New likely project - solar dedicated mini-split

[MountainGirl]

you would need much bigger guns for the moose and bears!

Those I have.

 

[jmohme]

I am in the planning phase of a 14x18 ft fireproof room and was planning on using a mini split in it, but had not even considerd solar.
I will be watching this thread. Not sure I would go that route, but curious at the very least.

 

[MountainGirl]

Interim thought/findings.

Mini-splits are pretty cool. That said - powering them directly from solar isn't the best idea, because of the cycling nature and needs of anything that utilizes a compressor - and the inconsistency of direct solar anywhere except maybe the sun-driven desert. (Big thanks to @TXAZ for his input & conversation. I learned a lot.)

My plan all along though wasn't for a direct solar feed - but rather a more typical setup [Panel > charge controller > battery > inverter > mini-split], and if I could find a DC appliance then the inverter could be dropped from that string.

What it's looking like so far to run one mini-split is that the required capacities, in dedicated batteries and panels, would be so great that with just a little bit more of each - the whole house could be powered. Which wouldn't be a bad thing.. but will take more thought because if we do set up bigger it would be set up differently.

Research continuing.

 

[reddog]

I live off grid in the desert, 2500 sqft house w/4 mini splits. I'm thinking where you are going that doing whole house might not cost much more. Recommend Outback equipment, been running mine 13 years with no failures.

 

[MountainGirl]

I live off grid in the desert, 2500 sqft house w/4 mini splits. I'm thinking where you are going that doing whole house might not cost much more. Recommend Outback equipment, been running mine 13 years with no failures.

I used an Outback charge controller up on the mountain. Ran perfect.
How are their inverters? I had two Schneiders fail on me.

Add: @reddog - if you'd be willing to share the details about your setup, either here or in PM, it would be very helpful and much appreciated.

 

[red442joe]

I don't see where you addressed the night only need for cooling, therefore no day time load on the solar....daytime is only charging the storage batteries...
Unless you and PO are just too busy...

Joe

 

[MountainGirl]

I don't see where you addressed the night only need for cooling, therefore no day time load on the solar....daytime is only charging the storage batteries...
Unless you and PO are just too busy...

Joe

LOL this whole thread is about night only need for cooling - without having to run a gen. The battery bank needs to be big enough to facilitate that ^^, and the panels have to be enough to charge the bank for the next night... rinse repeat.

 

[reddog]

I used an Outback charge controller up on the mountain. Ran perfect.
How are their inverters? I had two Schneiders fail on me.

I'm currently running four of the FXR3048A inverters in a series parallel configuration. I am also running 5 of their charge controllers, the whole system has been trouble free. The system is 13 years old and I'm looking to get at least another 13 out of it. Where I live a majority of the people living here are off grid and the equipment ranges from ebay Chinese crap on up and no one else has had the trouble free experience that I've had with Outback. If Outback had a poster child, that would be me

 

[MountainGirl]

I'm currently running four of the FXR3048A inverters in a series parallel configuration. I am also running 5 of their charge controllers, the whole system has been trouble free. The system is 13 years old and I'm looking to get at least another 13 out of it. Where I live a majority of the people living here are off grid and the equipment ranges from ebay Chinese crap on up and no one else has had the trouble free experience that I've had with Outback. If Outback had a poster child, that would be me

Thanks!
What's your total Ah if I might ask? 13 years old...lead acid? I'm not sure what was available that far back. My little 2nd system (for a primitive chalet) used 2 deepcycle AGMs.
Did you go 24v? 48?
I appreciate your sharing... and I'm still trying to wrap my head around the need for 5 charge controllers..
Your experience is worth more than anything online, imo.

 

[reddog]

Thanks!
What's your total Ah if I might ask? 13 years old...lead acid? I'm not sure what was available that far back. My little 2nd system (for a primitive chalet) used 2 deepcycle AGMs.
Did you go 24v? 48?
I appreciate your sharing... and I'm still trying to wrap my head around the need for 5 charge controllers..
Your experience is worth more than anything online, imo.

48V, running 4- 24V forklift batteries in series/parallel to get 48V at around 2000 Ah+. I ran 3 strings of 8 - 6V golf cart batteries for the first 5 years (their max life) then switched to the forklift batteries. Maintained forklift batteries have a known lifespan of 20 years + in solar use. I went with 24V because they are around 1500# each, 3000# for 48V and my loader maxes out around 1800#. 5 charge controllers because of the Voltage/Current limitations, over 16KW in panels currently. The panels are set up in arrays of 12, four sets in parallel of 3 in series. 3 in series keeps me under the 150V max input, the 4 in parallel keeps me under the max current input. There are more modern ways of doing it now I'm sure, but this works and it's paid for. As an aside I've been hearing of a lot of unhappy people here that are/were running lithium batteries, pack failures, cells swelling, and at least one fire. For the most part rumor and hearsay except for one fellow that works for me who is switching to forklift batteries after his lithium failure.

