40ft RV want to go off grid if possible needing advice on sizing the system

[Ampster]

Yes, I agree. The whole use of dogbone connectors to run an RV is not for the uninformed. It is a subject that needs its own thread.

 

[DerpsyDoodler]

Yes, I agree. The whole use of dogbone connectors to run an RV is not for the uninformed. It is a subject that needs its own thread.

not sure what you’re talking about, but it’s not that complicated. if you don’t know what you’re doing, anything electrical is dangerous. A 30 to 50 dogbone simply jumpers the hot leg of the 30a outlet to the second hot leg on the 50a side. If your rv is properly wired for 50a rv service, then no worries. When in doubt, reference the “if you don’t know what you’re doing,“ part. I’ll post some pics in a sec.

 

[Ampster]

not sure what you’re talking about, but it’s not that complicated. if you don’t know what you’re doing, anything electrical is dangerous.

"If you don't know what you are doing..." = Uninformed.
I think we are saying the same thing. As long as we are going down this path should we explain what happens on a dogbone connection when someone tries to run their 240 volt A/C?

 

[DerpsyDoodler]

Here’s what you need, minus the wire. I have 3 tandem 20a breakers for a total of 6x 20a circuits capability for initial install. The inline surge protection is a bonus but not necessary. You can also get surge protectors that you use on the 50a cord itself (like a dog bone), but I prefer this route.

I posted a pic of inside the ac distribution panel as well as the back of the 50a inlet. The thing to note is 50a service has 2 hot legs. Typically in an rv, the two 50a hot legs are not combined for 240. One leg feeds the left main and the other leg feeds the right main (refer to the ac distro panel pic) breaker as 2 separate 120v 50a circuits.

Edit: just attached another photo of the distribution panel with one of the 20a tandem breakers installed on the left side of the panel.

 

[Ampster]

Yes, installing and correctly wiring one of those Energy Management systems would presumably convert an "uninformed" person into someone who would "know what you are doing" or at least able to follow directions.

 

[DerpsyDoodler]

Yes, installing and correctly wiring one of those Energy Management systems would presumably convert an "uninformed" person into someone who would "know what you are doing" or at least able to follow directions.

I suggest you know what you’re doing before you attempt wiring one. it would be an expensive item to release the blue smoke from.

 

[Cdkipp]

Here’s what you need, minus the wire. I have 3 tandem 20a breakers for a total of 6x 20a circuits capability for initial install. The inline surge protection is a bonus but not necessary. You can also get surge protectors that you use on the 50a cord itself (like a dog bone), but I prefer this route.

I posted a pic of inside the ac distribution panel as well as the back of the 50a inlet. The thing to note is 50a service has 2 hot legs. Typically in an rv, the two 50a hot legs are not combined for 240. One leg feeds the left main and the other leg feeds the right main (refer to the ac distro panel pic) breaker as 2 separate 120v 50a circuits.

Edit: just attached another photo of the distribution panel with one of the 20a tandem breakers installed on the left side of the panel.

At first glance, that third picture looked like an rv toilet with the lid open. I thought "well that is unusual".

 

[DerpsyDoodler]

At first glance, that third picture looked like an rv toilet with the lid open. I thought "well that is unusual".

Isn’t the latest trend multi-function spaces and devices?

 

[Ampster]

it’s not that complicated.

For some people it is complicated.

I suggest you know what you’re doing before you attempt wiring one.

Yes, it all depends on where you are standing. Or how much you know.

 

[babybober]

now how long it will run a A/C unit after sun goes down is a matter of battery bank if I can get at least 6 hours of Air conditioner I would be happy

last night I was checking out some of the batteries recommended on the site here and saw these 300AH

Cold Temperature 12V 300Ah KiloVault or the Ampere Time units.​

this seems much simpler/safer saves me time & the pain of making the battery dealing with BMS etc, just wire up as many as can handle weight wise??.
thank you for your input I am grateful for any help this is going to be a fun project I am sure.

Marc B.

ok, basic math, assuming a bit of overhead and not running a battery from 100% to 0%. A 300 ah 12v battery will get you about 2 hrs run time on one AC unit if indeed 1500w ish. You want 6 hrs evening time and running the other things you mention you are at 4+ batteries assuming fully charged and you are fully depleting them. Now add in things that run overnight and maybe a cloudy day following you are looking at 8+ batteries, 2 banks of 4 for 48volts. More like 3 banks to play it safe. You just burnt you total budget on batteries ( from your earlier post) before you even look at your solar panels, controller, inverter, install costs, cabling, etc..... good luck...

