400 sq ft weekender cabin, off grid, designed for cooling

Mike 870
Mike 870 Registered Users Posts: 42 ✭✭✭
in Construction #1
I just received my iron ridge mounting hardware that I purchased here, so figured I might as well start a build thread about my small off grid weekend place.  It's many years in the making, crazy to think I have a 10 year badge here and I'm not even close to done.  I've just completed part of the roof and hope to mount the panels if my solar feet arrive on time.  The cabin is built using advanced framing per building science corp. and is part stick framed part timber framed.  It has an R 39 roof that is vented and will have a mix of R19 and R32 walls that are also vented via site build rain screen.  The solar setup will be 260 AH at 24 volts powered by the Bogart controller/trimetric combo with 640 watts of solar and room for another string if usage ever increases.  I have loads of videos on the build so far so check out my Chanel.  This one I posted is my best edited one so far.
 https://youtu.be/viabiXnrcjs
 
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #2
    Dont worry . my 5 year project is now at year 16 . still not finished . Life gets in the way .
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #3
    I'd wrap that OSB before nature reclaims it.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #4
    Well we did finally get the OSB wrapped.  The water off the roof is splashing off the deck and soaking it.  We really need some gutters.  Anyway, we just got our doors and windows in.  They are Marvin Wood Ultrex.  If anyone is building I really like them but they are pricey.  Low e is standard though which is nice.  Video update below. 

    https://youtu.be/RKb0X8bI6K8


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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #5
    Think about cladding with steel, low maintenance, lasts forever, wood is a PITA if you ask me, but then again I'm a practical person.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #6
    mcgivor said:
    Think about cladding with steel, low maintenance, lasts forever, wood is a PITA if you ask me, but then again I'm a practical person.
    Especially practical when forest fires are a possibility. Though a couple forest fire precautions are still necessary:
    Clad all of it in steel.
    Clear 50' of combustible materials around the cabin including trees.
    Nice to have access to water so a sprinkler system can keep the area moist.

    Sure would be nice if locations were presented. Location dictates so much. Plus that little C or F when referring to temps. Not talking about the OP here.

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #7
    I'm strongly considering doing a wainscoting strip using the same galvalume we used on the roof.  It would take all the splashing that hits the bottom half of the cabin.  Gutters are great, but in the woods they come with their own issues.  Fire isn't much concern, we're in the midwest, and we get a good deal of rain almost all seasons.  We used to have a dry season in late June/July/August, but honestly that doesn't happen any more.  All that said, I do take out one or two junipers near the cabin each trip and get them to the burn pit.  Next trip I'll probably get the panels up on the roof.  They are currently in the loft and well, I don't want them to walk away.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #8
    Be aware, generally metal siding (and structural supports) are not considered to be fire proof/resistant. Sure, sparks will "bounce" off of steel and aluminum sheets... But if you have something up against the material (brush, wood pile, other wooden structures), the heat from a well developed fire would go right through (steel starts to weaken over ~450F-800F).

    Using a true fire resistant/rated material would probably be a better plan.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #9
    BB. said:
    Be aware, generally metal siding (and structural supports) are not considered to be fire proof/resistant. Sure, sparks will "bounce" off of steel and aluminum sheets... But if you have something up against the material (brush, wood pile, other wooden structures), the heat from a well developed fire would go right through (steel starts to weaken over ~450F-800F).

    Using a true fire resistant/rated material would probably be a better plan.

    -Bill
    Thats why the property needs to be cleared for 50'. My friends log home survived a huge fire that wiped out everyone that didn't clear 50'. 

    Anyway the OP is reportedly not in a high fire risk area. My area just went through the 2nd largest fire in Colorado history.

    Good notes on heat transferability of course. Most people do something short sighted like leaving the wooden eave or wood porch totally exposed. Only property clearing gives them a chance.

