Truck ran and then drained the batteries. Help me out here

[koltin]

good then I pulled the correct one.

 

[doghead]

The diode (if one is bad) can be one of the 3 in the diode trio or any of them that makes up the rectifier.

 

[koltin]

The rebuild kits from the other threads would take care of it right? I was just going to rebuild both generators.

 

[koltin]

I got it tested at oreilly's and it didnt pass.

 

[koltin]

Soo the truck is still down. rebuilt alternators... guess that wasn't the problem. I was doing another parasitic draw test today and it drained the batteries while I was testing it... about 25 min. both alternators unhooked. I can't seem to figure this out... the weirdest part of the whole thing is that the truck had battery before I started the truck that day, and then after i started it, it drained the batteries, and has been doing so ever since. When I disconnect the 12V buss I have hardly any draw on the multimeter. But like I said, in the time It took to do a parasitic draw test, the batteries were dead. Pulling fuses doesnt seem to make a difference.

 

[ranchhopper]

I live near you and have had many CUCVs I could come by tomorrow and make sure everything is hooked up right and maybe we can figure it out call me at 847-468-9676.

 

[tobyS]

Contacts in high draw applications can sometimes weld closed. I service motor starters where that has happened. They will not turn off. Check that the contacts are not welded closed where the spring will not push them open. Even old grease can make this happen. It would show up as a closed circuit on the relay that provides battery power to the buss. On motor starters I remove the arc damage and flatten the silver contacts to get some more life out of them if not too bad. I would be looking for a weak or rusted spring also that returns it to the off position. In any case, if it is not opening you will read a closed circuit when it is supposed to be off (open circuit).

 

[koltin]

@ranchhopper, i tried to call you yesterday, no answer left a message. I feel like if its anything that has failed it would be a solenoid to the glow plugs, but I dont know where to test that. and I dont think it would effect the 12v buss because the glow plugs are still 24V

 

[tobyS]

Koltin....have you checked continuity across the contactor? Is it staying closed when it is turned off?

 

[Warthog]

Remove the 24v power lead to the GP relay and test for a drain.

That is what you will need to start doing. Disconnect each source of electrical draw until you find it.

Some of the items that come to mind:

horn
heater fan
GP relay
voltmeter and relay
GEN1
GEN2 and relay
etc.....

 

[koltin]

@tobyS Which contactor?
And thanks warthog, Ill be back working on it tomorrow.. its just so cold here it sucks to work on the truck.

 

[Warthog]

Watch your language. The F-bomb will get you in trouble.

 

[ranchhopper]

Had to catch a nap yesterday I was out plowing snow all night had the phone turned off.

 

[koltin]

Its all good man... Youd be doing me a huge favor anyway no worries. and sorry warthog.. I sensored it myself it that makes any difference. wont happen again

 

[tobyS]

Warthog said the contactor (relay) for the GP is "know for failing closed". He suggests testing it.

If you check for continuity across it with an ohmmeter, you can see if the contacts are opening and disconnecting it from the battery power. If not, it would explain the heavy draw of current that drains them. Of you can check voltage. If there is voltage on the buss (or output side of the relay), then it is not opening.

Sometimes relays can be repaired but it may be easier to replace it as mentioned above.

Living in North Indiana I understand the frigid weather. I didn't see any mention of how one would tell if it had failed closed, so offered it. Good luck.

 

[koltin]

Noo sorry if that was taken as me cursing you for asking if I checked it was total miscommunication. I was just saying that it was real cold, I have a tendency to use explicit language in my everyday talking. Thank you for your input. I honestly havent checked much of anything past the 12V buss wire because when i pull the wire there, the parasitic draw drops considerably. I wasnt able to figure out where that last wire from the 12V buss goes to. Ill check the GP relay first thing tomorrow.
I

 

[tobyS]

If you don't need the truck, why not wait until it's a bit warmer? The next few days are supposed to be frigid. Are you dependent upon this truck running?

If you do wait, I suggest you disconnect the batteries and get a charger on them, even if you have to reconfigure for 12v (parallel connection). Batteries setting dead through a very cold spell can entirely ruin them, never to come back. Been there, done that. Only took one really cold night.

 

[koltin]

I pull them every time I recharge them. I thought about getting them tested but they're literally about 2 months old. It's my DD I've been freeloading off my family for the past couple weeks and it kills me to have to ask them for help. But yeah tomorrow is supposed to be 15, which is slightly better than 5 which we had today. Hope I can stand it long enough to test the things that I need to.

 

[koltin]

Update: Got the alternators back in, batteries hooked up, started her up and it ran at idle for about 30 min when I shut it off. The Voltmeter definitely Isn't working, it started up and ran anyway

 

[koltin]

Looks like im changing the voltmeter tomorrow/ soon so i can park it without disconnecting the batteries.