You could, but then you are back to two units. Why not go stacked Victrons then?
Regardless, without at least two, you're downgrading your 100A service (50A x 2 legs) to 60A (30A x 2 legs) - not the brightest idea, even if you don't think you will be using more than 30A per leg.
I don't see what problem you are trying to fix with this, unless the sole motivation here is to save a few hundred dollars in what, in the grand scheme of things, is a several thousand dollar system you only want to have to buy once and have no regrets about.
All-Electric Plan Update
I have made some preliminary decisions, and am still researching and reading your comments. Thank you. :bow:
Please let me share what I have so far. And, this is subject to change. :whistling:
Battery Bank: 12VDC LiFeP04 batteries in a 24VDC configuration. Number of batteries will depend on results of electrical usage survey.
HVAC: Taking a very serious look at a two-zone 18-24K BTU minisplit with a small Indoor unit in the bedroom and a larger Indoor unit in the center of the coach facing forward. That still leaves the bathroom (the floor plan is a side hallway with a completely closed bathroom; not a walk-through bath). The Outdoor unit would go in one of the basement bays; possibly the one where the current gas furnaces live. There are 120VAC mini-splits, but they have smaller BTU's and that would require two complete installations for the coach. The larger Outdoor units require 240VAC.
Finding locations for the Indoor Units is a bit of a challenge. Since I am removing/redesigning/replacing most of the cabinetry, etc. anyway, I can redesign as needed. The installation manuals for some of the Indoor Units are helpful. Online youtube installation videos seem to be helpful as well. (What did we ever do before the Internet? :whistling: )
Remove the new Coleman heatpump from the roof up front.
Remove the original Coleman A/C from the roof over the bedroom. (It still runs, including the heat strip.)
Floor Heat: Looking at a 120VAC mat system to be installed over the existing 3/4" marine plywood floor. Then, probably engineered wood, or some type of vinyl flooring (no carpet). DW is still in the interior design phase. I priced a 24V mat system from one supplier. The price was about 5K, just for the parts. I would be providing the labor, but I still thought this was high. 120VAC pricing appears to be much more reasonable.
240VAC: This is needed for the above mini-split. Victron apparently makes an inverter/charger model so that two of them can be connected to supply 240VAC.
The existing generator will provide 120VAC to the two inverter/chargers.
Shore Power will provide 120VAC to the two inverter/chargers.
Victron apparently makes a unit that will convert 24VDC to 12VDC so I can power all of the 12VDC house items: water pump, lighting, etc.
A couple of you suggested using the 12VDC output from the system to supply 12VDC to the House lighting, etc. AND keep a 12VDC battery charged. I am not quite sure why this is that beneficial. I guess if the Inverters go offline I could still have lights and a water pump? Powered by the 12V battery?
I am considering NOT connecting the main engine alternator output to the House system. In fact, I think I want to completely separate the Chassis and House systems at all times. The only time I may need to connect them is if the Chassis batteries die and I need to start the main engine. Others have said a temporary connection with Jumper Cables will do the trick until Emergency Repairs can be completed.
Solar will provide some high voltage power to one or more MPPT controllers to charge the batteries. Not sure where they are connected yet, but will learn that once I start the electrical schematics. :D
This is a work in progress. No physical work on the new electrical system has started. I have removed the propane range, propane fridge, incandescent lighting, fluorescent lighting, and a few other things. I have temporarily installed new LED ceiling lights. I have removed a lot of the cabinetry, jack-knife sofa, carpeting, etc. Next, I will be working on removing the gas lines, propane tank, some skylights, etc. as I continue to plan the new electrical system.
The comments so far have been extremely helpful. Both what to do, and what not to do. Thank you!!! :bow::bow::bow:
Sounds like a great start to the planning process.
One suggestion would be to explore battery-to-battery chargers. We have a 24v chassis system and a 12v house system. I wanted a way to charge the house batteries from the engine alternator - redundancy and convenience. Let's us charge the house while driving when the generator is not needed. We arrive in campground with full batteries all around.
We use one of these: Sterling Power battery to battery charging system - DC to DC smart battery charger, marine grade DC powered charger 24v to 12v
It's a true smart charger, and it keeps the two systems totally separated. They make them in all kinds of configurations and I'm sure you can find one to work if you want.
