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skgershey

Dead Battery

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Recent purchase of 2014 Thor ACE 27.1. Picked up in Florida , drove 1100 miles home without incident. Home two weeks went to start...battery dead.

New battery was installed before drive home, charged battery, almost dead next morning. Removed neg cable put 12 v test light between battery and cable, lights up pretty bright indicating draw with everything off, microwave off, tvs unplugged, test light pulses, this is driving me nuts, usually pretty good at these things.....any suggestions beyond pulling fuses one by one????

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skgershey,.

Welcome to the FMCA Forum.

Either with that test light or better an ammeter (digital voltmeter with 10 amp ammeter):

Should not be many loads on the CHASSIS battery with ignition off.

If this is the HOUSE battery-- Remove all fuses and install one at a time.  Likely something like basement light that is not readily apparent.

 

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thanks for the reply, not the house battery, chassis battery keeps dying. trying a multimeter tomorrow to see how much draw I have. Had this problem with my class c, finally traced to auto step module, not the case here

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On some RV's the steps are stopped by a current limiting switch. This is electronic so there is a constant current to the step electronics. On my previous 2008 the trickle charge of the inverter was not enough to keep the chassis battery charged. After communicating with the Mfg they said to turn the step "off" so no current could flow. Once I did that I had no more problems. I was plugged into 110 v electrical.

Just to be on the safer side I leave the steps in the out position in storage. So far so good. Just a sayin'.

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The first thing I checked when a customer had the same condition, was disconnect the power wire from the back of the alt. and recheck. If the rectifier bridge goes bad, it will drain a good battery over night and will still charge. Also check and make sure the battery isolator is working properly. Another thought would be to check and make sure the brake lights are turning off. One other thing you can check would be the radio. I know its a pain in the butt, but you need to try and unplug it from the back. The clock in the radio will stay on all the time, especially if it is an aftermarket radio. 

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f442685,

It would be nice to know, what class and type of coach, you have?  In my coach (see below my signature), I have to remove the dash to get at the "plug" to the Radio!  There are 5 class of motorhomes.  A, B, C, Super C and Conversion & what your suggesting, would take most of the day each time I put mine in storage!

My Start batteries ( 2 Series 31, AGM), does not charge off of Shore Power or Generator, I plug into a maintainer and coach, at home & campground.

Back to Herman & Brett's idea! 

 

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Since this is a recent purchase of a used motor home, there exists the mystery of what was done to the rig prior to you purchasing it. No telling what modifications a previous owner did, nor what work was done by a shop before your purchase. By design, most manufacturers will connect a few house systems to the chassis/start batteries - could be the steps, could be a slide, etc.

However, there is a chance that someone along the way connected some other device to the start batteries that should be connected to the house batteries. I've seen photos of some battery bays with multiple wires piggy-backed on the positive terminal of the start batteries when there should only be one. Your initial testing was to pull the cable from the negative terminal. That wouldn't remove any of these extra circuits from the positive side.

Also, we're talking about a 2014 motor home. Likely the start battery is still the original, which means it could be 5 or 6 years old already. Might be advisable to test the battery before going much further. No sense in trouble shooting the entire coach when the problem is the battery itself. If the battery is the original, I'd replace it as a matter of maintenance regardless.

A picture or two of the battery bay will help us help you identify anything that looks odd or out of place as well.

And, welcome to the forum. Glad to have you join us here. Lot's of good information to be shared.

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If it were me I’d take Richard’s advice on the chassis and house batteries, how old, are they clean, terminals maintained and no crud buildup on top? If original they need to be pulled and tested. This should give you a good baseline at the beginning of the circuit.

Still have a draw, I have always gone to route Brett recommended above. For the starter unhook the battery cable, Alternator UN hook all connnections, do them one at a time, same with the fuses and watch the ammeter. If you can employ a helper, it will be easier on you and faster.

