Off-grid solar power

[ksJoe]

The last couple months I've been working on adding solar power to the metal building we put up earlier this yera. I'm not done yet, but I'm getting close.

I wanted the panels to also shade the entry to the building. But I didn't want to risk bumping the posts with the tractor, so I poured concrete piers that extend 2.5 - 3 feet above ground.




I learned that a tacoma with a 5 foot bed can haul 20 foot 2x10s


I cut mortise and tenons for the angled braces:


Here's the structure to hold the panels. 13' tall on the high side, 11' on the low side




Normally the roof tin adds a lot of regidity, but I don't want to rely on the panels adding rigidity. So there's extra cables to stiffen it.
Where the cable attaches to the concrete piers, there's eye bolts welded to 5' sticks of 1/2" rebar. So we shouldn't have any uplift problems in the wind.



Then 12 305w panels, for 3660 watts total pv power
They're in 2 parallel strigs of 6 panels. Open circuit voltage is around 250v. max current is around 18 amps.




Inside wiring is mostly done. I have a small breaker box and a few circuits. The kill switch is for the PV power to the inverter/charge controller.
The breaker box has a generator inlet plug to connect to the inverter. Its pretty much ready to connect to the inverter and power up.


I'm making the batteries and inverter into a semi-portable unit. This evening I cut up and welded an aluminum server rack so its self standing.
The inverter will mount on the high side of it. Two 5kwh LifeP04 rack mount batteries will hang on the horizontal rails. There's room for 4 rack mount batteries if needed. The inverter & batteries will connect the building with twist lock plugs so I can easily disconnect it and set in the back of the truck to haul around portable power if needed.


That's as far as I've gotten. The inverter came today. The batteries are supposed to arrive Monday. It should be done in a couple weeks.

 

[buckdeer1]

Looks great,thats alot bigger than my 2 panels.My main issue has been everything getting hot inside building and fan on controller using more power than I like.I did put motion 4ft LEDs in the end of building that I park tractor and the other end is used more so saves some power.Be sure and post rest of your pics when done

 

[omicron1792]

The last couple months I've been working on adding solar power to the metal building we put up earlier this yera. I'm not done yet, but I'm getting close.

I wanted the panels to also shade the entry to the building. But I didn't want to risk bumping the posts with the tractor, so I poured concrete piers that extend 2.5 - 3 feet above ground.

View attachment 57529


I learned that a tacoma with a 5 foot bed can haul 20 foot 2x10s
View attachment 57538

I cut mortise and tenons for the angled braces:
View attachment 57530

Here's the structure to hold the panels. 13' tall on the high side, 11' on the low side
View attachment 57531

View attachment 57532

Normally the roof tin adds a lot of regidity, but I don't want to rely on the panels adding rigidity. So there's extra cables to stiffen it.
Where the cable attaches to the concrete piers, there's eye bolts welded to 5' sticks of 1/2" rebar. So we shouldn't have any uplift problems in the wind.

View attachment 57533

Then 12 305w panels, for 3660 watts total pv power
They're in 2 parallel strigs of 6 panels. Open circuit voltage is around 250v. max current is around 18 amps.
View attachment 57535
View attachment 57536


Inside wiring is mostly done. I have a small breaker box and a few circuits. The kill switch is for the PV power to the inverter/charge controller.
The breaker box has a generator inlet plug to connect to the inverter. Its pretty much ready to connect to the inverter and power up.
View attachment 57534

I'm making the batteries and inverter into a semi-portable unit. This evening I cut up and welded an aluminum server rack so its self standing.
The inverter will mount on the high side of it. Two 5kwh LifeP04 rack mount batteries will hang on the horizontal rails. There's room for 4 rack mount batteries if needed. The inverter & batteries will connect the building with twist lock plugs so I can easily disconnect it and set in the back of the truck to haul around portable power if needed.
View attachment 57537

That's as far as I've gotten. The inverter came today. The batteries are supposed to arrive Monday. It should be done in a couple weeks.

What a great project. Thanks for telling us about it.

 

[SD51555]

Nice! What are you all going to power with your system?

 

[ksJoe]

Nice! What are you all going to power with your system?

