Boil-over From House Batteries

[bobbyks]

We are new FMCA members, have had two previous motorhomes. I find this organization offers more advice than any other group or coach mfg.

We live in hot southern La. and keep the coach under cover and powered up. I am always adding distilled water to the house batteries and now am seeing boil-over from the batteries. The repair shop said this is the result of low water. Is there a solution to the problem?

[hermanmullins]

Bobbyks, Welcome to the forum. In southern Louisiana you need to look up the Cruzin Cajens RV Club. Good strong club that has a lot of fun.

You didn't say how you are charging you batteries, Inverter or trickle charger. How old are your batteries? If your batteries are in good shape then it would seem that your charging system is just charging and not monitoring your Batteries.

You may get a response from Brett, who has a lot of experience in these matters. When you find your answer be sure to post the solution so others may benefit.

Again, welcome to FMCA and the Forum.

[bobbyks]

My coach is a 2008 Mandalay. I have only had it for two years. Previous coach 2005 Damon. Charging by inverter, never had this problem with the Damon, charged same way. May be operating the inverter incorrect.

[wolfe10]

As Herman said, welcome to the Forum.

Suspect you have an inverter/charger. If so, most have several IMPORTANT owner-settable parameters.

Pull out your inverter/charger's owners manual and look up your programming options.

They generally include:

1. Battery bank size (in amp-hrs).

2. Battery technology (wet cell in your case)

3. Temperature (an important one for you). If, for example it is set to cold temperatures it will definitely over-charge the batteries in really hot weather.

Please let us know how yours was programmed and if you changed anything.

If you don't have an inverter charger, but separate charger, let us know what it is.

Brett

[bobbyks]

Thanks everyone for your information. I may have solved the problem with my battery boilover. I reset the Mangnum inverter/charger to conform with the system. (amps,watts, charge rate and ect). The batteries are now maintaining around 12.5 to 13 volts while plugged into shore power.

I may have damaged two of the four batteries due to the overcharging, however the voltage is holding. The batteries are four years old.

I have only been a member less than 6 month ,the information I have gained is more than expected and more than any dealer has offered.

[wolfe10]

With a properly programmed inverter/charger, voltage in FLOAT MODE (long term shorepower-- minimum of over 24 hours) should be 13.2-13.5 VDC as measured with a digital voltmeter at the batteries.

A digital voltmeter is a real asset in an RV and they start under $20 at Sears, Radio Shack, etc.

Please verify that the float voltage is in that range-- if not need to determine why it is not.

Brett

[bobbyks]

Just checked system--float charging @ + - 13.3 V

[wolfe10]

Just checked system--float charging @ + - 13.3 V

Good, much better than the 12.5 to 13 volts posted earlier.

[whiteeagle]

If I understood the recent seminars correctly, the "boil over" experienced could just as well be from over filling the battery cells with the water to high - above the vent mechanism?

[wolfe10]

If I understood the recent seminars correctly, the "boil over" experienced could just as well be from over filling the battery cells with the water to high - above the vent mechanism?

Yes, boil over can be caused by several things:

1. Overcharging (Often because the smart inverter/charger that has not been programmed properly-- rendering it DUMB!)

2. Overfilling of the battery cells.

3. Battery with bad cell (so the charger will try to charge a 10 volt battery as if it were a 12 volt battery, resulting in severe overcharging of the remaining good cells.

Brett

[retiredblade]

Good information, mine was doing the same while plugged in, sitting in my drive way. So I unplugged, but it kept doing the same, so I got the inverter/charger manual and it said if your motor home is sitting for long periods, shut the inverter/charger off. Not having a "higher end" inverter/charger before, I didn't know you could turn it off, I did. No boil over but not charging, apprently the inverter/charger was running off the batteries when unplugged from shore power,and I found that my chassis battery was draining down so that I couldn't start the coach, even my power boost wouldn't work, guess I will go to the manual again and see what I can figure out, I've always been slow!

[wolfe10]

Retiredblade,

Sounds like several, perhaps unrelated issues.

Some coaches are not wired to charge the chassis batteries from the inverter/charger-- is yours?

Chassis batteries will discharge over a couple of weeks due to parasitic load, even if fully charged when your park. So for long-term storage, it is best to have a charging source for the chassis batteries such as a Xantrex Echo charger (so the inverter/charger charges the house batteries and the Echo charger then charges the chassis batteries). Another option is to disconnect the chassis batteries.

Yes, an inverter left on with shore power/generator off WILL take power from the batteries. Not a lot, but it is in "Stand-by" mode when left on. That is so it is instantly ready to supply 120 VAC if you turn on a 120 VAC appliance that is wired to an inverter-supplied outlet. When parked with no shore power, turn it off.

