Workshop installation - 2KW solar, MPP LV2424

[danb35]

Since it's pretty well all up and running now, here's what I have set up in my workshop. I'm using eight 250W panels from SanTan Solar, a MPP Solar LV2424, and 8x 272Ah LiFePO4 cells for storage, to run my server rack, and hopefully bring the electric bill for my workshop lower than the one for my house. Pictures:














And this is what I'm running with it:

 

[DThames]

Looks nice. I am curious about your roof mounting hardware. What is your load watts on that server rack? No power saws or drill press?

 

[danb35]

The mounting hardware is Rib Brackets from S-5, which I found at altestore.com. Surprisingly expensive, really--even without rails and racks, I still spent half as much on that hardware as I did on the panels. The server rack ordinarily draws 1-1.2kW, so the batteries power it for 5-6 hours--and while reducing the electric bill was one of my goals, so was having a serious UPS that would power the rack during the occasional outage. I do have power saws, a drill press, a lathe, and other equipment in the shop, but they aren't powered by this system--it's just running the server rack.

 

[DThames]

Yes mounting hardware is not cheap. Have you considered putting some of your lighting on your UPS system?

 

[danb35]

Hadn't thought about it, but it's an idea. It would take some re-wiring, but it could be feasible. Lighting for the main shop is a kW of LEDs, but the "clean room" in the back (where the server rack, 3D printers, reloading bench, etc. are) is about 200W worth.

What I don't yet have worked out is how to make best use of the solar power, while still maintaining this as a viable UPS. I could just configure the system to not charge from the grid at all, but I then risk not having much charge in the batteries if/when the power goes out. Maybe a combination of time conditions for grid charging (don't start charging from grid until mid-morning, say) and a fairly high cutoff voltage when grid is present.

OTOH, monitoring is working quite nicely:

 

[DThames]

I have been working to add some standby power to my house. You can wire in a subpanel that is powered from your UPS system and then just pull circuits out of your main panel and bring them to the subpanel, as required.

 

[Evertb1]

I am visiting here because of the link to this post on the TrueNAS forum. It's just to satisfy my curiosity. If I understood you correctly you use your solar installation exclusively for you server rack. I have a 12 panel (270 watt each) installation myself an I use it to deliver power back to the electricity company. For each kWh I deliver back, a kWh will be substracted from my electricity bill. That way I don't have the need to store energy, making the whole installation a bit simpler I think. Is that not a feasable model in your part of the world?

 

[danb35]

Yes, that is feasible in .us, and (since it doesn't require the purchase of batteries) it can be considerably less expensive. But there are a couple of reasons I chose to do it this way:

• I wanted the battery backup. I don't have frequent power outages here, but they do happen, and I've had a few that have lasted over an hour. That UPS you see at the bottom of the rack won't last that long.
• Done this way, I also didn't need to interact with my electric company at all--no inspections from them, no permits, etc.

I'm not sure this installation is any less simple than a grid-tied system. It's different, to be sure, and there are some different components, but I don't know that it's more complicated.

 

[Evertb1]

Done this way, I also didn't need to interact with my electric company at all--no inspections from them, no permits, etc.

In that respect we are lucky in the Netherlands I guess. There are regulations from the government that the electricity companies needs to follow. No exceptions allowed. And at this point in time those regulations favor the consumers. It will change a bit after 2023 but installation of solar panels will never be a problem here. There are even some governemental subsidy facilties available, so they are affordable for a lot of households and not just for the happy few.

Of course the installation needs to be signed off by a certified person but there is room for DIY. And always within in the regulations. I don't have hard figures but I think that 95% of the solar installations here are delivering back to the grid. I think that there are some sales of Tesla Powerwall and the likes but they are a very niche market. For now at least. DIY battery storage is not encouraged to say the least.

 

[sonny93]

View attachment 49204

Do you have a photo of your upper part of that lifepo4 box? Is the wood just resting on the terminals? I would like to build something similar as my batteries are in a bottom enclosure similar to yours.

