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Powering a 208V-230V A/C (e.g., Mini-Split) in an RV

HookEm

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For those of you that may be running a 208-230V A/C unit (e.g., a High-SEER Min-Split), how are you providing power to it?

It seems like running a dedicated 230V Inverter may be overkill, as it would always run from the "house" battery bank.
So I'm wondering if a 120V/240V Autotransformer may be a better option (e.g., Victron 120/240V - 32A), but don't know if the A/C unit would run OK from 240V.

Thanks for the feedback.
 
Why don't buy a 115V Mini Split unit? You get up to 12.000 BTU with 115V
 
Thanks.
I'm aware of 115V units, but high-SEER Outer units and those with a Cassette Inner unit only seem to come in the higher voltage.
(I'm considering removing the rooftop unit with a Mini-Split Cassette)
 
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I’m in the same boat. 110 volt mini splits that I have seen top out at around 19-20 seer. All the 30-38 seer units are 208-230 volts at 60 hz.
 
I’m in the same boat. 110 volt mini splits that I have seen top out at around 19-20 seer. All the 30-38 seer units are 208-230 volts at 60 hz.
the question is - do you ever use it in a RV so much that this difference matters?
From GREE you get a 22 SEER Mini split at 115V The upgrade from the 12 SEER RV A/C is already substantial.

Wonder what makes the voltage a higher seer. Shouldn't really matter.

Maybe just a matter of waiting another Year or two for the 115V units to get to that higher SEER Rating.
 
the question is - do you ever use it in a RV so much that this difference matters?
From GREE you get a 22 SEER Mini split at 115V The upgrade from the 12 SEER RV A/C is already substantial.

Wonder what makes the voltage a higher seer. Shouldn't really matter.

Maybe just a matter of waiting another Year or two for the 115V units to get to that higher SEER Rating.
I will not argue the virtues of a simpler setup at 115V, but the point of this post is to explore how to power a 208-230V unit.
Thanks.
 
I am curious if a transformer could be used for this too .... wondering if @Supervstech would have an opinion.
Not sure who other electricians are on the forum.
 
Yes, a 240V auto transformer will easily power a 208/230V unit.
However, the point of a higher SEER unit is energy efficiency... and using a transformer wastes 20% energy... so, you would be wasting the energy saved by the high efficiency unit... better to get a dedicated cheap 230V European inverter that can output 60Hz...
 
Yes, a 240V auto transformer will easily power a 208/230V unit.
However, the point of a higher SEER unit is energy efficiency... and using a transformer wastes 20% energy... so, you would be wasting the energy saved by the high efficiency unit... better to get a dedicated cheap 230V European inverter that can output 60Hz...
80% efficiency is a pretty crap transformer. Industrial 2kva transformers are much more efficient than that.. they have to be. At 80% efficiency a 2000 watt load would generate 400 watts of heat.. which would fry in short order. Do a search for 2kva 120/208 transformer.. lots of options for between $300-$500.
 
Yes, a 240V auto transformer will easily power a 208/230V unit.
However, the point of a higher SEER unit is energy efficiency... and using a transformer wastes 20% energy... so, you would be wasting the energy saved by the high efficiency unit... better to get a dedicated cheap 230V European inverter that can output 60Hz...
Wow... That bad! (~80% efficiency)... That would be like throwing the baby out with the bathwater!

I was looking at this Victron, but don't see an Efficiency spec:
 
I don't see a problem with an inverter off your battery bank that puts out 240v. I don't see your BTUs but the 120v mini-split I have on my trailer is 9000BTU and maxes out at 1000w or so.... and is 'soft-start' by its design... 2000w pure sine wave inverter with 240v output, would surely do it. Efficiency could easily be in 85% range for modestly priced equipment. If you want spend bigger $ and spec line up I read that Magna Sine Inverters can reach 96% efficiency.
 
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I would look at the industrial transformers.
This one looks good…
Again, 80% efficiency doesn’t fly in a commercial application where they often run at close to max 24/7..the would melt down generating 200-400 watts of heat.
 
I believe the higher SEER is a result of variable speed compressors and VFD fans.

Not sure this option is available on the 115V units.
 
I don't see a problem with an inverter off your battery bank that puts out 240v. I don't see your BTUs but the 120v mini-split I have on my trailer is 9000BTU and maxes out at 1000w or so.... and is 'soft-start' by its design... 2000w pure sine wave inverter with 240v output, would surely do it. Efficiency could easily be in 85% range for modestly priced equipment. If you want spend bigger $ and spec line up I read that Magna Sine Inverters can reach 96% efficiency.
The problem I see is always having to run the 230V Inverter from the batteries... On a 30A rig (120V, single-phase), it would be nice to run the A/C from Shore power via a 120V/240V Autotransformer... Assuming an Autotransformer would be efficient enough to justify not using an Inverter.

BTW, here's the Mini-Split Cassette combo I've been looking at:
 
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I believe the higher SEER is a result of variable speed compressors and VFD fans.

Not sure this option is available on the 115V units.
A variable-speed compressor translates to energy savings... which is KING when running from batteries.
 
I believe the higher SEER is a result of variable speed compressors and VFD fans.

Not sure this option is available on the 115V units.
yes, I got a 115V unit and it has variable everything

Many Units have Fans which are actually DC - in both the 230V and 115V units.

I think even the compressor is the same - just the control module inverter type thing is different.
 
Hi @HookEm --did you ever get this up and running? I am looking at the same unit. Would love to hear what you decided to do for wiring, how you like it, how noisy/quiet the system is, etc.

Thanks!
 
Well. I actually opted out of the Mini-Split idea and went with a rooftop A/C unit from Mabru RV A/C, 12VDC
The intent is to run the A/C 24/7 while Off-grid, and to that end, I've installed 1700W of Solar (4 * 425W LG panels) and 630Ah of Lithium batteries (2 * 315Ah Lithionics, with built-in BMS)... The Mabru is super quiet and efficient: I'm getting a 20+ degree Temperature differential with an average draw of about 42 Amps (at 12VDC)... Of course, Summer is still not here, so we'll see how it goes!

Here are some "Before" and "After" pictures of the work:
Before.png
After.png
 
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