Off-Grid Container 48V System, 120/240V Well Pump on Solar

[bruised-heel]

Off-Grid Container 48V System, 120/240V Well Pump on Solar

This is my first solar build. I want to thank everyone who is active on this forum, posting build threads, troubleshooting, giving advice, reviewing equipment, etc. and of course to @Will Prowse for his videos and hosting this forum. It has been a huge help, a source of knowledge and inspiration.

This was my first time working with conduit, raceways, etc and I went to school on this one. There are several things I will do differently on the next build but overall I'm very pleased with how it turned out, and feels great to now be pumping water off solar power alone instead of burning gas. Please let me know what you think, any questions, what improvements you might recommend, etc.

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Purpose
This build is 100% off-grid, and lives inside a 40ft shipping container. The primary purpose is to power a submersible 240V 2HP deep well pump and a 120V transfer pump that moves water from our 2k holding tank up to a larger 10k gallon tank that is 1000ft away on the property. Previously we've been running both on a Predator 9000 generator. This system will also power a few 15A outlets inside the container as well.

The AC output is temporarily wired up to a single 240V external outlet with an extension cord running to the pumps. The next step will be to pull wire through the buried conduit and wire up the pumps permanently. The diagram I posted varies some from the actual install in terms of where I placed the components but is largely accurate. Right now I am running only 5 panels, the plan is to build a small porch roof off the container and have 10 panels total.

Components
- Inverter: MPP LVX6048 120/240V output
- Solar panels: 5 X Solarever 445W panels (10 planned)
- Solar mount: IronRidge BX 10 degrees chassis
- PV combiner: Watts247 4-1 combiner
- Breaker box/breakers: Square D Homeline
- Raceway: 6" x 6" x 5' raceway from McMaster-Carr
- DC breaker: 150A double pole from Watts247
- DC fuse: 300A BlueSea class T fuse and holder
- Batteries: 4 X 48V EG4-LL batteries, 2 X 48V EG4 LifePower4
- Battery cables: Temco 2/0AWG copper, crimped with Temco hammer crimper

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[G00SE]

Looks awesome. What made you decide to mount your panels in landscape and not portrait? It looks like you’ve got 4 panels vs a potential 6 in a different orientation.
Then again you could have gone double rows also, so I figure you have an intentional reason and I’m curious

 

[bruised-heel]

Looks awesome. What made you decide to mount your panels in landscape and not portrait? It looks like you’ve got 4 panels vs a potential 6 in a different orientation.
Then again you could have gone double rows also, so I figure you have an intentional reason and I’m curious

Hey, thanks @G00SE. I was able to fit 6 5 panels in a row on this 40ft container. I mounted them landscape in order to maintain setbacks from the edge of the container. I did this so I have some access on the roof for install and maintenance, and to keep the panels from getting too much direct uplift from wind rushing against and up the side of the container. I will add another row of 6 5 panels once I've built some additional roof space in the form of a porch.

 

[G00SE]

Hey, thanks @G00SE. I was able to fit 6 panels in a row on this 40ft container. I mounted them landscape in order to maintain setbacks from the edge of the container. I did this so I have some access on the roof for install and maintenance, and to keep the panels from getting too much direct uplift from wind rushing against and up the side of the container. I will add another row of 6 panels once I've built some additional roof space in the form of a porch.

Dang, talk about an optical illusion. I only saw 4 so I assumed 20ft container. But 6 and 40 makes sense!
Thanks for the insights, I’m excited to see the porch

Have you monitored temps inside? Have you done any insulation?

 

[bruised-heel]

Dang, talk about an optical illusion. I only saw 4 so I assumed 20ft container. But 6 and 40 makes sense!
Thanks for the insights, I’m excited to see the porch

Have you monitored temps inside? Have you done any insulation?

It turns out I only was able to fit 5 panels up there. You made me go back and check from some other photos, I was thinking I had 6 up there this whole time (which was my original plan). Posting here has already paid off hah. I haven't been back up on the roof to count once I had everything mounted and wired.

Temperature inside hasn't climbed too high but I will measure more in summer. I'm in Southern California so it's pretty temperate overall. The back wall that this system is mounted to is insulated with 3.5" R15 Rockwool and 1/2" cement board over that. The plan is to keep framing out and insulating half of the container. The other half will be uninsulated storage.

 

[G00SE]

At least you’ve got some temperate weather. I hope to eventually transfer my trailer based power system to a container.
We are in AZ so heat is a bit of a concern in comparison. We aren’t in the valley so it’s not crazy, but I was afraid of the sun beating down on the metal all summer.
I’ve seen some heat resistant paints that some people coat the exteriors of them with. Your point about having work space on the roof is noted, my consideration was moreso that two rows of panels would absorb the heat/shade the container to help temps too.