 

[danb35]

Is the wood just resting on the terminals?

No, I have 1"-wide strips along either side. So it's resting on the tops of the cells themselves, but not on the terminals.

DIY battery storage is not encouraged to say the least.

The net metering rules here aren't the greatest, but again, battery backup was actually a big part of my design goals. It's nice to have a battery pack that will power the whole server rack for 6 hours or more.

 

[Evertb1]

The net metering rules here aren't the greatest, but again, battery backup was actually a big part of my design goals.

Understood. I am in a different situation. I will always be connected to the grid and I don't see a separate power source for my server in my future.. So that's a difference. In case of an power outage I rely on my UPS for my server. It's sufficient for 60 - 75 minutes. In that case I will not have power for my workstation anyway so I will not be able to work. If the outage takes longer the server will be shut down and I will grab a beer from the fridge before it is warmed up and then relax with a good book ?

 

[SolarPrep]

Evertb1: The US is great in some regards, but so far behind much of the world when it comes to policies. Here, it comes down to profit above all else. For example, we are the only major country that allows for medical/drug advertising on TV. And for some reason, we have the highest prescription costs in the world.

Our local utility will allow you to connect to their grid, and then they will generously pay you about 12% of what they charge you per kwh. But that is after they make you jump through all sorts of hoops that add to the cost of the installation, and charge surcharges on your basic connection fee. Such a deal....

 

[Evertb1]

Our local utility will allow you to connect to their grid, and then they will generously pay you about 12% of what they charge you per kwh. But that is after they make you jump through all sorts of hoops that add to the cost of the installation, and charge surcharges on your basic connection fee. Such a deal....

There is nothing wrong with running a business for profit but it all should be within reasonable limits. And the rules should also be uniform and reasonable. What you just described does not sound reasonable at all. So yes, you guys have every reason to try to get free from the grid.

Within the Netherlands the utility companies are subject to fairly strict policies. Historically speaking the utilities all have been state-owned and the state still keeps an eye on the utility market. The laws and regulations on European level are in most respects the same within the European union.

The rules for companies differ a bit from the rules for private households. At this moment in time private households can profit from the so called "Salderings regeling". The best English term for that would be netting arrangement I think. It just means that for every kWh my solar installation delivers back to the grid a kWh will be substracted from my bill. However that will change after the end of 2023 (or maybe 2024). We then will receive a monetary compensation for the delivered energy. But there will be just a couple of cents difference between the billed cost for a kWh and the compensation. For example: currently I will be charged about 23 eurocents for a kWh (prices can differ). The compensation will be somewhere around 20 eurocents. The only thing we are a bit afraid of is that when the prices go up the charging goes up but the compensation will not follow the market.

An household starting with Solar panels will be able to profit from another regulation. As soon as your solar installation is registered for delivering back to the grid you receive a so called BTW number. I think you will know BTW as VAT (Value Added TAX). It has a couple of thing in common with the sales tax in the US. The gist of the story is that almost anything a consumer buys will be taxed with BTW. For the solar installation that will be 21 percent. With that BTW number a consumer will get the BTW payed on the solar installation back. It's all part of the incentive scheme to get people into the solar energy business

 

[Bryanbr]

Since it's pretty well all up and running now, here's what I have set up in my workshop. I'm using eight 250W panels from SanTan Solar, a MPP Solar LV2424,

Good work! It's very similar to the design that I'm looking at.

Did you consider the GroWatt 3000? It's $100 more expensive but you get the 600 more watts output and it weighs a bunch more (which might mean larger heat sinks and inverter).

What monitoring software are you using?

You are not using an output breaker from the 2424?

 

[Bryanbr]

There is nothing wrong with running a business for profit but it all should be within reasonable limits. And the rules should also be uniform and reasonable. What you just described does not sound reasonable at all. So yes, you guys have every reason to try to get free from the grid.

Well, the Netherlands is going to ban the use of coal during this decade. Parts of the United States will be using coal probably for the next century.

Some of the utilities in the US are firmly in the control of the carbon producing cartels.