 

[glenbo]

Would someone define mini-split?

 

[ZX9RCAM]

Would someone define mini-split?

mini split definition - Google Search

 

[MountainGirl]

Would someone define mini-split?

It's not really a definition - but think about a window a/c. the cooling part is in the front and sticks out into the room, the compressor hot part is in the back hanging outside. In a 'split' unit (either full sized or mini sized) the front and back parts are separate units; the cooling half is in the house, usually hanging high on a wall, the compressor half sits outside, and they're connected by tubes that goes through the wall.

 

[thescoutranch]

You might look at the marine industry/ technology for 12 V air conditioners.

Sail boats specifically.

You might find some things available in 12 VDC, but the price, I think will shock you.

 

[MountainGirl]

In your case, 100ah 48v battery, inverter and charge controller (or an all-in-one) using a window air like the Midea U

Midea 8,000 BTU U-Shaped Smart Inverter Window Air Conditioner –Cools up to 350 Sq. Ft., Ultra Quiet with Open Window Flexibility, Works with Alexa/Google Assistant, 35% Energy Savings, Remote Control https://a.co/d/hT8kjBX

or better, something like this

GE Profile ClearView Window Air Conditioner 6,100 BTU, WiFi Enabled, Ultra Quiet for Small Rooms, Full Window View with Easy Installation, Energy-Efficient Cooling, 6K Window AC Unit, White https://a.co/d/cPt9ILq

might be a way to go...

I finally looked at the Midea U's - and - those might work pretty well, for a backup A/C now and then later with what I'm tryin to do... thanks again!

 

[thescoutranch]

Which wall of the house is the bedroom on? If it’s on the north or east side, you might need less cooling capacity / power than if it’s on the west side.

West side of the house gets the afternoon sun, which would make it warmer later in the day going into night. East side should be shaded late afternoon. Same thing with north should be shaded.

Just a thought.

 

[MountainGirl]

48V, running 4- 24V forklift batteries in series/parallel to get 48V at around 2000 Ah+. I ran 3 strings of 8 - 6V golf cart batteries for the first 5 years (their max life) then switched to the forklift batteries. Maintained forklift batteries have a known lifespan of 20 years + in solar use. I went with 24V because they are around 1500# each, 3000# for 48V and my loader maxes out around 1800#. 5 charge controllers because of the Voltage/Current limitations, over 16KW in panels currently. The panels are set up in arrays of 12, four sets in parallel of 3 in series. 3 in series keeps me under the 150V max input, the 4 in parallel keeps me under the max current input. There are more modern ways of doing it now I'm sure, but this works and it's paid for. As an aside I've been hearing of a lot of unhappy people here that are/were running lithium batteries, pack failures, cells swelling, and at least one fire. For the most part rumor and hearsay except for one fellow that works for me who is switching to forklift batteries after his lithium failure.

Holy shitski, you be a big boy. Respect. !!
And now I understand about needing 5 charge controllers, lol.

I considered a forklift battery for the mountain system - but no way to move/maneuver it re weight... and no loaders etc down here either. Everything, there and here, done by hand power.

I'm in the costing out phase... and I can get the same or more Ah with AGM at less than half the cost of LiFePo. Not to mention the operating temps aspect. Considering we only need this setup to last 10-15 yrs (we're really old, lol).. it might be the way to go.

 

[MountainGirl]

Which wall of the house is the bedroom on? If it’s on the north or east side, you might need less cooling capacity / power than if it’s on the west side.

West side of the house gets the afternoon sun, which would make it warmer later in the day going into night. East side should be shaded late afternoon. Same thing with north should be shaded.

Just a thought.

It's on the north end of the east side, all of which is also under a deep covered porch..so it's always in shade except for 1 hr at sunrise. We got lucky that way.

 

[easy rider]

How much amperage/ wattage does your air conditioner pull at start up? Might need a soft start.

 

[MountainGirl]

How much amperage/ wattage does your air conditioner pull at start up? Might need a soft start.

We're going to have a soft start put on the 3ton central A/C... waiting for the guy to call us back, which he will. He's understandably swamped at the moment -