Have you considered a mini split? I was planning on a small 7k btu unit for mine and just keep it programmed for something like 45-85 degrees to help keep temps regulated in summer and winter.

I really like the back wall you did, and the perspective is great with the combiner box, inverter, and rack

 

[42OhmsPA]

Nice work and welcome to the forum @bruised-heel !
I've been contemplating a container for my power house on my next build.

 

[bruised-heel]

At least you’ve got some temperate weather. I hope to eventually transfer my trailer based power system to a container.
We are in AZ so heat is a bit of a concern in comparison. We aren’t in the valley so it’s not crazy, but I was afraid of the sun beating down on the metal all summer.
I’ve seen some heat resistant paints that some people coat the exteriors of them with. Your point about having work space on the roof is noted, my consideration was moreso that two rows of panels would absorb the heat/shade the container to help temps too.

Have you considered a mini split? I was planning on a small 7k btu unit for mine and just keep it programmed for something like 45-85 degrees to help keep temps regulated in summer and winter.

I really like the back wall you did, and the perspective is great with the combiner box, inverter, and rack

The point about keeping direct sun off the container roof using panels is a good one. That is the one disadvantage to these ballasted mounts is they create a lot of wasted/open space between rows, and even at the edges of the array. That's good for being able to service the panels but not great for energy density or providing a sun break. That said, I'm opposed to drilling holes in a perfectly weather tight container roof and they were very quick and easy to set up, so I'll likely keep using them in the future. I'm considering a system that fills the gaps with green roof style low profile planters to help keep the sun off.

Once I have this half of the container framed in and insulated, we will be doing a mini split, yeah. This will function as an office also so will be nice to keep it a sane temperature and will also benefit the equipment. I installed a Mr. Cool 18k BTU in a garage recently and we'll probably go with that for this container as well.

 

[Shimmy]

What is your logic on the 2-pole 150A breaker for the battery system (with the 300A single pole fuse)? It isn't a typical approach, but nothing wrong with it.

What do you feel like you learned for the next go?

 

[bruised-heel]

What is your logic on the 2-pole 150A breaker for the battery system (with the 300A single pole fuse)? It isn't a typical approach, but nothing wrong with it.

What do you feel like you learned for the next go?

My logic on the 150A breaker size is that the inverter has a max surge AC output of 12kw (100A), so that breaker should cut off battery power if anything goes runaway with the inverter or downstream of it. I also included the breaker to act as a battery disconnect switch for normal operation. It's only two pole because that's what Watts247 stocks. I thought about using it to break both positive and negative but I like the idea of only positive being exposed at all in the raceway (negative is continuously covered/shielded from battery bus bar to inverter).

The 300A sizing on the fuse is more for redundancy in case the breaker fails or something unknown happens, at least the fuse will blow before it fully melts or blows apart the battery cables. So the fuse is really to protect the wires, the breaker is there as a shutoff switch and as a first level of protection against overcurrent. I was going to size the fuse at 200 or 250A but I only really want it to blow in a true emergency (also 250A was out of stock hah).

What do you feel like you learned for the next go?

Most of what I would change would be around how I used the EMT conduit, how I drilled or punched holes in the raceway, etc. Next time I would definitely make a cardboard template off the component knockouts and use that to drill the holes in the raceway. I hung components where I wanted and then fought with the tools in the small gap to drill or punch the raceway and fit the EMT, it was a pain and it's all turned out a little sloppier than I wanted.

I would also not use cement board straight over studs as the surface to mount to. I would probably go stud framing, then 3/4" plywood, and then 1/4" cement board for a non flammable backing. That way I could knockout the raceway with the template, fit the EMT to raceway or component, then hang the components exactly inline and mount anywhere to the plywood, rather than trying to find a stud or use anchors and have that dictate my placement.

Component wise, we'll see how it all fairs and what the longevity/reliability is. Next time I will probably try out a higher quality inverter like a Schneider XW Pro or something like the Sol-ark 15K or EG4 18KPV. Currently leaning toward a Schneider XW Pro for the next build. So far no major issues with the MPP LVX6048 aside from a few odd design choices like oval knockouts that don't fit any standard fitting, undersized 1/4" posts for the battery input with a fragile looking board, and high idle consumption (but I knew that going in).

 

[Shimmy]

Most of what I would change would be around how I used the EMT conduit, how I drilled or punched holes in the raceway, etc. Next time I would definitely make a cardboard template off the component knockouts and use that to drill the holes in the raceway. I hung components where I wanted and then fought with the tools in the small gap to drill or punch the raceway and fit the EMT, it was a pain and it's all turned out a little sloppier than I wanted.

Another approach is to mount one piece of equipment at a time, ensure the conduit stubs are level/plumb and anchor the panels where they go. It is easiest when nothing really is designed around the other components, but not great for planning out wireway penetrations.

It is interesting to me that DIY products don't have removable knockout panels to simplify the process.