Standard garage stuff: air compressor, misc. tools for projects, etc.
As soon as I confirm I extend wifi across the ag field, I'll move the cell phone providing internet access from my deer blind to this building. And install 4k security cameras on the garage that ding my phone when people/vehicles/animals approach. Like this.
I'll install a garage door opener and put the remotes for it on my tractor and atv so I can come & go without having to lock and unlock the door.
I thought lights would be a big priority, but we put 3' of clear panel horizontally on the north side of the building. During the day that lets plenty of light in. If the garage door opener light isn't enough for night use, I'll eventually add lights.

The solar panels put out 3.6kw. The invert can do 3kw sustained and 6kw surge for starting motors. That's a bit more than one fully loaded 20 amp circuit. The batteries I ordered total 10kwh so that will last quite a while. On sunny summer days I'll have pretty much unlimited 120v power. I think it should be enough to keep the cameras running through a spell of dark winter days.

 

[SD51555]

Do you have snow in your country? I've got mine pitched up higher than optimal for sun collection so they self shed the snow. I'm down to a 5000 watt battery bank. I'm gonna kick it up to 7500 before November though.

Can I ask what you paid for those batteries and where you got them? I have Duracell 12 volt 105 amp deep cycle AGM batteries, and my system runs on 12 volt the whole way, except for some small inverters at the TV and DVD player. Those are $300-325 depending on promotions.

I think with the amount of panelage you've got, you'll be able to get fully charged even on cloudy days. The best output I saw out of my 450 watt array was around 275 watts around the summer solstice at solar noon. If it's cloudy, I can still generate up to 75 watts. I've gotta be conservative on those days, but I get through.

 

[omicron1792]

Do you have snow in your country? I've got mine pitched up higher than optimal for sun collection so they self shed the snow. I'm down to a 5000 watt battery bank. I'm gonna kick it up to 7500 before November though.

Can I ask what you paid for those batteries and where you got them? I have Duracell 12 volt 105 amp deep cycle AGM batteries, and my system runs on 12 volt the whole way, except for some small inverters at the TV and DVD player. Those are $300-325 depending on promotions.

I think with the amount of panelage you've got, you'll be able to get fully charged even on cloudy days. The best output I saw out of my 450 watt array was around 275 watts around the summer solstice at solar noon. If it's cloudy, I can still generate up to 75 watts. I've gotta be conservative on those days, but I get through.

How much batter amp hours do you have? I run two 100ah lithium batteries. Runs lights, water pump, and 2 110/20 outlets. I’ve never come close to running out, but I do get alot more direct sun than you I bet

 

[ksJoe]

Do you have snow in your country?

Some, not much. Its southern Kansas. We might get a 4-6 inch snow once or twice a year, and its probably gone within a day or two.
I realize the slope is less than ideal. I would have slopped them much steeper, but I wanted it in front my 10' door and didn't want to limit the height of what I drive through it. I figured extra panels is easier and cheaper than building an entryway roof structure and a separate solar structure. I almost got bifacial panels, which would have been great in the snow. But I ended up getting a pallet of panels to use for the next several projects, so they're not bifacial.

Can I ask what you paid for those batteries and where you got them? I have Duracell 12 volt 105 amp deep cycle AGM batteries, and my system runs on 12 volt the whole way, except for some small inverters at the TV and DVD player. Those are $300-325 depending on promotions.

Before you buy any more AGM (or any lead acid) batteries, you should look into LiFeP04 (lithion iron phospate). Its different chemestry than the lithium ion batteries in laptops, but still lithium.

On your AGM batteries, you can only disharge to around 50% without damaging them. If you're nice to them, you should get 300 - 500 charge/dishcarge cycles and they'll last maybe around 5 years? That may not be exactly right, but I think those numbers are fairly close. So you're paying $300 for around 50 usable AH at 12v.

With quality LiFeP04 batteries you can dishcarge to 0% without serious damage. You can use 80% of the capacity (discharge to 20%) to maximize the life. But with 80% DoD you can expect around 8,000 charge/discharge cycles and quality batteries should last 15 years +. The big downside is the are damaged by charging below 32 F, or discharging below about 0F. So if they're not protected from extreme temps, you want to get something that has low temp protection. Some of the cheap batteries on amazon claim to have low temp protection but don't.

