Why are My Main Batteries discharging when the Rig is parked.

[Tuney]

I have an '04 Winnebago Journey DP.  There seems to be an ongoing problem with the MAIN Batteries discharging while the rig is parked, even just for a couple of days. Output drops by something like .25 to .5 volts per day according to the monitor panel.  The house batteries are fine.  I'm always connected to shore power when I'm at home or in a campground, and I have a solar charger on the roof as well.

I admit We've only been RVing for a little less than 2 years, and I haven't learned all the ins and outs of this machine yet.

 

[Steve CDN]

Welcome to the RV Forum!  Do you know if your chassis (starting) batteries are charged while plugged into shore power, and/or to the solar panel?  Not all manufacturers do both.

You may want to have a competent dealer or even better if Winnebago has factory service have the company techs check this out.  If your problem cannot be located by routine testing for a faulty circuit, your problem may lie in one of the computer controlled,  battery control panel circuit boards.  A faulty circuit board can drain a battery if no other circuit is at fault.

 

[fredethomas]

Many motorhomes do not charge the chassis batteries when parked without power.  Some do - our Dutch Star does using a small solar panel.  Our 1994 Bounder did not and did not even recharge from the genset.  Had to jumper the two battery sets together.

 

[Ron]

Usually the batteries are charged while on shore power.  I am not sure how Winnebago does it but a call to them may confirm the design operation.  I understand that some coaches do not charge the engine batteries when on shore power.  Our Eagle charges both battery sets whether on shore power, generator power or driving.

 

[Jackliz]

Welcome to the RV Forum!!

In our previous coach, a 1995 Serengeti, the engine batteries were given a trickle charge by a small solar panel. Didn't work too well, so we ran a jumper from the house batteries to the engine batteries. The house batteries were charged by our inverter/converter when we were hooked up to shore power.

Now in our present coach, a 1993 Blue Bird Wanderlodge, there is a rocker switch on the dash, labled auxilliary battery. One of the switch positions allows the engine batteries to be charged by the battery charger.

Regards,
Liz

 

[Steve CDN]

If a motorhome is designed so the chassis batteries do not charge from the converter, is there a risk of overloading the converter or affecting the charge rate of the coach batteries by installing a jumper across the chassis battery?

 

[Ron]

On the American Eagle, American Dream, and the American Tradition both the house batteries and the chassis batteries are charged no matter if on shore power, generator power or while driving.  If on shore power or generator power the house batteries have priority and will be charged when ever required.  When the House batteries are fully charged then the engine batteries will be charged if required.  When driving the chassis batteries have priority and will be charged as needed.  When the chassis batteries are fully charged then the house batteries will be charged if needed. This is all accomplished automatically.  These coaches all have a inverter and a three stage battery charger.  From what I was told the Country Coach motorhome have a similar system.  I don't recall exactly what the 93 Bounder had but we never had a dead battery or did we ever have to replace a battery in the 5 years we owned it.

 

[Tom]

... is there a risk of overloading the converter or affecting the charge rate of the coach batteries by installing a jumper across the chassis battery?

Steve, good question. Instead of merely jumpering battery banks containing different battery types, I'd suggest folks consider using a batter isolator which allows two or more banks to charge without one bank impacting the other. These are available at Napa and other auto parts stores. One of these was standard equipment on our prior Pace Arrow.

 

[Gary RV_Wizard]

All this discussion about charging begs the question of why are the chassis batteries discharging rapidly while parked and idle.  Initially I can see a fall-off of 0.5V as the batteries lose their surface charge (typically around 13.7 volts) and drop back to the  more normal 12.6-12.7 volts.  If they continue to drop below that, at a rate or more than 0.15 volts per day, I would say that something is wrong.  The most likely culprit is an accessory connected to the chassis batteries rather than the house circuits, but it could be a failure in one of the circuits which is supposed to be on the chassis system.  I'm not sufficiently familiar with Journeys to describe what all those may be may be, but the electric steps are one such thing in most coaches. Perhaps the under-step light be remaining on?  Alarm systems are another item sometimes on the chassis power system.

 

[caltex]

The Journey does seem to have a fairly heavy passive load on the batteries, everyone seems to complain about it.  On my '04 Journey there was no charge to the batteries except for the alternator, so when I was camped I kept a battery minder on the chassis batteries.  Also there seemed to be a lot of bad batteries, I had mine changed twice by the dealer under warranty.

 

[Jackliz]

All this discussion about charging begs the question of why are the chassis batteries discharging rapidly while parked and idle.

Very good point, Gary.

Regards,
Jack, RETIRED

 

[Treeman]

Another discharge oddity;
I had the same problem with an unknown discharge. I used a voltmeter to check between the pos. terminal on the top of the battery near the neg. terminal. I got a read-out of two volts! Seems that the combination of road grime and battery acid from an over-fill, will set up an unseen discharge path.
A baking soda wash helped, but I eventually had to replace the battery.
Just my 2?
Best,
Treeman