Intro & Off Grid Shed

Eaks77

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Jul 19, 2021
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26
Hello DIY Solar Power Forum!

I'm an avid Will Prowse YouTube viewer and I'm so glad he's setup this forum. I thought I'd start an introduction, with a current project that I'm sure I'll have a lot of questions! I'm looking forward to using this forum!

I live in Northern Canada, in a major city and I'm currently in the process of converting a 8x12' shed into an office to run a couple of my businesses. As of right now, the shed is coming together... A new roof, new exterior door and window. Next I'll be roughing in the electrical. The overall plan is to keep the shed off grid, but still have an AC extension cord hooked into a solar all-in one. I'm hoping to do the following:
DIY 280-320AH 24v battery pack - Aliexpress cells. Open to BMS suggestions.
MPP Solar LV2424 all-in one (or something similar)
4x400W bifacial solar panels - Probably installed on a pergola on the side of my garage - facing south.

While I know I'll have a lot of questions going forward, I thought I'd start with some that come to mind:
- Any suggestions from the solar setup mentioned above?
- It gets cold here! What's the most efficient way to heat a space?... I've read oil radiant heaters, but I'm also considering electric in-floor heating.
- As mentioned above, I'm about to start roughing in the electrical. I plan for 4-6 15amp outlets and 2 LED lights up top. I'm planning to install a sub-panel (or main panel?) to act as the distribution of power from my AC extension cord (from my garage-temp) and later from the inverter. Suggestions/thoughts? I'm confident I'll be able to install this, but my main confusion is regarding the grounding.. do I need to do this?

Thanks everyone!
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
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Messages
5,408
Location
Rural NE Ontario Canada
Welcome to the Forum, near Algonquin Park here.

1st suggestion: LFP Cell Supplier, Amy Wan @ Luyuan Tech, one of our Top Suppliers. She carries actual Grade-A Matched & Batched cells with factory test reports, 280AH = 125 USD Ea. and Bulk cells for $92 USD ea. You have to open a Chat/Messenger session to get a proper quote, the shipping guesstimator is way off.

The MPP is a good option, but I would seriously consider a 3000W, @ 120V/3000W that provides 25A capacity (uncorrected).
BATT Wires 2/0 Gauge Royal Excelene Fine Copper Welding Cable with tinned lugs. 3/0 if future-proofing (wise idea BTW).

I use Radiant Heating (in-floor hydronic), embedded into a Frost Protected Slab Foundation. Great for a house or shop, not small things. For my Powerhouse I use a recovered RV Furnace (Suburban NT-20S) for a wrecked 5 yr old RV. It's propane and runs off 12VDC, direct vent. It cost me $250 with the controls & dual regulator (2 tanks). Powerhouse is on an FPSF SLab as well and has 1/2 Radiant Pex installed in the slab (future-proofing). Highly insulated building with 2x4 construction, 3.5" thick HD-EPS-II Foam between studs, 1" XPS Foam thermal break between studs & sheathing. Roof is 2x6 with 5-1/2" of PolyISO foam insulation, built with a Cool Roof method.
* This foam is ONLY available to Commercial Users, I bought mine as "Take-Offs" from a Commercial Building Roofing Company. All good foam insulation removed from commercial buildings must be recycled and they have to ship it to recycle which is $$ so often they can be convinced (easily) to sell a skid or two... My powerhouse & house including the foundation insulation is ALL Foam, EPS-II (dump truck left 1/2" indent on a piece, very dense) XPS, and PolyISO.

Check out my About my System Pages, there is wiring and other info there that would answer some questions.
Hope it helps, Good Luck.
Steve
 

