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inverter charger

Hello, I have a little problem that has me perplexed.  My battery charger inverter is not charging the batteries for the coach.  I can start my engine and charge the coach batteries from the alternator. The kubota generator is not charging the coach batteries either.  I have it plugged in (again after we got home) and it is just not doing it. The panel on the wall inside says it is (inverter) overloaded.    It was doing just fine last week (while plugged in).  We took the FT on about 500 mile trip over the weekend and that is when it stopped.  It was plugged in and I am not sure when it quit but I came back after several hours and the battery low alarm was beeping and it was down to about 9.6v.  I started the generator and it did not charge the battery.  Then I started the cummins again and then it started charging the battery.  I now have a auto type battery charger on it and it seems to be charging now. It would not at first though until I got the battery somewhat charged by using the cummins alternator.  Thoughts on what to do?  I certainly can take it in to Nach, but it is about a 6 hour trip up there and probably would leave it there and then have another 6 hour trip to retrieve. 
Best of Travels

Re: inverter charger

Reply #1 –
Since both the generator and shore power charge your house batteries via the inverter/charger - and the alternator *does* charge them - it appears likely that your inverter charger is at fault. But it seems strange that your batteries drain so much when you are stopped and on shore power. Is the inverter side of this device on all the time? If you can turn that part off, then do so and see if there isn't some huge load on the inverter that you don't know about.

The alternator is capable of providing a lot more amperage to the batteries than the charger is (probably on the order of 170A versus 70A) and if the load on the inverter is higher than the out put of the charger then the inevitable result will be dead batteries.

Turn the inverter part OFF and see what that does first. Measure the battery voltage every hour or so and see if the voltage is increasing or decreasing. If it's increasing, let it charge the batteries up and then turn on the inverter side. If the battery voltage starts to decline then look for a heavy load on the inverter.

At least you'll know where to look next.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: inverter charger

Reply #2 –
Thanks Craig,
Have it plugged in, inverter off, will check again in AM.  This should indicate whether or not charger is charging.  Makes sense that alternator would charge the batteries despite the load (170 vs 70).  Do you think the refrigerator would drain the batteries that fast?  It is a dometic, and seems to be running primarily on 110 and 12v.  Charles
Best of Travels

Re: inverter charger

Reply #3 –
The refrigerator would be my very first suspect.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: inverter charger

Reply #4 –
Well, checked it this morning with inverter off, batteries are back up to 13.5 per the panel.  FT is plugged in 110 seems fine.  I have left the inverter in off position.  Refrigerator is running off 110 and has gotten cold again.  On the panel that says batteries are @ 13.5 there is in very small flashing letters "Lobatt".  This is confusing to me as it says it has 13.5 yet, low battery? 
Best of Travels

Re: inverter charger

Reply #5 –
For the "Lobatt" you might try to reset it by tripping and resetting the 120 volt breaker in the main panel at the foot of the bed for the inverter charger.  Not sure if that will do it, but worth a try.  Now that the batteries are recharged, turn off the charger breaker for about an hour and check the battery voltage.  If low you could have weak batteries, or one could have a dead cell, which will pull down the good battery.  If one turns out to be weak and the other OK, disconnect the bad one and use the good one until you can get a replacement. 

Regards the refrigerator, the absorption type found in most RV's, require a small amount of 12v power for the control and door light.  The actual cooling is provided by heat from a propane flame or a 120v heater element, and some refrigerators also have a 12v heater.  The auto switch preference is 120v first, then propane, and last 12v.  If 12v is used as a heat source, it is a big battery drain.  Normally the inverter does not power the refrigerator, as that is a big drain on the house battery.  It is possible that a previous owner may have rewired the refrigerator so that the inverter could power the 120v heater.  Makes no sense to do that if there is propane available or there is a 12v heater.

Another indication of weak batteries is the charge time.  Good batteries take longer to reach full charge than weak batteries from the same start point such as 12.3 volts on the weak and good battery.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: inverter charger

Reply #6 –
Does the refrigerator work on shore power with the inverter off? I think that someone may have wired a relay in there to let the refrigerator work on the inverter if the inverter is on; otherwise on shore power.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: inverter charger

