When would you switch the disconnect switch to off? I don't really understand the purpose of the thing.

We always do when on the road, by default if I don't it will auto disconnected anyways. Don't think having power in the trailer is wise when moving. More chance for a unexpected problems I would expect....

It makes more sense to me to call it a connect switch. Therefore, when it's "off", it's disconnected.I guess it's for storage.. dunno, never used one.

Many RVs have devices that are "on" and drawing power if the battery is connected. Fore example, my RV has a propane/carbon monoxide detector that I installed hard-wired to the battery. So if the battery is connected, it is drawing power.Likewise if you have a motorhome there are things that may draw power from the engine battery even when the vehicle is off.These parasitic loads can drain a battery. The solution is to use battery terminals to disconnect the battery when I put the RV in storage.It is also somewhat of a theft deterrent, as the engine cannot start until you connect the battery.Steve

The only time it's beneficial to turn it off is when you store the RV and dont have power available to keep the battery on charge. Otherwise the battery will go dead within a few days if left on from the radio, propane leak detector, etc. that draw from the 12v battery. Assuming you have a TT or 5th Wheel, I see no reason to set it to disconnect while towing as the umbillical cord hooked to the truck will continue to charge the battery while your fridge is on.

A Disconnect is for when storing the unit without 120 available. to turn off all 12 volts to prevent battery drain. Problem is, due to Liability concerns, some OEMs, leave the CO/LP detector/s connected direct to the battery and bypass the disconnect switch. Does not make sense to then have a disconnect switch. But they do install them this way sometime. DougPS, they are NOT meant to be OFF when using or transporting the RV. There is NOTHING bad that will happen by having the 12 volts ON. If your Battery disconnect is OFF, on a towable, then your break a way for your trailer brakes will not function.

Battery Disconnect Switch | Good Sam Community

myredracer
Explorer II
Mar 08, 2019
Or if you take your RV to the dealer for work or to a repair shop and it sits there for days, the battery can be dead when you go to pick it up unless they plugged it into shore power. You could easily just disconnect the battery cable. Same if you wanted to use a battery maintainer over the winter instead of letting the converter/charger keep the battery charged.

Each time we had our TT into the dealer for warranty (2 year) work, the battery was totally dead and couldn't use the tongue jack. Very annoying. The Interstate battery failed at around 2-3 years old and not sure if it was related to the number of total discharges.
ppine
Explorer II
Mar 08, 2019
The disconnect switch is to be used when the rig is in storage. It prevents the loss of power from all the pirate voltage like CO2 detectors.
Terryallan
Explorer II
Mar 08, 2019
fj12ryder wrote:
Our trailer has a disconnect switch right on the cabinet down low. Unfortunately that a misnomer as some things don't shut off. The carbon monoxide detector and the radio/dvd player aren't disconnected. So even though you would think the disconnect switch would disconnect the battery from everything, you'd be wrong. I installed a manual switch on the battery that disconnects everything from the battery. I use it when the trailer is in short term storage.

Having the battery disconnected while traveling is fairly foolish as your brakes will not engage when the Break Away cable is pulled.

Not only that. But the TV charges the trailer battery while underway. Disconnect the battery, No charging takes place.
The only time mine is disconnected, is between trips in the back yard
wa8yxm
Explorer III
Mar 07, 2019
jbrack wrote:
When would you switch the disconnect switch to off? I don't really understand the purpose of the thing.

Whem Refilling Propane on my class A

Or when replacing batteries
dougrainer
Nomad
Mar 07, 2019
DrewE wrote:
dougrainer wrote:

PS, they are NOT meant to be OFF when using or transporting the RV. There is NOTHING bad that will happen by having the 12 volts ON. If your Battery disconnect is OFF, on a towable, then your break a way for your trailer brakes will not function.

I thought on most trailers the breakaway brake system was wired directly to the battery, bypassing the disconnect switch (and often unfused). Legally I'm not sure if the federal vehicle standards permit it to be switched. From a battery drain standpoint, of course, it's rather a moot point because it consumes no power unless activated.

I don't doubt that a few breakaway brake systems may be (incorrectly) connected through the trailer electrical system disconnect switch.

My comment was meant for those that want the battery completely disconnected. I doubt there is a Federal code for HOW 12 volts is supplied to the Break-a- way system. It is assumed that there will be power when on the road. It is BEST to have the battery Break-a-way wired directly to the battery. Doug
Gulfcoast
Explorer
Mar 07, 2019
You need power on a travel trailer or fifth wheel when traveling to activate your trailer brakes, if your trailer decides to head off on it's own thru the woods or into another lane of traffic.
DrewE
Explorer II
Mar 07, 2019
dougrainer wrote:

PS, they are NOT meant to be OFF when using or transporting the RV. There is NOTHING bad that will happen by having the 12 volts ON. If your Battery disconnect is OFF, on a towable, then your break a way for your trailer brakes will not function.

I thought on most trailers the breakaway brake system was wired directly to the battery, bypassing the disconnect switch (and often unfused). Legally I'm not sure if the federal vehicle standards permit it to be switched. From a battery drain standpoint, of course, it's rather a moot point because it consumes no power unless activated.

I don't doubt that a few breakaway brake systems may be (incorrectly) connected through the trailer electrical system disconnect switch.
wopachop
Explorer
Mar 07, 2019
Another use for the disconnect is to keep from cooking your batteries during the summer if youre on shore power. Depends on your setup.
fj12ryder
Explorer III
Mar 07, 2019
Our trailer has a disconnect switch right on the cabinet down low. Unfortunately that a misnomer as some things don't shut off. The carbon monoxide detector and the radio/dvd player aren't disconnected. So even though you would think the disconnect switch would disconnect the battery from everything, you'd be wrong. I installed a manual switch on the battery that disconnects everything from the battery. I use it when the trailer is in short term storage.

Having the battery disconnected while traveling is fairly foolish as your brakes will not engage when the Break Away cable is pulled.
dougrainer
Nomad
Mar 07, 2019
A Disconnect is for when storing the unit without 120 available. to turn off all 12 volts to prevent battery drain. Problem is, due to Liability concerns, some OEMs, leave the CO/LP detector/s connected direct to the battery and bypass the disconnect switch. Does not make sense to then have a disconnect switch. But they do install them this way sometime. Doug

PS, they are NOT meant to be OFF when using or transporting the RV. There is NOTHING bad that will happen by having the 12 volts ON. If your Battery disconnect is OFF, on a towable, then your break a way for your trailer brakes will not function.