House battery problem

My house batteries were replaced three years ago.  I keep my coach on a pad next to my house, plugged in.  We keep stuff in the refer because we try to go out once a month.  A couple months ago I took it in for service and the house batteries went dead after a day or two.  I checked the batteries and could see no water in them.  Filled them both with distillled water.  Batteries took a charge.  My question is should I leave the coach plugged in.  I thought the batteries would take a charge and then taper off.  Also, the aux switch in the stairwell doesn't seem to do anything.  My manual says it disconnects the house batteries from the 12 volt system so they don't drain down but do they become disconnected from the system that charges them?  While my coach was setting on the pad plugged in my batteries got very hot and boiled out the water.  I am confused.  This weekend trip I had to run the generator a lot because the batteries just wouldn't hold a charge. 

It sounds to me like it is time to replace the batteries. Usually when fluids drop to the point where the plates are exposed they are goners. The fact that they run hot, don't take a charge and boil dry, pretty much confirms this. I would replace them ASAP and don't try charging them anymore.

You can leave a coach plugged into to shore power with a good 3  stage charger, which should float the batteries when fully charged. In case of wet cell batteries, I would check water levels once a month and top off if so needed until you establish your own pattern of water consumption for your batteries.

Batteries do need to be check for water level periodically -- I check mine every three months. As they get older, they will require water to be added more frequently. My chassis batteries had to be replaced at 5 years. During the last two years, I had to add water at least once or twice a year. If they are getting hot, they are shot and should be replaced soon.

Some RV chargers have a "float" function that will not overcharge the batteries if the coach is left plugged in -- will "taper off" as you indicate. But many do not have the float function, and they will overcharge the batteries and boil them dry. You need to know for sure which type charger you have. What some folks do is to plug the coach in on a timer that turns the power on a few hours a day to recharge the batteries, but keeps the power turned off a good bit of the time too so the batteries are not cooked by the charger.

It is very easy to see if the disconnect switch is working. Turn on a light inside the coach, then trip the switch. If the light goes out, the batteries are disconnected.  Does the disconnect switch disconnect the batteries from their charging circuit?? ...not on my coach.   I guess you could check by plugging the coach in, taking a reading at the batteries with a mult-meter -- if charging the reading should be at least 13.5. Then trip the switch and take another reading. If it is the same, the charging circuit is still connected -- if it is 12. something, the charging circuit is disconnected.

Just went out and did some testing.  The aux switch is in fact working doing your test.  The solenoid was hanging up or the switch wasn't making a good connection in the off position but now it is working and as far as the charging system, It does disconnect from the batteries from everything including the charging system.  My multimeter told me that.  I just don't know if it has a "floater" charging system or not.  My wife likes to keep basics in the refer so if I put the power on a timer for a couple hours a day, then the refer is off most of the time.  I suppose a timer could be put on the battery solenoid control circuit and have it come on for a couple hours a day.  Basically it would be like turning the aux switch on for a couple hours a day then turn it off.  I will have the batteries tested tomorrow. 

the57man said:

I checked the batteries and could see no water in them.

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Good answers from Paul and Harry.

It would be real helpful if you would add your model and year to your signature.  More expensive Winnie models will have a three-stage charger which can properly float a charge over a long period of time.

Odds are you have a bad battery cell (or cells) which is 'tricking' your charger into thinking the battery bank is discharged - the charger responds to this by pumping lots of current into the bank which causes gassing (boiling.)

I have heard that once the plates are uncovered (as in very low water), that battery capacity is effectively lost forever.  In any case, you are a candidate for new batteries.

I tried adding the info to the signature but it isn't showing uo.  I have a 2001 Winnebago Adventurer

If you click on the little guy next to the envelope the info can be seen. 

My wife likes to keep basics in the refer so if I put the power on a timer for a couple hours a day, then the refer is off most of the time.

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Here's another possible option for you -- use a timer to recharge the batteries as necessary, but run the refrigerator on LP the rest of the time. If you have a "normal" (not 4-door) fridge, it would keep the contents cold on LP, wouldn't use much battery power at all, AND it wouldn't use much LP in the process. I think mine would run for months on an LP fill. Even running our two furnaces during the few times we are in cold weather from Nov-Jan, and running the refrigerator on LP for 3-4 days a month, and the water heater a couple of days, we only have to refill the LP tank a couple of times a year. My Norcold refrigerator can be set to use shore power if it is available, but when the coach is unplugged it automatically goes to LP.  My refer is a 4-door Norcold and the fans hog a lot of power, but it would still run on LP for several hours a day (8 or more?) before the batteries need to be recharged.

I'd like to know what kind of converter you have

but 3 years and "I checked the batteries" is a bit long between service intervals

In fact 3 months is 3 times the recommended period between checks with most systems, 3 weeks in a few.

Check batteries monthly, top off with distilled water as needed (Annually in my case, but my converter is a PD 9180 with wizard)

All my batteries have some amount of "phantom load" that wear them down, unless I have them completely disconnected.  My converter/charger is a Progressive Dynamics PD9160 w/ Charge Wizard (one of the best 3-stage models that "tapers off" as you described) and even with that I still had to add water last year to my 1 year old house batteries.  They weren't completely dry but the levels were below the top of the plates.  Sometimes I can hear a slight hiss from the batteries if I have that storage bay door open, so I know some water is burning off with use.  Mine also went COMPLETELY dead last year when I discovered the water was low, and I thought they were toast but figured I'd fill them up and trickle charge before spending $300 on a new pair.  It took several days to charge, but lo and behold they have been working fine ever since.

