Battery Shut Off Switch

[wampler]

my 2017 Flying Cloud has a shut off switch located on the light switch panel immediately inside the door. This does not turn off all electric as there is still a drain on the batteries. Does anybody know how to hook up a BATTERY SHUT OFF SWITCH for my unit?
It has two 6 volt batteries. I have tried a "screw off" thing on the battery post with no luck so I have to disconnect all cables going to the negative posts on both batteries when I put it in storage.
thanks,
Rick

[lsbrodsky]

A very common topic with a lot of threads on the forum. Search. Basically you are right, the normal installation leaves the propane detector, tongue jack, and trailer brakes still connected to the battery. Some have found the radio and/or subwoofer also connected. In the normal configuration you do have to either remove the battery cables, just the negative is fine, or install a disconnect switch at the battery.
Larry

[wulfraat]

Boom.

[OTRA15]

Welcome to the forum! As suggested, many threads/posts on this FYI:

https://www.google.com/search?q=batt...=airforums.com
Phantom loads: https://www.google.com/search?q=phan...=airforums.com

Happy trails,

Peter

[Hans627]

I only have one battery (1 lithium equals 2 lead-acid) and I installed a cut off switch in this manner. I'm not advocating for only one battery but only want to show how I did it.

FWIW!

[Mollysdad]

Here's my humble offering.
https://www.airforums.com/forums/blo...sconnect-3036/

[SagaCapt]

Wait this reply didn't attach to the picture I wanted. The right picture has both the great diagram AND a picture of the battery box with cut off switch inside.

That almost looks like a picture of our battery box!

Yes, the answer is a REAL battery cut off switch.

[ROBERT CROSS]

Bob
🇺🇸



Ours...

[BoscoMN]

In our 2017 25' FC I replaced the two stock batteries with two 6V Trojan T-145 batteries. To give me a more comfortable safety margin above the battery terminals I had the local welding shop make up a spacer collar out of stock channel steel. I then cut the existing cover enough so it would swing up without hitting the Airstream shell and remounted it to the new collar.

To provide a foolproof 100% disconnect I use a circuit breaker in the cable between the two batteries - no more parasitic loads draining the battery while in storage! This past fall/winter had the batteries each down only 0.01 volts for 3 months of storage.

[gypsydad]

Here is a set of 12V with manual kill switch, and a set of 6V with same. Don't get confused; the wire in 6V picture (left) is between the negative and positive posts; the 12V Interstate picture goes under the switch in the picture to the battery negative post.

[gypsydad]

Originally Posted by BoscoMN

In our 2017 25' FC I replaced the two stock batteries with two 6V Trojan T-145 batteries. To give me a more comfortable safety margin above the battery terminals I had the local welding shop make up a spacer collar out of stock channel steel. I then cut the existing cover enough so it would swing up without hitting the Airstream shell and remounted it to the new collar.

To provide a foolproof 100% disconnect I use a circuit breaker in the cable between the two batteries - no more parasitic loads draining the battery while in storage! This past fall/winter had the batteries each down only 0.01 volts for 3 months of storage.

T145's or T105's? Mine are T105's...not sure the difference? But, I am very happy with mine over past couple years, vs the 12V Interstate's in the past.

[Pangolin]

How do you check the water levels?

[Mollysdad]

Originally Posted by Pangolin

How do you check the water levels?

In my case, I made new battery jumpers so I could route them outside the filler caps.
https://www.airforums.com/forums/blo...sconnect-3036/

[Boxite]

It’s fun/interesting to see the solutions some owners choose to make in order to meet perceived design-shortcomings of the factory. I am the same sort of guy that does that kind of thing, so don’t leap to the conclusion I’m being critical of the modifications shown here, please.

I choose to NOT modify the battery charge circuit, finding the AS design to be just fine...but operate/store with the following recent event in-mind:

Just to re-visit the issue: I had found a piece of black plastic in the middle of my shop (hangar) and tho’ it looked familiar, I had a difficult time imagining where it came from... It was a long “cup” with the words beneath it that read “Levantar aqui”.
I am somewhat literate in Spanish but it did not compute what “Lift here” meant.