If you want to stick with small 12v batteries in a "car battery" size, here's a 12v, 100AH LiFeP04 battery with low temp protection. The price is currently $269. I've seen it as high as $350 in the last year. Here's a teardown video of this battery, and another of the updated version.

I bought two of these (shipping was $360 for the pair). They're 48v 100AH, so that's equivalent energy to 4 of the 12v 100AH batteries. These have a 7 year warranty, low temp protection, and the metal case can be opened to replace damaged cells. Here's a teardown video.

Since my batteries will likely die of old age at 15-20 years, I'll set the cutouts to use 100% of the capacity.

 

[omicron1792]

I run Lifepo4 also. There are a lot of good solar panels. That tech is easy and old. Good modern batteries is the key.

You also want to have breakers on w very section of the setup. Solar to panel. Panel to battery. Battery to inverter. Inverter to plug or device. Don’t use fuse. Use breaker. Also want a large voltage breaker from battery to panel. It can surge and will burn up your inverter or equipment. Also having a master switch there is nice and I cut if off when not using. Also nice when you work on unit with no power to zap you. It can kill you. The solar panels run juice and can zap you but won’t kill uou. I also have a breaker there so can cut that line too.

You need a large inverter for surge protection. Mine has burned a panel before I put large master breaker in place.

 

[omicron1792]

I have stuck with 12 volt because parts and repair easier. You can just stack the batteries. Lots of panels and inverters are set up for 12v. If you go higher I would recommend and electrician install. If going to run large appliances or run all the time then I agree go with a real system.

For small setups they make portable systems with solar charger. Inverter. Outlet. And battery already installed with breakers. You just plug in the solar panels and go. Also nice you can unplug and take to tailgate or lake.

Solar panels take a little math too. Have to match amps and volts to your specifics Solar charger specs. Online calculators are your friend.

How to connect solar panels in series or parallel also affects voltage and amp output. Again use online calculator. Running a setup in series and parallel together is probably best way to do it.

 

[SD51555]

How much batter amp hours do you have? I run two 100ah lithium batteries. Runs lights, water pump, and 2 110/20 outlets. I’ve never come close to running out, but I do get alot more direct sun than you I bet

My current bank is 420 amps @ 12 volt. I try to keep it above 50% charged at all times. On a hard day, I'll draw it down 100 amps. That was when I was running everything. Now that's it's fall, i won't use more than 40-60 amps/day. It can get taxed pretty hard during rifle season, so I'd like to have it bigger by then.

 

[omicron1792]

This is the best easiest big name one to use

Yeti 6000X

Equipped with 6,071 Watt Hours and seven versatile ports for power-hungry devices and appliances, the Yeti 6000X can power essential home circuits, RVs, trailers, work sites, and more. features YETI 6000X HIGHLIGHTS Goodbye Gas Generator. Hello Yeti X. With a lithium-ion battery at its core, the...

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There are also companies that will make one for you in a premade rolling box. You get more bang for your Buck doing this, but not as streamlined.

I chose to make my own system. Had a lot of trial and error. It works great now. If I was going again I would buy a portable all in one system.

 

[omicron1792]

Mine is in a barn so I enclosed them all in Tupperware to keep birds and animals and bugs out. Ask me how I learned that. The panels sit on the roof. I have 6 100w panels in groups of 3 on the top of barn.

 

[SD51555]

Some, not much. Its southern Kansas. We might get a 4-6 inch snow once or twice a year, and its probably gone within a day or two.
I realize the slope is less than ideal. I would have slopped them much steeper, but I wanted it in front my 10' door and didn't want to limit the height of what I drive through it. I figured extra panels is easier and cheaper than building an entryway roof structure and a separate solar structure. I almost got bifacial panels, which would have been great in the snow. But I ended up getting a pallet of panels to use for the next several projects, so they're not bifacial.


Before you buy any more AGM (or any lead acid) batteries, you should look into LiFeP04 (lithion iron phospate). Its different chemestry than the lithium ion batteries in laptops, but still lithium.

On your AGM batteries, you can only disharge to around 50% without damaging them. If you're nice to them, you should get 300 - 500 charge/dishcarge cycles and they'll last maybe around 5 years? That may not be exactly right, but I think those numbers are fairly close. So you're paying $300 for around 50 usable AH at 12v.