But, with a smart charger PROPERLY PROGRAMMED (battery bank size, battery type, temperature) you should be able to leave it plugged in 24/7 without overcharging the batteries. Once fully charged and in FLOAT MODE, voltage should be 13.2-13.5 VDC. That should not boil a healthy battery with proper water level.

As I am sure you are aware, deeply discharging a battery materially shortens its life. Sadly, many batteries sit deeply discharged while in storage-- on dealer lots as well as by the owner, so shortened battery life is not unexpected.

Quality batteries treated right (not overcharged and not discharged below 50%) can last many years. The Lifeline AGM batteries I installed over 6 years ago in our coach are working just fine.

[retiredblade]

Retiredblade,

Sounds like several, perhaps unrelated issues.

Some coaches are not wired to charge the chassis batteries from the inverter/charger-- is yours?

Chassis batteries will discharge over a couple of weeks due to parasitic load, even if fully charged when your park. So for long-term storage, it is best to have a charging source for the chassis batteries such as a Xantrex Echo charger (so the inverter/charger charges the house batteries and the Echo charger then charges the chassis batteries). Another option is to disconnect the chassis batteries.

Yes, an inverter left on with shore power/generator off WILL take power from the batteries. Not a lot, but it is in "Stand-by" mode when left on. That is so it is instantly ready to supply 120 VAC if you turn on a 120 VAC appliance that is wired to an inverter-supplied outlet. When parked with no shore power, turn it off.

But, with a smart charger PROPERLY PROGRAMMED (battery bank size, battery type, temperature) you should be able to leave it plugged in 24/7 without overcharging the batteries. Once fully charged and in FLOAT MODE, voltage should be 13.2-13.5 VDC. That should not boil a healthy battery with proper water level.

As I am sure you are aware, deeply discharging a battery materially shortens its life. Sadly, many batteries sit deeply discharged while in storage-- on dealer lots as well as by the owner, so shortened battery life is not unexpected.

Quality batteries treated right (not overcharged and not discharged below 50%) can last many years. The Lifeline AGM batteries I installed over 6 years ago in our coach are working just fine.

I don't think mine is wired to charge the chassis batteries, I have two solar panels by each a/c that is suppose to do that. I turned both master switches off, coach and chassis, and put a little 1 amp trickle charger on the chassis batteries to keep them up, after a few days, it seems the charge is feeding to the house batteries, hence water laying around the caps of the batteries. So I took the trickle charger off and throw a volt meter on it every week to check on the charge, last I checked it was 12.50 volts, going to go out and check again, might put the trick back on.

Ran outside and checked with a volt meter, no trickle charger has been on them for over a week: chassis read 12.69 volts, house batteries 14.15 volts. But before I shut the inverter/charger off a month ago I went I to exercise the engine and not enough power to start, it read 11.50 volts, so I charged them up with a external charger, and it started up, no problem next day. Got to thinking again, so I ran out to the compartment where the batteries are and opened the door above the batteries where the fuse/distribution panel and inverter/charger resides, and, I had to get a mirror to read it, it's a wfco 65 amp power converter mod WF9865, positive wire from it going to positive wire on house battery, neg wire from it going to neg wire house battery, wire in back goes to 120v wire coming from the inverter/charger. What the devil it that? Is that like a echo charger, its not going to the chassis battery.

[wolfe10]

... wire in back goes to 120v wire coming from the inverter/charger. What the devil it that? Is that like a echo charger, its not going to the chassis battery.

May look like it, but that makes no sense. It is unusual to see a converter AND an inverter/CHARGER in the same system. And, you would never (at least not properly) wire an inverter to power the converter. That would create a closed loop that would quickly drain the batteries.

An Echo charger connects house with chassis battery bank. Once a certain (programmed) voltage is reached in the house bank, it will close the relay/Echo charger to allow the converter or inverter/charger to charge the chassis batteries as well.

Start by figuring out exactly what inverter/charger you have. An inverter/charger alone (without converter) is the normal configuration if you do, indeed have an inverter/charger. Now, if you have an inverter that does not have a built in charger, a different matter.

Brett

[retiredblade]

May look like it, but that makes no sense. It is unusual to see a converter AND an inverter/CHARGER in the same system. And, you would never (at least not properly) wire an inverter to power the converter. That would create a closed loop that would quickly drain the batteries.

An Echo charger connects house with chassis battery bank. Once a certain (programmed) voltage is reached in the house bank, it will close the relay/Echo charger to allow the converter or inverter/charger to charge the chassis batteries as well.

