Help starting a pole barn Solar system.

[SkipRiot]

Hello, I am building a new 24x48 pole barn that is detached from my on grid home. I want it too run off of solar power. At first I will need to just run LED lights, garage door opener and to power (igniter) a gas fired tankless water heater. Eventually I would like to power wood shop tools and have the ability to charge an electric car. Where do I start as far as which voltage system to pick and the ability to expand without having to upgrade inverter etc. Basically I would like to just have the ability to buy more and more batteries as demand grows. If a thread already exists please let me know, Skip.

 

[JJJJ]

If you are just getting started then 48 volts seems to be the emerging standard. I personally chose 24 volts but more and more are choosing the 48 standard.

I am sure there will be plenty of recommendations for equipment. Many utilize the DIY for batteries. Many are also opting for prebuilt options. There are pluses to both discussed in other threads.

I personally like the Victron and Midnite product lines. I leave the floor open for others to contribute since there are many options.

 

[12VoltInstalls]

At first I will need to just run LED lights, garage door opener and to power (igniter) a gas fired tankless water heater.

That’s somewhat easily and inexpensive to achieve, and it’s a good learning opportunity.
Assuming the LED lights will be 120V?

Eventually I would like to power wood shop tools and have the ability to charge an electric car.

That’s a whole lot more complicated and requires planning well beyond step “A” as well as A LOT of panels and batteries.

Where do I start

I’d start with either an AIO or individual components to handle basic expectations. Have no consideration for ‘down the road’ and charging an electric car- that’s a huge leap from lights and door opener, and the lights and door opener plus some headroom is only a couple $k whereas supporting high amp stuff will cost $10k to do poorly and double or triple that depending on your needs.

So I’d start with lights, door opener, a few basic 120V convenience outlets installed GFCI etc. All the 120V is going to be able to use the same wiring later - that’s standard everyday stuff.

You could hire it it out for $50k or whatever overprice the installer wants to get.

Start with the immediate goal holistically and build it getting some knowledge and experience under your belt. Then do the 10kW 48V system later on.

 

[SkipRiot]

That’s somewhat easily and inexpensive to achieve, and it’s a good learning opportunity.
Assuming the LED lights will be 120V?

That’s a whole lot more complicated and requires planning well beyond step “A” as well as A LOT of panels and batteries.


I’d start with either an AIO or individual components to handle basic expectations. Have no consideration for ‘down the road’ and charging an electric car- that’s a huge leap from lights and door opener, and the lights and door opener plus some headroom is only a couple $k whereas supporting high amp stuff will cost $10k to do poorly and double or triple that depending on your needs.

So I’d start with lights, door opener, a few basic 120V convenience outlets installed GFCI etc. All the 120V is going to be able to use the same wiring later - that’s standard everyday stuff.

You could hire it it out for $50k or whatever overprice the installer wants to get.

Start with the immediate goal holistically and build it getting some knowledge and experience under your belt. Then do the 10kW 48V system later on.

Thank you very much, this approach seems more logical. Next question is, is there a benefit to using server rack batteries vs. the standard Lith-Ir-Ph regular battery type?

 

[SkipRiot]

If you are just getting started then 48 volts seems to be the emerging standard. I personally chose 24 volts but more and more are choosing the 48 standard.

I am sure there will be plenty of recommendations for equipment. Many utilize the DIY for batteries. Many are also opting for prebuilt options. There are pluses to both discussed in other threads.

I personally like the Victron and Midnite product lines. I leave the floor open for others to contribute since there are many options.

Thanks a bunch

 

[Rednecktek]

Just a few quick thoughts here:

Most larger solar panels are about the same physical size so figure out how many you can realistically fit eventually and how good the sunlight there is.

Go for 48v system, you can parallel inverters as you go larger down the road and use the same batteries.

Going to a split phase AIO from the start will save you wiring down the line, then parallel in same units later.

Rackmount batteries are about the cheapest turnkey option out there. If freezing temps are a concern plan for that ahead of time and look at Trophy batteries.

 

[12VoltInstalls]

Thank you very much, this approach seems more logical.

It did to me- the equipment for that small approach is not that expensive up front and can be sold later- or do whatever you want- when you have the more robust system in place.

