Build sheet... with some variables I do not know...

[ericfx1984]

So getting ready to build a new house,. Gonna be around 800 square feet, well insulated, white roof, in the trees so it should not be getting beat on by the sun all the time.. Led lighting... 18000 BTU mini split, Heat will be wood (unless we are out of town) Refridge we are looking at will use around 1.25kwh per day (and that is on the inverter). my office equipment pulls around 1.5-2.5kwh in a day... various other items like water pumps and what not pull around 0.5-1.0kwh per day...

Still have not chose our TV yet, but we rarely watch at night

the inverter mini split we are looking at is 18000 btu... but we might consider a 24,000btu or even a 12,000 and a 9,000 btu unit(used together)... I have no concern about powering the Mini Splits on hot days... there will be sun that can run the heavy loads...

My real concern is energy usage overnight... when there is NO sun... only stored battery power... I mean the heat load on the house should be much lower and there for the Mini Split(s) should run less... But the inverter(all in one) is not exactly energy efficient lol

I know if I add an extra battery I will be more than fine, but my gut here tells me that there is nothing to worry about... even if the mini split runs full tilt all night I will have plenty of battery power left


Panels: 6000w of 310w used santan solar(this plan may change)
(going into)
ALL in one: mpp solar lvx6048

Eve Cells 304ah, x16, grade A cells, with JBD 200 amp

Note: not that it matters, but I will also be adding an EpEver 60amp SSC and an extra 1000-2000 just because I want a little extra juice

 

[chrisski]

I’m going to estimate 6 hours of runtime, but this won’t start at sunset, the clock will start about two or three hours before. That is just a educated guess. Real numbers would help.

You have 13 to 14 Kwh of cells, of which 10 to 11 is usable. I am having trouble seeing how much energy a mini-split uses, and the most reliable data I have is 500 watts to power a 8k BTU. If that is true, I would not want to take the batteries below 50%, so that could be 10 hours of run time, with power left over for the next day.

IF those numbers are correct, I would expect you have 9 or 10 hours run time on an 18K BTU unit with your batteries.

Since my battery bank is about the same sized, I Am getting ready to try my regular RV 15K BTU on solar next week. I’ve not taken any measurements yet, but I expect it to pull 1.6 kw. Since its March, I expect the solar to make enough power to run the AC from 9 am to 4 pm. The morning is not yet hot enough for A/C, but my goal is to run the A/C for 6 hours a day, from 12 pm - 6pm. I estimate that a mini-split uses 1/3 less power than the regular A/C I am using.

 

[timselectric]

Looks like you have a good handle on your needs.
Worst case scenario is you might have to increase battery storage. Won't know until you are up and running.

 

[Steve_S]

I designed & built my home to be Hyper Efficient but I won't get into that gritty. When I wired my place up though, I chose to install Switched Plugs to be able to turn off things when not required.
- 1 Switched Plug in the closet where the Power Panel & House Water Filter are, controls the Satelite Modem, Router/Ether-Switch.
- 1 Switched Plug in the closet with the Radiant Heating System (not used in summer obviously) so it can be totally turned off.
- 1 Switched Plug for the computer, screens etc... That way not even parasitic loads are live when not needed.
-- Powerbars for the Wall-Warts like phone chargers and such, so when not needed it can all be OFF. So make a "Charging Station" that has all those parasitic wall warts which you can then just manage simply.

PS: Thanks to IOT you can get SmartPlugs to turn plugs on/off via phone app. This can be used alternately BUT BE CAUTIOUS ! Some of the apps like those for Samsung want full access to everything on your phone, like e-mail, GPS, Camera, and more... I chose NOT to bother with such as they have no reason to access all that regardless of any excuse and I refuse to have Data on my phone just for that nonsense. Some of these IOT Apps will not work without an Internet Connection from the phone either... So be AWARE !

Spoiler: Cabin Build Overview - Appliances + w/ Links

Hyper-Efficient which also lists appliances etc used
NOTE: I designed, did the plans & blueprints and built the house myself, only contracting out the concrete forming & pour and the actual cladding of the roof in metal. Everything else, including milling my own Pine 6" patterned baseboards, casings and moldings all done by me.