Start by figuring out exactly what inverter/charger you have. An inverter/charger alone (without converter) is the normal configuration if you do, indeed have an inverter/charger. Now, if you have an inverter that does not have a built in charger, a different matter.

Brett

I have a Freedom 458 combi inverter/charger. Now this other thing is a WFCO Ultra 3 Deckmount converter WF-9800 series mod WF9865. The wiring schematic shows a 110 v plug in the back, the chassis is grounded. It show Neg side wire goes to ground bar then to neg side on 12v Battery, Pos side goes to distribution panel power center then to pos side of battery. Only trouble is, my ground side is wired ok, but positive side, instead of going to distribution center, goes directly to the positive side of the battery. How do you figure that? All I can figure that is when shore power is plugged in it gets its 110 volts and charges the house batteries, by passing everything. It looks like a add on, I don't think National put it on. Looking at the manual I download, it's wired wrong but I see no sense in having it if the inverter/charger is doing its job.

[Sundancer268]

I have a Freedom 458 combi inverter/charger. Now this other thing is a WFCO Ultra 3 Deckmount converter WF-9800 series mod WF9865. The wiring schematic shows a 110 v plug in the back, the chassis is grounded. It show Neg side wire goes to ground bar then to neg side on 12v Battery, Pos side goes to distribution panel power center then to pos side of battery. Only trouble is, my ground side is wired ok, but positive side, instead of going to distribution center, goes directly to the positive side of the battery. How do you figure that? All I can figure that is when shore power is plugged in it gets its 110 volts and charges the house batteries, by passing everything. It looks like a add on, I don't think National put it on. Looking at the manual I download, it's wired wrong but I see no sense in having it if the inverter/charger is doing its job.

The only reason to keep it would be as a back up charger if the inverter fails. I had that happen and I could not use the inverter's battery charger to keep my batteries charged so I could run my furnace. I have since installed an auxiliary battery charger for a backup. I think I would just wire it up correctly and then kill the power until or if you need it.

[chucknewman]

retiredblade,

I suspect someone at some point installed the converter to charge the chassis (engine) batteries since your inverter/charger is charging only the house batteries. I was going to do the same thing on our Safari until I realized the factory routinely installed the Xantrex unit. And it works fine.

In your case, based on your posts I think the converter was installed to charge the chassis (engine) batteries, but was connected in error to the house batteries. If the converter is connected to the house batteries, disconnect it from them and reconnect it to the chassis (engine) batteries. As Brett says you want only one charger for each set of batteries.

A couple other things to look at. Find the battery isolator. It will be either a diode isolator with fins on the top or a solenoid isolator, usually round and fairly large. Either will have a positive wire on one side from the chassis batteries, and a positive wire on the other side from the house batteries. Check both connectors with the voltmeter to ground. You will see a different voltage on each connector. This indicates the two battery banks are properly isolated. If the voltage is the same, you have a short across the isolator at some point.

The other thing is I recommend disconnecting the solar panels from the batteries at the solar regulator output (you should have one) until you get your charging issues resolved. Without a solar regulator, you can overcharge the batteries resulting in wet tops. And some panels do not have built in isolation diodes. Without a regulator this will cause the solar panels to act a DC load at night -- draining whatever batteries are connected to them. I'm not saying this is your problem, but it helps to troubleshoot systems by disconnecting accessories and starting with the basics.

Chuck

[wolfe10]

Actually, I am not a fan of using a "not-smart" converter (how is that for political correctness) to charge EITHER battery bank if it is to be left on 24/7.

Better a smart converter, smart charger or smart inverter/charger to charge the house battery bank.

And a smart battery combiner such as the Xantrex Echo charger to use power from the charger and house bank to charge the chassis battery after the house battery bank is up to full/pre-set voltage.

Brett

[chucknewman]

Brett,

I agree with you, but retiredblade's WFCO charger has Bulk Charge mode, Absorption mode, and Float Mode. See the specs at http://www.americanrvcompany.com/assets/images/wf9800.pdf

I have no experience with this brand. Are you saying it is not a multi-stage charger?

Chuck

[wolfe10]

Brett,

I agree with you, but retiredblade's WFCO charger has Bulk Charge mode, Absorption mode, and Float Mode. See the specs at http://www.americanrvcompany.com/assets/images/wf9800.pdf

I have no experience with this brand. Are you saying it is not a multi-stage charger?

Chuck

Chuck,

You are correct, he could use his current charger for charging the chassis batteries-- I should have looked to see if he had a smart converter in addition to a smart inverter/charger. As you know, most who install a smart inverter/charger are replacing a "not-smart" converter.

Thanks for catching that.

Brett