Electrical System Help,Thoughts,Ideas???
 

Hello,

I in the planning stages of a 240" Sleeper for my New Heavy-Haul Semi Tractor. I need some additional ideas about the Electrical System. I plan on using a 20 KW Diesel Generator,I want to use 2 Dual Sine Wave Inverters with Battery Charger. My unit will have 2-15,000 BTU Roof Air's,110v & 220V Home Style Appliances,Refrigerator,Electric Stove,Micro/Convection Oven,Washer/Dryer all in one,40 Gallon Hot Water Heater.Full compliment of Home Style Electronic's,Computer,110v & 12v Direct & In-Direct Lighting. I am looking for Battery ideas, Size and Quanity, Any other things to make a good system. The cost is not as important as durability and ease of use as well as a good long lasting power supply when I am off Generator. Thank's in advance for your help.
Robert:cool:

why do you need a 20kw generator ? and 40 gallons of hot water ?

Our 42 ft coach has an Onan 10kw QD and doesn't need that much (even when running 2 15kw ac units and all the other stuff inside).

Given that you're building a 20ft, I'm not sure you need 2 a/c units.

an Onan 18kw QD generator will consume close to 1.5 gallons per hour & even at no load it'll suck down 1/2 a gallon of diesel per hour.

Again Im not sure what you're use case is but a 40 gallon hot water heater seems excessive - especially considering space will be a premium in 240"

Our 10gal electric/propane water heater provides plenty of hot water for a family of 4 (we don't run out taking showers).

I'm with Don on this one. Seems like odd specs and such. Is the truck going to be used to haul a 5th wheel camper trailer? Do you need that much power to feed the trailer?

Hello,

Thanks for the reply, I am using the 20KW Generator because I have it and also I will need extra power for scene lighting at night when loading. I have a Kubota powered diesel that I purchased and there is no need to purchase another when I already have one. I want 2 roof Air's because we want to hang meat and also have a back-up in case of failure. I can agree on using a smaller hot water heater. I am in the trucking business of hauling Super Loads that are Over dimensional. Always over height,over width and over legal weight. We travel only daylight hours and spend a lot of off time in the sleeper.

how many of you in this sleeper ? i just think 40 gallons of water is gonna be huge....
where you gonna get a holding tank big enough for all that water (and the kitchen sink) ?

I'm wondering what the weight of that 20kw is ?

assuming you use a roughneck 15k BTU unit (like i have on our 42ft coach) you'll be able to do more than hang meat....youll be able to make ICE !

Aha, that explains it. I think the one thing you're going to need to determine for sure is how long do you want to be able to run it with the generator and engine off. That's what you need the inverter for isn't it? So, you need to figure out what exactly do you need to run and for how long. Then you can determine how much battery you'll need. I saw a truck that a guy built to be able to run his roof air (one unit) for 24 hours on battery power. He had a HUGE bank of batteries for it.

Just for reference. I have two 12volt deep cycle batteries, I don't maybe something like group 24 or something? I don't have an inverter. So my batteries run all the 12 volt house stuff. I can go for maybe 3-4 days on those. Using the lighting sparingly. I have almost all l.e.d. lights. I think running that roof air on the batteries is the big draw.

I've got 3 house batteries - 12v deep cycle giant bastards.
We never use our dc to ac inverter, so like bob ours runs the fridge, lighting, water heater (when on propane) and an outdoor electric cooler.

I can go a solid 24 hrs on the batteries (the outdoor cooler is the big consumer) - never tried to go longer....i run the gen at night to charge the batteries & run the air conditioning.

my roof top AC units consume anywhere from 11-15 amps (sometimes slightly higher if its really hot)....I can't find the spec not he 15k BTU unit but the 13.5 requires 1300+ watts (running, not startup).

assuming you'll have a heat strip int he ac unit you'll need at least 1800 watts for that....w/ a 20kw gen set I'm not sure you'll have enough room for all the batteries.

I found a great book that's helping me in my electrical design effort. Its called 'https://www.amazon.com/dp/0964738627/?tag=mh0b-20&hvadid=3520539328&ref=pd_sl_1y31reonfz_ee'.

Two ac's definitely overkill for 20'. I have one 15k rooftop carrier heat pump on the 20' living quarters on my race trailer and it will more than do the job. It will keep up easily on on 85-90 degree day in full sun, and my trailer has NO insulation whatsoever (not my idea, the lq was already partially completed when I got it). You will be more than fine with one ac. I like my heat pump vs a standard ac as it will also put out the full 15k btu as heat just as nicely as cold. A 5500w generator will run an entire rv with one ac and use a LOT less fuel than your 20k unit. At $4.25 a gallon for diesel you may be much farther ahead in the long run to sell that big ass generator and get something more appropriate to the load. That would also take up a lot less space.

I also think you will find that RV appliances, in particular the refrigerator, are much better in the long run than the home stuff. More expensive up front, and maybe at little more involved to install, but they are purpose built for what you are doing, more compact and will hold up far better to road abuse. You don't want to have to run the genny 24/7 to keep your beer cold, when the rv fridge will automatically kick over to propane when the power goes off and keeps everything nice and cold with no power. I think you will be shocked how much smaller 20' is in reality than is looks on paper once you start filling it up with oversized appliances.

Bushpilot also makes a really good point, that 40 gallon water heater is going to be useless, if you actually could take a long enough shower to use all that water, you'd never have gray water tank big enough to take it all. You need to consider the water consumption and how many days you have to go between dump stations. It is a pain in the ass that takes up at least a 1/2 hour of my time, and that is with a unit that can pull right up to the dump station at flying J, it sounds like with your rig that won't be easy so you need to have a realistic idea of the water you will need to conserve to get through the time you will need between dumps.

iirc my black & gray tanks are 50 or 56 gallons each....and my coach is 42 feet.
id expect a totter configuration to have considerably smaller tanks under the deck - especially w/ a 20kw gen set and solar / batteries.

hot rod makes a good point about the durability of RV appliances - i can't imagine a conventional hot water heater holding up well on the road.

lots of coach manufactures are installing residential refrigerators these days (i don't personally like it) - theyre cheaper yes, but theyre not build for the road - and they require 120vac all the time....even w/ a small (4) battery bank you'll only get a few hours of run time before you have to start the gen.

the RV refrigerators are incredibly efficient - run on 12v/propane for DAYS if not weeks consume a tiny amount of propane and voltage...yet still run on 120vac when available.

you can get a pretty good size RV (side by side) fridge, w/ ice maker - and they still take up less room than a residential unit.

when I'm on the curb of my father in laws - i have access to a 20a 120vac outlet - i can run a single AC unit and a few other things (like the converter/charger) w/out issue....so i keep the fridge on LP/12v & the water heater on LP as well - we've been curb side for more than a month and the propane use was negligible.

you COULD leach out the gray water under the cover of darkness - but its frowned upon - and it can smell pretty bad....i wouldn't wanna do it in the street (my brother in law in florida understands its just soapy water & he's happy to have it for his lawn)....but 40 gallons is A LOT of water (on a lawn or in a parking lot) - i wouldn't wanna do it more than a few gallons a day over the course of a less than 3 or 5 days at the most.