Casita SD wiring question

[UpstateCasitaFolks]

Can anyone tell me where does the 12 Aux feed from my 7 pin go when it gets into my 2007 Casita SD? Does it go to the converter first and then out to the battery and other 12 circuits including the fridge? Or does it go directly to the trailers battery hot (+) side first? Reason I ask, is I too have the battery drain problem when towing with the fridge on 12v. I suspect a large part of the problem may be an inadequate sized 12v feed wire to my factory provided 7 pin receptacle on my 2018 Nissan Frontier. Although I haven't looked, I doubt it is AWG 12 or larger.
Thanks,

[CalCop]

According to a wiring diagram the 12volt wire comes into the closet, black 10awg, and travels along the street side of the trailer. It branches to the converter and then through a 20amp circuit breaker to the battery. That circuit breaker is normally installed on the battery compartment case and is an auto reset.

[UpstateCasitaFolks]

Thanks for the info. Unless the feed gets sidetracked somewhere else in the converter before going to the breaker and on to the battery this shouldn't hinder the charging of the trailer battery while towing. I'll try to check the size of the 12v wire feed in my Frontier next. I saw a Utube video of an owner of a 2016 Ford F150 with a factory hitch setup, and found Ford using an 18 gauge wire feeding the 12 v pin in his 7 pin receptacle. He was quite irritated with Ford to say the least. He ended up rewiring with 12 gauge wire along with a relay and breaker.

[gordon2]

Originally Posted by UpstateCasitaFolks

....Reason I ask, is I too have the battery drain problem when towing with the fridge on 12v. I suspect a large part of the problem may be an inadequate sized 12v feed wire to my factory provided 7 pin receptacle on my 2018 Nissan Frontier. Although I haven't looked, I doubt it is AWG 12 or larger.
Thanks,

I dont have a Caista or Nissan Frontier, or know much about them, however no matter how it is wired I can almost guarantee that that tug and trailer battery are in parallel to the fridge, that is that either or both can power the fridge. Unless there is a battery disconnect switch perhaps.

The best way to see what is going on is to take some measurements with an ammeter inline with the charge line from the tug, and with one at the trailer's battery (and perhaps also only the fridge). But as you seem to be aware, it is more the rule than not that a charge line from the tow vehicle is not enough to run a RV fridge on 12 volts, and therefore the trailer battery also gets discharged.

Without an ammeter, you could disconnect the trailer battery (at the negative post) and then try to run the fridge while towing. If it does not run or fails to cool enough then its likely low power from the tow vehicle.

[ehoepner]

Check the wire size on your tow vehicle, the wire to pin seven needs to be 10 gauge. With a smaller gauge wire there is a significant voltage drop across the wire from the tow vehicle battery to the trailer plug-in. I had one tow vehicle where I had to change that wire on the vehicle.

[John in Santa Cruz]

on my Tacoma, I found the voltage drop with the Casita 16's tiny fridge on electric was sufficient that the battery was indeed discharging. I did some testing, 50% of this drop was on the Tacoma side, and 50% was on the Casita side. the Tacoma's battery was maintaining 14.2V so the alternator was perfectly capable of outputting enough voltage, the drop to < 12V was happening entirely in the wiring.

Rather than try and rewire both, I just ran the fridge on propane when traveling, problem solved.

16 feet of copper 10 AWG at 12 amps has a 0.2 volt drop. 12AWG has a 0.3V drop. each connector in the circuit also has some resistance.

[Jann Todd]

Originally Posted by UpstateCasitaFolks

Can anyone tell me where does the 12 Aux feed from my 7 pin go when it gets into my 2007 Casita SD? Does it go to the converter first and then out to the battery and other 12 circuits including the fridge? Or does it go directly to the trailers battery hot (+) side first? Reason I ask, is I too have the battery drain problem when towing with the fridge on 12v. I suspect a large part of the problem may be an inadequate sized 12v feed wire to my factory provided 7 pin receptacle on my 2018 Nissan Frontier. Although I haven't looked, I doubt it is AWG 12 or larger.
Thanks,

When towing with fridge on 12V we have problems keeping the battery charged also. We don't use 12V except for short periods like from the house to the gas station then put it on propane after fueling. We tow with a large vehicle with substantial output but it seems like the fridge just draws down the battery. We've used on propane for 40 years and feel safe. After all how many times have you seen a fire caused by the propane and fridge on? Most RV fires are caused by the engine in motorhomes. We've seen several of those but never a trailer fire caused by the fridge. Make sure you do turn off all pilots or igniters before fueling. We've never seen a propane tank fire yet.

[dmad1]

I had the same problem a few years ago when I bought a new Carriage trailer and truck. Ended up that with the new Chevy truck you had to actually install the required fuse in the fuse block on the truck. It came with the truck but just wasn't installed. Might ask around...

[gordon2]

Originally Posted by dmad1

I had the same problem a few years ago when I bought a new Carriage trailer and truck. Ended up that with the new Chevy truck you had to actually install the required fuse in the fuse block on the truck. It came with the truck but just wasn't installed. Might ask around...

Or just get your meter out and see if the aux line at the 7 pin on the tug has power (~13-14 volts with tug running). But I had assumed it was established that the charge line was working.. just maybe not enough for the fridge.

