Battery Kill Switch

[Tom Kramer]

Hi Bob,

One of the first things I did was install a kill switch as I was tired of unscrewing each of the battery connections. I interupted the main positive supply and installed the switch in series. I used #4, 3 foot cable that came with the spade lugs. I puchased the Blue Sea switch (http://www.bluesea.com) at Western Marine (http://www.Western Marine.com) and and the battery cable from Pep Boys. It took me 15 minutes to install. Hope this helps.

 

[illini trekker]

When buying a disconnect switch I'm seeing a amp rating for the switches. What do you ALL think the switch should be rated at in Continuous Amp Rating, and Surge Amp Rating. Am looking at keyed switches, I feel there is less exposed area to accidentally make contact with (arc).

 

[RickFox]

Dave,

The major problem with disconnecting via. the positive terminal is that unless the associatied wiring and terminals are insulated, an accidential connection to this exposed wiring will create a major spark and current surge. As mentioned in other threads, this spark can potentially create a major meltdown or fire. For example, even with the positive terminal disconnected - perhaps using a disconnect switch within the front storage area adjacent to the battery - any exposed switch terminals which still have 12V present can be accidently touched with a tool, tripod, or any other metal device that is also in contact with the frame. If this occurs, you will instantly know it and wished that it hadn't occurred.

On the other hand, any accidental contact with any portion of any switch or terminal connected in the ground circuit will do will cause no major problem or meltdown.

If you use a disconnect switch on the positve side, be sure to insulate all exposed connections or you may accidentially cause a major meltdown.

 

[dsprik]

Thanks, Rick. I think I understand - had to read it twice.

I just thought you could cause a spark on the neg end too.

 

[RickFox]

Dave,

You are correct. If there are circuits turned on - for example, my wife loves to forget to turn the furnace off when we break camp - shorting the disconnected negative terminal to the frame could cause the furnance fan to start - thus drawing a current spark. But, this is significantly less of a problem than accidentially shorting the positive battery to ground. In this situation, the current flow could be upwards of 100+Amps. Talk about welding - that's welding current - and perhaps with your hand on the welding rod.

 

[dsprik]

Thanks, Rick! I'll make a note... "THAT'S NOT GOOD!"

Now if I just remember to read it...

 

[RickFox]

For additional info on knife switches constructed for battery disconnect applications refer to the Wirth Engineering web site. A typical switch can be seen at http://www.wirthco.com/product_info.php/cPath/7_9/products_id/60

This switch, as with most other switches manufactured by WirthCo are designed to connect to the "negative" side of the battery.

 

[timandsusan]

I have a 2006 3475RL that has the battery disconnet switch in the same area with the water, cable, black tank flush, etc. Must be a new feature but it is really great!!

 

[Russ and Sandy]

When I originally hooked up the knife type switch on ours, I placed it in the battery compartment. I rigged a cover for it and even made up a label warning that it would have 12V on it - even when disconnected (to the terminal attached to the battery). I was always concerned that an "accident" was waiting to happen.

Well, about 3 weeks ago, I decided to change it to the ground side - after it finally dawned on me that it would function the same way regardless of which side it was attached to. After attaching it, I tested it - everything still worked with the knife up! Why? Well I had dutifully added a ground cable from the Onan generator to the battery as instructed during installation. I thought at the time that that cable was very large compared to the one Keystone installed (or maybe the dealer used when adding the second battery, but paid no attention to whether the generator ground connection was isolated from the generator frame.

End of story: The knife switch is now installed between battery -12V and the generator ground wire. I believe the 4 generator mounting bolts provide a very good ground to the frame. The worry of an accidental contact is gone, because about the worst thing that would happen is it would just make a "normal" connection to ground. Yes there would be a small spark, but there should be no flammable vapors in that area. And for that matter, any switch method used would probably create some spark if there is anything turned on. Then, to be totally safe, the switch would need to be designed to contain the sparks within a sealed enclosure.

I'm glad to hear that a disconnect switch is now being included in the new units.

 

[G McCall]

I consider the battery disconnect mandantory.
Even My 2001 Mobile Scout TT came from the factory with a knife style battery disconnect.
I am very disapointed that my new 2005 Mountaineer does not have the battery disconnect. I have one now to add to my new trailer.
We leave our trailer at our deer lease and use the disconnect every time we leave.
We do go to the lease year round to camp.

 

[richfaa]

We note that there is a battery disconnect swith in the "docking station" of the present 06 models..wonder how it is wired up???

 

[Driftwoodgal]

Ok you guys told me that there isn't a dumb question.

Why do you need a battery disconnect?

Thanks for your replies

 

[Longwell-MOC]

Driftwood, I asked the same question on March 13, but no reply yet. I guess it is supposed to be obvious, even to inexperienced fulltimers.

 

[CountryGuy-REDW]

battery disconnects are used by those who do not full time to keep the battery from discharging and dying IF we are in a storage mode. There are little things in the unit that will keep on running off the battery, like the Carbon monoxide detector, even when you are NOT plugged in. They will discharge the battery in, ohhhh, a few days to a week. Then you go back to the unit and you have no battery charge left. Solution, when you unplug and put Montana in a storage mode, you turn off the battery via the disconnect and all is well.

 

[Longwell-MOC]

Gotcha! Thanks. I wasn't sure if it applied to our needs or not, since we won't be storing; just using!
Because there were so many posts, I figured I'd better ask.
Thanks again, Al & Carol.
Larry

 

[Driftwoodgal]

Country Guy,

When we aren't using our rig it is parked near the house and plugged into our well house, so it has electricity to it at all times. Since it is plugged in we wouldn't need to have the battery disconnect?

I do remember when we first got the rig home we used the batteries to put out the slides, not a good thing. Won't do that again, and now understand what you are saying about the drain on the batteries. Thanks for taking the time to explain to a newbie learning the ropes.

Thank goodness hubby understands most of these things, but I am the computer person that ask the questions. Then I go ask him..... did you know? Sometimes he says yes and sometimes he says no I didn't.

Again thanks for taking the time to explain.

 

[houseof many dogs]

Longwell, be sure to check your battery water often. When we started BMOC (Before MOC), my battery was always "going dead" - and I was charging it a lot - ran it low on water - fried it, now I know better and have both the cutoff and check the water a lot.

 

[padredw]

I just posted on another thread some comments that may be relevant to this question. I will quote myself:

This is one answer to a question asked in a recent post: "why have a battery cut-off switch?"

With a battery cut-of switch, once the battery is in full charge the 30 or 50 amp can be disconnected and the battery switched off, thereby preventing any current drain. Our Montana rarely 'sits still' long enough to require recharge between uses, but I do keep a check on the water level occasionally. This does require "manual" monitoring, but it has soved the problem you raise for me.

I also replaced my one 12 volt battery with 2 6 volt "golf cart" batteries wired in series to produce 12 volts. I follow the above practice when the RV is not in use.

 

[CountryGuy-REDW]

Driftwoodgal,

If you leave plugged in ALL the time you might not need a disconnect. But, if it gets unplugged and you don't realize it, well, there goes the battery. Ours is plugged in most of the time, but there are times it must be unplugged for more than 15 minutes and the disconnect is our savings.

We have used the slides on battery, IF the battery is charged, there is no problem. One summer we had it unplugged, disconnect off, slides open, tornado and severe storm warnings, I went out, turned the disconnect to ON, went in, closed slides, turned disconnnect back to OFF, went in the stick house. Easy. And, no storm!

 

[Longwell-MOC]

Thanks, houseofmanydogs. I will be sure to check the levels regularly and frequently. It would be a mess without battery power.
Larry