My Cabin Overview:

• 500 Sq Feet, 1 br, 2nd story loft, 9/12 pitch roof (Cathedral Ceilings)
• FPSF Slab Foundation REF LINK: https://www.finehomebuilding.com/2010/11/11/frost-protected-shallow-foundations-2
• Radiant Heating in floor (*it's WONDERFUL and efficient) provided by REF: https://www.radiantcompany.com/
• Cool Roof System (saved 25-30% of Heating & Cooling costs and is incredible ! REF: http://www.houstoncoolmetalroofs.com/cool-roof-information/cool-roof-design-texas/
• Rain Screen Siding method (used Live Edge White Cedar as my finish) REF: https://www.greenbuildingadvisor.com/article/all-about-rainscreens
• INSULATION: (All obtained from Commercial Roofers - not available in retail land)
• -- 4" XPS Under the FPSF Slab and out the sides (wings) 24" providing R20, double code requirement.
• -- 5.25" High Density EPS-2 Foam between 2x6 studs R32)
• -- 7,5" Paper Faced PolyISO between Rafters (Cathedral Ceiling, roof is 9/12 Pitch)
• Appliances:
• Water Pump: Grundfos SQ-5, Soft Start 120V Deep Well pump, 260' deep pushing to 50 Gal Pressure tank then 75' to Cabin. Max Wattage 1000W @ 45PSI. REF: https://us.grundfos.com/products/find-product/sq.html
• Unique Offgrid Classic propane cook stove: REF: https://uniqueappliances.com/
• Danby (Magic Chef same) Apartment Size Energy Star Fridge (uses 220kwh per yr)
• EccoTemp FVI12-LP On-Demand Water Heater for Hot Water. (not suggested, get a 45 series or better brand !)
• Takagi TH-3-m Condensing On-Demand Heater (used for Radiant Heating exclusively as I had Antifreeze in my system) (got from Radiant Supplier best deal out there)
  **NB** I run a separate Hot Water System from my Radiant System. The other option is to use one On-Demand unit for both, very possible and not hard, The Radiant Company can design it either way for you, no extra charge, it's a part of their service and I can only PRAISE Them for their amazing work, quality products & support, and I do "not" praise anyone lightly !

The efficiency is a win with the slab & hyper insulation. Winter -30C, inside 25C, Radiant only run 2 hrs within a 24 hour period to maintain 25C (floor sensor). Summer: 35C outside, 21C inside, NO AC or Fans just open windows. Slab itself never goes above 20C in summer, it regulates everything inside. Should Note, I am on the South Face of a Granite Ridge, 1200 foot fall in front of me, this property get's the heat & in a bad heatwave 40C is not a shocker. The Cabin itself is shaded by Scotch Pines & Cedars on the south & west sides and nestled into a forest nook. Solar System is mounted to the side of a 20' Sea Can 50' from Power House.

One of the Biggest Comfort & Energy Saving things that really make the difference is having a Cool Roof System. That is Thermally Broken from the exterior and therefore No Heat or Cold get transferred to/from the house at all ! This works way up here in the North as well as it does in the hottest of regions (it is where the concept originated from over 1000 years ago). This DOES cut heating/cooling Very Significantly and makes a home far more liveable.
Summer, +40C/104F outside, inside NEVER more than 28C/82F inside. Temp difference between 1st floor & 2nd = 1.5 Celsius higher on 2nd floor. In winter there is also only a 1 Celsius difference between the main floor & upstairs. NB: I have Radiant Heating within a Frost Protected Slab Foundation with R20 Insulation under it and up the sides.

Attachments are for the Cool Roof System, one of the best descriptions that was out there... Company now gone as owner became a Covid Victim. This is also well described on Green Home Building, BuildingAdvisor and several sites and this technique is being rolled into Building Codes as well.

Hope this is helpful and of interest, Good Luck.

 

[timselectric]

Very interested, thanks for the info.

 

[steveIndonesiaTampahHills]

I designed & built my home to be Hyper Efficient but I won't get into that gritty. When I wired my place up though, I chose to install Switched Plugs to be able to turn off things when not required.
- 1 Switched Plug in the closet where the Power Panel & House Water Filter are, controls the Satelite Modem, Router/Ether-Switch.
- 1 Switched Plug in the closet with the Radiant Heating System (not used in summer obviously) so it can be totally turned off.
- 1 Switched Plug for the computer, screens etc... That way not even parasitic loads are live when not needed.
-- Powerbars for the Wall-Warts like phone chargers and such, so when not needed it can all be OFF. So make a "Charging Station" that has all those parasitic wall warts which you can then just manage simply.

PS: Thanks to IOT you can get SmartPlugs to turn plugs on/off via phone app. This can be used alternately BUT BE CAUTIOUS ! Some of the apps like those for Samsung want full access to everything on your phone, like e-mail, GPS, Camera, and more... I chose NOT to bother with such as they have no reason to access all that regardless of any excuse and I refuse to have Data on my phone just for that nonsense. Some of these IOT Apps will not work without an Internet Connection from the phone either... So be AWARE !