Two days later I found a crusty-white powder in a large area beneath the tongue of my Airstream. Suddenly I realized... my battery had blown up! The “cup” was the lifting handle previously incorporated into the plastic battery-box, which had been blown-apart when the battery exploded. (I’m not as rich as some of you guys/gals and have the Sport model AS with plastic box and plastic LPG covers.) The crusty white powder was the battery acid eating away at the concrete floor.

I threw two 4-lb boxes of baking-soda onto the area and moistened it with a spray bottle of water, letting it sit overnight, then the next day washed it all down the floor-drain with a water hose. I had to admit to myself that I’d neglected the battery for the last year. (We had taken a 3-month trip through the NW U.S. in the fall of ‘18, then had a health set-back which caused us to park it/store it in our hangar where it’s plugged into shore-power continuously. That has been our procedure previously, never having an issue with the battery. The converter has been reliably keeping it maintained at a “maintain-charge-level. But...I had not checked the battery water in all of ‘19. It’s a common lead-acid battery. It likely ran low on electrolyte and that is what caused the battery to blow-apart.)

Fortunately, no serious other damage appeared to have occurred. I bought a new battery and battery box and installed them after scrubbing the trailer tongue/battery-support area and touching up the paint in that area.

I then checked with a volt-meter to find that, with the AS battery on/off switch selected to ON that the battery was being maintained at 13.4 volts ...AND... that with the AS on/off switch selected to OFF...the battery terminals only measure 12.7 volts. This assures me that the battery is completely removed from the charging circuit when the AS switch is selected to OFF and is therefore in a safe, long-term storage position. I now keep it in the OFF position for storage. (The battery is still connected to the propane detector of course, but that device is also served by the on-board converter, so no battery dis-charge is occurring.)

I’m telling this story to remind everyone to:
1-disconnect your battery from the on-board charging circuit of the on-board converter when the trailer is in long-term storage.
2-if your battery is left on a maintenance-charge of any sort, to regularly check it’s electrolyte level (if it’s a flooded cell battery)
3-If the above cannot be conveniently tended to, then remove the battery and bring it home or to a place it can be regularly serviced safely. Isolate the positive battery cable from the trailer-frame so that ..should the converter be powered from shore-power... there will not be a “short” developed between the converter charge-circuit and the trailer.

Hope this helps others.

[Mollysdad]

Originally Posted by Boxite

(The battery is still connected to the propane detector of course, but that device is also served by the on-board converter, so no battery dis-charge is occurring.)

I’m telling this story to remind everyone to:
1-disconnect your battery from the on-board charging circuit of the on-board converter when the trailer is in long-term storage.

I never presume to tell anyone how they should wire their RV's. But the Propane detector is still in the circuit when the use store switch is in Store. It will drain batteries over time. There might also be other small loads which add up.
Pulling the terminals off the battery when stored certainly works, but can lead to quite a spark.
The Airstream battery box is vented to the bottom so no gas should build up,...but?

I'll recall an episode at work years ago. A vendor was running some electronics from 12 v auto batteries in a wooden box. The operator opened the box and connected alligator clips. "BOOM!" I heard it about a hundred yards away and thought someone may have thrown a M-80 in a trash bin. As I ran over the vendor was just rinsing his eyes with bottled water. He had the presence of mind to remember where the water was. He refused to go to the medics. Later that day his clothes sort of dissolved from the acid. He was fine, but embarrassed. He was lucky.

[Boxite]

Originally Posted by Mollysdad

I never presume to tell anyone how they should wire their RV's. But the Propane detector is still in the circuit when the use store switch is in Store. It will drain batteries over time. There might also be other small loads which add up.
Pulling the terminals off the battery when stored certainly works, but can lead to quite a spark.
The Airstream battery box is vented to the bottom so no gas should build up,...but?

I'll recall an episode at work years ago. A vendor was running some electronics from 12 v auto batteries in a wooden box. The operator opened the box and connected alligator clips. "BOOM!" I heard it about a hundred yards away and thought someone may have thrown a M-80 in a trash bin. As I ran over the vendor was just rinsing his eyes with bottled water. He had the presence of mind to remember where the water was. He refused to go to the medics. Later that day his clothes sort of dissolved from the acid. He was fine, but embarrassed. He was lucky.

Good point on re-emphasizing that, MollysDad. One of the issues with these RVs is the lack of consistent design/documentation ... and then if one buys “used” and the previous owner modified it... one might not know the situation.

I don’t know if AS did this... but I suspect they did (because the previous owner was one of those guys who was confused by simple water hoses and door-hinges, so I doubt he had the ingenuity to make any electrical modifications)...

But the propane detector on my Sport is connected to the 12v converter (WFCO 8955) output AND the battery positive-circuit UP-stream of the battery “disconnect” switch. That battery connection incorporates a diode, so that if the battery switch is in the “off” position, but the converter is still powered thru shore-power... no discharge occurs of the battery.

Don’t know if anyone else’s Sport is so-wired or not. It’d be interesting to learn of it from those owners who are knowledgeable of it. The schematic from AS does not have that level of detail.

<edit>. I’ve also learned some AS owners have added a switch to disable their propane detectors. I don’t know that I’d do that, but it’s another option, of course.
Additionally, it’s a good time to remind folks that propane detectors have finite lives. About 7 years and they should be replaced.
Same is true of CO detectors.

[gypsydad]

Originally Posted by Boxite

Good point on re-emphasizing that, MollysDad. One of the issues with these RVs is the lack of consistent design/documentation ... and then if one buys “used” and the previous owner modified it... one might not know the situation.

I don’t know if AS did this... but I suspect they did (because the previous owner was one of those guys who was confused by simple water hoses and door-hinges, so I doubt he had the ingenuity to make any electrical modifications)...

But the propane detector on my Sport is connected to the 12v converter (WFCO 8955) output AND the battery positive-circuit UP-stream of the battery “disconnect” switch. That battery connection incorporates a diode, so that if the battery switch is in the “off” position, but the converter is still powered thru shore-power... no discharge occurs of the battery.

Don’t know if anyone else’s Sport is so-wired or not. It’d be interesting to learn of it from those owners who are knowledgeable of it. The schematic from AS does not have that level of detail.

<edit>. I’ve also learned some AS owners have added a switch to disable their propane detectors. I don’t know that I’d do that, but it’s another option, of course.
Additionally, it’s a good time to remind folks that propane detectors have finite lives. About 7 years and they should be replaced.
Same is true of CO detectors.

Manual battery disconnect (cut off) switch.

[BoscoMN]

I incorporated this circuit breaker as my disconnect switch. I usually would not use a circuit breaker as a switch but I figure that I only use it once or twice a year so it should stand up to such light use. Plus if it does fail it should do it as I am switching it from one position to another - so I should be aware of the failure. I then can easily take it out of the circuit until I replace the circuit breaker.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I cut this bus bar in half to use in the circuit:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[pjshier]

My installation is identical to a previous diagram: coach and inverter to one side of the disconnect switch (output/common), POS battery post to the other side of the disconnect switch. Two small Zamp plug reversed polarity for my Renogy suitcase) and electric jack wires remain straight to the battery.

In checking the readout on the stock BATT (and tank status) panel, I selected OFF on the disconnect switch with shore power disconnected = nothing, as expected; no indication, propane monitor dark, etc. Selected ON with shore power disconnected and saw the propane monitor going through reboot and 12.7 when pressing the BATT button.

Connected shore power, disconnect switch in the ON position, shows 12.7, then 13.7 when pressing the BATT button. First push of the BATT button showed 12.7, a few seconds later, pushed again and the display indicated 13.7 - i have a Boondocker Power Center installed.

For grins, went outside to the battery box and selected OFF on the disconnect switch, then checked the stock status panel again - BATT displayed 13.7, I admit that was unexpected. Was thinking that the batteries isolated would show.... something else, tho not sure what, now that i think about it.

Any ideas? Is the fact that the coach and inverter positive cables are joined under the same post of the disconnect switch a contributing factor? Is what i've described normal?

[wulfraat]

With batteries disconnected and on shore power your converter will supply 13.6-13.7v to the trailer so 12v can continue to function without batteries. That is normal.