Battery cut off switch

[Dtaylor]

I want to put a battery cut off switch on my TT so I do not have to keep removing the cables when I store. The question, should I put on one or should on two to cut off both sides of the battery?

[F105]

beemerphile1 wrote:
The reason some instructions say to place in the negative is because they are considering a powered vehicle, not a trailer. In a vehicle the negative is preferred. However for a trailer that is required to have brakes the breakaway is required to be operable when towing.

If the disconnect is left open, the breakaway will only work if it is in the positive and wired in front of switch.

tenbear wrote:
Is there a requirement that the breakaway switch be wired directly to the battery? I don't know why you would ever be driving down the road with the battery disconnected, but just to cover all the bases it is probably best to wire it with the breakaway switch not affected by the disconnect switch.

The breakaway is required to be operable. How it is wired is discretionary providing it is operable when towing. I guarantee that sometime, somewhere, someone will tow with the disconnect open. If not you then the next owner.

F105 wrote:
...I tow my FW with the battery disconnected - don't see it causing any damage.

It won't cause damage providing it never comes off the hitch and needs for the breakaway to work. It could be considered negligence if the breakaway is made inoperable and people are injured.

I think you mis-understood what I meant by my saying I tow my FW with the battery disconnect switch disconnected.

The brake disconnect switch is hot wired to the RV battery and is independent of the battery disconnect switch. Neither the RV manual or the battery disconnect switch have any warning to not disconnect the battery when towing.

[tenbear]

beemerphyle, thanks for the explanation. I won't make the same mistake again.

[beemerphile1]

The reason some instructions say to place in the negative is because they are considering a powered vehicle, not a trailer. In a vehicle the negative is preferred. However for a trailer that is required to have brakes the breakaway is required to be operable when towing.

If the disconnect is left open, the breakaway will only work if it is in the positive and wired in front of switch.

tenbear wrote:
Is there a requirement that the breakaway switch be wired directly to the battery? I don't know why you would ever be driving down the road with the battery disconnected, but just to cover all the bases it is probably best to wire it with the breakaway switch not affected by the disconnect switch.

The breakaway is required to be operable. How it is wired is discretionary providing it is operable when towing. I guarantee that sometime, somewhere, someone will tow with the disconnect open. If not you then the next owner.

F105 wrote:
...I tow my FW with the battery disconnected - don't see it causing any damage.

It won't cause damage providing it never comes off the hitch and needs for the breakaway to work. It could be considered negligence if the breakaway is made inoperable and people are injured.

[F105]

tenbear wrote:
Is there a requirement that the breakaway switch be wired directly to the battery? I don't know why you would ever be driving down the road with the battery disconnected, but just to cover all the bases it is probably best to wire it with the breakaway switch not affected by the disconnect switch.

I have heard of occurrences where the breakaway switch was pulled out of its socket when the RV was parked and drained the battery and also activated the brakes. So I would think its wired directly to the battery.

I tow my FW with the battery disconnected - don't see it causing any damage.

[tenbear]

Is there a requirement that the breakaway switch be wired directly to the battery? I don't know why you would ever be driving down the road with the battery disconnected, but just to cover all the bases it is probably best to wire it with the breakaway switch not affected by the disconnect switch.

[F105]

tenbear wrote:
It has been many years since I had a TT. I don't remember having a breakaway switch, and looking online, it looks as if it is an optional extra???

In any case, all you need is one disconnect switch. If you have a breakaway switch, wire the disconnect switch as beemerphile says, if not, follow my earlier suggestion. Either way will result in no parasitic loads.

Not completely sure,but I think brake breakaway switches are required on all TT and FW RV's.

[F105]

Dtaylor wrote:

F105 wrote:

tenbear wrote:

F105 wrote:


The point being is even with a battery disconnect switch installed,some RV's are wired in such a way that there will be a small current drain.

This is why I was asking if one should be installed on BOTH sides of the battery, but was hopping one installed at the battery would eliminate the problem.

One switch is sufficient - all you are doing is breaking the electrical circuit when the switch is placed in the disconnect position. The same thing happens if you remove one of the battery cables.

However as stated before,your unit may be wired so there are small current draws for items such as carbon mox detectors.

[tenbear]

It has been many years since I had a TT. I don't remember having a breakaway switch, and looking online, it looks as if it is an optional extra???

In any case, all you need is one disconnect switch. If you have a breakaway switch, wire the disconnect switch as beemerphile says, if not, follow my earlier suggestion. Either way will result in no parasitic loads.

[Dtaylor]

F105 wrote:

tenbear wrote:

F105 wrote:


The point being is even with a battery disconnect switch installed,some RV's are wired in such a way that there will be a small current drain.

This is why I was asking if one should be installed on BOTH sides of the battery, but was hopping one installed at the battery would eliminate the problem.

[mdamerell]

Mines installed in the positive cable. It's mounted on the wall next to my battery in my forward compartment. When off it locks out all electrical. Best $10 I've spent in a long time. Since it also locks out the landing gear, I also view as one more step a thief has to take and hence a possible theft deterrent.

[beemerphile1]

The disconnect will achieve the desired function on the positive or negative BUT:

On a trailer the disconnect should be on the positive side and the breakaway switch should be wired directly to the battery prior to the switch. That way the breakaway is capable of operation regardless of the position of the switch. Safety first and foolproof.

[F105]

tenbear wrote:

F105 wrote:
Keep in mind that some RV's will draw a small amount of voltage from the battery even with the disconnect switch in the disconnect position.

If the battery disconnect switch is installed on the battery there will be no current drain on the battery. The battery will still self discharge very slowly.

Some RVs, mine included, have the battery disconnect near the converter and it does leave some parasitic loads connected which do draw a small current.

That's what I was trying to say,,but you said it better.

The point being is even with a battery disconnect switch installed,some RV's are wired in such a way that there will be a small current drain.

[tenbear]

F105 wrote:
Keep in mind that some RV's will draw a small amount of voltage from the battery even with the disconnect switch in the disconnect position.

If the battery disconnect switch is installed on the battery there will be no current drain on the battery. The battery will still self discharge very slowly.

Some RVs, mine included, have the battery disconnect near the converter and it does leave some parasitic loads connected which do draw a small current.

[F105]

T-10 Parabolic wrote:

Captain_Happy wrote:
Mine is connected on the positive side. Either way will work.

Question-- If you put the switch on the positive pole when you put the switch in the disconnect position does it not spark??? Also when put the switch in the connect position will it not spark??? T-10

No it won't - remember the advantage of a battery disconnect switch is both convenience and you don't have to remove any cables to isolate the battery. The sparks would occur during the removal or reconnecting of the battery cable if done incorrectly.

The disconnect switch elimates the need to remove a battery cable.

Just think of the disconnect switch as a way to remove the battery without actually removing it.

Keep in mind that some RV's will draw a small amount of voltage from the battery even with the disconnect switch in the disconnect position.