Eaks77

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Joined
Jul 19, 2021
Messages
26
@Steve_S Thank you for your response!
I'll consider using Amy Wan for my cells in the near future!
As for heating, i'm still considering all options, particularly electric in-floor heating... one problem though... The shed doesn't sit on top of a concrete shed. It's ontop of a couple 4x4's.
As for insulation, is the foam insulation that much better? I was just looking into insulation and figured I'd just go with R14 Rock wool all around. The walls are 2x4 studs @16".
My biggest hang up right now is around roughing in the electrical. Tomorrow I'll be putting in all of my electrical boxes for switches and fixtures, but I'm stuck on the sub-panel (6-spaces/fueses)... I'm assuming this is needed? Temporarily I'm going to have an extension cord from my garage, feeding into this sub panel. Once I have the MPP all-in-one installed, that extension cord will be plugged right into the MPP to provide AC battery charging (when needed) and then I'll have the same MPP unit feeding AC into the sub-panel. In theory.. this sounds about right... right? Where i'm lost is regarding the grounding. I understand some sub-panels don't have grounding bars and because power will either becoming from my garage or the MPP, is grounding necessary?
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,408
Location
Rural NE Ontario Canada
See here to see how I wired up my AC Panels: https://diysolarforum.com/threads/m...n-ontario-canada-24vdc-120vac.1484/post-12603

Foam Insulation cannot be beat but unless you can get it cheap (wholesale) there is 500% markup to Big Box stores... I mean $50 for a 2" thick 4x8 sheet = insanity. AVOID Fiberglass like the Black plague, Rockwool (Roxul) is hydrophobic, will not hold moisture, breaths, bugs/rodents HATE IT as they cannot nest in it (too prickly) and does not sag.

Solar Panels frames/aluminium racking etc MUST be grounded. Lightning Protection should be installed (common sense) for the panels as well (@ combiner).
Electrical MUST be grounded as well (separate ground) using a 6' Ground Rod pounded 4" below surface, 24" from building side and #6 Sheathed ground wire to Garage Panel (This is an AC Ground ONLY !) Grounding plates can also be used but much be buried 30" deep. All from Ontario Electrical Code.

About MPP to Square-D Subpanel (Pony Panel, no main breaker). See the diagrams link above.
I have a Square-D 70-A 2 circuits QO Sub Panel Model #QO2L70S , between my Inverter & Powerhouse Panel with a 45A Breaker as the "main" breaker. Inverter to "main-breaker" Panel, to Pony Panel is wired with #8. The incoming from Genset goes to another 2 slot panel with 40A Breaker then to inverter/charger, again with #8 AWG.

Hope that answers your questions.
FYI, Reason I used Square-D is because they are available everywhere and breakers are always available because they are so common, which also makes them cheaper too.

Electric Radiant Heating is extremely NASTY for power use... ANY resistive device east battery systems...
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Oct 29, 2019
Messages
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Location
Rural NE Ontario Canada
Well if you know of any Commercial Roofing companies (office buildings, shopping centres and such) they are a good source for foam sheets like PolyISO and HD-EPS and can be up to 6" thick.
 

Eaks77

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Jul 19, 2021
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@Steve_S what are your thoughts on Spray Foam for insulating all of the walls and possible above the ceiling?
https://www.homedepot.ca/product/to...omponent-spray-foam-insulation-kit/1000718744

It looks like it's Class 1 Fire Rated. Less expensive than R14 Rockwool. Has better R ratings and most importantly, if done correctly... It doesn't need a vapour barrier. I'm also considering just spray foaming the walls, while using rockwool above the ceiling.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
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Messages
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Rural NE Ontario Canada
Spray Foam is great BUT it is a PITA, you have to cover the floors, be ready to trim it & clean it up - lots of prep & post work to do.
If using foams, no vapour barrier as it is a vapour barrier on its own. I had this debate myself but you have to consider these kits don't offer that much in them... now when you have 2x6 studs and put 5-1/2" of foam in there you will have to do it in layers 1" at a time. Ceilings etc can be done. If a Cathedral Ceiling then you have to take other precautions or you'll make a sick house fast, many people do it without realizing they're doing it. You even have to prep the electrical boxes and whatnot to prevent foam from getting inside (instant fail if it does) so it is a task that needs serious consideration.

You will have to take the time & study how to spray the stuff and what prep & post cleanup. Roof/Ceilings can be done but pending on the structure how it should be done depends. You will require some form of Air Exchanger, preferably a Heat Recovering model, being your up here. The problem is the size of your structure being 100 square feet., they do not really make them for anything < 1000 sq'.

If using Foam Sheets you can cut it into 21" Wide strips and put it all together while framing the wall sections, like a SIP (Structural Insulated Panels) Again, commercial roofers can provide "Take Off" insulation, PolyISO, EPS, XPS . SIP method of prebuilding the walls with the insulation and then lifting the 8' wall section is not hard, PolyISO being the lightest BTW. Stuffing Tight Fit sheet between studs is a Royal PITA.

