 4Wheel Auto this afternoon. Changed that (once I found it hidden behind a kicker panel beside throttle pedal...) Started it up and light problem seems to be fixed. I still need to road test.