Next question is, is there a benefit to using server rack batteries vs. the standard Lith-Ir-Ph regular battery type?

Sometimes (usually) lower cost per watthour for rack batteries
A lot of power storage space-efficiently arranged
They often are integratabtle with their branded equipment for management and seamless use

To my way of thinking- since you don’t the brand and components for your eventual system the battery choice with the end-game in mind is relevant, yet. I’d calculate your minimal initial system for watts needed, figure out with math what that is in watthours, decide how much buffer/headroom for cloudy days you’d like, and then pick whatever battery system makes sense for your budget.
Most server rack batteries are 48V but your initial system description doesn’t require 48V, nor does it prohibit it. 24V and perhaps 12V would do what you want- 24V won’t hurt you as you didn’t mention any native DC needs.

Imho. Ymmv

 

[Bluedog225]

I’ve enjoyed a couple of 100 amp hour LiFePO4 12 volt batteries, a few panels, a couple of small MPPT charge controllers, and a couple of little victron 12 volt inverters.

It’s been good to learn about the variety of skills needed for a larger system. I can run dozens of light duty tools (Ryobi) and recharge the batteries on 12 volts. Good crimping technique, wire sizing, fuse sizing, bus bars, run the tv, radio, lights, fans, computers, charge phones,

I’ve got a stack of 48 volt server rack batteries in the closet for the next phase. But I’m saving a bunch of money by knowing what I need to to next and what equipment will best support my needs. I will keep and use the 12 volt stuff for backup, shop lighting, etc.

I’d watch the Will Powse videos to pick a battery brand (cheap can be ok). Or just buy an SOK from currentconnected.com.

 

[JK14]

I like Bluedog's take on the value of progressing from smaller to larger systems. While it may seem like a waste to buy 12 or 24 volt components if you need to 'replace' them later with higher voltage versions, they may not truly be wasted. You might have a small outbuilding that also needs lights and you could move your 'small' system there when you build the larger one.

To me a lot hangs on your word "eventually". Car charging will need many panels and multiple 48V batteries etc, but if that is 2-3 years down the road, all of that stuff should be cheaper later, so don't plan for it now.

So to start, look at the garage door opener as the minimum watts you need for version #1 (lights and heater spark are small needs). Then, decide how long from now you might want to hook up the table saw etc. If you have 12 woodworking tools, but you are the only one in the shop, you can size the system to manage the highest combination of tools (a saw, dust collector etc) that would be on at one time. If 3 colleagues will be working in there with you, the max watts would grow.

If the wood shop tools are only 3-6 months away, then starting with 48V (per Rednecktec) makes more sense.

 

[J.P.]

Having been where you are now (just a few years ago myself) here is my advice. Go 48V and don't look back. I have multiple 12V and 24 Volt inverters and SCC's sitting on shelves gathering dust.

Inverter & Charge Controller(s)
You will have to decide on Hybrid and Grid-Tie or pure Off-Grid. My only experience is with pure Off-Grid.
AIO's (All In Ones) are space saving, easy to wire and use but separate components make it easier to have back-up equipment and might be less expensive in the long run if/when you have something go out. AIO's (Low Frequency ones, which is the only kind I would have) can also be VERY heavy and a pain to get on and off of a wall. I ended up settling on a Growatt 12kW Split Phase | SPF 12000T DVM MPV AIO unit (it weighs 165 lbs) and was a challenge to get mounted on the wall. It has a few quirks but for the price, I am very happy with it. No matter what AIO, stand alone SCC (or combination of both) you choose. I would lean toward one(s) with as high* of a PV Voltage Input that you can find. The Growatt MPV allows for up to 250V (array open circuit voltage) input from the panels. The more panels you can combine in series the higher the voltage and the smaller the wire on the roof (and down to the unit) can be. Also, if 12kW is not going to be enough for you in the future, you will want to choose a "Stackable" unit(s) so you can get them synced up and working together. The Growatt 12kW I have is NOT stackable.
*CAUTION - High Voltage DC (above 50V) is dangerous and can KILL YOU so extreme caution needs to be taken when dealing with it!

