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Old 10-24-2021, 10:47 AM   #1
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48vdc mini split ac

There have been a lot of threads here over the years regarding solar and air conditioning. I used the search function but to be honest I donít have all week to read thru them to see if I find anything on this topic so if you know of any threads please share the link info.

So I am moving forward, slowly, on my build ( Bus 9906) and started working on my electrical design.

Of course the first thing I am looking at is air conditioning the bus.
All the threads I have read so far all include thoughts/ designs on mini splits that run off of 110v ac.

Searching the internet I found to websites that talk about 48v dc powered mini split units, with heat!

I am not endorsing either of these two sites but would like to hear from those who have gone this route, what are your thoughts on 48vdc powered mini split.

From what I am seeing, I and I know nothing about solar, this unit has some advantages over standard 110vac units.

Unit model DC4812vrf

Here are the two pages:

DC4812VRF spec sheet.

http://Greyhame.com/solar-dc-air-conditioners

Again not a plug for these sites, just would like some feedback on this system.

For those of you who have gone down this route, what are your thoughts on this unit as compared to what you did on your bus.

Thanks,

EdÖ

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Old 10-24-2021, 02:30 PM   #2
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Yes I looked at them too. I was shocked by how much extra it cost to remove the ac from the system.
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Old 10-24-2021, 02:40 PM   #3
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Quote:
Originally Posted by s2mikon View Post
Yes I looked at them too. I was shocked by how much extra it cost to remove the ac from the system.

Same here, I liked the idea of the higher theoretical efficiency of cutting out the DC --> AC --> DC conversion, but when I looked at the prices (and the lack of clearly documented efficiency numbers for the DC units, I pretty quickly cooled on the idea.


I still like the idea in concept, but when you are pay 3x, 4x, 10x for a unit that may not end up being any more efficient, it becomes pretty hard to justify in my eyes.
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Old 10-24-2021, 03:02 PM   #4
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I wonder what the hack potential is for the ac units?
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Old 10-24-2021, 03:14 PM   #5
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When we upgraded our small off grid home last year, I installed a 48v 12000 btu system that I sourced from Alibaba.

The positives are that running from our 560ah lifepo4 battery bank and cooling over the course of a summer, we have never used more than 25% of the battery capacity. Same goes for the heating portion, we have not utilized more that 25% of battery capacity. Fairly warm summer and no temps under 40 degrees, but has kept me from having to burn wood.


For my bus, I have sourced a Gree 230v 12000 btu mini split unit. Why? After much thought and a few minor issues with the 48v unit, it concerns me that the construction is rather proprietary and I may run into issues with getting parts/service in the future.


I really like the idea of having the efficiency of the 48v unit, but for future servicing needs I will stick with a unit that has some stateside support.
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Old 10-24-2021, 06:41 PM   #6
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Thanks guys for your thoughts on this unit!


Quote:
Originally Posted by jofred99 View Post
When we upgraded our small off grid home last year, I installed a 48v 12000 btu system that I sourced from Alibaba.

The positives are that running from our 560ah lifepo4 battery bank and cooling over the course of a summer, we have never used more than 25% of the battery capacity. Same goes for the heating portion, we have not utilized more that 25% of battery capacity. Fairly warm summer and no temps under 40 degrees, but has kept me from having to burn wood.


For my bus, I have sourced a Gree 230v 12000 btu mini split unit. Why? After much thought and a few minor issues with the 48v unit, it concerns me that the construction is rather proprietary and I may run into issues with getting parts/service in the future.


I really like the idea of having the efficiency of the 48v unit, but for future servicing needs I will stick with a unit that has some stateside support.
I am impressed with the results you posted, 25% battery consumption!

What were the minor issues you had with yours?

As far as parts are concerned, besides a possible mother/ control board, was there anything else that that could not be sourced or modified if a repair

???
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Old 10-24-2021, 10:29 PM   #7
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I should have stated that the battery consumption also included 13.5 cu feet of freezer space and house lighting. The array for this battery is (12) 305 watt panels, so on a sunny summer day it will be charged by 10:00 - 11:00 a.m. These are all DC loads and the AC loads that we have are ran from a separate battery and array.

The minor annoyance that it has is an error code that is displayed occasionally complaining about a temperature sensor on the inside unit. I first opened the unit to check the wiring and sensor, but found that turning the breaker off and back on would reset the error. Only happened a few times, but really got me thinking about future problems. The documentation that came with the unit is fairly sparse, but I've found that error codes appear to be shared between mini split manufacturers.

To be honest, I have not had to replace any parts and will try to avoid doing so. I did find that the indoor temp sensor was a common item that was easily sourced in the USA.
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Old 10-25-2021, 09:55 AM   #8
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Jofred99,

Very interesting indeed!

So really only a minor annoyance versus an all out problem? Sounds like my marriage...LOL...

Would you say it was worth the investment?

You said you bought a new unit, a 230 vac unit. Have you switched it over yet?
do you plan on running that off the solar or is this just a second unit for the super hot global warming days upon us?

You bought in on Ali baba so I guess so spare parts come from there too?
Have you enquired about spare parts availability in the us?
Did they provide an internal wiring schematic or parts list with the unit?

Sorry for all the questions...but this one has got me real curious.
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Old 10-25-2021, 02:59 PM   #9
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For functionality, it was worth the investment. Time will tell if anything breaks and the availability of parts becomes an issue.

The 230v unit is for the bus conversion and has yet to be installed. It will be ran off of a 48v 280ah battery with an inverter, but we only require 6-8 hours of a/c usage per day in the bus. Only other major loads will be a 12v refrigerator. The lighting and water pump are minimal usage and won't require much power.

A schematic and parts list was not provided with the 48v a/c unit. Most of the main parts are stamped with part numbers and should (should) be available.
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