Growatt SPF 3000TL and Autotransformer 220V mini-split A/C

JohnAlba

New Member
Joined
Mar 29, 2022
Messages
8
Hello All,

I am building a system for my 25' Airstream. Currently, these are the components and system requirements. I will update this thread as I go, I am looking for any qualified insights if you've already been down this road

GOAL - sustainable off-grid with moderate sun exposure ( I could use some help defining this :)


Loads:

110v Fridge 35 watts ( 24/7 )
110v misc TV/Computers/ phone chargers/ wifi/ etc ( approx <200 watts, when running)
220v Mini-split ( approx <9000 watts, concealed ducting when running-- correction 900 watts not 9000 ! )
12v H20 pressure pump ( approx <40 watts, when running)
12v H20 circulation pump ( approx <40 watts, when running)
12v heater fans 12v ( approx <100 watts, when running)

Equipment:

Growatt SPF 3000 LT ( currently own )
LIP04 Batteries 2) 24v 100 amp/hours 2)12v 100amp/hours --total 7200 watts -- ( currently own )
1800 W solar panels nine 200W panels ( correction- approx 9 approx 1800watts )
  • Maximum Power Voltage(Vmp): 37.6V
  • Maximum Power Current(Imp): 5.36A
  • Open Circuit Voltage(Voc): 45.4V
  • Short Circuit Current(Isc): 5.83A
Victron Autotransformer 32A or the SolarEdge 5000 ( I haven't bought one yet )
24/12 20amp Victron Energy Orion IP67 24/12-20 DC-DC Converter ( I haven't bought one yet)




This is the direction I am heading, this is the simplest, safest, reliable solution I have been able to come up with thus far.

We are currently in the middle of building the airstream, I have a few weeks before I need to start fitting components.

Thanks for looking

John
 
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mopat

Solar Addict
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Jun 22, 2020
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587
You will be able to get 9 panels on top of a 25' Airsstream ?
 

JohnAlba

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Mar 29, 2022
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8
You will be able to get 9 panels on top of a 25' Airsstream ?
Theoretically. There are some roof mods I am doing 1) closing up the A/C opening in the middle of the roof. 2) closing up the black tank breather because it's also almost in the middle of the roof ( the black tank actually has a second breather location near the valve, I will use it instead and tie this into the breather for the grey tank)

It is my hope to keep the front and rear fan ( replace with a max or fantastic fan) but maximize the space with a combination of panel sizes to fit in the space between the roof features.

To mount the solar I will be making my own stainless mounting brackets and utilize either 3M VHB tape or blind rivets with a sealant (my default would be rivets)
 

JohnAlba

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Joined
Mar 29, 2022
Messages
8
Good point. The curved roof would probably require some extension mounts. Consider some residential PVs in the 350-400 watt range.
I have considered the larger residential panels in the center/flatish areas, but at the end of the day I will tetris what I can.. Typically I begin my projects with time, money, and hope... in the end, it's my perseverance and adaptability that help me finish projects.
 

Bluedog225

Texas
Joined
Nov 18, 2019
Messages
1,144
I don‘t understand your AC load. Is it 9000 watts for the day? I thought a mini split would be about 1000w or less.
 

JohnAlba

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Joined
Mar 29, 2022
Messages
8
why not just buy another 3k instead of the transformer and double your output capacity and get split phase that way?
Richard yes.. I had considered this but ran into 4 reasons not to use another 3k Growatt (at least 2 good ones)

1) there is no way to utilize the additional output without a larger solar array, so there is no benefit
2) the utilization of the 3k unit for 220 would not be full-time ( only when the AC is running) but would have an idle draw. Or I would have to turn off/ configure the one unit to run when I want the second unit off and then reconfigure the 2 units to run when running the AC
3) Component size ( with a 25' Airstream there is really only 21' of Airstream and every inch becomes prime real estate )
4) cost

I am under the impression I can either turn the autotransformer manually or leave it on (with little to no ideal consumption when not in use)

John

Rich- I did reach out to your company regarding technical and component questions but never heard back (I'd like to buy from you because you're only about an hour away from me and I like how involved you are in the community )
 
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JohnAlba

New Member
Joined
Mar 29, 2022
Messages
8
I don‘t understand your AC load. Is it 9000 watts for the day? I thought a mini split would be about 1000w or less.
Thanks for the question. It was a typo 900 watts The mini split should be no more than 900 Watts. When I do the math I get about 650 watts but when I called the company they said 900 watts

 
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