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Help? Lost Power!

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1999 Winnebago Adventurer, 35ft Class A, Ford V-10, BanksPower, Onan 7kW, Solar Power System, Left Slideout, 3rd coach in 20 years, Fulltimer.

So, my start battery died this past winter. I pulled all 3 to load test and charge them, (if need be), about 4 weeks ago. The 2 coach batteries were good. The start battery had/has a bad cell. I finally found the time to reinstall them. One good to the start, the other to the coach, and did so about a week ago. My intent is to replace the third asap, but with the problem I'm having, I'm in no hurry. 

Anyway, I unfortunately, stupidly,  misread the crude schematic drawing I made when I removed the batteries, and cross wired the one coach battery upon reinstallation. I got a spark. I thought it was just a spark because the system was pulling current. I reapplied the connection and then heard a "pop/click" from somewhere inside the coach. The battery box is located in the entry stairwell, so the door was open and I was bent over the batteries. The pop came from inside, (as best my ears could tell), but which direction I'm not sure. Inside is all I can say. 

At any rate, now, without the coach battery connected, my fridge won't work. I tried plugging it in via extension cord, directly to a known working outlet in the coach...nothing. I ran it straight to the power pole...nothing...THIS, to the power pole, I DON'T UNDERSTAND!!!

When I reconnect the coach battery, the fridge works no matter which AC source I use. I take it out, the fridge loses AC. What did I fry?

I've checked literally, EVERY fuse and circuit breaker. 110v breaker panel...fine. All DC breakers...fine. Engine compartment fuses...fine. Under dash fuses...fine. 

I'm thinking converter or automatic transfer switch, though I'm not sure how either of those would have an effect. The transfer switch has nothing to do with DC power, so I don't think it's a factor. My thoughts lie with the converter in that I'm getting (guessing/unconfirmed as of ýet) zero 12vdc out, which in turn isn't powering a relay solenoid somewhere to let AC pass to the fridge, no matter the source AC, which doesn't make sense if I'm plugged in DIRECTLY to the fridge! That said, all of my AC elsewhere works...both TV's, Micro, Toaster Oven, box fan, etc...just NOT the fridge. When I put the coach battery back into the circuit, and plug the fridge in to its normal receptacle, it resumes working.

MY AC amperage consumption panel shows a code E1 when the coach battery is disconnected, and the fridge beeps saying no AC. When I reconnect the coach battery, the consumption panel doesn't reset until I reset the main AC power breaker, then the fridge works fine.

What I'm not understanding...is that my 12v system AND the fridge were working WITHOUT the coach batteries after I removed them for testing. Now, without them, after my misread schematic disaster, nothing with 12v works unless a battery is in the circuit, which would logically follow, until it comes to the fridge. 

So, if it's not a lack of a 12v output from the converter to a relay solenoid, that allows 110v to flow, I'm left with the converter itself. I'm thinking blown fuse or blown protection diode, but I can't find the converter. It's not behind the AC circuit panel, under the bed, or in/under ANY of the furniture with room for storage, or in any of the basement storage bins. Do I even have an converter? Wouldn't I need one for 12v?

On the inside of my 110v circuit breaker panel, I DO have a small 2" x 6" circuit board on one side, that may or may not be an converter. I'm assuming it's not, because it contains really fine circuitry, (a couple of integrated circuit chips and a transistor), that makes me wonder if it's even capable of handling the DC amperage required by the coach, but I could be wrong. 

Right now, as a bridge, until I can decide what to do for repairs, or actually repair it, I have a jumpstart pack hooked to the coach battery, and have it plugged in to the AC adaptor to keep the DC flowing to something somewhere, that keeps the AC flowing to the fridge. My thoughts are to buy a real battery charger tomorrow to replace the jumpstart pack. That said, if I'm keeping the DC flowing to a relay solenoid somewhere, wouldn't that rule out a bad solenoid? That said, maybe it IS the converter? That said, where the heck is the converter? Is it that little, delicate circuit board inside my AC circuit breaker box???

I have a solar system, but have no idea if it works, (I bought the coach used), if it's even hooked up, or if it's a factor.

I'm not sure what else to add, or how to describe things, or if I'm even making sense. I'm generally a DIY'er, and would appreciate any help, advice, or questions to better understand my gibberish BEFORE I put this thing in a shop somewhere that'll cost me an arm and a leg.  

Yes, I can afford a repair in a shop, but I'm a cheapskate, lol. If it's something simple like a fuse or a relay solenoid, I'd sooner not pay the $100/hr shop fee and the 150% markup on some $30 part, to find out it's a .69 cent blade fuse.

Thanks in advance. Bare with me to return a reply. I work 12-15 hours a day, 6 days a week, and I'm bushed when I get home. I promise I'll get back to someone who's taken the time to help. 

