Chassis battery keeps going bad

[scottydl]

I am about to replace my chassis battery for the 3rd time since I bought my MH (this past June).  It keeps dying, and somehow "goes bad" and cannot be recharged.  I figured out what's causing the constant drain... the LP sensor.  Why it gets it's power from the chassis (and not the house batteries) I don't know.  So when I'm parked I either have to unhook the battery (I have one of those spin-off quick disconnects) or keep a trickle charger hooked up.  I forgot this last time, and now the battery is dead AGAIN and won't accept a charge.  I'm sure it will be rated "bad battery" when I have it tested.  Is this normal?  I've never had a car battery go dead ONCE and then become unable to be recharged, but this is obviously a pattern with the MH.  The good news is the batteries are always under warranty and replacements are free - but it's getting to be a pain to pull this heavy thing out from underneath the MH to take it in and exchange.

[Tom]

Repeated complete draining of the battery will likely bring a premature death. Install a battery disconnect switch similar to this one, available at marine stores and RV parts departments. They sell a few different versions of the switch, but all you need is the simple on-off version without a key lock. Here's a different brand; There are others.

I installed one on our prior coach because of the continuous drain from various phantom loads. Our current coach had one installed at the factory (actually two - one for the chassis batteries and one for the house batteries). If I forget to turn off the switch, the chassis battery is dead in approx 4-5 days. Many RVs do not have their chassis batteries charged when on shore power.

[Gary RV_Wizard]

The LP detector is powered from the chassis battery so that it will still work when the house batteries get run down, e.g. by the furnace running all night. It's a safety feature. It is also likely that your electric step is powered from the chassis battery and a few other things of that ilk, for the same reason.   

While the LP detector etc. may run down the battery over several weeks, it is not normally a big enough drain to be a problem in routine use because the power draw is very low.  How quickly does the run down occur?  Does it happen only in storage or while camping? 

[scottydl]

I have a battery disconnect (the knob that you unscrew) installed, in this instance I just forgot to engage it.  I'm not sure how long it took to go dead, but my MH has been dormant in my driveway for a few weeks.  This battery was already fairly new and had never been completely discharged, so it happened this once and now the battery will not take a charge.  Ah well, I pulled the battery out awhile ago and will exchange it tomorrow.

[Weewun]

Most of today's Battery Chargers will not initiate a charge on a totally discharged Battery because of the sophisticated voltage sensing devices internal to the Battery Charger.  What you need to do is connect the Chassis Battery with Jumper Cables to a charged Battery and let it set for awhile (the good Battery will charge the Chassis Battery).  Then disconnect the good Battery and reconnect the Battery Charger, the Chassis Battery will have enough charge for the Battery Charger to initiate charging which may take several hours to reach full charge.

An even quicker way, if you can get your vehicle close enough, is to connect  the Chassis Battery to your vehicle Battery with Jumper Cables and the Vehicle running.  It will take about 15 minutes whereas using just a Battery will take about an hour'

 As for the Battery being bad after on full discharge is problematical.  I left the Nav Lights on  in my Pontoon Boat while I was in Florida for the winter and had to use the above method to restore the charge, that was three-years ago and I am still using the same Battery in the Toon.

I now check all the lights after I winterize and cover the Toon and I leave a 750 milleamp Trickle Charger connected for the winter, fact is I use a similiar Trickle Charger for each of the Jetskis, runabout, wife's car and my JD mower when we go to FL for the winter.  I also use a Trickle Charger on my Chassis Battery for the MH whenever it is going to set for mor than 3 days, it will run down when it is parked.

I know this note is long, but changing the Battery is not going to solve your problem, either get a Disconnect Switch or Trickle Charger.     

[John From Detroit]

As for what is causing the drain, there are several systems that always get power, for one the vehicle computer, the memories in the radio (And it's clock) and I'm not sure what else.  Doing a full chassis battery disconnect may be impractical on modern computer controlled vehicles.  The reason I say this is the computer on many vehicles "Learns" the vehicle, this can take up to 500 miles and as it learns it fine tunes your fuel/air, timing and selected other settings so as to get best performance.  Disconnecting the battery for an extended period resets it to "Out of the box" so for the next period of miles you are re-learning and thus costing you added fuel.

However one factor in a deep discharge recovery... I've used several brands of batteries on my towed.  Most of them, one deep discharge and they are toast.  Whatever they put in the last time has survived several deep cycles.  So brand of battery can help.

Second, Tell us a bit more about your coach

What brand of battery
What brand of converter (For the house) (and model)
What brand of battery control center (And model)

I keep my coach pulgged in 24x7 and the result is a fully charged battery all the time.

That said, the last couple of camping trips it was telling me the chassis battery was dead.  So before heading for warranty replacement I decided to do a load test, crawled under with my load tester and ... It passed

And after re-connecting it... The rig started normally

Humm... Bad connection?  These happen most often on the ground lead, and often as not at the CHASSIS end of the wire, However nothing prevents the other wire from having issues as well

[scottydl]

Most of today's Battery Chargers will not initiate a charge on a totally discharged Battery because of the sophisticated voltage sensing devices internal to the Battery Charger.

