Vampire drain on chassis battery

[mmartin_tdc]

They are probably doing the same thing I do, which is to look at the recent discussions on the right of the screen. They don't tell you which sub-group they are in, and unless you look at the header, once in the post, you may not know it is a FR3 sub-post.

[PenJoe]

Originally Posted by Larry-NC

No kidding! DW's new-to-us 2015 GMC Sierra 2500HD has a 120 mA drain once everything has gone to sleep. I've been tearing my hair out for a month trying to find it.

In a previous post, I mentioned our 2013 Silverado parasitic draw. A fully charged battery would not have enough charge to start the truck in about 2 days. Trips to two Chevy dealerships and two trips to an electronics shop did not solve the problem. I believe the two dealers responses were we can't find anything wrong.

Our Silverado is equipped with a dome light that come on when a cab door is open. When the door is closed, the dome light remains on for a time, then slowly fades to off-or so one would think. I turned the dome light off at the dash switch and voila-no more dead battery.

[rk06382]

Originally Posted by vacationlovers

It's a 10-month-old Diehard Platinum AGM.

I would check the dimmer switch. The overhead spotlights could be on.

The SDC-107A in the battery compartment should also be checked. It has power from the chassis battery.



I hope you find your battery drain. Please update when you find it.

[RVwino]

Originally Posted by vacationlovers

Does anyone know what is draining my chassis battery (not the house batteries) in about three weeks?

No idea. I've fought this problem with every motorhome I've owned and gave up trying to find the cause.

I keep the motorhome at a covered storage that's 40 minutes from my home. So, the solar doesn't help and there's no place for me to plug it in.

As a workaround, I bought a solar battery tender with battery terminal connections. I wired it up and then attached it to the inside of the front grill with black zip ties. It works for me.

[vacationlovers]

Originally Posted by rk06382

I would check the dimmer switch. The overhead spotlights could be on.

That's a good idea, but I'm 99.9% sure that I would've noticed them being on.

Originally Posted by rk06382

The SDC-107A in the battery compartment should also be checked. It has power from the chassis battery.

Thanks for the tip. I downloaded the Test procedure, and I'll do that next time I go over to charge the batteries.

[willykel]

My 2003 Duramax started doing that about 4 yrs ago. ended up pulling fuse to radio and solved problem. have thought about putting in switch just to turn off radio all of the way but it is kind of nice not having the noise. It would drain batteries in about 3 days.

[Ntantillo]

I had the same problem on my 2017 Georgetown. After putting in new batteries and having to put a charger on it after 3 weeks I had a cutoff put on the coach at the chassis battery closet. Turned off the chassis when I parked and never had a problem again.

[rk06382]

Originally Posted by Ntantillo

I had the same problem on my 2017 Georgetown. After putting in new batteries and having to put a charger on it after 3 weeks I had a cutoff put on the coach at the chassis battery closet. Turned off the chassis when I parked and never had a problem again.

I installed Two (2) Blue Sea battery switches.

1. A ON/OFF switch to disconnect the Battle Born battery bank on the left.
2. A 4-way Dual Battery Switch near the SDC-107A to power the steps from the chassis battery in the winter when it is below 32F.

[poihths]

If you don't read any of the other forums, you're probably missing out on great information. Different makes and models of RVs still have a lot in common.

[vi11agep]

Had that problem with my MB Sprinter. Discovered it has a battery disconnect just above the gas pedal.

[FollowTheSun]

If you have solar panels on your roof, then your house batteries will always be charged while the motorhome is waiting for your next trip. In this instance, you can then add a device called "Trik-L-Start" to also keep your chassis battery charged. I have Prism on a Sprinter 3500 Chassis. I have 200-watts of solar on the roof which keeps all of the batteries charged when not otherwise being used.
Your next step, which relates to your question, is to troubleshoot the quiescent current drain from the chassis battery. (See Next Post)

[FollowTheSun]

Troubleshooting the source of quiescent current drain requires an amp-meter (milliamps), patience, and persistence. A pen and notebook will also be helpful. Note the term quiescent in place of the term parasitic. Quiescent implies that the current drain is part of normal operation of your vehicle system while in a standby mode, whereas parasitic implies an unexpected or defective load. (Terms not really important at the moment.)
The troubleshooting process consists of connecting an ammeter to the battery and then disconnecting circuits until you identify the culprit circuit(s) causing the quiescent load.
Probably the most difficult part of this procedure is keeping the multimeter within viewable range of your work area. One solution is to use a couple of long wires (a power cord will work) so you can keep the ammeter near while remaining to connected he battery. A better/easier solution is to use a Bluetooth connected clamp-on ammeter.

1. Switch everything off so that the vehicle is resting in the state you normally leave it when your battery drains.
2. i. If using Wire-Lead Multimeter: Disconnect the negative battery cable from the battery. Connect the leads from the multimeter (set to read “Amps”) between the battery negative terminal (red lead) and the battery cable lug (black lead). Note the quiescent current, if reading less than 1 amp: set multimeter to read “Milliamps” and record this value in your notebook.
   ii. If using Bluetooth Ammeter: Clamp meter to negative battery lead.
3. Locate the vehicle fuse center(s). Once located you might want to take a photograph of it and record a sketch of it in your notebook. Also search on-line for schematics/wiring diagrams for your vehicle. You may need these to help trace within the circuit once you identify the culprit.
4. At a vehicle fuse center – one step at a time, remove a fuse, observe the ammeter, replace the fuse. Go to next fuse. Each time you remove a fuse, record which fuse/circuit and the ammeter value. When a fuse removal causes the ammeter value to change, then you have identified a culprit. However, continue the process until you complete every fuse circuit, or until you account for the total quiescent current drain.
5. If step 4 fails to identify culprit circuits, then refer to schematics/wiring diagrams and continue the process by disconnecting/reconnecting other circuits/devices that are not a part of the vehicle fuse center(s).

The important thing is to be methodical and meticulous. Once you identify the culprit circuit, continue the same disconnect/reconnect process through each device connected to that circuit.
In the end, I suspect you will identify items that need to remain a drain on the battery.

[vacationlovers]

FollowTheSun, thanks for your detailed instructions. Being a retired engineer myself, I have the tools & skills to do what you recommend. However, being retired and lazy, I was hoping someone on this forum might have already done the work!