Pics to follow if needed.


Edited by pjnickles
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First of all, welcome to the Escapee forums! We are happy to have you with us and we will do our best to help. Because I am a retired electrical service tech, I am going to give this a shot, but there are several others here who also have a lot of experience working with RV systems so I am sure that they will join in and among us we will hopefully get you pointed in the right direction.

First, I want to make sure that you realize that an RV refrigerator uses 12V-dc power for the control circuits no matter what the energy source for cooling is. Thus the fact that it doesn't work even with 120V shore power without the batteries connected, tells me that you don't have 12V power without them. That means that something has failed which should supply 12V when you have shore power.  Are you sure that the RV has an inverter, as much more common would be a 120V to 12v converter, which will make 12V but unlike and inverter, it doesn't supply 120V from battery power when no shore power is available? The difference could be important, although as of now we are not sure.

It sounds like what happened was that you connected the batteries with polarity reversed, or the positive lead where the negative should have been? Is my understanding of that correct? The automatic transfer switch (ATS) would not have been involved as there is no 12V power to it and it is just a 120V relay device to shift between the shore power cord and the onboard generator. Battery polarity would not impact that at all. It may well have caused a serious problem with the converter, or there may be a reverse polarity protection device to protect it that needs to be replaced. The converter is where I would look for the problem since it seems that all 12V items will work (lights, furnace, water heater) if the batteries are connected. While I don't know where it would be located, there are some hints that may help. The output would be connected either directly to the coach batteries, or it could also connect to the 12V fuse panel where the battery connects as there will be a common connection point since the converter not only supplies 12V when shore power or the generator power is available, but it also sends excess power to the batteries to recharge them. The circuit board that you found could be a part of the inverter but the converter probably has at least a 40A output capability so there should be some larger leads to some part of it. What is the brand name of the power distribution panel with the breakers? Does it also contain the 12V fuses? There are several brands of combination distribution panel converter combinations that are in common use.  Does what you have look something like this?


Both WFCO and also Progressive Dynamics make combination versions that look pretty much like this. Any additional information that you can supply and even a picture may help us to identify what you have and then figure out what has happened.

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Sorry, I don't have the time now to dig deep into your problem, just to note many RV electronic devices have reverse polarity protection which may be as simple as a small fuse right in the open where its easy to find and test. As noted above devices like a fridge, even if operated on LP Gas or 120 VAC, require 12 VDC house battery power to operate often via a small terminal board easy to locate at the rear of fridge..  

Are you sure you have an "Inverter" "??? its so when dry camping with no shore power available it can change your 12 VDC battery power over to 120 VAC.

If you have a Converter/Charger (typical and what I suspect)  it takes the 120 VAC shore or genny power and changes it to 13/14 VDC to charge your house (NOT engine see below) batteries.

 Typically (cant say what you have) a motorhomes RV engine starting battery is NOT connected to your coach house batteries (unless an emergency switch is engaged) so charging or jumping one does NOT charge the other. If the RV house batteries lack power (causing RV items not to function) they need jumped or charged or replaced and charging the engine battery doesn't help

  Sorry this is easier if there armed with a meter to help but figuring it out over the net with sooooooooo many unknowns is tough. It may be as simple as a fuse or circuit breaker perhaps located in your AC or DC distribution panel or else some sort of a reverse polarity protection fuse on a piece of electronic equipment..LOOK THERE ALSO then make sure all your batteries are okay, charged and there are no missing connections or blown fuses in or near your house battery area..  

 John T Nooooooooo warranty on any of this I didn't have time to study this deep, I may check back later, in the meantime you're in good hands with Kirks good help.......

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Thanks all for the advice. 

Thanks to another, different RV forum, I was able to locate my 120vac to 12vdc power converter. I about tore this place apart and there it was, under the drawer that's under the oven! 

Two blown 30A fuses. Replaced. All is well. Whew!

Safe Travels.  🙂

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pj, Thanks for the feedback, congratulations and glad you got help locating your power converter. Indeed, something as simple a fuse or circuit breaker can often be the problem. Without any means to charge your house batteries which power the coaches 12 VDC (including the fridges necessary control circuitry) if they were dead and/or with no 12 VDC Converter/Charger to replace the power they provide if unhooked (even without coach batteries a working power converter can, subject to how wired, supply 12 VDC to the coach including the fridge) you were  left "in the dark" lol.  Perhaps some reverse polarity protection and/or the converters blown fuse did its job and saved your power converter or something worse ??????????

Best wishes be thankful be safe,

John T

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5 hours ago, pjnickles said:

Two blown 30A fuses. Replaced. All is well. 

That is great news! It is what we call a learning experience. It seems like that is something all of us have sooner or later. Do continue to participate in our forums as we appreciate having you with us.

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