I wired ours so that the battery-to-battery works only when I flip a toggle and that allows me to have total control of where the battery charge comes from.
cool.... the battery to battery chg may be a good addon, since even with the solar you can back charge chassis if you feel the need.. LOL
With all the electric heat, floors and splits, 220V will save on wire size, splits have the same effiency on 110 or 220 with inverter technology. ..watts are watts. btu=watts is a constant..
Depending on the design, space etc. maybe 2 single splits may work ..to get them where you want or the cartridge system instead of the long wall mount indoor. not sure on what you plan on remodel.
I can see a 10K genny and a full roof of solar with maybe a remote add on with all this you are planning.. LOL building a rv castle so live like a king..
What floor heat are you looking at?
If it is something like "Warm Floor" it is really not made for space heating, just taking the chill off the floor.
You and I discussed some of these in depth on one of the FB solar forums several months ago, so I know you're aware of them.
If the additional features don't justify the costs, or footprint in your case, you are free to buy whatever fits your budget and location.
Very Long Post. Personal experiences and suggestions that likely have been mentioned already.
For the fridge, rather than replace in entirety, I would change cooling unit for a compressor based cooling unit. Run on 12vdc or 120vac.
Swapping out LP water heater for a typical electric one will penalize you by losing ability to heat water using engine. There are electric models available that have a second heating loop built inside. Most are described as hot water storage tank for solar and usually geature a single heating element as well. There are also external heat exchangers that setup a thermosiphon inside the water heater. Externals are also somewhat common in solar catalogs.
Radiant floor heating is wonderful if using mats. Pretty good using strips as well. If you are considering strips, might also think about running a few loops of pex in each room. Then circulate engine coolant from the DP or Generator to gain heat.
Remove all LP... You might be passing up an opportunity here, especially with an old deisel. I added propane injection to a nearly wore out C7 Ascert. Climbed hills very easily afterwards. A few gallons will last a LONG time. Propane is similar to a diesel as nitrous is to gasoline except your limiting factor is exhaist gas temps. Research it.
Victron systems are spectacular but expensive but highly customizable and modular. Consider 48vdc battery bank.
48v loads have only a quarter of the current draw that a 12v loads do. 48v has half the current draw that 24v loads do. I suspect you will find more availability, system component wise, in 48v than 24v configurations. Especially for inverters.
If your motorhome has basement air, you are golden for using mini-split air conditioners. There are several "off brands" that are 24v and 48v solar ready. No AC power connections. Research them, especially in solar catalogs.
There are also dc rooftop air conditioners from King Solar (I think). I have not used them but have had an interest. Unfortunately, their published data didnt add up when looking at compressor specs.
Saw a youtube video about a guy that built his own camper (goes ON a pickup). His solar panels extended outward when he was parked. I have seen flexivle panels sewn into awning fabrics. Not sure about long term durability. Owner was clueless - "it just works" was common response.
Personally, I would keep the generator in place until you work out the bugs in your new alternative energy system. You may find that you absolutely dont need it anymore. You may find that you need it to charge batteries. You might even find it useful for when batyery bank is dead. In the latter scenario, you can remove the genset to install a larger / more batteries. Or use it for storing everything else the family cant do without but wont fit anywhere else. If generator weight is removed, the front suspension may need to be changed as well. Same goes for adding additional weight.
Large engine alternstors are typically available in 12 or 24v. I happen to know that Neece alternators are available in 12, 24, and 48v. You can always knock down voltage (and gain current capacity increase) to 12vdc for coach and driving electronics. Keep coach and driving separate. It is harder / less efficient to boost voltage (and lose current capacity).
Lothium can *tolerate* a high current to charge with. What is most important is that charge voltage does not exceed specs of your cells / bank. They can be charged at a lower current, voltage will drop accordingly but will rise again. You absolutely want the Lithium Phosphate chemistry. Much safer (compared to others), better temperature range, bit at a cost of reduced cell voltage and hence Watt-hour capacity.
A Boost regulator takes a lower voltahe and raises it.
A Buck regulator takes higher voltage and reduces it.
A Buck-Boost regulator is able tobgo either way, but you trade efficiency on both modes to gain capability with both modes.
If I remember correctly, Victron has a boost regulator available as a custom design. Not only is it able to charge multiple chemistries, bit it is also able to share with rest of Victron system.
A few personal keypoints...
