12v House Battery Problem

[Belgique]

I posted a query on this awhile back but nothing seemed to work. The problem is still there and I can't get a service appointment before we leave for an unanticipated mega Westward and Mexico trip so it is a DIY thing.

Problem is that house batteries drop to about 10V within an hour or 2 of disconnect from mains or not driving. Nothing that I can control is on. Even though the batteries are new, had them checked by a knowledgable tech and they are ok.

I'm a little handy with 12v so I wanted to kill all the 12v circuits and then activate one at a time to find the culprit but my 2001 Itasca 35U uses the pop-out breakers and I know of no way to "pull" them out to kill the individual circuit. Is there a way to kill all and then turn on, one at a time, the circuits? (I know you can kill eveything with the switch by the door but then you can't fault isolate).

Thanks in advance! Steve

[Belgique]

I posted a query on this awhile back but nothing seemed to work. The problem is still there and I can't get a service appointment before we leave for an unanticipated mega Westward and Mexico trip so it is a DIY thing.

Problem is that house batteries drop to about 10V within an hour or 2 of disconnect from mains or not driving. Nothing that I can control is on. Even though the batteries are new, had them checked by a knowledgable tech and they are ok.

I'm a little handy with 12v so I wanted to kill all the 12v circuits and then activate one at a time to find the culprit but my 2001 Itasca 35U uses the pop-out breakers and I know of no way to "pull" them out to kill the individual circuit. Is there a way to kill all and then turn on, one at a time, the circuits? (I know you can kill eveything with the switch by the door but then you can't fault isolate).

Thanks in advance! Steve

[Moder2]

Steve,

Arre you sure they are being charged? If your coach has a Converter, you might want to make sure that it is charging them.

I do not believe there is a way to "Pop" the breakers in the 12 volt side.

If it were mine, I would pull the batts, charge them on a seperate charger and then have them load tested. If your close to an Auto Parts store, many of them will do this for free for you (Advance, AutoZone, Pepboys, ORieley's), thought you will have to take the batts in to them.

My suspicion is that they are not being recharged, and when you are plugged in, the converter is powering your 12 volt stuff, the charger sections are know to give out, but I would check the fuses on it.

We ran into this once on a trailer we had (Our first one). Luckily it was just a fuse, but it simply wasn't charging the batts.

John

[Joe-K]

I agree with you that those pop-out breakers can make finding a current drain a hassle since they can't be popped out one at a time like a fuse can.

The only way I can think of would be to pull the wire off the back of the breaker one at a time if the breaker panel is accessible in your rig.

Another option is to use a DC clamp on ampmeter to measure the current flow though each of the wires coming from the breaker panel. Check each wire to see if there is a current draw somewhere.

[NR4A]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Another option is to use a DC clamp on ampmeter to measure the current flow though each of the wires coming from the breaker panel. Check each wire to see if there is a current draw somewhere </div></BLOCKQUOTE>

The clamp-on ammeter is a good idea, however if it is low current draw (less than 1 or 2A) you may not get the resolution you need for an accurate reading. A multimeter in series with either the Positive or Negative battery post will give you that accurate reading. You might consider that.

When I initially read the first post it jogged my memory of an incident I had with an old Datsun I once owned. The battery kept discharging on me. I did the series ammeter trick after going through 3 batteries and 2 alternators. The culprit turned out to be a bad switch for the light in the glove box. The bulb remained on all the time and overnight discharged the battery to less than 10v.

You might want to check the storage compartments for such light switches and see if adjustments are in order.

Like the refrigerator light syndrome - does the light REALLY go off when you close the door??

[dirko]

Hi Ho: Another common gotca is one of the lights in the basement storage compartments. It is easy to bump the switch and not notice if it is sunny. You really need to figure out what is discharging the batteries. However, it is still possible that one battery has a bad cell. These things just take some time and effort. The easiest thing as has already been suggested is to just disconnect the batteries from the coach and see if they maintain a charge. They should measure about 13.8 volts + or - a few tenths when being charged and should stay at about 12 volts with no load for several days. Good luck.

[Pubtym]

I have a 2006 Suncruiser 35U and I'm currently experiencing a similar problem with rapid voltage drop off (overnight/non use/parked) following shoreline disconnect. No load voltage drops overnight to 10.2 volts. Operator's Manual says prolonged (20+ days) of non use of house batts withour batt disconnect can contribute to sulfate/capacity problems. I had a converter go out about a month ago and there was a 10 day period of 10 volts and below on house batts.
My converter is charging house batts on shoreline and engine alt at 14.4V. Electrolyte fluid in batts is good. Op Manual says to expect 14.4 V for 13 hours then Voltage charge drop to 13.5 +- on house batts. Compartment light switch master is "off". As soon as I see charging volts drop to 13+- I'll cut shore power and turn off Batt disconnect to see if house batts maintain 12V no load for day or two. If voltage drops to 10 =- in day or two with no load..I believe it's time to assume bad house batt cells etc. Any other thoughts here?

[Pubtym]

Update: I just checked house batts after 3 hours by diconnecting shoreline. House batts read 11.5V....up from 10.2V. I reconnected shoreline for another 12 hours.

[NR4A]

Update: I just checked house batts after 3 hours by diconnecting shoreline. House batts read 11.5V....up from 10.2V. I reconnected shoreline for another 12 hours

Lead-acid batteries are 2.1 volts per cell, 6 cells give you 12.6 volts. Normally. However, a surface charge (aka static charge) should, in most cases, read 12.2 volts after it has sat for a while after charging. Removed battery cables.

If you are seeing less than the 12.2 volts, you have a bad battery. Period.

A hydrometer is the best way to read cell charge in the form of specific gravity.

Regardless of what these dealers are trying to make you believe, if the battery is charged and disconnected from any load - if you are
measuring 10 to 11 volts, replace the battery.

If you are running 2 batteries in parallel then you could also be loading one battery down from the other one in-circuit. Which might also have a sulphated cell or cells.

When in doubt - Change it out!

[Pubtym]

Great info...Thanks.

Do you use a trickle charger for engine Batt?

[NR4A]

Do you use a trickle charger for engine Batt?

There was a thread regarding Trik-L-Start which you can add on to your system that keeps the engine battery charged off the converter.

Personally, we are parked more than on the road so I use a trickle charger on mine.

[Pubtym]

Thanks NR4A. Both house batts tested "bad" at local Interstate dealer...and replaced under warranty. This morning...after 14 hour no load..house batts were strong at 12.6V.

[NR4A]

Another success story !!! Im delighted to hear this, and glad I could be of some help.

This forum has been invaluable in resolving some of my own coach issues, the owners deserve the pat on the back.

Again, congratulation on getting the problem fixed (and for free, too!!) Sorry that you had to go through the frustrations.

Happy miles ahead.

Sam

[Belgique]

Not fair!!! I'm the OP and still don't have a clue as how to attack this problem. But very glad someone had success!!! Yet another kudo for this forum!

My battery dealer is a good friend and the batteries check out fine. No lites etc left on (incl the basement). We're back at home for a few days before a LONG trip so I'll try some diagnostics but really am at a loss. I'll try going off shore power and see if the batteries are being charged as was suggested. Wish I could get it too the dealer so that someone that has a clue could look at it.

Still welcome any suggestions. Thanks, Steve