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Battery disconnect switch

Given my battery problem (see other thread), I was thinking it would be a good idea to add a battery disconnect switch at the house batteries.  Good idea?  If anyone has done this, I'd like to hear how you did it.  Thanks in advance.

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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #1 –
George, I understand your frustration but I would not consider a battery disconnect for a few reasons, instead I would try to find the WHY what happened.  With so many coaches out here with out having an issue, I bet you will find the offending issue.
Good luck
Dave

Re: Battery disconnect switch

Reply #2 –
Quote
I was thinking it would be a good idea to add a battery disconnect switch at the house batteries.  Good idea?  If anyone has done this, I'd like to hear how you did it.

I agree with Dave, but if you want to do it you can get a master disconnect switch from www.colehersee.com similar to what is at your front door.
but coming directly off the batteries.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Battery disconnect switch

Reply #3 –
Admittedly, there is normally no need to disconnect the house batteries.... until something goes wrong, which unfortunately is not a rare event in our aging, complex coaches.  I'd just like to put it in "hiberation" with nothing running.  Is there a problem in doing this?
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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #4 –
George, My opinion is simply that if you shut the electrical system down in proper order, then have a heavy enough contactor/switch capable of handling 200-300 amp for a disconnect and have it  properly installed and wired, sure would be fine.
My point is that it is very costly for the 4/0 battery cable and the heavy contactor needed, then finding the space and getting it done.  I would simply turn every thing off and remove the neg cable at battery terminal.
But I am cheap and teach.
Have fun
Dave

Re: Battery disconnect switch

Reply #5 –
Would this have enough amps for our RV’s?
 
http://tinyurl.com/297ncru
 
Cheap, and convenient to battery if batter is accessible (it is in my 2000 U-320)
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Battery disconnect switch

Reply #6 –
George, I understand your thoughts about a disconnect switch. there are times when you want to be able to quickly turn everything off. Take a look at the Blue Sea ML-S Remote Battery switch...
 
http://bluesea.com/category/1/productline/385

They have a 500 amp continuous, 700 Amps Intermittent and a whopping 2500 amp cranking rating. There a latching switch so there is on current draw in the off or on position. The nice thing is you can mount the switch down next to the batteries, with the control switch up on the dash. Another neat thing is there is a manual locked off knob mounted on the switch. So there is no way someone can jump start you coach. If I remember right my cost was about $125.00 from Fisheries Supply Seattle.

Cheers
Ted

"97 40' U320 build 5035

The best things in life are not things.... It's fulltiming in a Foretravel.

Re: Battery disconnect switch

Reply #7 –
Thanks for all the ideas.  I did contact James Triana and he said it was OK to disconnect the house battery when it was not plugged in to shore power.  So that is what I did when we took the coach to its storage area. 

One strange thing.... with the house batteries disconnected, the electric door locks still worked with the key fob.  When the house batteries were dead they didn't work, so I thought they were off that set of batteries.  Any ideas?

It was easy to disconnect the house batteries, but I might get one of the suggested switches to make it even easier. 

Added 10/23/10....  We've had the house batteries off about 6 weeks now with no problems.  Had to recharge everything after about a month, but it only took about 48 hours of AC power.  We do have a slide, but even with it deflated there is very little space between the bladder and the slide (maybe 1/16 to 1/8"), so that is not a big problem.  We store the coach inside a rented building. 

George
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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #8 –
A Small point about turning off everything. IF you have  SLIDE.
I prefer to keep power on to keep the air pump working keeping pressure on the slide seal..  Maybe with no air, the bladder/seal might open and make a entry for critters ?
I prefer paying for the electric to keep the pump up and critters out.
Dave

Re: Battery disconnect switch

Reply #9 –
Here is the switch I ended up with.  It costs about $25 from Camping World and is rated at 250 amps continuous, 750 surge.  It is meant for the negative terminal and that is the way it is installed.  Fit surprisingly well.

