Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 08-08-2013, 05:43 PM   #1
Junior Member
franknslots's Avatar
Join Date: Dec 2012
Posts: 11
How long will starting batt's last when swithched off?

Newby here.

I have a disconect swith in the engine compartment, when swithed off there should be no parasitic drain on the starting batteries. Any ideas on how long I can store the rig and still get it started?

Frank & Janet 04 Fleetwood Revolution 40C
350 Cummins
07 Jeep Sahara Toad
franknslots is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-08-2013, 07:09 PM   #2
Junior Member
Newmar Owners Club
Ford Super Duty Owner
Join Date: Sep 2011
Location: Overland Park, KS
Posts: 27
How long will battery hold charge

If there is NO parasitc drain, including the battery installed, not sitting on concrete (which can drain a battery), then the time will depend somewhat on the age, condition and original quality of the battery. If you use nothing but distilled water to top the battery off, to reduce the calcium in the battery fluid, it would help. You can be pretty sure that with a strong battery you will get 90 days, maybe even 120 days. After that it becomes a game of luck -- with luck it might even last 6 to 9 months, but without a "top off charge" you are in the range of "who knows" -- individual batteries might hold a charge longer, but don't count on it.

Chuck in Kansas City
1996 Newmar Kountry Aire
38' class A Motor Home
ChuckinKC is offline   Reply With Quote
Old 08-09-2013, 03:56 PM   #3
Senior Member
Playtime III's Avatar
Holiday Rambler Owners Club
Join Date: Oct 2012
Location: Tampa FL
Posts: 477
I would be shocked if there were no parasitic drain even with the shut off. Several items on my coach and chasis are routed around the shut offs (CO detector, radio memory, ECM, etc.).
2006 HR Scepter 42DSQ
Playtime IV
Holiday FL
Playtime III is offline   Reply With Quote
Old 08-09-2013, 04:13 PM   #4
Senior Member
GaryKD's Avatar
Newmar Owners Club
Join Date: Jul 2006
Location: Wellington, Florida
Posts: 11,772
Hi franknslots,
A battery, in storage, will loose 1 to 3% of the battery's power each month of storage. In a motor coach, there will almost always be some parasite drain.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours
GaryKD is offline   Reply With Quote
Old 08-09-2013, 05:09 PM   #5
Senior Member
Pigman1's Avatar
Join Date: Sep 2011
Posts: 1,644
Pull a ground cable off to be sure there's no parasite drain. The battery in my car that I leave when we are RVing for 3 1/2 month starts my stay at home car fine, and I don't disconnect the battery.
2013 Tiffin Allegro Bus 43QGP
2011 Chevy Silverado 1500 Toad
Pigman1 is offline   Reply With Quote
Old 08-09-2013, 09:21 PM   #6
Join Date: Jul 2013
Posts: 68
No one can say how long. I left my car for two weeks and it wouldn't start. My 1990 Triple E sat for 7 months through a dang cold Canadian prairies winter outside with the battery disconnected via the switch in the coach, and it started like it was a brand new car. A good battery should last for quite a long time.... or it may not.
Raist11 is offline   Reply With Quote
Old 08-10-2013, 09:28 AM   #7
Junior Member
Newmar Owners Club
Ford Super Duty Owner
Join Date: Sep 2011
Location: Overland Park, KS
Posts: 27
How long will batteries hold charge

There is another issue to consider. If you don't take special care to "pickle" the engine for longer term storage, then leaving the coach (and the generator engine if you have one) without starting it for over 60 days will cause rust to start forming on the cylinder walls and in the crankcase area of the engine. This might be worse in a "sea side" environment and better in a desert environment. Most of the owner's handbooks that I have seen suggest that you start both engines every 30 days during the off season to keep the engines in good condition. Since you would want to run the engines long enough to bring them up to operating temperature, in order to boil off the water in the oil that starting creates, you will charge the batteries when you do the maintenance run of the engines.
Chuck in Kansas City
1996 Newmar Kountry Aire
38' class A Motor Home
ChuckinKC is offline   Reply With Quote
Old 08-10-2013, 01:40 PM   #8
RV Mutant #14
Wayne M's Avatar

Winnebago Owners Club
Texas Boomers Club
Freightliner Owners Club
iRV2 No Limits Club
Join Date: Aug 2008
Location: Texas
Posts: 11,244
Besides parasitic drains being present when wires are connected, there can be a parasitic drain across the top of the battery. Dust, dirt, debris are all conductors and can cause current to flow ever so slowly across the battery top. If you presently have a dirty battery top, use a volt-ohm meter in the amp position and touch the probes to only the case near each of the posts.

So, clean the batteries regularly besides disconnecting them. If you use a disconnect switch that you install you can isolate all RV parasitic but be prepared if you have computers that you may have to reload software.
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2008 Winnebago Destination 39W
It is what it is, and then it is what you make of it.
Wayne M is offline   Reply With Quote
Old 08-11-2013, 10:30 AM   #9
Senior Member
elbeau54's Avatar
Join Date: Mar 2012
Location: timmonsville sc
Posts: 116

Has anyone tried one of the chargers that plugs into cig lighter as a trickle charge
elbeau54 is offline   Reply With Quote
Old 08-11-2013, 11:48 AM   #10
Senior Member
Tony Lee's Avatar
Join Date: Sep 2012
Location: Peru heading for Brasilia, Brazil
Posts: 1,875
including the battery installed, not sitting on concrete (which can drain a battery)
Might be somewhat outdated advice.

Has anyone tried one of the chargers that plugs into cig lighter as a trickle charge
Most are too small to do a lot of good but do help - provided the lighter socket is live when the ignition key is removed.

If you have a way to keep the house battery charged, then adding a Trik-l-start will solve the chassis battery problem
Tony Lee - International Grey Nomad. Picasa Album - Travel Map
RVs. USA - Airstream Cutter; in Australia - MC8 40' DIY Coach conversion & OKA 4x4 MH; in Germany - Hobby Class C; in S America - F350 with 2500 10.6 Bigfoot camper
Tony Lee is online now   Reply With Quote
Old 08-11-2013, 01:32 PM   #11
Senior Member
VanDiemen23's Avatar
Join Date: Oct 2010
Posts: 726
I got tired of chasing all the issues with systems that charge the chassis battery when the house batteries get "full". of course when the house batteries degrade and you take into account the voltage drop across some of those follower chargers the chassis battery doesn't get much.

I just bought a schumaker trickle charger, mounted to the inside of the engine compartment and tied it in to one of the 115 outlets that's NOT on the inverter when not plugged in (that way you don't burn house batteries charging chassis batteries).

However, if the tops of the batteries are clean and the ground disconnected, there's an easy way to calculate the amount of time the batteries should be viable. There should be in the manufacturer's specs a listing for internal resistance and a self-discharge rate. If you know about how many amps the starter motor draws, then you can calculate when the drop across the internal resistance pulls the batter voltage down below the point where the ECU will reset. At that point, you're done.

Practically though, you really only need enough juice to fire up the generator first. Then, once that is running, tie the house batteries to the chassis batteries and most of the time it will start.

VanDiemen23 is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:02 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.