System for off-grid cabin in Canada

[Green18]

Hello,

I'm new to this forum and am trying to figure out what my best options are for an off-grid system. I've watched a lot of Will's videos and was leaning towards the 48V/3000W DIY system on a hand truck, but now I'm not sure if I even need that much power.

This system would be for a cabin in Canada (if that matters) and it's totally off-grid with no plumbing or anything. It's a glorified tent in the woods that the family loves, but would like to start upgrading with amenities and solar/electric seemed like an easy start.

The system I'd like to create would only get used for a few summer weeks out of the year and would possibly be trucked back home so that it's not lying around in the winter months (the battery atleast). At this point, the family would like to run a small refrigerator (something in the 10 cu. ft. range), a few lights, and to charge cell phones and flashlights. I'd love it if we could have a system that could grow with us over time as people decide that they'd like more things.

Ideally the system is as basic as it gets so that folks who are not as technically inclined can show up, connect the few cords that need connecting, and be up and running. Maybe an all-in-one system is our best bet, given the ease of use, but I wasn't sold on the idea. They also seem to cost more once you price out the pieces.

What do folks think? Is the 48V/3000W too much for our needs or is that a good starting point? Am I better going with a 12V system? All-in-one?

Thanks for your time.

 

[ElectricIslander]

48V 3000W is a good sized system, especially if you will ever expand use. No sense in spending money on gear that will have to be upgraded. However some folks run fridges on smaller systems.

Running a refrigerator 24/7 can be a significant load, depending on fridge efficiency, size, ambient temperature and use pattern.

If you get a top ranked Energy Star fridge (we use a120V LG Inverter fridge) they are not too hard to run on a solar system (non inverter fridges have higher compressor startup surge). The fridge choice is a tradeoff between the low cost and all the features / size availability of typical 120V fridges vs the greater efficiencies but higher cost of the DC fridges from Unique etc .

 

[DIYrich]

Growatt 3k or eg4 3000 would be a good place to start. Plugging in a battery, or panels into an inverter/battery is easy.

 

[Xhumeka]

I've been using a Growatt 3k for 3 years now (Ontario - just south of Algonquin) and no complaints! I use the 24v version but personal preference. Watts 247 has them on sale now $499, great deal if you ask me. That plus a few panels and a battery and you're set.

When I'm not at my cottage the only thing running is my fridge (usually about half-full of food) and starlink router... the fridge is a cheap Frigidaire 13.9 Cu. Ft that we got on sale and the Growatt handles it no problem. We also run a jet pump for our water supply and i've seen surges of over 5kW when it starts up and even with the fridge running the Growatt has never shut down.

Here's what the energy usage looks like when I'm not there for the fridge and starlink (below represents a 4 hour peroid) You can see that the fridge kicks in about every 50 mins:


(Growatt reports about 2kW/day usage for just starlink and fridge)

 

[Green18]

Greatly appreciate the feedback everyone.

 

[dopeassjackson]

You should have no problem running a good sized fridge with that system.

I run a 4.3cuft minifridge with separate top freezer and it generaly only draws 50-60w when its on.

 

[mvonw]

You should have no problem running a good sized fridge with that system.

I run a 4.3cuft minifridge with separate top freezer and it generaly only draws 50-60w when its on.

I have a 10 cuft fridge and a separate minifreezer and they draw about the same. I don't even know there are there in terms of battery/power use.

 

[Steve_S]

I'm near Algonquin Park, 100% offgrid solar powered, year round residence.
I run my place on 24V with 4000W Low Frequency inverter that can provide 120V/32A but can handle 12,000W surge.
This runs everything here, deep well pump, 3HP compressor and 120V MIG Welder without issues.
Typical running loads (from battery bank) 6A up to 11A with a couple of lights & fridge "running". My usage Year Round averages 3.5-4.0kWh per day. NOTE THOUGH: This is NOT a typical home, it has thermal broken walls & roof with radiant heating in a Frost Protected Slab Foundation.

