CUCV charging system

[the skull]

My M1008 is 24 volts. I went through it and put the
voltmeter in it. Replaced the popped 28 volt fuse.
Made sure the block ground is good (it wasn't).
Had #2 alt redone by someone who KNOWS electrical, he
rebuilds alternators and starters, as well as the fact
that he's the diesel tech I trust. He is the best I know.
Anyway, I have 14.7 at alt 1. I have 27.6 at the
output on alt 2. BUT the guage on the dash is just
past the "tick" mark in the green. Normal? 2 new 31
batteries.Belts good and tight I'm pretty sure. I'm going to
drive it to work tomorrow, not really expecting disaster.
I think I'm going to go with the guage on this one.
Looking for comments on this. My diesel tech says to
convert it to 12 volts. But I'm not willing to do that, at
least not yet. If I have to I will take everything apart and
redo it I will, I just hate electrical work. Thanks

 

[Warthog]

27.6v puts the GEN2 output at 12.9v. Way to low

What are your voltages at each battery with the engine off and engine running?

 

[the skull]

I'll check tomorrow. I've checked it before. I thought maybe since the
voltmeter was in the green, it might be good. But common sense says
28-29 volts, I was afraid of that.

 

[Skinny]

Troubleshoot it using the manual. You also could have gotten a bad component installed during the rebuild. Anything is possible so spend quality time troubleshooting. I think you will regret doing a 12v conversion.

 

[the skull]

Warthog, voltages are
batt #1 12.6
batt #2 25.3
engine off

batt #1 14.6
batt #2 27.2
engine running after glow plugs are done cycling

Really not wanting to go 12v.
I should probably mention, (forgot) Gen 2 light didn't work at all til the
alternator was redone. Now, it does not light up when you turn the key.
But sometimes lights after startup, stays on until I shut the truck off.
Wife says I put the bulb in backwards when I checked it.
I'm really busy at work, and I have some other stuff I'm doing, so
I think I'm going to hold off for a couple days. I believe there is an
intermittent bad connection, and I just haven't found it yet. Like the
ground cable on the ground bus that had the cable, but no nut to hold it
on????

 

[the skull]

Skinny, Thanks. My diesel tech put the alt on his test stand after
he redid it, and said it worked just fine. He also said that it wouldn't
do anything before, and when he took it apart there was no way it
could charge anything. Makes me think it's on the truck side. I might
swap the alternators out #1 for#2 & see if the problem follows.
Give me a few days, I'll be back later. Keep the comments/suggestions
coming please. And I will be reading the manual.

 

[Warthog]

Check the voltage at the terminals of the batteries. running and not. Don't use the chassis as a ground. Looking for the "12v" reading on the rear battery

Also unplug the 2 wire exciter plug and check the voltage at each wire with the engine off and the in the off and the run position. Use the chassis as ground.

 

[the skull]

Thanks Warthog. I will. Didn't think about checking it like that.
In the Honda world I usually use chassis ground. Duh!