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diy solar

New Winter Battery Shed Build-Canada

Skythings

Solar Enthusiast
Joined
Apr 25, 2024
Messages
51
Location
Calgary, Alberta
Reading lots of discussions on winter battery operations so I thought I would post what I have done for my grid tied system thus far. This is my first winter with solar and so far things have worked well in terms of keeping the batteries warm.

I purchased an already commercial built demo shed which was insulated with 4 inch rigid foam sandwiched between magnesium oxide panels on all four walls, and six inches of rigid foam for the roof and floor. The builder indicated the shed has an R20 insulation value with the exception of the door and the window. I sealed all the inside joints with caulking and added 3/4 inch plywood interior walls and wood plank flooring. I purchased a good insulated door and window and wrapped the entire exterior, added hardy board siding, a metal roof and sealed the door and window installations very well. Both the door and window do open for summer ventilation.

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My long term plans were to add a direct vent propane heater to the shed to keep five SOK batteries within charging temps during the winter. I didn't have enough time this year to install a heater so I simply went with an oil filled 1500W two setting electric heater controlled with an external thermostat. I expected this to be an expensive way to heat the shed using electricity but I am still grid tied and chalked it up to the cost of doing business for the first year.

So far this year when the temperatures dipped down in the -25C range overnight the heater came on once every 4 hours for 15 minutes at a time on the high setting. I have a small lamp which also turns on so I can see the light on inside the shed from my house so I know when the heater is running visually. In the daytime at -10C the heater comes on about every 6-7 hours for 15 minutes at a time. I set the thermostat to turn on the electricity to the heater when the sheds inside temperature reached 43F and turn off at 50F. A seven degree spread. I use the Fahrenheit settings as the scale is slightly more precise with smaller increments for the thermostat settings. It has a temperature probe with about 6 feet of cord so I can measure the temperature close to the floor near the battery rack. Here is the Amazon link for the thermostat I used. INKBIRD Temperature Controller C226T Amazon It is rated for 15A & 1800W. I could actually lower the temperature settings some based on the SOK battery perimeters but so far these settings are not horrible in terms of electricity consumption. The inverter actually provides some heat inside the shed and the oil filled heater does stay warm and radiates heat for well over an hour after the power to it is turned off by the thermostat.

January & February will be interesting as we typically endure a week or two stretches of -35C to -40C temperatures. I am going to monitor this closely this winter and I may even reconsider installing a direct vent heater and just continue with this electric heater setup into the future. After factoring the cost of a direct vent heater, a couple of propane tanks and the cost of propane usage, I'm thinking it may not be worth it to go that route. I am adding an additional 7000W of solar panels this spring so my generation capacity next winter will provide the extra electricity used by this heater.

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Very nice!
Your information about how much your heater runs is very helpful to me.
My inverters live in a similar shed and I have been thinking about how to heat it when I have batteries.
We can make electricity. Making propane is more difficult.
 
Nice build, congrats! A couple of questions:

What's the foundation?

What's the big box on the outside (and is there a piece of conduit missing below it?)

Sounds like a case where thermal mass would be your friend, have you considered something along the lines of a 50 gallon drum full of water? Might help moderate the day/night temperature fluctuations summer and winter.
 
Looks great. Definitely a ton of insulation in there to keep things under control. May want to consider building insulating foam sandwiches to put over the windows for the winter as thats usually an R rating of 1-5. Versus rest of building at r20. Love my oil filled portable radiators. In your use case the thermal inertia is handy.
 
Nice build, congrats! A couple of questions:

What's the foundation?

What's the big box on the outside (and is there a piece of conduit missing below it?)

Sounds like a case where thermal mass would be your friend, have you considered something along the lines of a 50 gallon drum full of water? Might help moderate the day/night temperature fluctuations summer and winter.
I appreciate the kind words.

There is no foundation. The shed sits on two 4x6 skids bolted to the underside of the shed and sits directly on the ground.

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The big box is;

Maple Leaf Solar Combiner Box - 600 VDC Disconnect Box 2-In 2-Out | W/ Surge Protection | IP65 Waterproof & Lightning Arrester​

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When I dug the trench for the power lines between the house and shed this past summer, I included an empty conduit line to accommodate the lines for a future 14 panel solar array which I am currently building on the other side of my house and should be ready for connection to the combiner box early this coming Spring.

