2655 Cab shuttle phantom current draw - Any ideas?

[OldTrix]

I have a 2019 2655 Cab shuttle with about 210 hrs on it. The tractor has been working great. On my last trip north (VT), I discovered the battery was dead flat, wouldn't accept a charge. I wrote it off to the cold weather and put in a new battery. Blew off the driveway and did some other timber work and parked it.

2 weeks later, I'm back up north and the same thing. The battery was flat and had obviously frozen. Another battery...

The tractor is charging, I get about 14.3/14.4 volts while running. Turn it off, and the voltage begins to trickle down slowly.

An ammeter between the battery and harness reveals about an .85A draw. I pulled every fuse in the panel under the instruments, no change. pulled the relays and 40/50a fuses next to the air cleaner. nada. Still the same parasitic draw.

I assume I have a harness chafing somewhere, unless I've missed a fuse or relay of which I'm not aware. Has anyone encountered this problem on this model? Any likely places to look first? I was thinking alternator, but the charging voltage looks OK, and I would suspect it would show other symptoms.

The shortstop fix is to disconnect the battery while it's idle. I'll begin chasing wires when it gets warmer outside.

Any ideas?

 

[3gunr]

My cub cadet always did that until i figured out it was a switch for the lights , It had to be in a certain position even with the lights off. My mahindra 2810 has a seperate kill knob and if you dont turn the key off it will kill the battery, My neighbor has done this to me several times after using it. How about a radio or cab lights that are staying on.

 

[duffer]

Could be any # of things. Cab accessories, ECU, an after market accessory you installed (if any), and on and on.

Easiest fix might be to install a battery disconnect switch. Almost all of the farmers have one on all their tractors. Especially with a cab, there just seems to be so many things that could cause the draw, along with what you outlined.

 

[OldTrix]

The radio is powered with the ignition, but I powered it down and removed the faceplate to be certain. Just weird, working fine one day, draining the batt the next. I'm more concerned there is a harness chafe somewhere, as that could turn ugly if it worsens while in use.

I guess I need to find a wiring diagram somehow so I can chase a few more possibilities. Anyone had any luck finding one?

 

[mwayne]

Have you checked for a bad diode on the alternator?

 

[5030]

If it has an ECM it's the ECM that is draining it. They require constant current and a minimum of I think 9.5 volts to stay alive. I'd be putting a tender on it or a solar powered maintainer.

Far as buying a new battery and dropping it in, bad idea. Always trickle charge a new battery for at least 12 hours before installing.

 

[OldTrix]

Have you checked for a bad diode on the alternator?

That is on the list to check. It seems unlikely, as the voltage looks good while running, but it could explain the current leak.

 

[OldTrix]

If it has an ECM it's the ECM that is draining it. They require constant current and a minimum of I think 9.5 volts to stay alive. I'd be putting a tender on it or a solar powered maintainer.

Far as buying a new battery and dropping it in, bad idea. Always trickle charge a new battery for at least 12 hours before installing.

I don't think the ECM requires nearly an amp of current to stay lit. Usually those draw milliamps. And why would it now suddenly start pulling that amount of power?

Yes, I charged the battery overnight before starting. Like I said, unexpected new issue, so I now unhook the battery and keep the tender on it while I'm gone.

 

[5030]

I don't think the ECM requires nearly an amp of current to stay lit. Usually those draw milliamps. And why would it now suddenly start pulling that amount of power?

Yes, I charged the battery overnight before starting. Like I said, unexpected new issue, so I now unhook the battery and keep the tender on it while I'm gone.

What I did with both of my pre 4 tractors when they sit in the barn is, I added a knife switch disconnect to the negative battery post that isolates the battery when not in use. Like 25 bucks at any auto store.

I think I'd use a multi meter and measure the current consumption the ECM is pulling to be sure.

 

[OldTrix]

When i get back up in a week or so, I plan to pull the ECM plug and note the difference in current draw. I'm also going to disconnect the alternator and see what happens. I'm leaning more toward a bad diode, but will need to confirm.

 

[OldTrix]

Well, if I unplug the alternator, I still have a .8A current draw. I guess I have a relay stuck somewhere, or something else going on. I'll just do the knife blade switch thing and wait for the smoke to get out to find the problem.

 

[OldTrix]

Well I went ahead and installed a cutout switch on the battery. After some digging around and tracing things back, I discovered the issue- The dome light. It is a push on/push off type unit, and I had used it for the first time the other night when I was blowing the drive as arrived after dark. Apparently, pushing off was turning off the light, but wasn't shutting off the current flow. Some sort of weird leak. sorted now.

Current draw when key is off is now zero. The ECU is also off, by the looks of it, until you turn the key on.

Mystery solved.