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diy solar

Building cabin - what are min needs to scar for solar

LB3

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Sep 12, 2020
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I’ve got an RV with a DIY solar system and LiFePO4 battery so I understand the off grid solar pretty well.

We’re currently building a 535 sqft fishing cabin an an area with marginally reliable electric power. I would like to eventually install solar (even if it isn’t strictly economical) and a battery backup system and eventually take the cabin off grid some day.

Loads include a mini split heat pump, refrigerator, etc. What must I have to scar for this? Is it sufficient to just put a NEMA 14-50 outlet near where an inverter would eventually live that could be rewired when needed? Or do I need to install a transfer switch and sub panels?
 
To keep it simple & clean, in a similar situation, I am 100% offgrid, 24V DC with only 120VAC - no need for 240 I used a Samlex EVO Inverter/Charger which has built in ATS and AGS so it can use a GCSM to start/stop an appropriate generator. Only use the L5:30 line, which can give me 24V/75A charge nicely.

The new crop of All In Ones from MMP Solar, Growatt and many others further simplify many things.

Have a peek at the links in my signature.
 
To keep it simple & clean, in a similar situation, I am 100% offgrid, 24V DC with only 120VAC - no need for 240 I used a Samlex EVO Inverter/Charger which has built in ATS and AGS so it can use a GCSM to start/stop an appropriate generator. Only use the L5:30 line, which can give me 24V/75A charge nicely.

The new crop of All In Ones from MMP Solar, Growatt and many others further simplify many things.

Have a peek at the links in my signature.
Thanks, I would know what to do if it were off grid but trying to scar for the transition from grid power looks pricey. There are some generator transfer switches that are built into load centers (breaker boxes) I’m thinking that using one as a sub-panel would work but they’re a bit more money that I was hoping for. I may go with a sub panel for critical circuits and just put a transfer switch in between down the road.
 
We are 100% off grid, as there is no power option at all.
What I did is wire the entire cabin for 120. I wired 2 separate circuits, so that all essential lighting plus 3 outlets for charging phones went to 1 circuit, and the rest (Kitchen outlets, 2 ceiling fans, TV outlet) went to a second circuit.

Our situation is a little different than yours, so this is where it's wired differently...
We also have a gas powered generator, so I installed a Male inlet on the exterior.
That inlet is wired to a 4-plex outlet on the inside of the cabin.
This way I can connect the 2 circuits either to my inverter or to the outlet leading to the generator.

I know in place of that you'd be looking to install a ATS.

In the end, our cabin is wired to eventually handle grid power if it every is available, but honestly, our system is working well enough at this point that the only time we need the generator is when we are running heavy power tools or a window AC unit.

Set-Up:
(3) 100w in Panels
190ah worth of AGM Batteries
Renogy Rover Elite 20a MPPT Charge Controller
1000W Mode Sine Inverter

Cabin is wired with 12ga Romex

Our load is approx. 1200w per day
(7 LED lights, 2 ceiling fans, 32" LED TV, charging 3 cell phones and 2 laptops, DC Water Pressure Pump)

Final goal is to add 1 more panel and 1 more battery to hopefully run an electric coffee maker (Draws 895w @ peak).

Our cabin is 24' x 32' (768 sq. ft) so I think your power needs would be quite similar.
Ours is a hunting cabin.
I will attach some pics for reference.
 
@HARG Hunter you should do an About My System page for your setup, that would come in very handy for several of our members here. Peek at mine and you'll see why... Many folks are not trying to solarise a 3500 square foot Cape Cod shack in Urbanium and DIY'ing it.
On Post 2 of my "About my System" I have the 120V AC Schematics with several circuits, my place is wired and circuited no different than if it was on-grid with 100A+ service. Actually I have 6/3 & 8/3 AC Wire already run from Powerhouse to Home Sub-Panel just in case, for down the road, if needed/wanted & to allow for future upgrade. (I got a great deal on the wire so I took advantage of it).

Will's blueprints and such are fine "basic" designs & schema's but it helps folks see Real World this is how I did and it works well examples, such as yours & mine. His video's are more focussed on the RV/Camper to light solar "power room" type things but he never touches on the AC Side of things (tricky area that - international differences and all the code stuff). Doing a whole house of off-grid place from the ground up is not Will's thing. Boy there's some lessons to learn there LMAO.
 
@HARG Hunter you should do an About My System page for your setup, that would come in very handy for several of our members here. Peek at mine and you'll see why... Many folks are not trying to solarise a 3500 square foot Cape Cod shack in Urbanium and DIY'ing it.
On Post 2 of my "About my System" I have the 120V AC Schematics with several circuits, my place is wired and circuited no different than if it was on-grid with 100A+ service. Actually I have 6/3 & 8/3 AC Wire already run from Powerhouse to Home Sub-Panel just in case, for down the road, if needed/wanted & to allow for future upgrade. (I got a great deal on the wire so I took advantage of it).

Will's blueprints and such are fine "basic" designs & schema's but it helps folks see Real World this is how I did and it works well examples, such as yours & mine. His video's are more focussed on the RV/Camper to light solar "power room" type things but he never touches on the AC Side of things (tricky area that - international differences and all the code stuff). Doing a whole house of off-grid place from the ground up is not Will's thing. Boy there's some lessons to learn there LMAO.
Now that my system is somewhat fine tuned, I will definitely do that.
 
Now that my system is somewhat fine tuned, I will definitely do that.
Ohh Absolutely, such is GOLD in a place like this. People NEED to see working examples and to be able to compare ideas & implementations to figure out what may fit their needs better. Just think back to when you started "plotting" your Solar Adventure and were looking for how others did it and trying to visualize it for your own setup.... How many places did you search and how many articles, designs, schematics and drawings did you collect ? Ohh the amount of hours lost doing that... when you could'a been swingin the hammer !

There is another side benefit....
What if you get hit by a Rabid Transport Truck tomorrow, Mrs Harg & Friends / Associates would be left to figure out a puzzle and try to understand it from scratch. I think of it right up front BUT being terminal with cancer and knowing I won't be here more than 2 more years, I have to leave everything fully documented for my Mrs & whatever the future presents later.
 
I’ve been looking at this integrated ATS and load center from Generac but it’s not a stock item and has to be custom ordered. I’m hoping to start wiring in the next two weeks so I’m guessing I’ll have to graft on a transfer switch later.
rxg24sha1_95041_1000.jpg

https://www.powerequipmentdirect.com/Generac-RXG24SHA1/p95041.html
 
For my own cabin off-grid, I went with a split-phase 120/240V inverter, and then wired my whole cabin with standard AC wiring through a standard L1/L2 main service panel. Now I can operate all standard 120VAC appliances transparently.

One bit of advice I would give you is to skip 12V completely. The really high quality components start at 24V, and reach 48V. These are the components that are designed to be hard-wired directly into your main panel, and can handle all the household loads you throw at them. They also allow things like seamless generator charging, and some have the capability of a grid-tie.

You can make a rotating single-pole ground mount that can hold 1500W of panels. Take a look at some of my previous posts concerning ground mounts. You could easily accomplish that with six 250W grid-tie panels, which are my personal favorite. With a rotating mount, your array should make 8kWh per day even at the winter solstice.
 
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