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Nice build, congrats! A couple of questions:

What's the foundation?

What's the big box on the outside (and is there a piece of conduit missing below it?)

Sounds like a case where thermal mass would be your friend, have you considered something along the lines of a 50 gallon drum full of water? Might help moderate the day/night temperature fluctuations summer and winter.
I like the idea of thermal mass, but I'm not sure how comfortable I would be introducing moisture into my small electrical shed.
 
Why not just keep them inside?
In Canada the fire code does not allow you to store batteries inside your house. You are allowed to store up to 20Kwh of batteries inside your garage but my garage is not heated and I wanted more than 20Kwh of battery storage. With an isolated shed I can keep up to 80Kwh of battery storage. That is why I decided to purchase the shed as I intend to grow my battery storage.
 
do they have a laser welder...asking for a friend...
Not the same company. These folks provide building panels for construction.

 
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SIS?
Seniors in service?

Looks ( no offence) like one of the Covid shacks from the plant gates...
But its in Alberta?

My son works for SIS....

The company is SIS Panels. They used this shed as a demonstrator and trucked it around to trade shows promoting their fire rated panel products. They decided it was getting a little tired for marketing purposes and put it up for sale on Facebook Marketplace where I found it. It was perfect for me as it is insulated and made out of magnesium oxide outer panels which gives it a two hour fire rating. I paid $1800 for it which included delivery to my place. It would have cost me that much just to buy insulation for any other shed I built or purchased.
 
In Canada the fire code does not allow you to store batteries inside your house. You are allowed to store up to 20Kwh of batteries inside your garage but my garage is not heated and I wanted more than 20Kwh of battery storage. With an isolated shed I can keep up to 80Kwh of battery storage. That is why I decided to purchase the shed as I intend to grow my battery storage.
The way I read CEC 64-800 Storage Batteries, you could have 20kWh + 20kWh separated by 100cm/3-feet, in your house {not in a basement below grade, not in a closet of a bedroom, not in ...etc etc) yeah long list of where they can't be}...not leaving a lot of options really other than an attached garage...or separate non-attached space where they increase the total to 80kWh. My understanding is the 80kWh is still supposed to be in stacks of no more than 20kWh each, separated by 100cm to one another - or 1hr fire-rated assembly between each stack.

But I am working from the last edition - not the 2023 version. Since they decided a public safety document would be best kept behind a pay-wall.
 
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With your oil filled heater cycling once ever 4-6 hours - there is no value in adding a tank of water.
Covering the window with an insulated panel for the winter would have value - likely your greatest heat loss.
I agree - I think I will look at picking up some material to build an insulated window insert for the winters. The door would be more problematic as I use it often and a foam cover would be a pain. As I mentioned I'm still grid tied and when I have all my panels hooked up I will have plenty of power to run the heater unless it's an emergency. Down the road I am building an enclosure on the far end of the shed which will house an 8Kwh Onan gas generator for such emergencies.
 
They way I read CEC 64-800 Storage Batteries, you could have 20kWh + 20kWh separated by 100cm/3-feet, in your house {not in a basement below grade, not in a closet of a bedroom, not in ...etc etc) yeah long list of where they can't be}...not leaving a lot of options really other than an attached garage...or separate non-attached space where they increase the total to 80kWh. My understanding is the 80kWh is still supposed to be in stacks of no more than 20kWh each, separated by 100cm to one another - or 1hr fire-rated assembly between each stack.

But I am working from the last edition - not the 2023 version. Since they decided a public safety document would be best kept behind a pay-wall.
You are correct. Thats what my research uncovered when I did my planing. I'm told there is talk of changing those rules to align more with the USA regulations, but those changes may be some time away.
 
This enrages me.
yeah, imagine the stupidity of such a policy.
Lucky for me, the NEC and the CEC are very similar - and the NEC is not hidden behind a pay wall - so I mostly follow your code.
And I work with electricians all the time, so I get to peg questions at them. lol. most don't know the solar requirements though.
 

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