Battery Switch On? Off? When?

[gregpallen]

OK so there seems to be differing thoughts on the recommended battery cutoff switch position depending on the state of the RV.

1. During the walkthrough of my Reflection 5ver my dealer told me that the battery charger in my new rig does not provide a trickle charge and therefore the the battery switch should be in the “off position” when connected to A/C shore power. If left in “on position” it will fry the battery. This seems to be in conflict with equipment literature in my owner’s packet which clearly indicates that the battery charging system adjusts its output based on battery condition and when the battery voltage approaches fully charged the system goes into trickle charge or maintenance mode. I was able to confirm this with Grand Design customer service so I think this situation is clear.

2. When towing, the TV charging system will take over and the RV battery switch should be in the “off position” according to Grand Design. The TV will safely maintain the battery. This situation is not addressed in the owners packet but intuitively it made sense to me.......that is until I recalled again conflicting information from my dealer (see #3 . below)

3. My dealer stated that the battery switch should always be in the “on position” when towing otherwise the RV’s emergency brake will not activate if the rig is separated from the tow vehicle. At first blush this sort of makes sense if you assume that with the battery switch in the “off position” there is no power to the emergency brake when/if the umbilical cord between the TV and the RV is separated. But then as an engineer, logic would tell me that surely GD has the emergency brake wired directly to the battery so that it is always powered regardless of cutoff switch position? Does anyone know for sure?

Anyway, I thought that others may have some confusion as to what to do when based on the three states described above, so hopefully you experts out there can shed some light on this topic and provide definitive direction to those of us that may be a might confused.

[Keebler]

I am reading this with interest because I always leave my factory battery switch in the on position. I am not aware of any issue with doing so, but am no expert and willing to learn.

That said, I do know for a fact that there are things left powered, even in the off position and I am 99% certain that the emergency brake (item 3) is always powered.

I am not sure of the complete list of what gets power when left in the OFF position, but for me, I had enough drain that ~ two weeks in storage (I don't have access to power in storage) and my battery was dead. This lead to me installing my own disconnect switch right at the battery; shuts off everything. There is no way I can forget to turn it back on when I hook up because I can't raise my front legs without power.

[Country Campers]

There is a dependency on how the 12 volt system is wired.
With the battery switch in either position you should have the following conditions,
1- Battery power to the emergency breakaway.
2- Charging from the converter.
3- Charging from the tow vehicle.

There are lots of stuff still with power when the switch is "off",
Motion lights in the basement storage , pass thru as well as the front.
Propane detector inside.
Radio, and some of the interior lights.

Even with the battery switch in the "off" position my battery was drained in a couple of weeks , with no shore power attached. This is why I installed a "true" battery disconnect.
As @Keebler said above , if you add a switch you can not do anything until you turn it on.

Brian

[huntr70]

Run away from your dealer....quickly.

[gregpallen]

FYI - I have in fact installed a master battery disconnect to prevent drainage while in storage. Obviously this needs to be “on” when towing for emergency brake to be functional. Does anyone know for sure if the other cutoff switch needs to be in “on” position?

[Skiddy]

You could verify this yourself. As you installed a disconnect switch, assume you might have a clamp meter or at least a multimeter. If you have a DC current clamp meter put it around one of your battery cables when the factory disconnect is OFF. Draw should be <500mA for the sniffers, radio etc... Pull your breakaway disconnect switch to activate the brakes and the current drain should be in the 10 to 20A range, assuming 5 to 8 amps per axle.

If you don’t have a clamp meter, you can connect a DC multimeter between a battery post and battery cable. Again, you should observe low draw in the <500mA range, and it will jump to 10 to 20A when the breakaway switch is activated.

EDIT - if you want to run your fridge, either propane or 12V, you will need the factory disconnect switch to be in the ON position.

[Steven@147]

Run away from your dealer....quickly.

As fast and as far as you can!
I think what got some people confused is how the switch is labeled "Battery Disconnect". Double negative - Disconnection Off meant battery was connected to the coach. Disconnection On meant battery was disconnected from the coach. Depending on how one interpreted the label.
Do you think they probably been better off labeling the switch "Battery Connection". But dealerships and service people should surely know how the switch works.

As far as I know there can be issues with the battery if using shore power and the converter charging circuit , and using lead acid battery, the acid level gets too low or goes dry. But if using this type of battery one should have it on their maintenance check list or replace it with a different type battery. Or In very cold climates? RV not being used battery can freeze.

At our residence I can't always keep the RV close to an electrical outlet (15 or 50 amp). If our coach is going to set for a short time (a month between uses) I keep the shore power applied and the Battery Disconnect switch lever pointing to ON (normal mode batt power supplied to coach).
For really long periods (three months or more) of non RV use, warm climate, shore power disconnected, I disconnect the battery cable terminals and kill all power to coach. A week prior to intended usage of the RV, Reconnect battery cable terminals and apply shore power.

[J&G garage]

In four years of ownership I've never turned that red key. Don't even know if it turns. Can't see any reason to turn it off as it doesn't shut down the 12v system. I installed a switch for that as my first mod.

[LV Naturist]

This probably does not answer your question, but to share my perspective... I see no reason to turn the batteries off except while in storage. If I understand the converter correctly, it will not overcharge a battery(ies) assuming they are not defective. Therefore there is no real advantage to turning them off. Also, we know that components in the RV rely on the 12 V system to operate. The fridge comes to mind. Yes, while in a campground and plugged in to shore power the converter is supplying the 12 V necessary, until there is a problem with shore power. Power goes out and since the batteries are off, the fridge turns off. Probably not a big deal for a few hours, but the alternative leaves the fridge running. While running down the road, we run the fridge on propane. Again, batteries on. I just don't see the downside to leaving the batteries connected at all times except while in storage. YMMV.

John

Edited to add: To the OP, please don't misunderstand. You have a valid question in understanding how the RV functions. Just don't overthink it...

[gregpallen]

This probably does not answer your question, but to share my perspective... I see no reason to turn the batteries off except while in storage. If I understand the converter correctly, it will not overcharge a battery(ies) assuming they are not defective. Therefore there is no real advantage to turning them off. Also, we know that components in the RV rely on the 12 V system to operate. The fridge comes to mind. Yes, while in a campground and plugged in to shore power the converter is supplying the 12 V necessary, until there is a problem with shore power. Power goes out and since the batteries are off, the fridge turns off. Probably not a big deal for a few hours, but the alternative leaves the fridge running. While running down the road, we run the fridge on propane. Again, batteries on. I just don't see the downside to leaving the batteries connected at all times except while in storage. YMMV.

John

Edited to add: To the OP, please don't misunderstand. You have a valid question in understanding how the RV functions. Just don't overthink it...

You bring up another point about the fridge. My belief is that it is powered via 120vac or propane. I was not aware that it could or would operate on 12vdc. I will have to check that out.