[Frank R.]

Upstate, we towed our 17' Casita all over the country several times, including Alaska, and I can tell you from experience that you will never get it to charge the battery adequately while towing with the fridge on 12V. I say that after virtually heroic efforts to eliminate as much voltage drop as possible. I paralleled the original wiring with a second #10 wire and that didn't help. Then I paralleled all that with a #8. Still no deal. The only way you can keep the house battery charged is tow on propane. Yeah, I know that blasted thing keeps blowing out. Among all the other drawbacks to the 3-way fridge.

Finally, I yanked the absorbtion fridge out and replaced it with a Nova Kool 5810 12V compressor driven fridge. End of problem, absolutely the best thing I ever did to the trailer. Disclaimer: We don't boondock except an occasional overnite at a Wal Mart or similar. I installed an auxillary battery "just in case", but have not yet used it.

[thrifty bill]

Traditional RV refrigerators will not keep up on 12V DC when you are on the road. You either go with a more efficient refrigerator (as pointed out above), run the refrigerator on propane, or just run it when you are not in motion (propane or 120V hookup).

Endless discussions on whether it is safe to run on propane while you are moving. I'll leave that topic alone.

[Sebas]

Why fridge hage 12v option? It dont work well and drain lot of energy from the battery. Is it ok to run with the gaz on ? I am new in the RV world.
Thanks

[thrifty bill]

Frig has 12v option because customers want them. Google running refrigerator on propane when driving and you will get thousands of opinions. No need to rehash it.

[Jann Todd]

Originally Posted by Frank R.

Upstate, we towed our 17' Casita all over the country several times, including Alaska, and I can tell you from experience that you will never get it to charge the battery adequately while towing with the fridge on 12V. I say that after virtually heroic efforts to eliminate as much voltage drop as possible. I paralleled the original wiring with a second #10 wire and that didn't help. Then I paralleled all that with a #8. Still no deal. The only way you can keep the house battery charged is tow on propane. Yeah, I know that blasted thing keeps blowing out. Among all the other drawbacks to the 3-way fridge.

Finally, I yanked the absorbtion fridge out and replaced it with a Nova Kool 5810 12V compressor driven fridge. End of problem, absolutely the best thing I ever did to the trailer. Disclaimer: We don't boondock except an occasional overnite at a Wal Mart or similar. I installed an auxillary battery "just in case", but have not yet used it.

Our fridge in our Casita has never blown out when traveling with it on propane. We have driven in heavy winds also. Kansas is always windy almost and we did fine on propane. We also know there's no way to keep the battery charged while driving with the fridge on 12V. We boondock a lot and the absorption fridge has been wonderful for over 35 years in several RV's and our Casita for 11 years. I'd never go to a fridge that had to have electric or would drain the battery in a short time.

[Jann Todd]

Originally Posted by Sebas

Why fridge hage 12v option? It dont work well and drain lot of energy from the battery. Is it ok to run with the gaz on ? I am new in the RV world.
Thanks

Have no idea why the fridges have a 12 volt option since we've never been able to use it for more than going to the gas station from our overnight stop so we wouldn't have to stop and go inside to shut off the fridge so we could fuel up. Then after fueling up we pull away from the pumps, go inside and put it on propane.

[UpstateCasitaFolks]

Thanks everyone for your input on this thread I started. I too am now a believer that towing with the fridge on 12V is just not feasible. While heavier wiring my help, the infrastructure of most tow vehicles and trailers are just not equipped to deal with this type of current draw. There are basically two options, tow with propane on or get the fridge good and cold before you leave and don't open the door until you get to your campsite. (providing the it doesn't take all day)

[Glenn Baglo]

In October, several years back, we drove home to North Vancouver from Nehalem State Park. The fridge was turned off and not opened for the six hour trip. A pint of ice cream in the fridge freezer was just soft enough to scoop when we got home.

That said, I now travel with the fridge on propane.

[Joe MacDonald]

fridges have 12v option so you can use converter when plugged in to 110v campground. for a long time options were 12v and propane only, 110v came along after
Joe

[Jann Todd]

Originally Posted by Joe MacDonald

fridges have 12v option so you can use converter when plugged in to 110v campground. for a long time options were 12v and propane only, 110v came along after
Joe

But fridges now have 12V, 110 and propane. So maybe long time ago your idea is right but in the last 15 years at least that is how they come. So why 12V now? If you are hooked to electric you run on 110V. I think if you run on 12V while hooked to electric your battery will run down. The battery charge does not keep up with the drain it gets from the fridge. I've never tried it but charging the battery while plugged in to electric is a slow process.

[John in Santa Cruz]

Originally Posted by Jann Todd

But fridges now have 12V, 110 and propane. So maybe long time ago your idea is right but in the last 15 years at least that is how they come. So why 12V now? If you are hooked to electric you run on 110V. I think if you run on 12V while hooked to electric your battery will run down. The battery charge does not keep up with the drain it gets from the fridge. I've never tried it but charging the battery while plugged in to electric is a slow process.

hmm? your Casita power converter should be 35 amps or something, of which about 20 amps is available to charge the battery... that should fully charge a 50% discharged group 27M battery in like 5-6 hours or something.

and that 35A converter should have MORE than enough power to run the fridge on DC.