# Battery Cut Off Switch



## Chris 312BH

I recently purchased a 312BH that came with 2 batteries and a cut off switch. My question is this. If I am plugged into shore power should I turn the switch to off to prevent the batteries form continually charging/overcharging, or more to the point when would I want to cut off the power.

During our walk through the person showing us our rv stated that you only want to turn it to off when you are storing for an extended period of time and that if I turn it off while plugged into shore power the converter will assume the battery is dead and try to send more charging power to the battery possibly overcharging it.

I have another buddy who says that's horse crap and that if the battery cut off switch is set to off then the converter can't charge the battery much less overcharge it. Looking for insight from those of you who know better. Also will my TV charge the battery if the switch is set to off as I would like to make sure the batteries are charging while in tow.

Chris


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## jozway

Leave the switch on when pluged in to shore power and turn off when not plugged in, You will be less likely to have a dead battery the next time you go to use it.


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## outback loft

You can shut off the switch when you are plugged in, but if you put on one two many lights the converter/charger will shut down as it can only provide so much power. What I have done in the past is leave the switch on when I am plugged in or out using the trailer, if I am not out I would shut it off so that I don't come back to dead batteries for the next trip.

Basically what the person doing the walkthrough told you, is crap. The charger cannot charge or overcharge the battery if it is not connected.


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## CamperAndy

A point to remember. the batteries must be connected to run slides in and out. Leave the cutoff on during trailer use and when plugged in, turn it off only when you put it in storage and only after you have fully charged the batteries.


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## W4DRR

We store our Outback next to the house, and keep it plugged-in to shore power 24/7. Never had a bit of problem. And FYI, the original el cheapo dealer-supplied battery lasted over 5 years before giving it up, so it must not cause any problems. (Not as good as my "Taco" pick-up truck, though. I've replaced the battery only once since I bought the truck new back in '95.)

Bob


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## hautevue

I respectfully disagree with jozway about turning the battery cutoff switch off when you are not plugged into shore power.

Turning it off kills all 12v circuits. Thus no propane detector, no power to the reefer, no lights, no water pump, etc.

You should turn it off when storing the TT so that hidden battery drains don't do you in. Hidden ones include the propane detector, the stereo (mine's a Jensen) and the smoke detector if it's like mine and served by 12v power and has one of those little 9v batteries for backup.

Otherwise leave the batteries active. Just conserve power, of course, but you know that.


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## jozway

hautevue said:


> I respectfully disagree with jozway about turning the battery cutoff switch off when you are not plugged into shore power.
> 
> Turning it off kills all 12v circuits. Thus no propane detector, no power to the reefer, no lights, no water pump, etc.
> 
> You should turn it off when storing the TT so that hidden battery drains don't do you in. Hidden ones include the propane detector, the stereo (mine's a Jensen) and the smoke detector if it's like mine and served by 12v power and has one of those little 9v batteries for backup.
> 
> Otherwise leave the batteries active. Just conserve power, of course, but you know that.


For the record I dont have a battery cutoff switch and leave my trailer plugged in 365 days a year. If I stored mine without power than I would utilize said switch.


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## jasonrebecca

Mine is plugged into a 30 outlet when stored. The battery is disconnected once it is fully charged. A couple days before we leave for camping I turn the switch just to make sure its fully charged before we leave.


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## Chris 312BH

Won't the fridge, lights, and water pump still run off shore power even if no battery, or dead battery. I thought the converter would still run everything as long as i don't overload it. Maybe I need to get better educated on how the converter works. Thanks to everyone for your responses.


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## Nathan

Chris 312BH said:


> Won't the fridge, lights, and water pump still run off shore power even if no battery, or dead battery. I thought the converter would still run everything as long as i don't overload it. Maybe I need to get better educated on how the converter works. Thanks to everyone for your responses.


The converter will do it until you overload it. Turn on all of the lights on a larger trailer and you'll be pushing the limits. Then run the water pump or try to operate a slide and you're talking about trouble. In fact, as already stated, make sure the battery is connected prior to running the slideout. If everything is working well, it will run off the converter but is hard on it.


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## wolverine

I have a 2005 21RS with the factory 2 stage charger. I never charge my 6 volt batteries using the converter/charger. I am afraid of cooking the batteries therefore I alwasy charge them with my deep cycle marine battery charger. When I am connected to shore power I disconnect the batteries using my switch. I have never had a problem running all of the lights, furnace and water pump at once. I do know if you have a power slide that you will need to use the battery.


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## Mark W

Hi All!

This may be a dumb question, but should I have the battery disconnect switch set to "on" or "off" while towing my Outback? Any positives or negatives (no pun intended) to doing so?

Thanks!

--Mark


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## Snow

Leave it "ON" .. if your Outback is wired like mine, the battery also provides power to the break-away switch in the event of a hitch failure ....


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## Leedek

So if your battery gets overcharged when the cut-off switch is off, does that mean if I plug in my cell phone charger and put my cell phone in another room it will get overcharged? Hmmm mm wireless charging has come a long way.









Seriously, the cutoff switch isolates the batteries from the charging circuitry and the batteries will NOT power anything in the trailer when the cutoff switch is OFF. Robert's advice on the batteries being charged during transit is solid. Check your number #4 pin on your trailer connector. If you don't have power there when your truck is turned on then your batteries will not be charged during transit. If you want power there then you'll need to check your vehicle's fuse block. It normally takes a 30A fuse to function the pin. My Silverado has it's fuse in the fuse panel under the hood, drivers side. Here are four photos so I save 4000 words.... aren't you lucky!!??










Here are the diagrams and photos of the fuse panel:



















This might help!!


















Hope this helps someone!


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