Batteries
Server rack batteries are very convenient and space efficient but if you are a hard core DIYer (and have the time) then building your own LiFePO4 batteries is still a lot cheaper and easier to work on (service) down the road if/when something in the battery goes wrong. I prefer JBD Smart BMS's and save a lot of money purchasing them from the JBD BMS Store on AliExpress https://www.aliexpress.com/store/1102178034?spm=a2g0o.store_pc_home.pcShopHead_2003013642813.0
From my research, (currently) the best (and safest) place to get LiFePO4 cells is the 18650 Battery Store https://www.18650batterystore.com/collections/lifepo4-prismatic-cells
Personally, batteries is NOT something I would try and purchase from overseas.

Panels
This is an area where you need to pay close attention as your panels (at least for each PV input) need to be matched. If you mismatch panels, they are only going to perform to the weakest one in the array. I was fortunate enough to find a seller on my local craigstlist that sells pallets of panels (at a great discount). I purchased a whole pallet of (25) 325W panels and have 24 of them installed. I later went back and purchased a few more so I have several backups in case any go out. I recommend that you (as some else mentioned above) figure out how many panels you can install on your roof and plan to (size the output of panels accordingly. You might have to purchase higher Watt panels to have enough production for your purposes. Also, look up what "over-paneling" means and considering your location and the pitch of your roof, consider how you want to handle this to maximize your PV production.

If you want to start slow, at least purchase enough panels to max out one of your Charge Controllers (or PV input on your AIO). It's always good to have a few backups. Don't count on that same exact solar panel being available a year from now. If the ridge of your barn roof is going to run North-South, then you could put panels on both sides and catch sun all day (wire each array into a different PV input). If your ridge runs East-West, then you will be limited to the panels on just the South facing side. Something to think about if you have not yet built it and you have the option to go both ways. You will need a lot of panels if you really want to charge an electric car some day.

 

[Eastgip]

Hey Skip, sounds like an exciting project you have there! Building a solar-powered pole barn is a great way to harness clean energy and reduce your reliance on the grid. Here's some advice to help you get started. First, make a list of all the electrical devices you plan to run in your pole barn, including their power ratings and estimated daily usage. This will help you calculate your energy needs and determine the size of your solar system. For smaller-scale applications like LED lights, a garage door opener, and a gas-fired tankless water heater, a 12-volt or 24-volt system should suffice. These lower voltage systems are commonly used for off-grid setups and are more cost-effective for smaller loads. When selecting an inverter, look for one that can handle your current needs and also allows for future expansion. A hybrid or grid-tied inverter with battery backup capability would be a good choice. Choose deep-cycle batteries designed for solar applications, such as lead-acid or lithium-ion batteries. Plan for future expansion by ensuring that your solar charge controller, inverter, and wiring can accommodate additional solar panels and batteries as your demand grows. I try to renovate my barn as well by installing solar panels as well as a new door, I chose a rustic door. It is of great quality btw and really cheap.

 

[FredVenture]

Hello, I am building a new 24x48 pole barn that is detached from my on grid home. I want it too run off of solar power. At first I will need to just run LED lights, garage door opener and to power (igniter) a gas fired tankless water heater. Eventually I would like to power wood shop tools and have the ability to charge an electric car. Where do I start as far as which voltage system to pick and the ability to expand without having to upgrade inverter etc. Basically I would like to just have the ability to buy more and more batteries as demand grows. If a thread already exists please let me know, Skip.

It's summer 2024, did you ever get your solar setup? If so what did you end up doing?

Just got our temporary solar in our 50x54 pole barn. 3k inverter with 2 server rack batteries and 3 450W panels. Can easily run any 120v power tool, chop saw, table saw, planer, 120v chainsaw, pancake compressor, etc. Final system will be 6k 240v for 3 zone Mr. Cool minisplit and larger 220v air compressor.

 

[FredVenture]

I highly recomend these LED lights. I used the dimmable version (compared to the high output non-dimmable) because we often entertain in the barn. 4 16w tubes to light the main barn which is 30x50. https://store.toggled.com/collectio...c-16w-3000k-soft-white?variant=32826971881571

If you want really bright light, use the 25w 4k lumen tubes https://store.toggled.com/collectio...2-direct-wire-led-tube?variant=39347548455011