Battery Disconnect Switch

There is one switch in our coach that glows red all of the time. As far as I know, this switch has never been used. Probably because the ominous glare of the red light is so frightening, particularly at night.

Not hard to miss when you open the command panel. A piercing red light beside a switch with the label BATTERY DISCONNECT.

Newmar seems to overlook even the most basic industrial design practices. Newmar elected to use a momentary rocker switch for the battery disconnect. Looking at the switch, the operator will not be able to determine whether the battery disconnect is ON or OFF. The switch stays in the middle position. And what is the purpose of the red light? If the red light is on, does that mean the BATTERY DISCONNECT switch is on? Or is it off?

And why would I need to use the battery disconnect switch?

I have 65 manuals for our coach all digitized in Evernote for easy access and reference. There is but one mention of the Battery Disconnect switch. And this is what it says:

Battery Disconnect Panel

The battery disconnect panel for house batteries is located above or near the entrance door. There are two switches on the panel. The top switch is used to measure the battery voltage. The lower switch is used to disconnect the battery when the unit is stored for any period of time. Pressing downward disconnects the coach batteries, not the chassis batteries. This is done to prevent the coach batteries from being drained during storage. It disconnects all of the 12 volt circuitry from the batteries, with the exception of the LP detector. When taking the unit out of storage, press upward to re-connect the batteries. This will make the 12 volt system ready for use.

Depending on the chassis of the coach, diesel pusher motorhomes may be equipped with a second disconnect switch strictly for the chassis batteries. If equipped, this “Master Kill Switch” may be located in the rear engine compartment. This switch disconnects all power to the coach so that it cannot be started. It is used to prevent accidental ignition when the engine is being serviced.

“There are two switches on the panel.”

There is only one switch for the battery disconnect panel.

“Pressing downward disconnects the coach batteries, not the chassis batteries. This is done to prevent the coach batteries from being drained during storage.”

This is the intended function of the battery disconnect switch. It disconnects the house batteries if you are storing your coach for longer periods of time and when your coach will not be connected to any form of shore power in storage. Pressing down will disconnect the batteries (OFF) and pressing up will re-connect the batteries (ON).

“It disconnects all 12 volt circuitry from the batteries, with the exception of the LP detector.”

We have an all electric coach and we do not have a liquid propane detector. And there is some debate on the forums as to whether some devices still draw power from the house batteries even when the battery disconnect is activated (e.g., smoke detectors).

We have stored our coach for several months over the years. I made sure that we had power to the coach in storage and I would go in and check the water level of the batteries on a regular basis.

A battery disconnect is a simple and safe way to disconnect the house batteries. No need to get out to the battery bay and remove battery leads. It is used when storing the coach without a source of power. It could be helpful for certain types of electrical work although I would prefer to leave that decision in the hands of a knowledgeable electrician.