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Coach Batteries / Xantrex /

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Dave Porter:
Greetings all!  Don't know what I broke this time and I'm looking forward to your suggestions/ideas.  We have a new to us 2005 Beaver Monterey which had corroded coach batteries (a sulphur bloom) on the two outboard batteries.  After using a wire brush, baking soda paste, and some anti-corrosion spray, I was pretty proud of myself.  "Was" is the key word as when we went to visit our coacn to load more "goodies" this past weekend only to find none of the interior lights would come on.  I do have it plugged into a 30A shore outlet, so I found the lack of lights a little confusing.  Thinking maybe I had turned the inverter off, I opened the door to access the the Xantrex controls only to find it was "dead".  I checked voltage on the 4 cells, two at 6.xV and two at 4.5V.  Each "pair" is at 10.5V.  I had only cleaned two of the batteries (they were the two "outboard" ones and one is at 6.xV and the other at 4.5V.  I have double checked my battery wiring, just in case I got the cells in backwards....but all looks good there.  The battery switch is in the "on" position (it was in the "off" position when I did the cleanup).  I did notice that the stud connector for the battery to battery connections that attaches to each neg post was a little loose...like the connector maybe is a tad oversized to grip tightly around the smaller negative post.  In my zeal to make firm connections, I had been thinking I may have been too hard in tighening the stud extender on one of the negative posts of the battery that is reading 4.5v.  I don't know enough about batteries to know the internal workings and was afraid maybe I destroyed an internal connection.  That said, what's confusing is that I never touched any of the posts on the other battery that is also reading 4.5V so I've talked myself out of being a battery destroyer.  There is also a little grey Xantrex connector which, according to the manual is a heat sensor, that I feared I reinstalled on the wrong connector...but after reading of the manuals, I think I got it right as it is installed on an outboard neg terminal.  My plan for today is to return to the storage facility where I park the coach, take apart all I have done....especially focusing on cleaning up any of the anticorrosion spray, and start all over again.  Is that a reasonable plan or am I wasting time?

Another concern is determing the status of the hydrohot as I use it to keep the coach above freezing.  I can't tell if it's going to work (I fear not as the switch on the controls in the kitchen wasn't green).  

So I need some real education here.  1.  How to resolve my battery (or is it a Xantrex) issue.  2.  And as none of the lights come on inside the coach (and the hyrdohot), do I assume that the Xantrech is essential to have any inside power?   Even with being plugged into shore power?  3.  So is the easy solution to buy 4 new coach batteries and start all over?

OK, standing by for my education!  And boy, do I need it!

Edward Buker:
I do not know your battey configuration. To start out, for clarity use "battery" when you are refering to measuring the positive to negative terminals of one battery. The term "cell" is used to define a battry segment that is internally wired in series. I think you are refering only to the house battery bank which are 6V batteries (3 fill caps) each.

I would doubt that you damaged the internals of any battery tightening the post lugs. You did not connect anything backwards because that would have shorted and produced a large arc and possibly a battery explosion. There is a lot of current in the batteries when charged so be careful to label things if needed and not drop connected plus leads on the chassis metal.
 
Before you ever touch the battery switches you must be sure that the AC power leading to the inverter is off. The inverter needs a load and can be damaged if on and you disconnect the batteries from it using the switch. Also always have the battery switch back on before you reconnect the AC to the coach. Easiest way to disconnect is to pull your coach power cord. You can then turn off the battery switch and work in the battery bay. You can use the main AC breaker to disconnect also.

In your case it would seem that the batteries were already discharged so I do not think the charger was working before you did the work. You need to check the water level in each battery. See if it is above the plates, add distiilled water if it is not. Look for a cell that is abnormally low. That would indicate a bad cell (shorted) that is boiling out water. You would need to change that battery before proceeding. There may be a power disconnect switch in the coach that kills most of the 12V power and that may be off and not able to be turned on due to low voltage. Once the batteries are O.K. water wise and you see no abnormally low cell, I would leave the AC power off and the battery switch off and get an external decent charger and connect it to the batteries. Set it on 12V and connect it to the point that the main ground and plus leads from the coach are located. You should have measured the 10.5V here (should be 12.7V without charging going on) You should see amps drop over time and the batteries recover voltage wise. Once charged you can see if the batteries are O.K. and if coach electrical 12V systems are working. Reconnect AC and see if the Xantrex comes to life. If not you have assured yourself that the batteries can take a charge and are acceptable with the independant charger. If the Xantrex is not working then verfy it is getting AC power and refer to your manual for troubleshooting that unit. Your Xantrex display should help here. Hope this helps...

Bill Sprague:
The Xantrex on my 2004 has a circuit breaker on it.  As I recall, it is a red button.  Mine popped once.  I reset it and it has continued to work for a couple of years.

You didn't say how old the batteries are.  If they are the ones that came with the motorhome, you should consider replacing them.

The corrosion on the terminals comes from battery acid that naturally gasses out during charging.  I was never completely ahead of the corrosion blooms until a friend suggested that I hose off the batteries when ever I wash the motorhome.  I have had no corrosion since I started doing that.

You didn't say where you are, but if it is cold, your biggest threat is the hydro-hot.  Do not let it freeze!  The repairs will be difficult and expensive.

Edward Buker:
From my previous post, the alternate charger, water fill, checking for significantly lower cell, is to get a battery bank charged and up and running. That should allow you to get the aqua hot that Bill mentioned online so it does not freeze. You can leave that battey charger running and connected until you have the Xantrex issues resolved. You would want a charger that will deliver 30 amps or more continuous to get the job done. If the charger amps does not slowly taper off and the battery bank does not come up to 13+ volts with the charger on for 8hrs or so then change out the batteries. You will need the backup charger on the new batteries also if the Xantrex is not working.
Do not run any charger on the coach leads alone without the batteries also being connected to those leads. The batteries are very low impedance and absorb any votage spikes over 12V so that the coach electrical wiring does not see spikes from the "dirty" charger. These chargers put out pulsating DC that is not very clean. Hope this helps.

Bruce Benson:
I'm going the simple route on this one.  Is there a master power switch inside the entry of the coach?  If so is it on or off?

Bruce

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