Question...  What would happen if I disconnected the battery (i.e., opened the switch) with the shore power on (charger off)?
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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #10 –
Quote from: George Hatfield –
Here is the switch I ended up with.  It costs about $25 from Camping World and is rated at 250 amps continuous, 750 surge.  It is meant for the negative terminal and that is the way it is installed.  Fit surprisingly well.

Question...  What would happen if I disconnected the battery (i.e., opened the switch) with the shore power on (charger off)?
George,
I can't be certain w/o the electrical diagrams, but I think the 12v circuits fed by the house batteries would not have power.  If the start batteries are connected, anything fed by those batteries would have power.  And, with the shore power/generator as the source for 120 VAC, your 120 VAC appliances would work.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Battery disconnect switch

Reply #11 –
Quote
Question...  What would happen if I disconnected the battery (i.e., opened the switch) with the shore power on (charger off)?

I did this inadvertently.  It's rather uneventful.  If the charger is "on", the power stays on - the coach is running on the charger output only. 

If the charger is "off", well..everything goes off.  This was with an RS3000 charger/inverter.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Battery disconnect switch

Reply #12 –
The previous owner had those switches installed on both batteries.  I found out why the hard way.  Leaving the batteries connected with everything off still drained them.  The only way to keep the batteries in good order was to keep them disconnected with those switches.  The stock converter charger in mine was not capable of running the coach on shorepower with the batteries disconnected.  There was power but I ran the risk of frying the fridge or doing other damage.  I replaced it with a modern converter charger that claims to be able to provide clean 12v via shorepower with the batteries disconnected but I don't do it in any case.  The new charger also has 3 stage charging so I keep the rig plugged in all the time now.  I never had any problems keeping the batteries disconnected however it is good that you asked James because I understand on the newer units, prolonged lack of power can damage the ECU.
Dwayne Keith
1992 U240
3116/MD3060

Re: Battery disconnect switch

Reply #13 –
I hate to admit my stupidity regarding how the house batteries are wired, but I realized that since they are in parallel, one would need a battery switch for EACH battery when wired in at the battery.  I realized this when I closed one of two battery switches I had installed and the HWH air pump came on!  A quick diagram of parallel wired batteries showed why.  So with my original switch all I did was pull one battery off line.  With two, I pulled two off line.  I guess I will have to install a third one to get them all off.  Live and learn.  This also explains why the key fob worked with the single battery switch off (see above)!
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George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #14 –
Parallel batteries often have a common connection point, where the multiple cable ends connect to single motorhome cable.  Putting in a disconnect switch to keep the motorhome cable from being powered would remove a battery bank.

Re: Battery disconnect switch

Reply #15 –
Quote from: George Hatfield –
I hate to admit my stupidity regarding how the house batteries are wired, but I realized that since they are in parallel, one would need a battery switch for EACH battery when wired in at the battery.  I realized this when I closed one of two battery switches I had installed and the HWH air pump came on!  A quick diagram of parallel wired batteries showed why.  So with my original switch all I did was pull one battery off line.  With two, I pulled two off line.  I guess I will have to install a third one to get them all off.  Live and learn.  This also explains why the key fob worked with the single battery switch off (see above)!

George,
You can install the disconnect switch to get all 3 batteries.
Put it here like in the diagram.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Battery disconnect switch

Reply #16 –
Thanks for the advice.  I'm sure there is a way to do it such that one switch isolates all three house batteries.  But I didn't want to cut any wires and splice in a switch.  My "easy" approach was not what I thought it was...  just want to inform others what I found.
The selected media item is not currently available.
George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Battery disconnect switch

Reply #17 –
Quote from: George Hatfield –
Thanks for the advice.  I'm sure there is a way to do it such that one switch isolates all three house batteries.  But I didn't want to cut any wires and splice in a switch.  My "easy" approach was not what I thought it was...  just want to inform others what I found.

George,
I don't think you need to cut any wires.
Just move your disconnect switch and connect it to the wire that feeds all three batteries like like you did before on one battery.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"