Reply #7 –
Craig,
It does seem to be working on shore power.  I am now at work and refer was cold this am.  I turned off the inverter, and will check if still working on 110v this evening (check light did not go on this am when I was there for a few mins).  I think the 12v refer is the cause of the low battery/overload of the inverter (on 110v).  I have tried to insure that the dang refer will go to propane but alas it will start working and shortly after will revert to electrical drain either 12v or 110v.  The problem seems to stem from the refer.  In March I took it to Nach, spent 700 getting it so it would run on propane and still seems to be not working on propane (for long) and draining the battery when it reverts to electricity (12v or 110).  At first thinking that the battery charger was out (and may still be the issue).  The batteries are about 2 years old.  The flashing "lobatt" is confusing to me......(especially since the panel voltmeter reads 13.5).  I am almost ready to get a new refer. 
Best of Travels

Re: inverter charger

Reply #8 –
I think that the key is to NOT turn the inverter ON unless you want to use it and then turn it back OFF as soon as you're done. Otherwise the refer is going to end up powered by the inverter and drain the batteries.

The next experiment would be to keep the inverter off and the shore power off and see if the fridge runs on propane. :)

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: inverter charger

Reply #9 –
Quote from: drcscruggs –
I have tried to insure that the dang refer will go to propane but alas it will start working and shortly after will revert to electrical drain either 12v or 110v.  The problem seems to stem from the refer.

Is this a 3-way fridge (LP, 12VDC, 110VAC)?  Many of the newer ones are dual-mode (LP/110VAC) for cooling only (although they still used 12VDC for control circuitry).

Just a random thought, but have you looked at the burner flame when operating on propane?  Any issues with soot on the burner or a poor flame that might be related to the propane regulator (or a spiderweb in the line)?  I believe if you're getting a "check" light on LP then a thermocouple/probe isn't sensing the heat from a properly burning flame, so possibly either a bad flame or a bad thermocouple (or a bad control board). 

-M

Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: inverter charger

Reply #10 –
Some of these coaches had 2 120 volt receptacles at the rear of the refer and one of these is hooked to the inverter for the ice maker part of the refer. Might want to check if the refer is plugged into the inverter receptacle, which if it is would explain the batteries being discharged rather quickly.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: inverter charger

Reply #11 –
Hello, got home tonight and checked out the motorhome, turned on the LP on the refer (3 way) left it for a couple of hours and it went into default/check light status.  I have enclosed a photo of the burner flame and it appears to be ok to me.  There is only one plug in for the refer, as the ice maker that I have is separate unit (not inside the freezer). 
I will definately leave the inverter in the off position (until needed).  I learned that the inverter even being in the on position can cause a drain on the batteries (from the forum, thanks to the forum).  I had always been leaving it in the on position.
The batteries appear to be charging fine.  I note the voltage is now @ 14+v.  But note the lowbatt flashing note still on. 
Best of Travels

Re: inverter charger

Reply #12 –
You might have to do a hard reset, which you take away the 120 and then disconnect the 12 volt also. When you hook up the 12 volt and the 120 the lo bat may not be there.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: inverter charger

Reply #13 –
Thanks Red T,
Will do this today (unplug everything 110 and 12v).  I will try that as it sounds logical (reboot?).  Now 13.5v the meter, refer working fine off the 110 line.  I have tried again to enclose the photo of the propane burning (does not stay lit).  Thanks Steve for the tip on the thermocouple, this may be the issue and will work on that first.  I think this may be the issue as the flame looks fine to me.  Even though this is an older motorhome, it only has about 45k miles on it and believe it or not, when I purchased about 2 years ago, the dometic still had tape on some of the shelves and appeared to have been used minimally.  I truly believe I have used it more than it was in the previous 14 years over the past 2.  Thanks again to all.  Charles
Best of Travels

Re: inverter charger

Reply #14 –
One of the important things with the burner partthat most owners do not do is service the burner assembly. This causes more trouble than if it were just looked at and tweeked once a year. I do a lot of maintenance things on rv's when in Mexico for people as most do not know the first thing about them.
This area of service is simple and can be done by anyone with basic tools and a bit of care. There is a certain amount of rust that falls down the tube and lodges in the burner which will cause an erratic flame(or not stay lit) and sometimes the edges of the burner slots get a deposit on them and does the same. You can take the parts off to clean out or as I do use a bendable plastic straw to blow it clean then a nail file to clean up edges of burner slots. DO NOT FILE THE SLOTS JUST CLEAN THEM!
then blow it out. This will fix most problems as will a light cleaning of thermocouple end.
Looking at your photo Charles your's looks ok to me.
John H
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.
 

Re: inverter charger

Reply #15 –
From your picture it looks like there is some deposits on the insulator on the spark probe, that can if damp cause the spark to go to ground instead of jumping the air gap. You mightr try to clean that up a little also
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins