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Off Grid Farm ~ Mobile Power Cargo Trailer Build: Growatt 12kw Install

MrM1

I'm Here, But I'm Not All There
Joined
Mar 1, 2021
Messages
2,421
Location
N. Central FL
Installing The Big Growatt SPF 12000T 12kw Inverter into a Cargo Trailer for a 12k watt mobile power generator. All the panels will be installed on a pole/post barn and I will connect the Inverter's Solar Charge Controller MPPT to the panels via 8 awg SOOW cable and Anderson Connectors.

First phase of the 11.8kw array pole barn install. Final setup will be the 11.8kw Array. A Growatt 12000T 250vdc input Inverter / Solar Charge Controller. And 2 DIY EVE 280ah 16 cell batteries with BMS.

There are 32 URECO Glory Bifi 370w panels pictured in 8 strings at a total of 189.4 vdc VOC each string. These will go into two 4 in 2 out combiner boxes (from Watts247)
- The first combiner will feed PV1 and PV2 of the Growatt 12kW SPF 12000T DVM MPV Inverter and MPPT Charge Controller 5920 watts from the array
- The second combiner will feed PV1 and PV2 of a Growatt SC48120 MPV 250V PV 120A Charge Controller 5920 watts from the array


I will be installing the Inverter, Charge Controllers, Batteries, and all connections inside a dual axle trailer (the one in the picture below) probably in a week or so.

This set up is for our off grid farm that has no grid power available. We were quoted $37k+ to run power on to the property. I will build this system out for less that $22k. Liking How it is looking so far. :)

roof1.jpgroof2.jpg

FROM THE MAIN ROAD AND WITH THE TRAILER I WILL BUILD OUT LATER

roof3.jpgroof4.jpg
 
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I want to do a 30 x 40 pole barn once I get other projects completed. I looked into the steel trusses like yours but not to many in my location. Plus even more room for panels.
 
First phase of the 11.8kw array pole barn install. Final setup will be the 11.8kw Array. A Growatt 12000T 250vdc input Inverter / Solar Charge Controller. And 2 DIY EVE 280ah 16 cell batteries with BMS.

There are 32 URECO Glory Bifi 370w panels pictured in 8 strings at a total of 189.4 vdc VOC each string. These will go into two 4 in 2 out combiner boxes (from Watts247)
- The first combiner will feed PV1 and PV2 of the Growatt 12kW SPF 12000T DVM MPV Inverter and MPPT Charge Controller 5920 watts from the array
- The second combiner will feed PV1 and PV2 of a Growatt SC48120 MPV 250V PV 120A Charge Controller 5920 watts from the array


I will be installing the Inverter, Charge Controllers, Batteries, and all connections inside a dual axle trailer (the one in the picture below) probably in a week or so.

This set up is for our off grid farm that has no grid power available. We were quoted $37k+ to run power on to the property. I will build this system out for less that $22k. Liking How it is looking so far. :)

View attachment 110392View attachment 110393

FROM THE MAIN ROAD AND WITH THE TRAILER I WILL BUILD OUT LATER

View attachment 110394View attachment 110395
starting to look nice !
 
I want to do a 30 x 40 pole barn once I get other projects completed. I looked into the steel trusses like yours but not to many in my location. Plus even more room for panels.
Yeah we also left room for 8 more panels on the south facing roof if necessary. We should have more than enough to power.
 
Why the longitudinal spacing between panels? Looks clean.
No reason. I wasn't there for the install. My son-in-law and his crew did it. They'd never installed solar b4. I gave them a drawing and let them them do it. This is what we ended up with. But it looks really good I think .

Here's the drawing.

4s8p With Rails To Kevin.JPG
 
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We're still not sure how we're going to bring the 8 pairs of #10 pv wire down yet. Though the roof via a weather head, or around the eve using either flex conduit or elbows.

Ideas?
 
So here's the plan. We will build out the 12 ft dual axle trailer with the 200 lbs 12k inverter on one side, and the 32 EVE 280K batteries on shelves on the other side. Plan to use compression frames for the batteries and then lightly ratchet strap them down to the Shelves. For the wall with the inverter we are adding an additional 3/4" plywood skin that will be bolted to the steel wall frame of the trailer to support the weight of the Inverter.

We will then purchase a small water tight RV type lockable cable access door to open a small access pass on the inverter side for all the cables to run in from the DC solar array (on the pole barn) and then AC back out to the 50amp 240v service panel that will have a "generator" connect input in the pole barn. Building in extra shelves so if needed we can expand the battery bank. Well start with 32 cells in a 13s2p config giving use 28.5kWh of storage, and if needed can add 64 cells 16s4p which should give us a whooping 57.3 kWh.

This rolling power plant will allow us to keep the set up out at the farm for power, but since the farm has no buildings (other than the pole barn) and no need for a lot of power except for equipment and RV hook ups at this time, (a well is coming soon and a building) ... but with the rolling power plant, in case of a hurricane we can take it home and have a few solar panels and a fuel generator there to keep the batteries charged. Should work well.

THE RAW TRAILER

Trailer.jpg
Trailer2.jpg

THE BUILD PLAN

Trailer Inverter Side.JPG

Trailer Battery Side.JPG
 
We're still not sure how we're going to bring the 8 pairs of #10 pv wire down yet. Though the roof via a weather head, or around the eve using either flex conduit or elbows.
The spacing is so clean, I would lift one panel and conceal the penetration inside for each set.
Plan to use compression frames for the batteries and then lightly ratchet strap them down to the Shelves.

This rolling power plant ...
Personally, if you want it to be portable then I would build the shelves out of unistrut, and have a side rail on the front and back, and a top rail to hold them down. I don't think the ratchet strap is going to do much to secure the ~10 middle cells of each bank.
 
Im thinking of building the shelf out of 2x4 but instead of having the 3/4" shelf board sit on top of the 2x4 box (for each shelf) plan to screw the 3/4" ply to the bottom of the 2x4 box, thus making like a 3.5" tall box that the batteries will sit in, And they will also be in compression frames, but I do not plan to really over compress, just enough to keep them together.
 
I would want the batteries much closer to or on the floor.

Lower center of gravity etc.

Especially in case of an accident or sudden stop or turn while towing even if that is not the primary use case.
 
Or I might make my own since I have some many. I'll have 16 wire 10awg to pass thru

Kevin roof pass thru idea 3.jpg

Kevin roof pass thru idea 2.jpg
 
I would want the batteries much closer to or on the floor.

Lower center of gravity etc.

Especially in case of an accident or sudden stop or turn while towing even if that is not the primary use case.
agreed. I probably will. i drew it that way because we will probably add 2 more battery banks
 
Got the trailer for the Build at my house a few weeks ago. Have had some time to get things started.

Batteries are Almost Done
- They're mounted in shelves I built into the trailer
- I built room for 5 battery banks, but we are starting with 2
- Got all the battery electronics in, and 1 out of the 2 banks connected
- BMS is up and Bluetooth app is working

Inverter is mounted on 3/4 inch plywood that is screwed and glued to one wall.
- I'll start laying out that sides electronoics, connections and service panel in a few days

Power will be carried from the batteries via 4/0 cable up one wall (2/0 from banks to busbar, then 4/0), across the top, and down the other wall to the Inverter and Charge Controllers

One thing I am not sure of (need to study up). A Victron shunt goes on the Negative Battery cable? Yes?
- I want the shunt to work even when I turn othe Inverter / Charge Controller master switch off
- I think that switch ( see the 48v switch build in the forum resources) will go on the positive,
- But as long as I keep the shunt powered before the switch turns everthing off, I should be able to connect to the shunt for battery voltage correct?

OK ... A few Build Pics. I'm Shooting video of the build I hope to edit soon.

Pre Build (Inverter is installed on wall)
04 Pre Build.jpg


Inverter Installed
01 Inverter Iinstalled.jpg

Shelves Before Any battery connections
IMG_20220924_175402.jpg


Battery Electronics Going In
02 Electroncis.jpg

One Battery Bank Finised. One Mounted and ready to connect

03 Batts on Shelf.jpg

Finished Shelf. Compression is Used to secure the batteries in the trailer
05 Install.jpg

One BMS Reporting
BMS Connected.jpg
 
That's called a post framed barn since it was built with posts not poles, folks get them mixed up all the time or don't know there is a difference.
This is my pole barn and is more complicated to build due to more complicated mathematics to make the cuts line up with the poles such as the saddles.
End cap.jpeg
 
The 300 Amp busbars under the inverter are there because I have another charge controller to connect to the battery cables.

The bus bars are in that location because I had 2 15 inch 4/0 cables left over from my ol' lead acid days. I didn't want to waste other lugs and I had those ready to go so I just put the bus Bars Under the inverter
 
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