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diy solar

Solar Only Mini-Split

bwmccall

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Joined
Jun 9, 2021
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We have a large commercial building where a huge part of our electrical cost is the demand charge from Oncor.

A fairly low tech study of our usage indicates that electric heat used in one room is a big part of this, and Air Conditioning is another.

As a way to side step into solar, I would like to install one or more mini split units that run 100% off of solar. This will drop our demand during the day, greatly lowering our overall cost. If needed, we can add batteries later, but by then we would have more data on actual usage to make good decisions with.

I have seen numerous articles that discuss these units, and visited websites that claim to have them, But where can I actually buy one?

Are there any available with the charged line sets?

Is there anybody in North Texas that installs these?




On another topic, would love to find solar - LED High Bay lights for the same general purpose. (Replace 50% of our lighting with an off-grid low voltage system.
 

Still have to pull a vacuum on the unit above, I have not seen the above model available with precharged quick connect line sets.

Yeah, it seems like all of the articles lead back to these guys, but (20 years into the internet age) I am not too impressed with "call for pricing and how to buy".

Keep hoping there might be another more main stream option for a small system.
 
If you need to cool a large Warehouse split units are going to save you a ton of money. However they need constant power to operate so I'm not sure how you would do it without at least a few batteries for when it's cloudy. Don't hesitate buy some Mr Cool units the biggest ones you can get and get it going even with agm batteries as a backup. It's going to be a hot summer this install will save you a ton of money I guarantee it. The units will pay for themselves by fall.
 
If you need to cool a large Warehouse split units are going to save you a ton of money. However they need constant power to operate so I'm not sure how you would do it without at least a few batteries for when it's cloudy. Don't hesitate buy some Mr Cool units the biggest ones you can get and get it going even with agm batteries as a backup. It's going to be a hot summer this install will save you a ton of money I guarantee it. The units will pay for themselves by fall.

We have heating and cooling in place that will remain as backup. Trying to stay low voltage and avoid the cost of inverters, batteries, permits . . .
 
I think the most practical way if your building is grid tied is to add a grid tied solar system and only run your A/C during good sunlight hours.
 
Yeah, it seems like all of the articles lead back to these guys, but (20 years into the internet age) I am not too impressed with "call for pricing and how to buy".

Keep hoping there might be another more main stream option for a small system.
Try this link Sunshine
 
You can actually have a dedicated circuit for your cooling that can/would be ran by a hybrid inverter as was suggested inverter mini splits sips power once cooling temp has been reached, you would need to know your hvac sizing and current draw to work out the pv system for it.
 
If you need to cool a large Warehouse split units are going to save you a ton of money. However they need constant power to operate so I'm not sure how you would do it without at least a few batteries for when it's cloudy. Don't hesitate buy some Mr Cool units the biggest ones you can get and get it going even with agm batteries as a backup. It's going to be a hot summer this install will save you a ton of money I guarantee it. The units will pay for themselves by fall.
I’m new here. Can you tell me how to run a mrcool unit off solar? I don’t have any solar experience.
I just posted my first post on here asking for help.
Thanks.
 
I’m new here. Can you tell me how to run a mrcool unit off solar? I don’t have any solar experience.
I just posted my first post on here asking for help.
Thanks.
@bwmccsll hasn’t been here since august so We don’t know what their solution was

In your case, there’s also unknowns. Solar only?!
IMHO any solar only units are a compromise with no buffer for clouds, etc. The buffer is batteries and inverter, or one of the grid-sharing AIO solar controllers that use grid pass-through. I think these will operate battery-less.

But what is your application? Vehicle mounted, off grid, RV, home, commercial?
There’s a bunch of variables- just that one known element is that you’ll need enough power to run it. Just need to know how you expect to use it and what your situation is.

Do you already have (some) solar now?
 
Answers to the best of my knowledge below.

In your case, there’s also unknowns. Solar only?
Answer: I don’t know. I think I want solar panel and batteries. Why? When power goes out I want mini split to still run even if a Florida hurricane makes power go out for a week.

But what is your application? Vehicle mounted, off grid, RV, home, commercial?
Answer: residential home. Mini split installed in garage connected to breaker for power.
Electrician installed disconnect box ont exterior garage wall.

Do you already have (some) solar now?
Answer: no. Never had solar. I don’t know anything about solar systems. I’m here looking for help.
 
I’m going to recommend going to the ”DIY blueprint” page linked on the top middle of the screen. On that website he has some information about AC systems. It’s very good for understanding the basics and what it may take.

You already have a mini-split in the garage, so you can get a system to run that.

I’m going to give some numbers below just to show you what I think when I’ve thought about something similar and how much it would cost me to do it my way. Any estimate you get will vary wildly.
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I caution you that this is so expensive that most people decide that generators are a much better option for power outages. My guess is that solar will be ten to twenty times the cost of a generator if you install it yourself.

I think you could probably build a 12 kWh battery pack out of lithium cells that will give you 9 kwh useable power. If the single mini split is what you want, that would cost you at least $3k Problem is, that likely will not be able to be signed off as a grid tied in a permit, and would need to be an off grid installation. SO for grid tied likely will need a TEsla Power Wall or equivalent UL listed device.

My rule of thumb for grid tied pricing, just for planning in my area is $15k per 5 KW of panels installed pre-rebate with all permitting and work done by the company. My 3500 sqft house would probably require 15 kw of panels to break even with my power requirements.
 
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