Alternately there is this solution as well called EZsips https://structuralinsulatedpanels.com/
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
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Messages
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Location
Rural NE Ontario Canada

And when it is -30C outside and bringing in that cold while pushing out hot air the condensation will be ludicrous. What is needed up here is not an ERV but an HRV (Heat Recovery Ventilator) that is equipped to handle the condensation and drain it away.
 

12VoltInstalls

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Ok. I’m in Vermont and they seem to work fine here.
I can’t remember if they had condensate drains or not; our winters are cold though -30 is rare these days. I did pitch the ducting just cause it seemed like a good idea. I don’t recall any complaints.
 

Eaks77

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Alright, I'm so lost with the conversation about heat exchangers and HRV's.... what? haha. To clarify, the attic to the shed is ventilated.. there's vents in the roof and soffits.

I'm also now leaning back towards R14 Rockwool for insulation. I was really looking forward to spray foam because it's way more effective and I don't have to use a vapour barrier (one less step), but before I renovated this shed, it was in rough shape! The roof was shot and there was a lot of wet/rotten wood... which brought a massive carpenter ant nest in the walls. The walls had the foam boards and I found that even after I removed all of the wet wood, there were still some rogue ants burrying into the foam boards. For this reason and from what I've read... I'm not liking the idea of spray foam. I've used a fair bit of ant killer and removed 99% of the wet/rotten wood (1% being the stuff I cant see). :( I'll also be sealing as much as I can with silicon or no more nails.

@Steve_S
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
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Messages
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Location
Rural NE Ontario Canada
Well funny thing about foams, the older stuff at one point was "Bug Neutral" meaning bugs would go for it but that got changed a few years back and they now have added repellant into the mix. Vapour Barrier is not a big deal, just remember to use Accousti-seal at every lap

HRV Heat Recovery Ventilator, exchanges air from inside with the outside. This prevents creating a "Sick House" which can be a very serious issue and many non builder's do not realize it. The recovery part is the transfer of the heat going out to the cold air coming in and also dealing with the condensation created during the exchange process.

IF you still have Bare wood framing (no insulation in there) then I very strongly suggest getting some Borac (20 Mule Team Brand - about $6 a box) and a clean (no chemical) garden pressure sprayer (hand pump type). Mix the Borax with Hot Water (1/4 cup borax per gallon) mix well and make sure it is dissolved, then spray ALL of the wood, very liberally let it soak in and dry. 2nd coat is optional but not a bad idea. Carpenter ants and most others will die when ingesting Borax, it is one of the main ingredients in Ant killers. It's not toxic to humans and won't harm the environment either.
 

12VoltInstalls

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A) silicon is sand and computer wafers. Silicone is a poor but very popular sealant caulking. Which is what I think you meant.

B) borax is elemental. You can buy WAY more weight for way less per pound btw than a brand name. It desiccates insects, it basically dehydrates them. Less toxic than table salt but illegal to use as a pesticide without a license unless you just like very clean wood I suppose. I’ve used it just spreading powder on sill plates.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Messages
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Location
Rural NE Ontario Canada
We have many Log & Cordwood homes here and more being built, Most are soaking the bottom 3' layer of log with Borax prior after cutting & prep prior to assembly, One popular builder of these (30 years now) has a mix of Borax & Allum, Allum is a natural Fire Retardent. We also sprinkle the Borax powder around our Wood Piles, I sprinkle a 3" wide strip around my house as I am in a forest and my siding is Live Edge White Cedar. Ever since I started that 4 years ago I have not seen any ants or other bugs in the house, not even earwigs.

I mentioned the Mule Team product because it's easy to get not that expensive and 1 or 2 boxes would be all that he'd need.
 

Eaks77

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Thanks for the insight! I'm definetly thinking about soaking the wood with some water and borax.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
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Messages
5,408
Location
Rural NE Ontario Canada
Thanks for the insight! I'm definetly thinking about soaking the wood with some water and borax.
There are Toxic Chemical Options but really not a great idea if it's a building you will spend much time in. Also, regarding ant's, TERRO Ant Killer packs are Great, note the active ingredient is 5.4% Borax but if you suspect an ant colony may be established, put a couple of these along their trails.
 
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