Skythings
Solar Enthusiast
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.
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.
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.
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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