John From Detroit said:

I'd like to know what kind of converter you have

but 3 years and "I checked the batteries" is a bit long between service intervals

In fact 3 months is 3 times the recommended period between checks with most systems, 3 weeks in a few.

Check batteries monthly, top off with distilled water as needed (Annually in my case, but my converter is a PD 9180 with wizard)

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My converter/charger is a Magnetec 7445.  series 74.  I read up on it and it is a 2 stage charger. 

The 7445 is an ok charger, but it will boil away the electrolyte from the batteries over a period of time, e.g. a month or two.

At three years your batteries are probably shot, unless they were top of the line deep cycles such as Trojans.  The typical "marine/rv deep cycle" sold in local stores just won't last under typical RV usage scenarios.

Went ahead and replaced the batteries tonight.  They were tested and were bad.  Since my aux switch completely disconnects my batteries I can just turn it on a couple hours a week and leave my coach plugged in so the refer, lights etc. work. 

Since my aux switch completely disconnects my batteries I can just turn it on a couple hours a week and leave my coach plugged in so the refer, lights etc. work

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You'll have to test that theory --- sounds reasonable but it isn't that easy. Most/all the lights are normally 12v so with the battery disconnected they will not work. You can always sit a plug-in lamp in the coach and use it on 110v.

I don't know for sure that the fridge will work on 110v w/o 12v power -- the boards/controls may be 12v. It definitely won't work on LP w/o 12v -- may not work on 110v either unless it also has 12v -- maybe someone else can tell us for sure. I do know for sure that my water heater will not work on 110v power unless it also has 12v connected.

When my converter died and the batteries lost charge I took the refrig access cover off the side of the coach.  The refrig plugs into a receptacle in the compartment.  I used an extension cord and ran the refrig until I got home and replaced the converter with an Iota 55.



This works on my 1998 Winnebago Chieftain.

Russ

1. if your batteries were 'dry' for an extended period of time - they're 'history' and need to be replaced -

2. if your converter/charger doesn't have a true 'float' setting that will keep the batteries charged without elevating the voltage to evaporate the water, you will need to take action to prevent fluid loss....

2a. put an inline AC time to your converter/charger so it only runs a short time each day - easy to do, get a cheap timer from Lowes, etc and wire it into the AC circuit going to the charger -

2b. replace converter/charger with a newer model 3-stage type to insure longer battery life - the cost of this new unit will probably save you money spent on new batteries over just a few years...

3. if one of your batteries had a shorted cell, the charger couldn't go to the 'float' setting, as it was trying to recharge the batteries all the time, causing the 'overcharge' and heated condition....

4. if you turn off your charger while the RV is is storage for extended periods, you run the risk of the batteries self-discharging over time, which accelerates the formation of sulfates on the plates, causing capacity loss or cell damage...you have to periodically let the charger run to bring the batteries up to snuff if stored long periods...

5 if you want long battery life, you have to keep em' fully charged, just like your auto's battery - otherwise, you'll just have to put up with shorter replacement intervals...

All good advice from Mexray.  The Magnetek 7445 is fairly aggressive by today's standards and not a good "float charger", so switching it off part time is a good move.

afchap... it is quite common for the battery disconnect to be located between the battery and the converter, which means the converter can supply 12v power to the coach while the battery is disconnected and not being charged.

scottydl said:

All my batteries have some amount of "phantom load" that wear them down, .......
..... Sometimes I can hear a slight hiss from the batteries.....

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Much Clipped

The PD's with charge wizard are indeed as good as it gets. They are not the only one in that class, but they are in it for sure.

Phantom loads include things like propane (Explosive gas) Detectors, control power for steps and a few other thigns and internal leakage in the batteries themselves.  No way around it save to disconnect and/or add some kind of battery minder.. Your existing converter is a 1st rate battery minder too so you already have that covered.

The slight hiss from time to time......

The charge wizard, per it's manual, will do a short "Equalization" period every 20 hours or so (As I recall) if you are watching you will actually see the voltage jump up for a few minutes, then drop back down, Lights get brighter, fans run faster, that kind of thing. Have seen it many times on my rig  This should cause that "Slight hiss" you mentioned.  This is normal and in theory is good for the battery.. (NOTE: I say therory because I have not compared with and without)  In fact, there are times when it is very good for the battery (IE: When you top 'em off with distilled water)

As to adding water.. Yes, you should check them at least every month or two (With a PD wizard 2 months may do, with some converters 2 weeks is a long time)  I find I need to water mine a bit less than once a year (So I do it every mother's day)

Winnebago does indeed wire the disconnect switch so that the converter is not connected to the batteries in the off position.

At a Parallax converter seminar  at the GNR last month, the spokesman said the 7000 series will not overcharge batteries if left on. Of course he then went on the say you had to check the water level once a month or so.

My owners manual says to use the disconnect switch if you are going to be connected to shore power for a while. I do and my batteries are close to seven years old and still work fine when I am off the grid.

They would probably show some reduction in load capacity at this point during a test though.

Clay L, Guess I am just dense but how do the 12v applications work when you are on 'shore power' with the battery disconnect in off position??