M915 and electical drain

[Bighurt]

Mine's been draing the batteries for ahile now. I really need to put a disconnect on the system and add a solargizer to the truck.

What I found weird was that it's only killing the forward two batteries, the others are running 12.39 volts the dead ones are dead at 10.69 volts.

I found the procedures in the -20 to identify the bad component if any that's causing the drain. However I still feel the cut-off is a good idea.

Just curious if anyone has done so already, and where they mounted the kill?

Also any ideas on what may be drawing the voltage? Everything is off, even the J bar (open).

 

[NDT]

Are you sure they are getting a charge? Your transformer-rectifier could be bad.

 

[Danl]

Danl M915A1

in your dash were the breakers are located is the starter cilernoid open that up, your main line is there frist. thats is were you need to put your kill switch. but a kill switch is a bandaid. ther is something drawing or not charging. the kill switch hidden in the dash is more for anti theft .

 

[Bighurt]

Are you sure they are getting a charge? Your transformer-rectifier could be bad.

I'll test it, but wouldn't that effect both groups, not just the forward group?

Testing the Transformer rectifier is direct support maintenance but I can't find it in the -34?

I didn't realize it was a 14 volt alternator.

 

[JH1]

I have a plain Jane M915, except mine is 100% 12v, starter and all. A possible drain on your batteries might be the starting pushbutton switch on the dash. This seems to be a common problem on deuces, too. The problem is that every time you push and release the button, the inductive kickback from the starter solenoid creates a small arc inside the pushbutton. That leaves a thin deposit of metal inside the switch on the normally nonconductive plastic. After enough of that, there is a slightly conductive path to ground and that will slowly drain batteries.

A master disconnect switch is always a good idea, especially at shows, where someone may hop in the cab and push buttons. Happened to me but I got them out of the cab before they rolled over any bystanders. Not as big an issue with the Cat tranny or Allison Auto, but still there.

Jim

 

[NDT]

I'll test it, but wouldn't that effect both groups, not just the forward group?

Testing the Transformer rectifier is direct support maintenance but I can't find it in the -34?

I didn't realize it was a 14 volt alternator.

The transformer-rectifier charges the forward two batteries all by itself. Very slowly I might ad, at 15 amps or so. After starting the truck, the battery voltage will very slowly creep up to 13.8 or so, but will be greater than the voltage when the batteries are resting.

 

[Bighurt]

The transformer-rectifier charges the forward two batteries all by itself. Very slowly I might ad, at 15 amps or so. After starting the truck, the battery voltage will very slowly creep up to 13.8 or so, but will be greater than the voltage when the batteries are resting.

Alright that makes sense...

Any suggestions on how best to test the transformer rectifier?

 

[Danl]

Danl M915A1

Good ? I'll sit in and hopefully find out too

 

[codyharper15]

What are the stock batteries that come in the m915a1's?

 

[Bighurt]

6tl

 

[Ferroequinologist]

The clock in the tach takes power continuously. I have Group 31 batteries in mine, the NG put those in.

I know for a fact that my alternator isn't working right, but I have yet to find a replacement.

 

[doghead]

The M915 uses a 100 amp J-180 long hinge frame.

Google J-180 mount, to find replacement options.

 

[Ferroequinologist]

Thanks for the info DH, I guess I should clarify my statement!

I know for a fact that my alternator isn't working right, but I have yet to find a replacement.

Should be-

I know for a fact that my alternator isn't working right, but I'm a cheap bastard and don't drive the truck a lot anymore, so I've been waiting to find a super cheap or trade for replacement.

 

[Hooty481]

So I have just had this problem come up my self. When I purchased my truck from Andy1234 in Missouri he only had 2 batteries on the truck which started the truck just fine. Even through the winter here in Kentucky they started the truck with no problems.

Last week I jumped in there to go some where and all I got was a click. The volt meter said 12v or so. All that was clicking was the starter solenoid. I jump started the truck with my pickup truck and I noticed that only one battery was low. The front battery. So it fired up just fine and away I went. The gauge said the truck was charging just fine. The truck run for about an hour and when I got back home I shut her down. Just wanted to see if the batteries had charged up and she had because she fired right up.

2 days later I got in her and had the same problem. Went for a good trip that day got to where I was going I shut her down while I was loading. Got back in her about an hour later and she was dead. So I got a jump there and I left her running the rest of the trip until we got back home. I put a battery tester on the battery and it read a little over 10volts. I hit the load button and it bottomed out all the way to 0v. I put a battery charger on it for about a hour at 10amps came back and run the test again. Had the same voltage and same results when I put a load on it. So battery is bad now.

Has any one else came up with any answers.

What replacement batteries would you recommend.

 

[mdmorgan]

Let me start by saying "I am NOT an electrician in any form of the word, but I try." That being said, I too am having battery drain issues on my M915a1, but mine are the back 2 batteries that are draining, I have 2 solargizer kits installed, 1 kit for each 24v bank (the inboard 2, and the outboard 2), are the back 2 the 12v side? Which wire should I break with a shut off switch? Thanks for any insight.