Hello. I have a 32 ft new to me RV in the shop right now getting a new roof. The dometic air conditioners will not be going back on so that pretty much leaves the whole roof to play with. It is a rubber roof, so I know about the panels needing screwed in (but am interested in wind deflection). I live next to Death Valley and so really need something working by summer. I am interested in solar or solar assist units but cant find them with 2 indoor units. I want about 9000 in the back bedroom and 12000 in the front. So this is leaving with needing a 230v setup. Currently the setup is old school 50amp. I need a shopping list and advice (both general and where to buy) please. Thank you.
Newbie wanting to run a 230v mini split with 2 indoor units
- Thread starter AER
- Start date
Well my thoughts are to run the coach separate from the mini split, panels and all. Separate the current system from the mini split system and have panels and batteries and inverter dedicated just to the mini split. But in order to run a mini split of the size I want takes a 240v ..............
I have been shopping around and emailing manufactures. They are all pretty much the same, but I want 2 indoor units because it gets really really hot here (over 115f and last summer even 125f not too far away from me). I cant imagine that just one indoor unit will get it. Even the 120v at 18,000. I have also explored the 48v systems run direct off the solar panels or batteries, but everything 120v or even 48v has only one indoor unit that can be used. In order to get 2 units it is 230v systems.............. The New Horizons has mini splits as an option on their 2021 RVs, but even they have 2 indoor units (both are 9000btu)
I'm in Phoenix, so I feel your pain.
I can't help you with the specifics of a system or shopping list, but I can run through the general numbers:
32' x 8' = 256 sq-ft
256 sq-ft = 23.8 m^2
Maximum possible solar in 23.8 m^2 is:
23.8m^2 * 1000W/m^2 * 20% = 4760W assuming you can use 100% of your available roof area.
Using link #6 in my signature to simulate the above:
In December, that array can produce 296/31 = 9.5kWh/day
A 21,000 BTU 20 SEER A/C system will use 21000BUT/20SEER = 1050W.
Assuming you would need to run it the equivalent of 12 full-power hours per day, that's 12600Wh/day.
While there's lots of assumptions or guesstimates, that's probably a good target once you can establish your actual available solar max.
Mr. Cool has some multi-zone options too:
I can't help you with the specifics of a system or shopping list, but I can run through the general numbers:
32' x 8' = 256 sq-ft
256 sq-ft = 23.8 m^2
Maximum possible solar in 23.8 m^2 is:
23.8m^2 * 1000W/m^2 * 20% = 4760W assuming you can use 100% of your available roof area.
Using link #6 in my signature to simulate the above:
In December, that array can produce 296/31 = 9.5kWh/day
A 21,000 BTU 20 SEER A/C system will use 21000BUT/20SEER = 1050W.
Assuming you would need to run it the equivalent of 12 full-power hours per day, that's 12600Wh/day.
While there's lots of assumptions or guesstimates, that's probably a good target once you can establish your actual available solar max.
Mr. Cool has some multi-zone options too:
I am so sorry but I lost you as soon as you got into the math. Yes I am thinking I will need to fill the roof with panels and just have a narrow walking space in the center. Also would 300w be over kill for the panels? The 100w panels seem to be easy to get and a lot less expensive, but I am concerned that even with a roof full of them they will not be enough to power a 240v system during daylight hours?
This is a Mr. Cool I would consider but need to figure out how to run it on 240v https://iwae.com/shop/27k-btu-22-se...ss-heat-pump-split-system-9k-12k-ha21022.html
Here is how I would run it:
That Mr Cool requires 35 amps on each 120v leg. That's a 4200 watt inverter on each leg. - Verify the invertor will work - it may be too close.
I like (and installed on my rig) Victron Equipment - that's what I know - so you get that list.
I would go with a 48v battery.
So 2 Victron Quattro 48/5000 hooked up in split phase (4000watt continuous & 10,000 watt peak)
As much solar as can be fitted using 200watt panels or 300watt panels - (more efficient panels are better in space limited areas).
Solar Charge controllers to fit the panels (Need to know the # of panels - voltages, etc) Probably two 150/45 or one 150/85.
Generator (240v would be better) for bad solar days - or grid backup.
Does your rig have a 50A connector? If not re-wire
A 48v to 12v convertor to run all the 12v stuff.
Battery Monitor BMV712
CCGX or Cerbo GX to tie all Victron equipment together.
Size of Lithium Battery... humm... My guess is a 500ah 48v battery - that's 32 280ah lishen or eve cells in a 2p16s arrangement. (Maybe just 16 cells would work, but I don't know how long it would run in the evening and night).
Anyway that's a lot of storage space for the Quattro's and batteries - Do you have room? I assumed a pull trailer RV - is it a MotorHome?
That Mr Cool requires 35 amps on each 120v leg. That's a 4200 watt inverter on each leg. - Verify the invertor will work - it may be too close.
I like (and installed on my rig) Victron Equipment - that's what I know - so you get that list.
I would go with a 48v battery.
So 2 Victron Quattro 48/5000 hooked up in split phase (4000watt continuous & 10,000 watt peak)
As much solar as can be fitted using 200watt panels or 300watt panels - (more efficient panels are better in space limited areas).
