120V to 240V conversion

[tomy2]

I would like to add a mini split system to my house, it is 240V and my solar fed subpanel is 120V.. Can I safely use two legs of the subpanel to feed 240V to the compressor unit? The subpanel is fed by a 5000w EG4 inverter with 30A breaker. I need to decide between two mini splits, both are 1 phase 208/230 V. One is a 1800BTU which has a Minimum circuit ampacity of 16A and a rated Current of 7.3A, max fuse 25A, and draws 1700 watts max.. The other is a more efficient but smaller 1200 BTU with a Minimum Circuit ampacity of 15A and a rated current of 4.1A, max fuse15A and draws 907 Watts. So my question is, will a two legged breaker in a 120A subpanel work for either or both of these units, or do I need to add some kindof transformer?

 

[Bkord]

To get 240 you need 2 120v 180deg apart. Sounds like you only have 120v from the inverter not 240. You would need a transformer, but transformers are not 100% efficient. A transformer will use electricity 24/7. You would probably be better off with a 120 mini split or parallel a second inverter to get 120/240, if your inverter can do that. Or get an inverter with 120/240.

 

[Browse]

I think you left a zero off both of your BTU ratings. Unless you're ready to upgrade your solar system to 240 split phase, I would get a 120V mini split but they are limited to 12k BTU.

 

[tomy2]

I think you left a zero off both of your BTU ratings. Unless you're ready to upgrade your solar system to 240 split phase, I would get a 120V mini split but they are limited to 12k BTU.

Thanks for your reply. yes, missing zero. I do have the option of going to 240 split phase, I have two systems with two EG4 5000 inverters and each system has about 2.4KW of panels and two 5K lifepo battery packs. It will take some major re-wiring but that was my plan anyway. I was just trying to be lazy and go the simplast route. I really don't understand why it wouldn't work, but I'll take your word for it, since my understanding of electricity is limited.
Oh by the way, if anyone is in the market for a mini split, I bought a senville on Ebay with an offer of $300. less than the Buy now price or the same thing on Amazon.

 

[good4politics]

Thanks for your reply. yes, missing zero. I do have the option of going to 240 split phase, I have two systems with two EG4 5000 inverters and each system has about 2.4KW of panels and two 5K lifepo battery packs. It will take some major re-wiring but that was my plan anyway. I was just trying to be lazy and go the simplast route. I really don't understand why it wouldn't work, but I'll take your word for it, since my understanding of electricity is limited.
Oh by the way, if anyone is in the market for a mini split, I bought a senville on Ebay with an offer of $300. less than the Buy now price or the same thing on Amazon.

If you want cooling at night, you'll need a lot more battery or transfer to grid at night. 5k of battery will evaporate between 4PM and 10PM on the smallest of air conditioners (9000 BTU). I am running 2 units on 26k of batteries. Then again, it was 111F yesterday

 

[HarryN]

Not at all an expert, but I believe that auto transformers are designed to do this type of conversion.

They are pretty common AFAIK.

Autotransformer - Wikipedia

en.wikipedia.org

 

[good4politics]

Not at all an expert, but I believe that auto transformers are designed to do this type of conversion.

They are pretty common AFAIK.

Autotransformer - Wikipedia

en.wikipedia.org

You are correct. they can be used to create the missing leg (L2) but they are not very efficient and nothing is free. they will cut amperage to less than half of the inverter output.