Solar power question for barn....what do I need?

[Rmally]

Hey folks,

I've searched google and watched a few videos but can't really find the answer I'm looking for which is what exactly do you need to power a barn?

My building is going up next week, a pole barn that will be 40x48. It will be finished with the exception to electrical. The barn sits in the middle of the hay field, no trees, no shade, just full sun all day long. What will it take to power the barn so that I can have decent lighting, run a few stall fans, and maybe a coffee pot.

I'm pretty handy but have no clue on power as it relates to solar. Most everything I've read states you need the panels, an inverter and battery banks. What else? Does anyone have any input good or bad on going solar for a barn? Any recommendations on a plug and play package out there.

Thanks for any suggestions or help.

Best,
Randy

 

[TnAndy]

Questions:

1. This going to be your only source of power or will you have grid tie in there as well.

2. List exactly what you want to power...those stall fans, for example...what size are they, watts used, etc. Number of hours they will run, etc. Just for hot weather cooling or year round, that kind of thing. With conventional power, things like this aren't too critical...you stick in a 100amp or 200amp service, or whatever, and pretty much do what you want. With solar, you need to match your anticipated use with the amount of stuff to install.....so you need to get a pretty good handle on the use, as best you can.

3. Last...how much do you want to spend ? Running conventional grid power is 'usually' going to be cheaper unless your needs are pretty low, assuming you're within reasonable distance of a power line. Separate meters on barns (here in the TVA service area) mean a separate commercial meter charge and commercial rates on the power use...so there is that to consider too.

 

[Rmally]

Thank you for the reply, I was planning on this to be the only source, I would have to bring power down from the house which is about 2,000 feet away.

We primarily will only have 2-3 horses in the stalls and the box fans pull 50 watts each, I would have at least two running for approximately 4 hours a day in the really hot weather.

The lights would be LED just to light up the aisle and maybe in 2 stalls and a 12x12 tack room. I'm not sure on the lights watts because I'm not sure what works with solar.

In terms of budget I'd like to keep it under $3,500 if thats possible. I priced out the cost to get electrical down there and it was around $6,200. That was with me renting the backhoe and digging 4 feet trenches 2,000 feet, laying the 2" conduit, getting the vault boxes, wire, and hookups etc.

I thought solar would be easier to setup but I honestly have no idea.

Thanks for the help.

 

[EarPlug]

Do a search for "off grid solar system". Here is one example of a package 45??W Off-Grid Solar System with Schneider SW4?48 Inverter | Webo Solar for $10,170.

Also consider the cost of maintenance of the solar system. The underground feed would be a once and forget about it.

 

[TnAndy]

You wouldn't need near the size system Ear Plug referenced about.

I would consider DC fans personally over box fans. You'll pay quite a bit more for them, but you get a REAL fan. The savings comes in because you can run them directly off a solar panel with no batteries required, nor a need to invert the power from DC to AC to be able to plug in the fans

A 12" one of these would likely more than equal a cheap 20" box fan.
Products | Snap-Fan Solar National Air Propulsion

I have a 16" 3 blade version of these in one of my small greenhouses connected to a 100w solar panel (18-19v output) and it works great.

BUT since you want lights (and LED's are definitely the way to go) and maybe a few 120vAC receptacles for other handy things, you can go with the box fans and set up a panel(s)-charge controller-battery-inverter setup. You aren't going to need a huge setup based in the info you've supplied. You CAN buy 'off the shelf' kits, but what I find is they often contain stuff you really don't need and tend to be overpriced.

Example: Tiny House 61 Watt Solar Power System - Small Base Kit | altE

Small setup, 1900 bucks + another 1100 if you want to add maintenance free AGM batteries.

Non kit, buy individual components:

I'd go with 300-500w of panels (they can be bought for 60-70 cents/watt), Say $400

Then a decent MPPT charge controller...this Midnite (good brand) 30amp controller is feature packed: MidNite Solar MNKID-B The Kid MPPT Charge Controller | Northern Arizona Wind & Sun $325

Then a 1500-2000 watt 24v inverter. Go with a hard wire one, put a small 60amp panel in the building for the AC circuits.
Here is a middle of the road one:

$1,000

Some wiring/panel mounting/etc allow few hundred more. It gets to the price of the kit above, BUT it's a lot more capacity......600w versus 1800w.

Then you have to add some batteries, 24v worth of something. You could probably get by with a couple of Autozone/etc AGM Optima batteries for $300 ea.....your load is going to be fans running during hot, sunny weather when the panels are doing their best output and the batteries are doing nothing. Using the LEDs at night will draw from the batteries, but two of them have a lot of reserve, so unless you run the light all night and have multiple days of rainy weather, you're unlikely to need more.....if you do, then add them....you'll just have to see base on your use.

So that setup gives you decent electrical capacity and hits your $2500 budget pretty close.

 

[kenmbz]

What voltage are the box fans? Probably easier to pick a voltage and figure your lights from there. For lighting you would need to figure out how much light you need in each area as you don;t want to buy too small, and don;t want to just shell out $ for any overkill. You will need panels, a place to put them and something to hold them (ground or roof is possible, south facing) and if you need this day and night you'll need batteries, inverters, controllers etc. There are kits out there, but they seem to be expensive for what you get.
How comfortable are you with the wiring? Sounds like you know how to do 120V work so this is doable.
There have been some threads on here with some people putting in small solar farms. Hopefully they will chime in with their experience.

 

[PEJ5]

Larger solar systems run at 24v or 48v to reduce loss in cabling. Then the voltage is stepped down for lighting and appliances as required. You should definitely go with low voltage DC LED lighting since your system is already DC. Likewise fo fans - most big trucks are 24v and run DC Fan motors so they should be easy to find.

The solar panels are normally connected in series to produce energy at 80v to 160v and then run through a charge controller to charge the battery banks. You will need an inverter to produce some 120VAC.

Check out The Cabin Depot Off-Grid Living Solutions There must be local companies that specialize in off-the-grid tech.

 

[Rmally]

Hey guys,

Thanks so much for all the info, I'm checking out a few systems and looking into the different fans and lights. We are delayed a few days on the barn due to rain but should be completed end of next week.

I'm sure I'll have some follow up questions, so thanks in advance for all the input.

 

[grsthegreat]

Why did they want to go down 4 feet for power. Nec requires 24 inches in driveable area. Second question...how are you getting water out there. Most outbuildings i work on have a water trench that we utilize for power run....just wondering. For the load you suggest and the distance, i have run 2/2/4 uf direct bury to non critical buildings without conduit .... for people more worried more about cost than duration of use.... and provided a 30 amp service, 120 volt. Wire size prevents voltage drop. Wire is about $0.80 per foot. I can buy this on spool from wholesale house and not even need a splice for 2000 feet.

 

[Rmally]

Why did they want to go down 4 feet for power. Nec requires 24 inches in driveable area. Second question...how are you getting water out there. Most outbuildings i work on have a water trench that we utilize for power run....just wondering. For the load you suggest and the distance, i have run 2/2/4 uf direct bury to non critical buildings without conduit .... for people more worried more about cost than duration of use.... and provided a 30 amp service, 120 volt. Wire size prevents voltage drop. Wire is about $0.80 per foot. I can buy this on spool from wholesale house and not even need a splice for 2000 feet.

The county we are in requires all electrical to be 4 ft, If I dig it and lay the conduit they will pull it and hook up at no cost. The water is supplied by the main house well, I have a T in the casing and will run it down to the barn. The good news is that it only needs 2ft depth and a walk behind trencher will knock that in a few hours.

Thanks for the info on the 2/2/4, I will have to ask about that.