Ah, this is something I did not realize.  I got the new battery today, so if I end up accidentally discharging it in the future (as has been the case with the last few) I'll be sure to try to jump-start trick first to get a primary charge in there.

I know this note is long, but changing the Battery is not going to solve your problem, either get a Disconnect Switch or Trickle Charger.

And I actually have both, as mentioned in my earlier posts.  The trick is remembering to USE them.    The battery I've been using is  the biggest one in the Wal-mart Everstart Maxx series... probably not the best, but as I said every replacement has been free.  And the warranty starts over whenever I get a new one, so at this rate I'll never have to pay for another chassis battery as long as I own the MH! 

[Ron]

I like our battery experience better.  The original Trojans 105/s are on their eighth year now and still going strong.  When they do require replacement it sure won't be anything made by Exide cause I would probaby have keep turning them in for warranty.  They will be replaced with Trojans.

[Shayne]

Scotty  I agree with Ron on this one    WW batteries don't cut it,

[scottydl]

Scotty  I agree with Ron on this one    WW batteries don't cut it,

Yeah I figured as much.  It was the battery that was in here when I bought the MH, and aside from the labor to remove/install it - so far the free exchange has been the cheapest option.  If we hit the road on a longer trip next season, I will seriously consider upgrading to a more dependable battery.  Where can the Trojans be purchased retail?

[Ron]

Trojan batteries are usually available at places that sell Golf carts and at many RV stores.

[Gary RV_Wizard]

Ron,

Scotty is talking about his chassis battery, not the house ones. Trojan makes them too, but T105's golf carts are not what he wants/needs.

Scottydl,
Even a cheap Walmart/Exide battery shouldn't fail that quickly, even with a small constant load from detectors, ECM, etc. Something is wrong here. I think I would stick with the free replacements until I figured out what it is.

[Ron]

Ron,

Scotty is talking about his chassis battery, not the house ones. Trojan makes them too, but T105's golf carts are not what he wants/needs.

Whoops sorry about that.  For a chassis battery Interstate would be a good choice.  But I still wouldn't recommend an Exide battery unless of coure you just like exchanging them for warranty?

Scottydl,
Even a cheap Walmart/Exide battery shouldn't fail that quickly, even with a small constant load from detectors, ECM, etc. Something is wrong here. I think I would stick with the free replacements until I figured out what it is.

IMHO there is a good chance it is the batteries.  I had a similar experience with the 73 pickup until I wised up and bought a good battery.

[scottydl]

And I was always relying on the trickle charger to revitalize the battery before... but the charger always shut off, most likely because of a voltage sensing error as weewun described above.  There's probably a good chance I traded in a couple batteries that would have recovered just fine if given a jumper cable charge-up first.  I never tried that before.

[leethehund]

When we are home and the MH is going to sit for a while (more than a week) I put a jumper between the house bats and the chassis battery. With the MH plugged in, that keeps all the batteries on trickle.
Lee
PS: Don't forget to keep all of them watered as the trickle will cook off some water over time.

[scottydl]

When we are home and the MH is going to sit for a while (more than a week) I put a jumper between the house bats and the chassis battery. With the MH plugged in, that keeps all the batteries on trickle.

That is a great idea... do you just use a length of wire w/ alligator clips on each end?

[rsalhus]

When we are home and the MH is going to sit for a while (more than a week) I put a jumper between the house bats and the chassis battery. With the MH plugged in, that keeps all the batteries on trickle.

I've seen that done before for another MH.  But why doesn't your MH charger/controller charge both sets of batteries normally when on shore power?  Our MH is a 2001 and it charges both sets of batteries when on shore power.  Is this because yours is an older MH or what?  What year did the MH manufacturers start to charge both sets of batteries when on shore power (if anybody knows)?

[Dave Stringham]

That is a great idea... do you just use a length of wire w/ alligator clips on each end?

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. chassis and house batteries should last for quite a while if just sitting idle in the drive way (not counting that you left some big turned on).  Once you get a good battery in there, I would suggest you sit down with an amp meter and check draw.  You can probably hook up on the chassis or house side of the fuse box.  You may have something that is supposed to turn off that is not and drawing your batteries down.  Most applications that are designed to stay on usually have a very low amp draw..........

[leethehund]

That is a great idea... do you just use a length of wire w/ alligator clips on each end?

Yep, thats it. Very simple!

The MH is a '96 Flair. I don't know when they started charging everything from shore power but that's the way I think it should work.
L

[Tom]

... why doesn't your MH charger/controller charge both sets of batteries normally when on shore power? Is this because yours is an older MH or what?

Rolf,

There does not appear to be a rule of thumb. FWIW our 2003 Monaco doesn't charge the chassis batteries from shore power. Our 1985 Pace Arrow did and I had to disconnect the charge wire to stop it overhcharging with that old style charger.

[scottydl]

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.

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.

[Jeff]

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.

[Tom]

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.

[Ron]

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.

[Gary RV_Wizard]

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.

[Jeff]

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.

[rsalhus]

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.

[Tom]

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.

[Weewun]

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.

[blueblood]

Has anyone ever used a solar powered trickle charger ? I'm ignoring the roof top Ac one when i ask this question.