With quality LiFeP04 batteries you can dishcarge to 0% without serious damage. You can use 80% of the capacity (discharge to 20%) to maximize the life. But with 80% DoD you can expect around 8,000 charge/discharge cycles and quality batteries should last 15 years +. The big downside is the are damaged by charging below 32 F, or discharging below about 0F. So if they're not protected from extreme temps, you want to get something that has low temp protection. Some of the cheap batteries on amazon claim to have low temp protection but don't.

If you want to stick with small 12v batteries in a "car battery" size, here's a 12v, 100AH LiFeP04 battery with low temp protection. The price is currently $269. I've seen it as high as $350 in the last year. Here's a teardown video of this battery, and another of the updated version.

I bought two of these (shipping was $360 for the pair). They're 48v 100AH, so that's equivalent energy to 4 of the 12v 100AH batteries. These have a 7 year warranty, low temp protection, and the metal case can be opened to replace damaged cells. Here's a teardown video.

Since my batteries will likely die of old age at 15-20 years, I'll set the cutouts to use 100% of the capacity.

I am in far northern MN. I can go below zero for 4-5 months a year. The charge controller I've got now will send extra charge to the batteries to keep them warm through the winter. I don't use my place during the winter if the snow gets deep. But that cold weather is the real deal up there.

I bought a couple batteries from a guy that ended up going to crap shortly after I bought them. When I upgraded my charge controller, I got bluetooth access to the controller on my phone, and I can view all my stats in real time. That's really helped understand my system capabilities better.

 

[omicron1792]

My current bank is 420 amps @ 12 volt. I try to keep it above 50% charged at all times. On a hard day, I'll draw it down 100 amps. That was when I was running everything. Now that's it's fall, i won't use more than 40-60 amps/day. It can get taxed pretty hard during rifle season, so I'd like to have it bigger by then.

I would start converting to lithium batteries. You can run them down to almost zero, giving you twice the USABLE power at same amps.

 

[omicron1792]

I am in far northern MN. I can go below zero for 4-5 months a year. The charge controller I've got now will send extra charge to the batteries to keep them warm through the winter. I don't use my place during the winter if the snow gets deep. But that cold weather is the real deal up there.

I bought a couple batteries from a guy that ended up going to crap shortly after I bought them. When I upgraded my charge controller, I got bluetooth access to the controller on my phone, and I can view all my stats in real time. That's really helped understand my system capabilities better.

I would enclose them and put small gun safe goldenrod to run off batteries. Would keep them warm with very low draw.

 

[SD51555]

I run Lifepo4 also. There are a lot of good solar panels. That tech is easy and old. Good modern batteries is the key.

You also want to have breakers on w very section of the setup. Solar to panel. Panel to battery. Battery to inverter. Inverter to plug or device. Don’t use fuse. Use breaker. Also want a large voltage breaker from battery to panel. It can surge and will burn up your inverter or equipment. Also having a master switch there is nice and I cut if off when not using. Also nice when you work on unit with no power to zap you. It can kill you. The solar panels run juice and can zap you but won’t kill uou. I also have a breaker there so can cut that line too.

You need a large inverter for surge protection. Mine has burned a panel before I put large master breaker in place.

What's the advantage of breakers over fuses?

I've got fuses all throughout my system, a 40 amp between panels and battery, battery and fuse block, and then 10's and 15's between fuse block to end unit. I run 15 amp marine lighter socket outlets. Those have 10 amp fuses so I don't accidentally roast my outlets. I also did the math on each run to ensure they don't go north of 70% of the fuse capacity.

 

[SD51555]

I would start converting to lithium batteries. You can run them down to almost zero, giving you twice the USABLE power at same amps.

Will they have cold weather charge and discharge issues like KSJoe mentioned with the other ones?

 

[omicron1792]

What's the advantage of breakers over fuses?

I've got fuses all throughout my system, a 40 amp between panels and battery, battery and fuse block, and then 10's and 15's between fuse block to end unit. I run 15 amp marine lighter socket outlets. Those have 10 amp fuses so I don't accidentally roast my outlets. I also did the math on each run to ensure they don't go north of 70% of the fuse capacity.

I just find easier and more reliable than changing fuses.

Also you need a loooooot bigger breaker or fuse between batter and inverter.

 

[omicron1792]

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