Consideration TIP: a 24V/280AH battery Pack weighs in close to 50kg while a 48V/280AH is double that.
Notes on Battery bank draws:
I use a Danby 11 cubic foot fridge (energy star uses 250kWh per yr) Start demand is 12A but running demand is 4A.
A Panasonic 1200W Inverter Microwave uses 73A while running on 100%
A Galanz 900W Microwave with Air Frier + using 62A at 100% power.
An Oster Perc Coffee maker with thermal carafe uses 55a while brewing.

* These AMPS are what is recorded by the Smartshunt as being pulled from the 24V system

Essential Considerations for a Light Use P-T place...
Device Efficiencies are really Important. Inverters can be anywhere from 85% to 97% efficient and that makes a big difference in consumption, most especially the running overhead (even at idle) The more the inverter wastes while doing little work adds up really fast. IE My Inverter (Tier-1 Samlex) uses 18W idle (non-powersave mode) while my previous APC-3000 used 60W idle (non-powersave).

Some Realities:
A fridge (any device with compressor) has a bigger start surge hat lasts for a few moments. They will generally not go over 120V/15A (1800W) to startup , so when considering the system you want to be able to handle at least 2 devices coming on at once. High Frequency inverters are ok for light things but not heavies like a compressor or mig welder. Low Frequency is best for all possible uses from light electronic to heavy motors or major inductive loads.

A Heat Pump is also the best option for a small solar powered cabin. Mr Cool makes a lovely 120V/25A (max start amps) DIY unit that can handle up to 700 square feet. That can easily handle your Cooling/Heating loads if you build your right.

A system to grow with:
There are different ways to do this today - so many options. AIO's (All in ones) have many advantages and if staying in the same family of a brand many can be setup in parallel. They all have Solar Controllers built into them but they are not the best SCC's in reality, most are setup for High Voltage arrays. In turn that means more panels etc are needed so added costs on the other end. Then you have Tier-1 Companies like Victron (worth every penny) which have numerous devices (SCC, Inverters & more) that can all interconnect & work together in perfect harmony and well supported by community & company. AIO's are NOT the panacea that many leap on, there are definite trade-offs.

Usage Case Example:
Right now I am pulling 11.8A from SCC & Battery (freakin thunderstorm happening)
That is running 2 lights, ExplorNet Sat Receiver/modem, Router, HP Desktop computer with 47" LED Screen, Stereo, Refrigerator (running) 3 wall-warts, plus coffeemaker & microwave displays. With Fridge off 6.6 to 7.0A is what my system pulls to run everything else.

Hope it helps add some perspective & real world experience.
Steve

EDIT: oops...
System Solar Sizing:
It should be setup to provide generation & recharge when you need it most and that depends on your cabin usage... summer only or all season etc and how much time you will spend there during the seasons. This also depends on how much Battery you will have to charge and how many Sun Hours you have during your usage times. Systems can be optimized for Summer or Winter or averaging for all seasons, so there are several considerations. Even things like Shading (if you're in a forest like me) will affect Solar Panel choices as some do much better with cloud & shade while others don't do well at all. Solar Panel Price is a BAD GAUGE to make such choices. The REALITY is for us up here, having Panels that handle Cloud/Shading & Low Light conditions are the better option and NOT significantly different in $ either, just needs smart selection.

 

[45North]

You save conversion losses if you stick to DC only. So, skip the inverter and get a little portable 12vdc frig. You can plug it into the car's cigarette lighter socket on the way to the camp.
Lots of 12vdc lights, and usb chargers available for RV's, autos, etc.

 

[SoggyShoes]

I am just curious. If a system is completely off grid, would it be better to treat it like an RV? Taking advantage of all the 12V and 24V stuff that are made for that?
If that is the case, it almost seems like you would want to go with a 24V system as there are a lot of 24V items (especially in the European truck and camper market) and it is easy to step down to 12V. There are also a lot of things from lighting to CPAP machines that can run on a range from 12V to 24V (nominal).