 

[Freqz]

AC on solar is a HUGE ask in a RV but doable. Suggest as many panels as will fit.

I imagine you’ll still be topping off with a gen for a bit every other day or so depending on your battery capacity. I can run my 15kbtu (1800W) for about 5 hours on my 10kwhr bank.

 

[cinergi]

Hello everyone I am purchasing a 39ft toy hauler and want to get it 100% off grid if possible it has a 50 amp plug for shore power.
been watching tons of videos etc. still have no idea how big I need to go.
I watched 1 guy had 2500 watts on roof and 20 battle born batteries $$$ OUCH. I will build my own batteries after watching all the videos I can pull that off no problem. I know they need padding between and under for vibration dampening of traveling on the road.
Panasonic makes some nice panels that produce 340watts and 71 volts thinking 8-9 of them, there supposed to be good for RV roofs as far as durability from the research I have done.
any suggestions I will be happy to listen to people that have experience as I have zero knowledge.

I am thinking 280AH lifepo4 48v system would be best.
not sure of size this was what I thought would do it 2 - 48v x 16 bank batteries was what I was thinking of course I have no clue if that's enough power.
as far as inverters/chargers/BMS same issue not sure what I need. what should I get??? I do want it all to have a nice control board that shows me all power and where it is going like the Victrons panel
Have looked at the Victron quattro but that may be overkill and not even what I need.

doing calculations gets confusing for me on this stuff with inverter power loss & conversion from 48v to 110AC power so there for I am here to ask for HELP PLEASE.
Here is what i have figured on total power consumption pretty sure I am going over.
it will have 2 roof air units that pull 1500 watts AC without surge each as well fridge I am thinking 400 watts AC, 150watts TV another 200watts misc modem router & LED lights.
I looked at putting Soft Starts on the Air units as well to help the compressor start load this will make a big difference.
most times 2 air units would not be needed at the same time and only run 8-10 hrs a day max but would like to build the system to accommodate them both just in case but not really needed.

thank you everyone for your help I am grateful. have a nice day & be kind to your fellow man.

Check out my system/thread/info (all in my sig). I'm using the Panasonic 335 Watt HIT panels (10 of them). 48v battery. 28kWh battery. The big difference is I'm using a mini-split (800 watts even with both cassettes running).

 

[time2roll]

Yes, I agree. The whole use of dogbone connectors to run an RV is not for the uninformed. It is a subject that needs its own thread.

Just don't cram a 30-TT plug into a 10-30 connector and you will be fine.

 

[eXodus]

A 7.6cu-ft propane/electric absorption fridge will burn up to 5kWh/day in warm weather. They are horribly inefficient. If you have one of the big double units, count on 7-9kwh/day. Absorption fridges use 5-6X the electrical energy of a comparably sized residential compressor fridge.

• Convert LPG litres to kWh: 1 L = 6.9 kWh of energy from LPG​

  • Convert LPG kg to kWh: 1 kg = 13.6 kWh of energy from LPG​

• one lbs of propane is about one day runtime of the fridge in hot weather. If you can - run the fridge on propane or a get compressor unit.​

 

[eXodus]

Not all of us are living on the edge like that. My panels each have six brackets and each bracket has at least one screw that is in the roof truss.

how did you locate the roof trusses? I'm thinking either that or getting 80+ inch panels and just mounting all across the RV into the metal side walls.

 

[snoobler]

• Convert LPG litres to kWh: 1 L = 6.9 kWh of energy from LPG​

  • Convert LPG kg to kWh: 1 kg = 13.6 kWh of energy from LPG​

• one lbs of propane is about one day runtime of the fridge in hot weather. If you can - run the fridge on propane or a get compressor unit.​

Yep. That's consistent with my observations. When I have surplus solar during the day, I run it on AC and then switch to propane overnight.

 

[HRTKD]

how did you locate the roof trusses? I'm thinking either that or getting 80+ inch panels and just mounting all across the RV into the metal side walls.

Details in this thread:

How To: Mount Panels to an RV Roof

This details the steps I went through for mounting my Mission Solar 320 watt panels to the roof of my RV trailer. While there are multiple methods to secure a panel to an RV roof, this focuses on using standard Z brackets. Other methods include DIY brackets, Unistrut, adhesive tape and all the...

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