Chassis battery keeps going bad

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Dave Stringham said:
I am certainly not a battery expert but reading your post, it sounds like your batteries are going dead fairly fast.  I dont even know if the batteries you keep getting for free are the right battery for the application.

The one I'm getting is the biggest 12v car battery that Wal-mart sells, so I don't think that's the problem.  I'm guessing the drain time is around 3-5 days, but I never have tested the draw as you mentioned to know for sure.  As a contrast, the 2 6v house batteries were only about halfway drained after sitting for 3-4 weeks - so they are lasting much more than the chassis battery.


rsalhus said:
But why doesn't your MH charger/controller charge both sets of batteries normally when on shore power?

I wish I knew!  I would love to have that handy little feature.  But as Tom mentioned it's a feature that may or may not be there, depending on make and model I suppose.
 
Rather than using the cables between batteries there is a great little charger called a Battery Minder that will not cook your batteries. It is a 110v 2 stage charger that I have seen plugged into the RV's 110v system and permanently connected to the chassis battery. That way anytime the coach is plugged into shore power or running on generator the chassis battery is being maintained by the battery minder.

That was Monaco's fix for a 400k Holiday Rambler that kept running down the chassis batteries. ::) ::)
 
I use the BatteryMinder on cars and small boats to keep the batteries topped up without getting fried. Wish I had power at the coach when in storage so I could use a couple of BatteryMinders there.
 
Our coach like other American Coach products do charge the chassis batteries.  When parked and on shore power the house batteries are charged until fully charged then the chassis batteries get charged if needed.  When driving the chassis batteries are charged and when fully charged the house batteries will be charged if needed.
 
By way of explanation on the chassis charging question, it is desirable to keep the chassis battery(s) isolated from the house batteries so you don't run down the chassis battery overnight and get stranded with a no start condition.  That means that the manufacturer has to add some monitoring and a control system to determine when and if the chassis batteries should be charged from the house charging system.  Some manufacturers have provided this extra cost circuitry for years while others spent the dollars on something else they felt was of more benefit to most buyers.  And on lower end models it is likely left off simply to keep the price down. 

Winnebago and Monaco, to name a few, were late in  adding this nice feature while Fleetwood has provided it in most of their motorhome brands for many years. I won't debate the value judgment involved, but chassis battery discharge is not a common problem in motorhomes except in long term storage and many (if not most) owners don't have 120VAC available in storage anyway.  That is changing these days and so is the electrical load on the chassis battery as vehicles gain more and more electronic systems that remain active all the time. This is driving nearly all manufacturers to provide chassis battery charging in at least their mid-to-high end models.  The fact that electronics costs for this sort of thing have come way down also helps - the cost of the circuitry is barely a blip on the bottom line.
 
Our 2001 Tradewinds came equipped with a Xantrex Freedom 2000 system and National added the Xantrex Echo Charge that appplies the same rate of charge to the chassis batteries that the coach set are receiving so we have never had a chassis discharge system.

I did learn to disconnect the chassis batteries when equalizing the coach deep cycle as they aren't designed to take the gassing.
 
FWIW our 2003 Monaco doesn't charge the chassis batteries from shore power.

Tom,

What a hunk of junk!  Just kidding, but kind of hard to believe of Monaco.  Especially since the electronics industry has solved the problem with overcharging batteries quite a few years ago.  Why wouldn't Monaco use their charger/converters to charge the chassis batteries when connected to shore power?  Surely for Monaco, it's not a cost issue for the monitoring and control system as pointed out by RV Roamer.  Looks to me like a design deficiency, but I've been wrong before.

...but chassis battery discharge is not a common problem in motorhomes except in long term storage...

RV Roamer,

It is a common problem if you stop for extended stays and don't have any way to charge the chassis battery except for starting the engine.  Again, looks to me like Monaco (and others) overlooked something in their designs.

 
rsalhus said:
Why wouldn't Monaco use their charger/converters to charge the chassis batteries when connected to shore power?

I have no idea Rolf, nor do I know if they do so on later model coaches. (I keep forgetting to check it out when we look at their new coaches). Personally, I don't find it to be an issue now that I'm aware of it, provided I remember to turn off the chassis battery switch.
 
I have an 07 Monaco and it does not charge the Chassis Battery from Shore Power.  I was perturbed at first when I had my older Monaco but I have gotten so used to hookong up my Battery Tender Jr. that I don't even think about it anymore.
 
Has anyone ever used a solar powered trickle charger ? I'm ignoring the roof top Ac one when i ask this question.
 
My Winnebago charger did not charge the chassis batteries when on shore power. I purchased a TRIK-L-START and installed it. It works fine. A google search will locate the supplier. It hooks from the house batteries to the chassis batteries. Winnebago now supplies the part on their coaches.

Wayne
 
It looks like the TRIK-L-START is a DC-powered charger that charges the chassis battery(ies) from the coach battery(ies).  It's actually a 5-amp charger that is wired directly to the coach battery(ies) where it gets its power to charge the chassis battery(ies) - no AC power needed.  Is this a good idea?  You're robbing Peter to pay Paul.  What happens if the coach battery(ies) get low?  I think I like the idea of putting a jumper between the house battery(ies) and the chassis battery(ies) better because you can easily add it and just as easily remove it, whereas the TRIK-L-START may be permanently wired in.

I still don't see why BOTH the coach battery(ies) AND the chassis battery(ies) aren't charged by the charger/converter.  There must be a good reason because the TRIK-L-START is now standard equipment on all Winnebago/Itasca diesel motorhomes.

 
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