    Lets maybe get back to solar since fire isn't the issue here.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #10
    I redid my cabin with 4" rigid foam added, cedar t&g, and cetol finish. Metal roof, but just couldn't bring myself to do metal or vinyl siding. The bottom 12-16" of walls above grade, I used roll aluminum over typar to mitigate problems from splashing, weeds, etc. at grade, also to deter rodents. Seems to be working well so far.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #11
    Well this is an exciting time.  After 10 years or so of wanting to install solar, got my second batch of equipment in the mail from NAWS and started installing the panels!


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  • NANOcontrol
    NANOcontrol Registered Users Posts: 275 ✭✭✭
    edited October 2018 #12
    I used Hardie concrete plank siding on mine with PVC trim. Holds paint like crazy, won't burn and will never rot. Vinyl siding looks like (hell) in a few years.  I found the installation quite easy.  I only had a small box of pieces less than 4" long after a 24X24 two story building when completed. That made it extremely cost effective.
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  • Aguarancher
    Aguarancher Solar Expert Posts: 315 ✭✭✭
    #13
    +1 for Hardie Plank and it sends all termites to the dentist to get fitted for dentures.. lol
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    edited October 2018 #14
    I have good quality vinyl siding on part of my city place, and it still looks the same as it did when installed 20 yrs ago (although one could argue it looked like (hell) the day it was installed :blush: )

    Will have to repaint wood (board & batten) sided parts in the next year or two, and will be seriously considering adding insulation and cement plank over the wood.  Seems to me it can be bought prepainted vs field finished... any thoughts on whether that's worth considering?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #15
    One warning about vinyl siding... These days many homes are using double pane windows--Which for some reason, many times, are slightly concave (vs single pane windows that are pretty flat)--And with low E (reflective) glass, they can focus the sun on neighboring buildings, and if the conditions all add up (angle of sun, windows design, hot climate), the reflections can be focused enough to melt the next door vinyl siding.

    https://www.greenbuildingadvisor.com/article/window-reflections-can-melt-vinyl-siding
    https://inhabitat.com/are-low-e-windows-melting-your-neighbors-house/

    And it is (typically) not covered by mfg warranty.

    Usually a single cabin in the middle of nowhere--Should not be a problem (although, not fire "proof" if that is an issue in your region).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #16
    Interesting.  When I was considering siding for the cabin a few years ago, pricing on dark vinyl colours was a premium.  Maybe higher potential warranty costs?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #17
    I made a video chronicling my solar install,  it's more of an entertainment video than a technical one.  I've still got a bit of work to do but thankfully done climbing on the roof.  

     https://youtu.be/fBAVOnBKEpM
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    edited November 2018 #18
    Did you drill a weep hole in the bottom of the right angle pull box at the wall? I have a bit of concern that water could follow the wiring/conduit and bring water inside the cabin.

    Generally, a weatherhead with drip loop keeps things a bit drier...
    Free stock photos - Rgbstock -Free stock images Weatherhead RWLinder May - 01 - 2014 2

    Boy, that is a nice area... Unfortunately my wife thinks anything just south of San Francisco (suburbs) is as rural as she wants.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #19
    I didn't drill a hole, but thats a pretty easy precaution to take.  I thought about using a mast, but didn't want to drill through the roof if I could afford it.  The way that I did the strapping under the roof would have made it tough to get a tight seal with any gasket because I wouldn't have any wood to drill into in some parts.
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #20
    I'm curious what your plan is for good air sealing (Tyvek doesn't usually test out well, even when fully taped).