It seems that sticking with 12V to 24V Dc is safe and very efficient.
Or is using 48V for energy storage and inverting it all to AC just overwhelmingly easy and familiar? (more powerful inverter options)
Is there something else that I am completely missing? (probably) Or just no consensus?

 

[mvonw]

Is there a even a grid in Canada? What's up there?

 

[ElectricIslander]

Is there even a grid in the US? What's down there anyways?

 

[mvonw]

Is there even a grid in the US? What's down there anyways?

More sun?

 

[SoggyShoes]

Is there even a grid in the US? What's down there anyways?

We have a grid... and it works...
...well...
as long as it is not too hot...
or too cold....
or the wind isn't blowing too hard...
or there are no fires...
or no freezing rain...
or we get enough rain...
or no hurricanes...
or not too much snow...
or our power isn't sold to another state...
or...

Well anyways, as long as all mass of an object is at a singular point at it's center, or at least is always has uniform density. And as long as for "small" values, we can just use x for sin(x). And as long as all chickens are perfectly spherical, our system works great!
Solid as a rock! (just be careful not to trip over those loose wires.)

 

[Gold Country Russ]

If I were installing a PV system that had to reliably provide power in snowy weather, it would have vertically mounted bifacial panels, similar to a fence but a lot of room below the bottom of the panels for snow. They would effectively self-clear of snow and collect lots of power from the back side on cloudy days.

 

[NC_hydro]

Consideration TIP: a 24V/280AH battery Pack weighs in close to 50kg while a 48V/280AH is double that.

FYI That’s not a truthful comparison. A 24V280Ah battery is only 7.16kWh but the 48V/280Ah is 14.33kWh. So yes it’s double the weight but that’s because it’s double the capacity.

 

[Steve_S]

280AH cell = 5.5kg X 8 = 44kg/96.8 lbs. 16 cells = 88kg/193.6Lbs
Add Casing, BMS etc

 

[NC_hydro]

280AH cell = 5.5kg X 8 = 44kg/96.8 lbs. 16 cells = 88kg/193.6Lbs
Add Casing, BMS etc

You still missed the point. You’re comparing a battery with twice the capacity so yes it will have twice the weight. Not because it’s 48v vs 24v but because it has twice the power capacity.

 

[ohmboy]

You still missed the point. You’re comparing a battery with twice the capacity so yes it will have twice the weight. Not because it’s 48v vs 24v but because it has twice the power capacity.

I think that is the point that @Steve_S is trying to make, comparing the weight. The original post mentioned

"... and would possibly be trucked back home ... "

So hauling 8 cells vs. 16 cells can get heavy. 16 cells, in this case is almost 200 lbs.! It would be a team lift.

 

[NC_hydro]

I think that is the point that @Steve_S is trying to make, comparing the weight. The original post mentioned



So hauling 8 cells vs. 16 cells can get heavy. 16 cells, in this case is almost 200 lbs.! It would be a team lift.

Right so you get a 100Ah 48v vs a 280Ah. 100Ah 48v is same kWh as a 200Ah 24v

 

[SoggyShoes]

I think the point is that sliding 100lb cases in an RV basement is hard enough.
Trying to do this with a 200lb case can become too much.

 

[Steve_S]

I think the point is that sliding 100lb cases in an RV basement is hard enough.
Trying to do this with a 200lb case can become too much.

As well as picking them up EVERY WEEKEND to stuff them in a vehicle to get them charged "at home". Most people are not looking for a WORKOUT at the end of their holiday at the cabin. Then again, maybe some think that "everyone" can heave around a 200 Lbs Box like a 6 pack of beer.

Of course some have a notion that ONLY 48V Works to run a Cabin or home... For MANY Years I have been entirely offgrid with 24V & now 43kWh of storage in Northern Canada experiencing -35C/-31F to 40C/104F temp swings through the seasons.

 

[NC_hydro]

Nothing wrong with 48v or 24v but just because it’s 48v doesn’t mean the battery is heavier for the same capacity, that was my point.