What drains the battery on a FC25 when it’s off?

[daleyocum]

I’d like to rewire my 2018 FC25 so that when you turn off the trailer at the master switch the thing really IS completely off for long term storage with no external load on the battery. I know I need to rewire the LP gas detector, are there any others devices? I’m never going to use the trailer with the power turned off and always shut of the LP tanks when the trailer is in storage.

I’ll be using a portable batteryminder 10 watt solar panel to keep the battery charged.

[rmkrum]

The typical loads are the propane detector, and on some models the sub-woofer is always connected to power.

You could trace down the wiring to those items and see if their fuse and associated wire can be moved to the 'load' side of the battery disconnect relay instead of the battery side.

Be sure you don't rewire the fuses and wires going to the use/store switch...that would be an interesting troubleshooting exercise. (grin)

[Dtrentr]

Don’t forget the antenna booster

[afk314]

It's hard to believe, but it is true. On my 2013 Intl, the subwoofer is wired straight to the battery through the street side electrical port to the A frame. Good enough for AS, I guess. Not good enough for me.

-a

[bwpaint]

On ours, I disconnected the 1000w inverter. It was wired directly to the battery
and was drawing about 1/2 amp even if turned off. Also put a switch on the propane detector and removed the fuse from the sub woofer.

[SeaLevel]

I simply installed an on/off switch on the outside of the battery box. Now when I park it after a trip, I just turn it off and everything is disconnected.

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

I had to rewire things so that the positive connections to the batteries and power jack go through the switch.

[billrector]

Originally Posted by bwpaint

On ours, I disconnected the 1000w inverter. It was wired directly to the battery
and was drawing about 1/2 amp even if turned off. Also put a switch on the propane detector and removed the fuse from the sub woofer.

Agree, the inverter is one of the big current draws even when off!

[billrector]

Originally Posted by SeaLevel

I simply installed an on/off switch on the outside of the battery box. Now when I park it after a trip, I just turn it off and everything is disconnected.

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

I had to rewire things so that the positive connections to the batteries and power jack go through the switch.

A couple of questions for you:

1) Did you mount the switch in the wall of the battery box?

2) Were the cables long enough to do this?

3) So you did the red cables? They are shorter than the black cables on mine.

4) Why did you decide to wire the power jack into the switch?

Thanks!

[SeaLevel]

Originally Posted by billrector

A couple of questions for you:

1) Did you mount the switch in the wall of the battery box?

2) Were the cables long enough to do this?

3) So you did the red cables? They are shorter than the black cables on mine.

4) Why did you decide to wire the power jack into the switch?

Thanks!

1) Yes. See the picture below.
2) Yes. One of them just barely.
3) Yes. See the picture below.
4) I replaced my power jack with one that is wired (both positive and negative) directly to the batteries, and I didn't want it to be connected when the trailer is parked for storage.

I've been very happy with how this works. I used to lose some charge in-between trips, but now it's negligible, even after about a month, which is the longest we've gone between trips so far. They might go from 12.86 to 12.84 as measured with my Fluke meter.

[wulfraat]

I’ve mounted the switch both ways - inside the box and outside. Inside is my preference if there is room.

I’ve also used single and dual pole switches. Use a blue sea switch - they are about $30 bucks or so.

This question gets asked once a week so I went ahead and drew up wiring diagrams for fellow airstreamers - see attached.

Enjoy.

[chaseav]

What everyone said above PLUS: I believe that the USB ports have a parasitic draw as well.

Also, I listened to the fellas above and installed the cutoff per their instructions and the parasitic draw problems became completely irrelevant and are saving batteries.

[Twinkie59]

Disconnect the battery completely it will really be off and costs alot less then rewiring a brand new trailer

[daleyocum]

Thanks everyone! This is truly crazy on Airstream’s part to have a master switch that clearly isn’t. It really could give people a false sense of security. I’m an electrical engineer and thus can’t seem to leave things alone. I plan on doing a lot of electrical work adding solar, Lithium, and a hybrid inverter so I’ll add a Blue Sea master switch then. For now I’ll just put one of these in the battery compartment. Not elegant but it solves my immediate problem. I’ll ignore the AS master switch except maybe as just a handy way turn turn off stuff when leaving for the day.

[overlander63]

Originally Posted by daleyocum

Thanks everyone! This is truly crazy on Airstream’s part to have a master switch that clearly isn’t. It really could give people a false sense of security. I’m an electrical engineer and thus can’t seem to leave things alone. I plan on doing a lot of electrical work adding solar, Lithium, and a hybrid inverter so I’ll add a Blue Sea master switch then. For now I’ll just put one of these in the battery compartment. Not elegant but it solves my immediate problem. I’ll ignore the AS master switch except maybe as just a handy way turn turn off stuff when leaving for the day.

Just use a simple knife switch on the negative terminal of the battery set, and connect all the negative wires to it. Then simply lift the knife switch when not in use. Simple to use, nothing to twist, turn, or get lost, no extra stuff to drill, screw, or mount.

[billrector]

Originally Posted by wulfraat

I’ve mounted the switch both ways - inside the box and outside. Inside is my preference if there is room.

I’ve also used single and dual pole switches. Use a blue sea switch - they are about $30 bucks or so.

This question gets asked once a week so I went ahead and drew up wiring diagrams for fellow airstreamers - see attached.

Enjoy.

Yes, thank you very much for the wiring diagram! I have not only seen it, it is saved on my desktop! I'm actually well down the road on this project but keep getting new ideas. I have been working with Mollysdad on putting the switch in a pvc junction box attached to the battery box. This has the advantage of not taking up any room in the battery box and providing some weatherproofing of the connections (the Blue Sea switch is waterproof). One problem is that the positive leads are really too short to do this and I did not want to splice the cable. I may also need to move the Zamp solar port to install the box. It looks like the negative cables are longer and may work.

A new idea is to run a 1/0 cable into the wiring compartment inside the front storage and mount the switch there.

[Wayne&Sam]

My guess is the the lp detector has to be wired so it’s always on by code

[Gleverett]

2015 25' FC I simply disconnect the main back ground wire from the battery terminal and it kills all power to the trailer. Have done this for winter storage the last 3 years with no problems.

[CruizinDux]

Originally Posted by Gleverett

2015 25' FC I simply disconnect the main back ground wire from the battery terminal and it kills all power to the trailer. Have done this for winter storage the last 3 years with no problems.

This is what I do as well if I'm not using the TT for a couple of weeks. If longer then I bring home the batts for a warm spot on the corner of my workbench and a C-Tek smart charger as needed.

Also (on our unit) the radio is parasitic draw (along with the Prop Det and maybe the Sub woofer)

Bob

[rogerdog1]

It’s not just Airstream....I have a Leisure van on order, and it has a .4 amp parasitic load when “disconnected”, so I am going to also install a separate disconnect switch (on the battery negative side).

[gypsydad]

As you can see, many of us have had this question...answered. I installed a knife kill switch and attached all the trailer connections to it. simple and easy. I like the other integrated kill switch in earlier post also, but I have used this before and works fine for me.