    I am available for custom hardware/firmware development

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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #21
    I'm just accepting a moderate level of air sealing.  We've been caulking seams, using sill sealer, foaming gaps, etc and will also tape the tyvec.  Basically going into it knowing we won't achieve a super insulation level of air sealing.  That said the small size of the structure means that we have some margin when it comes to heating and cooling.  
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  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    #22
    My house in central America had a weather head that someone forgot to add a drip loop to the mains coming in. We awoke one rainy night to a blue arch flashing about every 5 seconds as the now rain filled conduit dropped water on the unprotected water heater connection down below us on the first floor. The entire homes conduit would flood every time it rained. ..I ended up duct taping a trash bag over the weather head and main lines coming in.... Problem solved 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #23
    jonr said:
    I'm curious what your plan is for good air sealing (Tyvek doesn't usually test out well, even when fully taped).
    Interesting note about sealing. Something I'm half way decent at. As a result my indoor oxygen levels are currently at 20.0 percent instead of 20.9 percent. Not terribly significant....yet. The alarm will go off when it hits 19.5 percent which I sort of expect next month. Still not a big concern but getting interesting.

    Whats the point of ultra sealing when it means that one has to keep doors or windows cracked for ventilation? 

    Tyvek can help quite a bit from what I gather.


    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #24
    Steel vs. vinyl siding? I've seen vinyl siding destroyed by hail and I'm pretty sure it is somewhat flammable.

    I'm a fan of steel. If rust starts to form after a few decades, it is very easy to paint. Lends strength as well. Not hard at all to cut with a steel cutting blade on a $12 (HF) grinder. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #25
    Still mulling my siding choices over, I did get out there and take out 5 or 6 cedars closest to the cabin.  Didn't make much of a dent in it.  It's been raining almost twice a week though, so I don't think it matters much at this time. 
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited November 2018 #26
    > Whats the point of ultra sealing when it means that one has to keep doors or windows cracked for ventilation?

    1) wind varies widely, so depending on cracks for ventilation means you will often be over or under ventilated.  Ie wasting heat or stewing in pollution.
    2) you use an ERV or HRV so you don't need to rely on open doors or windows.  And to save heating/cooling energy.


    I am available for custom hardware/firmware development

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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #27
    Biggest issue of being OFF GRID is a scarcity of electricity.  I dropped any thoughts of having a more modern house when I found the minimum consumption of a unit would be higher than my fridge.... that would have been > 2.5 KwH per day, pretty hard to make even that amount with < 4 hrs of sunlight  in winter..
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #28
    WestBranch,

    I assume the ~2.5 kWH per day was for an ERV or HRV?...

    Any mechanical or heating device tends to use lots of power if they are running 24x7... 5 minutes in a microwave or electric tea kettle, not so bad.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #29
    You got it Bill, I looked at the running amps at all 3 settings on a friends  system when he put it in....scary, the very lowest fan speed it had pulled  > 1 Kwh/day..     and it had 3 speeds....
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • softdown
    softdown Solar Expert Posts: 3,915 ✭✭✭✭
    #30
    Mike 870 said:
    I made a video chronicling my solar install,  it's more of an entertainment video than a technical one.  I've still got a bit of work to do but thankfully done climbing on the roof.  

     https://youtu.be/fBAVOnBKEpM
    Pretty slick ladder move getting from the ground to the 7th rung. Wish I could move like that.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Mike 870
    Mike 870 Registered Users Posts: 42 ✭✭✭
    #31
    I have a question for you guys regarding my Honda EU6500 IS generator, my SD 1500 hard wire inverter (with auto transfer switch)  and my Iota DLS-24-40-X.

     Would I want to run my generator on 240 split phase, then split the phases and have 1 go to the inverter input and 1 to the Iota?  I suppose I would run the input off the generator through something like this?  https://www.homedepot.com/p/Square-D-QO-30-Amp-2-Space-2-Circuit-Indoor-Main-Lug-Load-Center-QO2L30SCP/100157760?cm_mmc=Shopping|G|VF|D25T|25-9_PORTABLE+POWER|DREMEL|NA|Versa|LIA|71700000044136618|58700004605584227|92700038787350835&amp;gclid=EAIaIQobChMI9LuLj9Hb3gIVz0oNCh0sqgp_EAQYASABEgJW__D_BwE&amp;gclsrc=aw.ds ?

    Or should I run my generator on 120 volt and just plug the iota in when I want to use it?  or is there some better way of doing this that I'm not even thinking of?
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