23fd Battery disconnect switch install

[Bobbo]

He put one on the main trailer hot wire thinking it would stop the phantom drain. When it did not, further research showed that the phantom drain was the inverter, so he put one on that hot wire.

I may put a relay on the inverter hot wire that is controlled by the fuse board under the refrigerator. That way, if I put the batteries in STORE mode, the inverter will also be disconnected.

[wulfraat]

Positive side is the way to go.

I used a single switch that allows me to select:

1 - main 12v trailer feed
2 - inverter feed
1+2 - trailer+inverter
all off

Both the main 12v feed to the trailer has a parasitic draw (propane detector) and the inverter also has a standby draw.

You need to disconnect both when in storage assuming you are not connected to a float charging source.

[pfcardwell]

Not being up on my battery technology Airstream has the positive and negative of the inverter go to one battery and the positive and negative of the main going to the other battery, I'm assuming for battery health

[wulfraat]

Yes they do that to balance load across the batteries... unfortunately they also use 6ga parallel cables to connect the batteries together when the inverter cables are a larger 4ga. Good grief.

I re-wired the parallel cables that join the 2 batteries with 1/0 gauge and connected all pos loads to a single pos terminal and all neg to the neg terminal on the other battery.

[Coalman]

Battery drain and work around

I just brought home a FC 25 and I'm curious if anyone see a problem with hooking up a Battery Tender to battery bank and leaving it plugged in to shore power between outing.

[DKB_SATX]

Originally Posted by Coalman

Battery drain and work around

I just brought home a FC 25 and I'm curious if anyone see a problem with hooking up a Battery Tender to battery bank and leaving it plugged in to shore power between outing.

That's exactly what I do. I have a battery maintainer that plugs into the SAE 12v port for the portable solar system and just leave that plugged in when the trailer is in storage, where I have a few amps of 120v available.

[pfcardwell]

So I guess I could eliminate one switch by doing what wufraat did and putting both circuits on positive post of one battery with the switch and the negative circuits on the other battery. I did change all wiring to 2g that I could. Wednesday reading 12.75 3rd day.

[Cispook]

Originally Posted by wulfraat

Positive side is the way to go.

I used a single switch that allows me to select:

1 - main 12v trailer feed
2 - inverter feed
1+2 - trailer+inverter
all off

Both the main 12v feed to the trailer has a parasitic draw (propane detector) and the inverter also has a standby draw.

You need to disconnect both when in storage assuming you are not connected to a float charging source.

Wufrat - did you make your own cables or order them pre-made? Source for parts or maker if you can share. Regards

[wulfraat]

Ordered them pre-made from Amazon. 1/0 sized cables with 3/8th inch ring terminal ends. One black and two red.

https://www.amazon.com/dp/B07113NT8K..._tHFkeT96m8UqD

I did have to add ring terminal ends to the main 12v leads from the trailer (I cut off the automotive clamps, which is necessary for the hot/+ lead at a minimum as it fastens to the switch) - I had some of those in my toolbox and I also own a crimp tool....

[Cispook]

Originally Posted by wulfraat

Ordered them pre-made from Amazon. 1/0 sized cables with 3/8th inch ring terminal ends. One black and two red.

https://www.amazon.com/dp/B07113NT8K..._tHFkeT96m8UqD

I did have to add ring terminal ends to the main 12v leads from the trailer (I cut off the automotive clamps, which is necessary for the hot/+ lead at a minimum as it fastens to the switch) - I had some of those in my toolbox and I also own a crimp tool....

As I read it, you added 3/8" terminal rings on the cut off wires for placement in the cut off switch? Thanks

[wulfraat]

Correct, this is required for the main pos 12v feed as it connects to the rotary switch in the picture. This is a 6ga wire.

I did the same for the beg feed for consistency although strictly speaking adding a ring terminal to the negative feed is not required. (Also a 6ga wire)

Pop/neg feeds from the inverter are already equipped with ring terminals. These are 4ga wires.

I used 1/0 gauge wires to replace the 2 parallel connections across the batteries for good measure. Stock from the factory the parallel connections are 6ga wires. Too small!