Spoiler: Cabin Build Overview - Appliances + w/ Links

Hyper-Efficient which also lists appliances etc used
NOTE: I designed, did the plans & blueprints and built the house myself, only contracting out the concrete forming & pour and the actual cladding of the roof in metal. Everything else, including milling my own Pine 6" patterned baseboards, casings and moldings all done by me.

My Cabin Overview:

• 500 Sq Feet, 1 br, 2nd story loft, 9/12 pitch roof (Cathedral Ceilings)
• FPSF Slab Foundation REF LINK: https://www.finehomebuilding.com/2010/11/11/frost-protected-shallow-foundations-2
• Radiant Heating in floor (*it's WONDERFUL and efficient) provided by REF: https://www.radiantcompany.com/
• Cool Roof System (saved 25-30% of Heating & Cooling costs and is incredible ! REF: http://www.houstoncoolmetalroofs.com/cool-roof-information/cool-roof-design-texas/
• Rain Screen Siding method (used Live Edge White Cedar as my finish) REF: https://www.greenbuildingadvisor.com/article/all-about-rainscreens
• INSULATION: (All obtained from Commercial Roofers - not available in retail land)
• -- 4" XPS Under the FPSF Slab and out the sides (wings) 24" providing R20, double code requirement.
• -- 5.25" High Density EPS-2 Foam between 2x6 studs R32)
• -- 7,5" Paper Faced PolyISO between Rafters (Cathedral Ceiling, roof is 9/12 Pitch)
• Appliances:
• Water Pump: Grundfos SQ-5, Soft Start 120V Deep Well pump, 260' deep pushing to 50 Gal Pressure tank then 75' to Cabin. Max Wattage 1000W @ 45PSI. REF: https://us.grundfos.com/products/find-product/sq.html
• Unique Offgrid Classic propane cook stove: REF: https://uniqueappliances.com/
• Danby (Magic Chef same) Apartment Size Energy Star Fridge (uses 220kwh per yr)
• EccoTemp FVI12-LP On-Demand Water Heater for Hot Water. (not suggested, get a 45 series or better brand !)
• Takagi TH-3-m Condensing On-Demand Heater (used for Radiant Heating exclusively as I had Antifreeze in my system) (got from Radiant Supplier best deal out there)
  **NB** I run a separate Hot Water System from my Radiant System. The other option is to use one On-Demand unit for both, very possible and not hard, The Radiant Company can design it either way for you, no extra charge, it's a part of their service and I can only PRAISE Them for their amazing work, quality products & support, and I do "not" praise anyone lightly !

The efficiency is a win with the slab & hyper insulation. Winter -30C, inside 25C, Radiant only run 2 hrs within a 24 hour period to maintain 25C (floor sensor). Summer: 35C outside, 21C inside, NO AC or Fans just open windows. Slab itself never goes above 20C in summer, it regulates everything inside. Should Note, I am on the South Face of a Granite Ridge, 1200 foot fall in front of me, this property get's the heat & in a bad heatwave 40C is not a shocker. The Cabin itself is shaded by Scotch Pines & Cedars on the south & west sides and nestled into a forest nook. Solar System is mounted to the side of a 20' Sea Can 50' from Power House.

One of the Biggest Comfort & Energy Saving things that really make the difference is having a Cool Roof System. That is Thermally Broken from the exterior and therefore No Heat or Cold get transferred to/from the house at all ! This works way up here in the North as well as it does in the hottest of regions (it is where the concept originated from over 1000 years ago). This DOES cut heating/cooling Very Significantly and makes a home far more liveable.
Summer, +40C/104F outside, inside NEVER more than 28C/82F inside. Temp difference between 1st floor & 2nd = 1.5 Celsius higher on 2nd floor. In winter there is also only a 1 Celsius difference between the main floor & upstairs. NB: I have Radiant Heating within a Frost Protected Slab Foundation with R20 Insulation under it and up the sides.

Attachments are for the Cool Roof System, one of the best descriptions that was out there... Company now gone as owner became a Covid Victim. This is also well described on Green Home Building, BuildingAdvisor and several sites and this technique is being rolled into Building Codes as well.

Hope this is helpful and of interest, Good Luck.

This appears to be a version of "perfect wall" (roof, & foundation), from Joseph Lstiburek https://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall