Batteries not holding a charge

[kenz5380]

That last post sounds kinda funny cause I was originally thinking of starting a new thread, but then everyone would lose out on the background here. Also, I don't know how to test the starter. It is a brand new unit that came with the truck (uninstalled) If anyone has some input on how to test it I'd appreciate that. I guess I would just put the amp meter on the starter where the main power cable connects and have someone turn it over. Does that sound right?

 

[kenz5380]

I also forgot to mention that I took the batteries in and they both tested fine.

 

[kenz5380]

Guess I'm on my own with this one

 

[Warthog]

Did you ever remove the feed wire from the single wire 24v alternator and test to see if the batteries drained overnight?

One of the reasons no one is responding is because of the way the alternayor is wired. Not many peopel do it that way and don't know how to answer the question.

With only one 24v alternator and drawing 12v from the front battery, you have created an inbalanced load. The alternator doesn't know how to recharge the batteries. You may want to look into an battery equalizer.

Each battery have 6 cells that provide 2 volts each. You are drawing voltage from only 6 cells of the 12 total. The alterntor can cook the 6 cells from the rear battery and undercharge the 6 cells from the front battery.

You need the proper equipment to truely test the starter. An alternator/starter rebuild shop can do it.

 

[Ferroequinologist]

If one battery is undercharged it won't start the truck. This happened to my M818 one day. Only had two batteries in it instead of 4. The intake heater is 12v, so it is hooked to only one battery. I drove it all day and someone had turned the heater on- I didn't notice. Went to restart the truck later, and nothing. Got out the meter, and I had 6.5 volts on the one battery and 18.3 on the other.

At this stage of the game, with all the other wiring issues, I would recommend going to just a 12v system

 

[kenz5380]

This has been really helpful, I never thought of the imbalance. I'm going to do some more investigating and report back.

 

[kenz5380]

So it's been a while, but I think I finally got this thing licked. With the help of all of you guys I came to the conclusion that I had a battery imbalance caused by my use of a single 24v alternator in place of the two alternator setup while still using a sizable 12v load with all of my trucks accessories. It took a while to track down a battery equalizer within my budget of $0, but eventually my buddy, a heavy equipment mechanic, found one for nothing off a piece of equipment they were parting out. I wired it up per the manufacturers specifications and bam! the truck works! I appreciate all of your help, I would still be scratching my head without it.