Rewire lights for own circuits. Run with higher voltage LEDs. Harder to find, but much closer to residential.
Use multiple 24/48vdc to 12vdc BUCK regulators in your load center for dc loads. It is much better to lose a single converter than to lose all of your DC capability. Besides, as current capacity goes up, efficiency will decrease and standby losses will increase. Matching a converter to a load with reasonable overhead is more efficient and sometimes cheaper.
I once setup an old splendide combo washer to run off of battery. Bank was 12vdc (SLA), and I used 3 12-48vdc isolated boost converters in series to supply 140vdc direct to inverter inside washer. Stupid porter at camper repair killed washer with fork from forklift. Repair shop was sued, I won. You wont be able to do the same, but thunk outside the box. Your air conditioners can be reworked by a professional to increase efficiency (a lot!).
I added a second air conditioning compressor to my engine. Allowed me to build my version of air conditioner. My coach was wired for three, bit only had 2. I moved the rear all the way to the front, and installed my frankenstein ac in rear opening. When engine ran, it blew cold air into ductwork and went to all areas. If you approach this method, be sure to reinforce ductwork. Dont blow yours out like I did with too much airflow / pressure.
To augment your hot water, consider using solar collector on roof. Mine were 8foot lengths of 3" abs pipe. My 3 collectors each held about 7 gallons, for a water weight of 165 pounds. They did circulate to Atwood XT water heater that had engine coolant loop. Yes, i did have to use a 12v taco pump.
I made solar covers for my slideouts. Basically flex panels glued to fabric and laid on top of slideout awning. Anchored in place using bungee. Dont forget to remove when retracting slides.
There is an engine based inverter sysyem available from Vanner Systems and other companies. Engine alternator is basically a high voltage dv alternator that feeds an inverter that then supplies ac and dc power where needed. Almost bought one installed until I realized that spares are not available everywhere.
Hope this got you thinking.
I recently saw a Custom made Prevost that was Totally Electric. I mean stove , water , ac, heat, refrigerator , heated floors every system on this Coach was electric. You name it , itís electric. Just like a totally electric house, and No solar , Nu Lithium batteries. He had increased his fuel tank size and had a Diesel 25 KW Generator. He said is was simply easier to maintain only one power supply system. Said he had Boondocked for 10 days and still had plenty of fuel left. It was him and his wife. And sometimes 2 grandkids....( It was a 650hp automatic Volvo engine , and No he never said what it cost $$)
They do make 24V alternators. Most alternators can be rebuilt with 24V regulators, or if they have external regulators, just buy one. The alternator itself is capable of sourcing up to 48V.
Bob '14 Winnebago 37F Adventurer; Jeep toad.
As usual, a lot of people are telling you it can't be done, and they are the folks that never try anything challenging. I'; doing the same thing with a 1978 GMC motorhome. They are much smaller than most modern motorhomes, and I managed to put 1860watts on the roof. My battery is two modules from a Tesla Model S--11.2KWH. But enough about mine, let's talk about your choices.
YES in big letters, to the idea of disconnecting the house battery and electrical system from the motorhome. Two reasons--they are independent functions, and the most efficient voltages are not compatible. You should be looking at 48V for your house DC. That will let you decrease the size of all your major DC wiring. Sigeneer makes 48VDC. split phase 240V inverters which will give you both 120V and 240 AC. That means you can bin the rooftop AC and install multi head unit mini split AC. A fraction of the power demand and starting current, noiseless and very efficient.
I'd also consider a refrigerator like the Nova Kool--extremely efficient and simple. My simple interior uses induction cooking plates instead of a stove. You can cook inside or outside and the better ones can also function as slow cookers or do multiple temperature complex cooking.
I'd say step WAY back in your planning and take your time. Find out what is available and don't just look at the usual RV stuff, which tends to be very expensive on a per-watt basis. I'm well on the way to building exactly what you are planning and so far everything works MUCH better than i expected.
I posted some stuff about a year ago on this blog. It's kind of out of date, and some of the choices i made are limiting. But so far I'd say this is a much more usable RV than any I've experienced--I don't need to plug it into anything, just stick it in the sun. You'll need to dig around here, but there's some information you should find useful. I need to update all the work I've done. I almost wish I was starting over--I know a lot more know and could make this even better.
As a home builder, I think you may find that the amount of net energy in a tank of propane in more than you think.
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