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Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 2:42 pm
by Dano-Mich
We did a two week trip back in July and I don't recall the trailer being excessively hot when we stopped. We did mostly sandwiches on the road so we would pull over and go into the trailer to get foods and make lunch. I did paint the roof with Henry 587 and most of the time it felt like the trailer was cooler inside than out. We have a Fantastic fan that can exhaust air out or pull air in and that helps tremendously. Just saying you might want to consider the Henry 587 roof paint to reflect heat.

Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 3:30 pm
by Iconfabul8
flboy wrote: you don't want to run the generator 24/7 just for the refrigerator nor run the generator while driving.

Just curious, what is the problem with running the gen while driving? Providing the wires are designed too and not flapping in the wind. Looks like if you are anticipating a stop, you could get the air going a few miles down the road and have a nice cool trailer when you stop.

Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 3:55 pm
by flboy
I do not believe there would be a real problem at all if you did that as long as wires and etc. were run properly with safety in mind. Large RVs run their generators going down the road to run the rooftop(s) to keep the entire coach cool every day. I never saw much use for that with a pull behind since nobody should be in it under tow.

I certainly would not consider doing that for a fridge with all the other charging options, but in the case of traveling with infants and etc. where they would prefer instant comfort and want to turn the air on in advance of a stop... why not if you can and it makes your life easier.

Trying to run a large AC off a large inverter and a very large battery bank supplemented by a Tow Vehicle alternator and appropriate charger would be so expensive and unnecessary, the gen is the way to go for the few times that is needed.



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Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 5:15 pm
by McDave
Sounds like you need to vent while driving. So the trick is to use the inherent wind to your advantage. The strongest force on a trailer with a flat vertical rear surface is probably drag or suction pulling that surface opposite the direction of travel. if you let air in somewhere, (probably best not low where hot asphalt and exhaust fumes live) and allowed the natural suction to pull it through the trailer while in transit, at least you would start at ambient temp. What you must avoid is a low pressure zone in the bathroom. if it is lower than the pressure in and around the black tank the fumes will enter even with water in the traps. so just provide for suction at the tank vent. there are vent caps that rotate and weather vane to do this. You may want induct fresh hi pressure air at the bathroom. Think of a hood scoop that "forces" air into the carb of your hot rod. Then a smaller area vent at rear to pull air out, but at a lesser cfm than the intake scoop causing a positive pressure in the cabin, keeping tank gasses pushed out of the cabin and traps pressurized correctly.
RV propane reefers won't and can't work while in transit since it needs flame to boil the ammonia. So they are usually running on 12v, with a element heating the ammonia tank. They are not efficient and may not be working at all since the elements have a short lifespan. If it is a 3 way reefer it may also have a 120 element, also not efficient but you would have a lot more power available to heat the tank. But lets face it, keeping things cold with heat is not the best way. Pressure = Heat. Make pressure and remove heat, much better.
Just sayin',

McDave

Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 6:44 pm
by Ottsville
McDave wrote:RV propane reefers won't and can't work while in transit since it needs flame to boil the ammonia. So they are usually running on 12v, with a element heating the ammonia tank.
Just sayin',

McDave


Lot's of good information in your post so please don't take this as an attack, but this statement is flat out wrong. Fridges can and do run on propane while the vehicle is in motion. Three way fridges can run on 12v(usually not well as you say) but there are also many RV fridges that only run on propane or 120 which means that if the fridge is running while you're driving it's on propane. Some people question the safety of driving with an open propane Flame. I would encourage anybody that does it to do their homework and understand the safety factors. Some people question the legality of it; my research has shown that there are few areas where driving with an open propane cylinder is illegal.

Re: TT Power While Driving

PostPosted: Wed Aug 08, 2018 11:26 pm
by McDave
Ottsville wrote:
McDave wrote:RV propane reefers won't and can't work while in transit since it needs flame to boil the ammonia. So they are usually running on 12v, with a element heating the ammonia tank.
Just sayin',

McDave


Lot's of good information in your post so please don't take this as an attack, but this statement is flat out wrong. Fridges can and do run on propane while the vehicle is in motion. Three way fridges can run on 12v(usually not well as you say) but there are also many RV fridges that only run on propane or 120 which means that if the fridge is running while you're driving it's on propane. Some people question the safety of driving with an open propane Flame. I would encourage anybody that does it to do their homework and understand the safety factors. Some people question the legality of it; my research has shown that there are few areas where driving with an open propane cylinder is illegal.


I stand corrected, indeed you can run on propane while in transit with the caveats that you stop and turn off all flames in your rv BEFORE entering a filling station and some tunnels require this as well. It has been many years since I have wrestled RV Fridges but the only times I would see one was when it was broken. Lots of flame sensor problems and ignition issues due to drafting, or not while at speed. Also remember that 2 way really is more complicated than 120 or LP. it takes 12vdc to open the LP solenoid, so 120ac/LP+12vdc

Re: TT Power While Driving

PostPosted: Sun Oct 13, 2019 10:27 am
by Margali
Just an update for anyone coming across this thread. The cargo trailer is 7'x16'x7'h Covered Wagon. On our first trip last week, we had 1" R5 insulation in roof (held by batten strips) and walls. The R5 roof insulation made a HUGE difference. No additional fans installed or OEM roof vent open while driving. It was great for popping in and changing diapers on quick stops. Temperatures on drive ranged from mid-to-high 90s with lows down to 55. The lows did not require additional heating, just heavy PJs and extra blanket.

Re: TT Power While Driving

PostPosted: Sun Oct 13, 2019 1:30 pm
by jwhite
can you run a generator in the back of a pick up while driving down the road, I know it's probably done all the time and that the on board generators in motorhome run that way.
I know that roof top AC's will work while driving on motorhomes that could be a selling point for having one.

Re: TT Power While Driving

PostPosted: Sun Oct 13, 2019 3:06 pm
by bdosborn
Make sure your generator is one that can be used while bumping around. The carburetor float on my Yamaha 1000 will bounce around enough to fill the crankcase with fuel if I don't turn the fuel off during transport. I have a log splitter that will do the same thing when I haul it over to the wood pile.
Bruce

Re: TT Power While Driving

PostPosted: Sun Oct 13, 2019 9:07 pm
by Margali
Thanks for the warnings about generator issues in transit. With the 1" R5 and the planned additional 1" to make roof R10, I've pretty much decided we don't need AC to run while driving.

We have a trailer monitor that includes the ability to trigger a power relay based on temperature reading. The plan is to swap out the standard no-fan vent for a powered vent with hood that can run while in transit. The temperature sensor will be set to bump fan on if temp in trailer gets above setpoint from software.

Our refrigerator solution is designed and just waiting on funds. We have a temperature sensor PID controller to run our chest freezer as a refrigerator. Currently it only runs on shore power and uses peak 1.8A 120VAC. Husband has spec'd out the inverter, battery, truck battery drain protection, etc to run fridge off battery / truck charging. He's the electrical engineer, I don't have the details. We just need husband's current client to pick up his electrical widget and fork over the cash.

Re: TT Power While Driving

PostPosted: Mon Oct 14, 2019 6:12 pm
by featherliteCT1
[quote]We just need husband's current client to pick up his electrical widget and fork over the cash./quote]

Your "electrical widget" comment made me LOL!