[pcskier]

Originally Posted by wulfraat

Positive side is the way to go.

I used a single switch that allows me to select:

1 - main 12v trailer feed
2 - inverter feed
1+2 - trailer+inverter
all off

Wulf this is the switch you used, yes?

https://www.bluesea.com/products/600...y_Switch_-_Red

Can't tell from pic, how did you mount the switch, or is it just held in place by the wires?

After seeing your switch in person, do you think the 2-terminal switch would work, i.e. is there enough room to attach the lugs from both the inverter and main 12v feed to one lug, resulting in "all on" or "all off" condition, or would it be too tight with the heavy gauge wire?

Thanks for the intel, this is next on my list.

[wulfraat]

That is the switch I have. It's floating in place and secured by a zip tie and 1/0 gauge wire which won't budge much.

Yes there is enough room for 2 lug connections (one from the inverter and one from the 12v main trailer hit feed). The 1/0 gauge wire goes to the battery and has its own terminal connection.

[rmkrum]

There are 4 nice holes in the corners of the switch that will accommodate a faster of your choice, be it wood screws or machine screws...

[pcskier]

Originally Posted by rmkrum

There are 4 nice holes in the corners of the switch that will accommodate a faster of your choice, be it wood screws or machine screws...

Yes, but I was asking what those screws were mounted to. One person used a sheet of plexiglass on the center threaded rod which was slick. Wulf just let his be held in place by the cables which is the route I'm taking. It won't be going anywhere attached to those heavy cables.

[pcskier]

Originally Posted by wulfraat

That is the switch I have. It's floating in place and secured by a zip tie and 1/0 gauge wire which won't budge much.

Yes there is enough room for 2 lug connections (one from the inverter and one from the 12v main trailer hit feed). The 1/0 gauge wire goes to the battery and has its own terminal connection.

Thanks again. Based on that, is there a reason you chose the 3-position switch with 3 terminals, vs the 2 position switch with 2 terminals, and put the invertor and 12v feed cables on one lug? Just want to make sure I'm thinking this through all the way before ordering!

[wulfraat]

Originally Posted by rmkrum

There are 4 nice holes in the corners of the switch that will accommodate a faster of your choice, be it wood screws or machine screws...

Yes on a previous install I used those holes and put two screws into the side of the battery box and mounted the switch on the outside.

With the newer battery boxes however they are deep enough to accommodate the switch on the inside sitting on top of the batteries.

For this latest install I just used zip ties through the holes to keep the casing of the switch buttoned up and then a single zip tie that attach the switch body to a cable to keep the switch from bouncing about inside the battery box

[wulfraat]

Originally Posted by pcskier

Thanks again. Based on that, is there a reason you chose the 3-position switch with 3 terminals, vs the 2 position switch with 2 terminals, and put the invertor and 12v feed cables on one lug? Just want to make sure I'm thinking this through all the way before ordering!

No worries. I'll draw you a picture and upload when I get home this evening

[pcskier]

Originally Posted by wulfraat

No worries. I'll draw you a picture and upload when I get home this evening

Thanks. Based on your earlier description and photo, I think I'm clear on how you wired yours, using this switch, you had one cable on each of these lugs, from the 12V Main Feed to trailer; the Inverter Cable; and lastly the jumper from the second battery + side. Giving you the option to choose 12V Trailer feed only on, Inverter only on, both on, or 'all off'.



I was thinking of using this switch, and putting the 12V feed to trailer and the Inverter feed on one lug, and the feed to battery on the other lug. What I was wondering is if there is enough space on the lugs to be able to put the Inverter and Trailer feeds on one of them. This would allow me the choice of 'all on' or 'all off.'



Assuming there is enough room for me to put both cables on one lug, was there an advantage you saw in having the ability to choose between 'all on', '12V Feed only,' 'Inverter only', and 'all off'?

Thanks again for bearing with me. Not a big deal either way, I just like to see how others arrived at their solutions to be sure I'm not missing something that might be helpful later!

[wulfraat]

Let me know if this makes sense.