Solar Charge controllers to fit the panels (Need to know the # of panels - voltages, etc) Probably two 150/45 or one 150/85.
Generator (240v would be better) for bad solar days - or grid backup.
Does your rig have a 50A connector? If not re-wire
A 48v to 12v convertor to run all the 12v stuff.
Battery Monitor BMV712
CCGX or Cerbo GX to tie all Victron equipment together.
Size of Lithium Battery... humm... My guess is a 500ah 48v battery - that's 32 280ah lishen or eve cells in a 2p16s arrangement. (Maybe just 16 cells would work, but I don't know how long it would run in the evening and night).
Anyway that's a lot of storage space for the Quattro's and batteries - Do you have room? I assumed a pull trailer RV - is it a MotorHome?
Yes it is a motorhome. And yes it has a 50amp plug. Also according to my calculations ( considering poorly insulated compared to a house and the climate I live in), I need a mini split with 12400 BTU. The highest BTU in a 115v I can find now is 12000, so I for sure need 2 indoor units. But I am very tempted to just run a 12,000 BTU for a couple seasons and see how it does. If it lives but cant keep up then I will put it on my sunroom at home or in a shed, if it gets overworked and dies then I will give it a proper burial, but if it works then it will save me 1000s lol.
For what it's worth, I'm building a New Horizons 5th wheel now and have 3.3kW of solar going up, 28kWh of battery, and 2 Victron 5k's to create the 240 split phase for the mini split that NHRV provides. As it's not built yet, I don't have any practical experience with whether it's enough.
Hi,
I have been running a 12K Senville Cassette for about 4 years now in a 40FT Dutch Star motorhome. I have 1800W of panels (300ea) in 2 strings,Victron: 150/35, 2 48V Quattros in split phase, BMV712, and Color Control module. My battery is 48V 200A Lithium and a DC-DC converter for 12V loads. I put in 2 subpanels for the 50A service and Quattro distribution. The mini split was able to keep up with 105 AZ heat..sort of. My cassette is located just forward of the mid coach bathroom and has a little trouble getting past the bathroom doorway. I used a tower fan to push the air back to the bedroom. This kept the bedroom some what cool but I had to "freeze out" the front of the coach. If had the chance I would put in a 240V multizone with 2 9K wall mount units. We were able to run the AC all day in full sun and put some charge into the batteries. I did not like how much battery I had to use into the evening when solar dropped but the temps was still high, but doable. Run the genny every couple 2-3 days to top off batteries. Good luck sir.
I have been running a 12K Senville Cassette for about 4 years now in a 40FT Dutch Star motorhome. I have 1800W of panels (300ea) in 2 strings,Victron: 150/35, 2 48V Quattros in split phase, BMV712, and Color Control module. My battery is 48V 200A Lithium and a DC-DC converter for 12V loads. I put in 2 subpanels for the 50A service and Quattro distribution. The mini split was able to keep up with 105 AZ heat..sort of. My cassette is located just forward of the mid coach bathroom and has a little trouble getting past the bathroom doorway. I used a tower fan to push the air back to the bedroom. This kept the bedroom some what cool but I had to "freeze out" the front of the coach. If had the chance I would put in a 240V multizone with 2 9K wall mount units. We were able to run the AC all day in full sun and put some charge into the batteries. I did not like how much battery I had to use into the evening when solar dropped but the temps was still high, but doable. Run the genny every couple 2-3 days to top off batteries. Good luck sir.
BTW: I did not do any deflection for the panels but I did add another z bracket along the sides of each panel. Also note that if I did not have the issue with the doorway and the unit being flush with the ceiling, I would be ok with the 12k single unit. I forgot to mention that I converted the entire rig to electric including 21 cu ft residential fridge and induction cooktop. (factors into a/c loads and inverter/battery size) Our new rig (27ft TT) that I am building will be with 11.6 fridge and 110V 12K wall mount mini split. I will be keeping the propane for cooking and heat this time. Single multiplus, 4 270W panels (2x2) and 16 272 Lishen cells in 2 pack 24V config. I used 3K to 4K daily usage and .8 solar harvest and about 3 days on battery in case of no sun to size the system. Can wait to start testing in the next few weeks. Safe travels..
awesome thanks! This gives me great hope. Right now I’m just crossing my fingers this will be enough to “never” need a generator.
What temps did you try to maintain inside?
I did 2 5k's because it would be very easy to overwhelm 1 leg of 120 with a 3k serving it. The 3k will max out at under 3000 watts in most conditions (highly temperature dependent). A/C running consuming 700 watts on a leg, a microwave, and a toaster and you've overloaded the 3k. I didn't ever want to have to think about my power usage in the RV - I don't want to have to be careful ... I just want to use it. I don't want to have to instruct guests or my future SO about what they can/can't do. So that was the driving reason for the 5k's.
It's a 48v system with a 48-12 DC-DC converter. This diagram is a little outdated but it's close enough: https://diysolarforum.com/threads/c...ar-10-kw-inverter-rv-build.13786/#post-153647