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thanks to all the responses.....battery is new, clean. suspected steps all along but doesn't explain 1100 mile trip home with everything operating normal. the test light flicker is still throwing me.....gonna pull the step plug and go from there. okay, not sure what I did but test lite between positive post terminal and  disconnected cable barely glows. radio and tv standbys may be the draw...?hooked everything back up will see if dead tomorrow.

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On the 1100 mile trip home.  I will presume you where on shore power and while driving, you was charging the start battery/batteries!  The generator should do the same as shore power.

Have you read your owner & engine manuals?

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Still seems to be some confusion - the TV standby should have nothing to do with the start batteries unless the house & start batteries are bridged together. Do you have a switch to bridge them together (for starting assistance, etc)? If so, make sure that it's not stuck in the bridge mode.

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have checked all but bridge switch for emergency start power. rt side entering door ...5 switches, top-inside lights, porch lite .Bottom row awning, step, annnnd, battery disconnect use/store. Anybody know what use/store switch does ? went thru owner manual page by page, wife too, no mention at all!

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1 hour ago, manholt said:

We call it the "Sales man switch!"  Turn it off & nothing works!

In general, absolutely true.

But there are exceptions. On many coaches, the refrigerator, smoke detector, propane detector, etc are NOT controlled by the salesman switch.

So, many consider this a "turn off all the lights at one time when you leave" switch.

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35 minutes ago, wolfe10 said:

In general, absolutely true.

But there are exceptions. On many coaches, the refrigerator, smoke detector, propane detector, etc are NOT controlled by the salesman switch.

So, many consider this a "turn off all the lights at one time when you leave" switch.

Yup, that’s how ours worked when it was connected, it also shut the roof top AC units off. Stumped me then I realized it actually turned the control off for the AC which in turn stopped both units. 

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A current draw substantial enough to drain a new battery overnight will not be from radios, step control, LP detector, etc.; otherwise everyone's MH start battery would be dead every morning when dry camping.

IMO the simplest and logical way to locate the current draw is to begin removing fuses one-by-one until a temporary inline ammeter(inductive 12VDC ammeters are now available) on the positive cable registers when current draw is drastically reduced. Matter-of-fact, those inductive ammeters were used in the 1950's when I worked in my uncle's garage

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have what may be a dumb question.....read ford chassis manual, if battery removed necessary to have computer "relearn" for optimum performance. True? If so a disconnect switch would require procedure each time?

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5 hours ago, skgershey said:

have what may be a dumb question.....read ford chassis manual, if battery removed necessary to have computer "relearn" for optimum performance. True? If so a disconnect switch would require procedure each time?

There are no dumb questions on this Forum !

       If the power is removed from the Engine ECM, the engine will need to be run for around 100 miles before all the correct data for proper operation is reset and this will be required each time the chassis battery is removed or disconnected.

Rich.

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Actually the hard (factory) data remains locked in memory, what it must learn is the drivers style. Immediately after a battery reconnect, the ECM reverts to factory settings  it takes approx. 100 miles for the ECM to "learn" the drivers habits and style.

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5 hours ago, RayIN said:

Actually the hard (factory) data remains locked in memory, what it must learn is the drivers style. Immediately after a battery reconnect, the ECM reverts to factory settings  it takes approx. 100 miles for the ECM to "learn" the drivers habits and style.

Ray, The Base program is always intact as you mentioned. Learning the drivers is always a necessity. One needs to also drive the required distance to check and set any error coders that can turn up. Things tend to popup after units set. Not knowing the state where the unit is registered and their requirements is the only reason I mentioned the ECM set millage required. 

Rich.

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We just proved there are different ways to say the same thing, should we blame it on geography?:) I just had a thought, is the ECM another item that is not disconnected when we use the "salesman switch"?

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How many chassis batteries does this motor home have?

Any chance you could post a photo of the chassis battery bank as well as the house battery bank? Might help us help you identify the problem.

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