Battery Disconect Switch

Sure ... a Blue Sea m-Series Mini Model #6007 will do exactly what you want.

Terminate the disconnect switch onto the (+) phase wire that enters the trailer. Be sure you still have some manner of circuit protection like a fuse or circuit breaker inline.

westend wrote:
Terminate the disconnect switch onto the (+) phase wire that enters the trailer. Be sure you still have some manner of circuit protection like a fuse or circuit breaker inline.

This. Also be sure to connect the breakaway switch prior to the disconnect so it is always hot for safety. Sooner or later, you or someone will tow the trailer with the disconnect open.

Except that it may be REALLY inconvenient to get a main cable from BOTH sets of batteries routed to one common place to go through a switch.

It really is best to have a switch for each one, mounted at a point near the battery so that you don't have to extend the heavy gauge cables.

If all the trailers I have seen with two batteries, I have never came across one with two cutoff switches (one for each battery. No matter if they were wired in parallel or a series, there was only one main + and one main - cable exiting the battery box or uncovered battery area.

Sam Spade wrote:
Except that it may be REALLY inconvenient to get a main cable from BOTH sets of batteries routed to one common place to go through a switch.

It really is best to have a switch for each one, mounted at a point near the battery so that you don't have to extend the heavy gauge cables.

Disagree completely ... done correctly there's no reason at all to not use a dual battery switch as I described earlier. In fact, I'll be adding one to my own trailer this spring when I also install a pair of G31 batteries to replace the current G27 which itself is wired through a similar Blue Sea m-Series Micro single battery switch.

SoundGuy wrote:

Disagree completely ... done correctly there's no reason at all to not use a dual battery switch as I described earlier.

I think some clarification is needed.

What does the OP mean by "both" batteries ??

If that is two sets, one for house and another for "truck" that are not located close together then you are wrong.

If there is more than one battery connected in a "bank", then there should be a common point for both positive and negative and a single switch should work......and then why ask the question at all ??

If this is a travel trailer or 5er and there is more than one bank of batteries.......WHY ??

Sam Spade wrote:

SoundGuy wrote:

Disagree completely ... done correctly there's no reason at all to not use a dual battery switch as I described earlier.

I think some clarification is needed.

What does the OP mean by "both" batteries ??

If that is two sets, one for house and another for "truck" that are not located close together then you are wrong.

If there is more than one battery connected in a "bank", then there should be a common point for both positive and negative and a single switch should work......and then why ask the question at all ??

If this is a travel trailer or 5er and there is more than one bank of batteries.......WHY ??

This is the TT section of the forum so I make my replies assuming a TT.

SoundGuy wrote:
Disagree completely ... done correctly there's no reason at all to not use a dual battery switch as I described earlier.

Sam Spade wrote:
I think some clarification is needed.

What does the OP mean by "both" batteries ??

If that is two sets, one for house and another for "truck" that are not located close together then you are wrong.

If there is more than one battery connected in a "bank", then there should be a common point for both positive and negative and a single switch should work......and then why ask the question at all ??

If this is a travel trailer or 5er and there is more than one bank of batteries.......WHY ??

Nice try there Sam but no cigar for you! :R. This is the travel trailer forum so of course the OP is talking about dual batteries on a travel trailer. :S. Obviously one may choose to run dual 12 volt batteries simultaneously in parallel BUT with the use of a dual battery disconnect switch such as I linked to before one may also alternately choose to run those two batteries sequentially - i.e. run on one battery until it's drawn down 50%, then switch to the second AND if there's a convenient means of recharging one can then even recharge the first depleted battery while the second full battery runs the trailer ... all because the user chose to install a dual battery disconnect switch.

SoundGuy wrote:
all because the user chose to install a dual battery disconnect switch.

And ALL a waste of time and money.
Discharging only one at a time accomplishes exactly NOTHING.
Charging only one at a time, likewise.

A battery will provide XX amp hours of energy. Two of the will provide twice that much. Whether they are discharged together or separately makes no difference. Same thing going the other way with replenishing the power with a charge.

The only exception I can imagine is if the owner/operator is prone to leave something running until the battery is totally flat. Then you could recover just by throwing a couple of switches.

P.S. This ain't my first trip to the Rodeo. I've been in the electronics industry for 50+ years.