battery in cab is going dead.

binycrna · 09-10-2016, 11:04 AM

Hello all. I am having trouble with my cab battery going dead. I have had our rv for a year now and just now started having problems. I just replaced the old one a month ago thinking it was just time. I just went out there a month later and the new one is dead again. I always keep it plugged in to shore power, so I dont know why it is draining the battery. House battery is fine. Any suggestions? I have a disconnect switch near door that i have never used before. Just FYI. Thanks for any input.

abarkl · 09-10-2016, 11:18 AM

If your RV does not include a connection from the installed charger to the cab battery you can install one of these to maintain it; Ultra TRIK-L-START Starting Battery Charger/Maintainer

The switch by the door disconnects most draws on the house battery but is not for long term storage.

Greyhawk01 · 09-10-2016, 11:32 AM

Start with the easy stuff making sure the doors are closing all the way, the lights(interior exterior) and radio are off etc. If no luck you can see how many amps are being drawn from the battery with everything off. You can do this with a (DVOM) Digital Volt Ohm Meter. Pretty much what you do is disconnect you negative battery terminal and and put your DVOM between the ground cable and battery terminal and check the draw. If it is excessive you pretty much start pulling fuses until the draw stops. When it stops you have found your problem area. You will want to research how to do this online as it has been a long time since I have done this and could be leaving something out. It will also be more complicated with a motorhome since Jayco has tapped in to the Ford wiring harnesses. Good Luck...

binycrna · 09-10-2016, 12:04 PM

Thank you. I think it is the radio but not sure why it took this long to drain the battery.

hoppers4 · 09-10-2016, 01:10 PM

The chassis battery can go dead after a month of sitting due to parasitic drain. Like you said, the radio would be one and believe it or not the transmission has some parasitic draw. Shore power doesn't charge the chassis battery. I use a Battery Tender to keep mine charged whenever my rig is parked.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I made my own plug so I could plug it into a cab power port without having to hook it directly up to the chassis battery.

binycrna · 09-10-2016, 01:31 PM

Thank you. Any chance you have a pic of plug you made. Definitely getting this.

hoppers4 · 09-10-2016, 03:27 PM

I just looked on Amazon and they now have these. The wire from the Battery Tender has a plug that will work with this.

https://www.amazon.com/BATTERY-CHARG...F4ED2ZAEE32GQ7

I didn't know about those when I adapted mine. So that's really an easy way to go.

binycrna · 09-10-2016, 03:36 PM

I saw these but am curious as to how you supply the AC power?

hoppers4 · 09-10-2016, 03:39 PM

My rig is plugged in all the time so I just plug the Battery Tender Jr. into an AC outlet over the cab. The wires that come with the Tender are quite long. I edited my previous post several times so go back a couple of postings to make sure you get my latest info. I also have a four way splitter so I can add other stuff to my power point plug such as chargers and GPS.

binycrna · 09-10-2016, 03:59 PM

Ok. Thank you.

LI-Camper · 09-10-2016, 04:02 PM

I use a Battery Minder also with a accessory plug that fits into 12V outlet in the dash. I plug it in the the same 110v outlet as the TV. As was previously said it works well as long as your MH is plugged in.

binycrna · 09-10-2016, 04:04 PM

okay great thank you. Did you run the wire from the battery through the cab to the cigarette lighter to make it a more permanent

hoppers4 · 09-10-2016, 04:48 PM

Sorry, don't understand the question. The cigarette lighter/aka power point is connected directly to the battery (via fuse of course) with no additional wiring. The power points in my cab are always hot irregardless of ignition switch position.

binycrna · 09-10-2016, 04:52 PM

If your power point is hot, doesn't it come from the cab battery? If so, is it ok to plug your battery tender in that? Also, how did you run the cable from the battery to inside the cab? Thanks. Sorry I am new to the whole electrical system of a motorhome.

hoppers4 · 09-10-2016, 04:56 PM

The power point is fed directly from the chassis aka cab battery. No need to run an additional set of wires. The power point will feed the battery. The wires don't care which way the power is going. The battery will feed the power point or the power point will feed the battery. Plug the Battery Tender directly into the power point which will charge the battery.

binycrna · 09-10-2016, 05:03 PM

so to clarify. the whole unit (the battery tender junior) stays in the cab connected via cigarette adapter to power plug? Nothing is wired to the battery correct?

hoppers4 · 09-10-2016, 05:24 PM

That's right. The Battery Tender is connected to AC power, then the 12VDC output of the Battery Tender is connected to the power point on the dash of the cab. This cab power point goes directly to the cab battery and charges it via the Battery Tender.

binycrna · 09-10-2016, 05:27 PM

ok great. so all i need is the tender junior and the cigarette adapter. Thanks Don for all of your help.

hoppers4 · 09-10-2016, 05:30 PM

No more dead batteries for you mon! I struggled with the problem on my first MH until I figured out the parasitic draw. I've been using the Tender for the last 9 years and have had no battery problems since.

binycrna · 09-10-2016, 05:49 PM

Amazon here I come.

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