One of my best friends has a cabin way out in the middle of nowhere in northern lower Michigan. We're talking twenty minutes of travel on sometimes-marginally-passable two-tracks.

He's tired of the noise of running a generator whenever they want/need power, is tired of much of the gasoline going to waste running a generator with often little-to-no load, and wouldn't mind having a full-time surveillance system with which he could see from home what's happening on/around his property--which would require constant power.

He wants to put in solar with dozens of hours of kWh of battery, said batteries of which can also be charged from the generator's excess capacity when it's running.

I've signed-on to try to help him with this project.

He's got a BIG pole barn, the ridge of which runs east/west, so he's got a large south-facing expanse atop, upon which a solar array can be installed. Pretty decent clearing to that direction, so he probably won't need to take down additional trees.

The area does experience heavy snowfall at times, and temperatures as low as -20°F in the January timeframe.

He's leaning toward going with lithium batteries for their cold-weather performance.

Two "performance" issues I perceive:

• Snow covering the panels in wintertime
  
• Battery de-rating in the coldest temperatures
  

I'm trying to convince him to have a cellar dug under the "electrical" room he had made off one corner of the pole barn, to mitigate the de-rating issue, but he's resisting that notion.

One of the things he's looking at is the Tesla Powerwall.

He wants to get it done NLT this fall, in part for the tax write off advantages.

The solar panels are not going to make any power if the cells are covered with snow. If you use AGM or GEL batteries you could put the batteries on something, like starboard on top of the ground for the batteries to sit on and build an insulated box around them to keep the ground heat in. I really don't know the characteristics of Lithium in a situation like this if putting an insulated box around them is ok.

I would still keep the generator just in case. Why doesn't he just pour the gas in his vehicle when he leaves and then bring fresh gas each time he goes? OR use rec 90 and put good stabilizer in it.......OR get a diesel generator......diesel lasts years and years with a good biocide in it and no moisture. He could have a big battery charger, like 100 amps and run the gen loaded just to recharge the solar batteries and then shut it off and run off of them 100%.

Powerwalls are expensive, locally quoted at $8K each, the amount he'll need of course is relative to the amount of power and time he'll need the power. With snow covering the panels if it's for a week he could drain a single bank of batteries easily depending on amount of power use then.


Tesla panels are pretty decent priced, less than what I got quotes from locally, I would shop of course,

There's some decent discussion here on the process.

https://sigforum.com/eve/forums...280046274#2280046274



You may want to go here https://pvwatts.nrel.gov/ and see what the amount of solar your location will achieve, will help in determining panel count for kWh desired...

quote:

Originally posted by jimmy123x:
The solar panels are not going to make any power if the cells are covered with snow.

Of course not. Thus my listing that as a concern.

quote:

Originally posted by jimmy123x:
If you use AGM or GEL batteries you could put the batteries on something, like starboard on top of the ground for the batteries to sit on and build an insulated box around them ...

The disadvantage to an insulated box is it would also keep heat in, which is also bad for batteries.

quote:

Originally posted by jimmy123x:
I would still keep the generator just in case.

Of course, which is why I noted:

quote:

... said batteries of which can also be charged from the generator's excess capacity when it's running.

quote:

wo "performance" issues I perceive:

Snow covering the panels in wintertime

Hows the wind up in his area, perhaps could supplement the solar with wind powered energy,

Wonder if there is some kind of cellular service up there where he could get a notice of power outage to the battery.

You asked about battery degradation in the cold, which is probably why it was suggested to build some kind of insulated box to protect against below freezing temps.

HOpefully this battery info will help.

How cold weather impacts batteries


Heres an interesting article on Solar Power and Upper Michigan, while it's about the You Pee, the same principles apply,
Snow Covered Panels, does solar work in the UP

Make the insulated battery box that's easily removable or removable lid when it's not cold. Or has vents you can open when it's warmer outside or a small computer fan on the case that you clip the leads on a battery when it's hot out.

The higher the DC voltage of the battery bank, the easier it is to charge faster and less conversion losses. 48V banks are common.....which is just 4 12 volt batteries wired in parrallel.

Akin to the wind power, if there is running water or a pond nearby that could feed a simple water turbine driving an automobile alternator, or DC generator. This can go a long way to keeping those batteries charged up.

As far as a "battery box" goes, mounting it on a trailer can make things a lot simpler when time comes to change out the batteries. Back the trailer into the barn when it gets cold, drive it down to town when you buy new batteries.

quote:

Originally posted by HRK:
Powerwalls are expensive, ...

Not looking to waste money, but initial outlay costs are not a prime issue, I believe.

quote:

Originally posted by HRK:
There's some decent discussion here on the process.

https://sigforum.com/eve/forums...280046274#2280046274

Thanks for the link. Not oriented toward off-grid, but a lot of useful info there. I'll have to re-read it, again.

quote:

Originally posted by HRK:
You may want to go here https://pvwatts.nrel.gov/ and see what the amount of solar your location will achieve, will help in determining panel count for kWh desired...

Thanks!

quote:

Originally posted by HRK:

quote:

wo "performance" issues I perceive:

Snow covering the panels in wintertime

Hows the wind up in his area, perhaps could supplement the solar with wind powered energy,

We've talked about that. Problem is the area around the cabin is heavily-treed. I doubt wind power would be particularly effective.

quote:

Originally posted by HRK:
Wonder if there is some kind of cellular service up there where he could get a notice of power outage to the battery.

Certainly, but I'm not sure what would be the point?

quote:

Originally posted by HRK:
You asked about battery degradation in the cold, which is probably why it was suggested to build some kind of insulated box to protect against below freezing temps.

Yeah. But my thinking is put 'em below-ground, where the temperature is fairly constant throughout the year. That way they're not exposed to the mind- (and battery-) numbing cold in the dead of winter nor the heat of summer.

I tend to over-engineer things

quote:

Originally posted by HRK:
HOpefully this battery info will help.
How cold weather impacts batteries

Heres an interesting article on Solar Power and Upper Michigan, while it's about the You Pee, the same principles apply,
Snow Covered Panels, does solar work in the UP

Thanks for those links!

quote:

Originally posted by jimmy123x:
Make the insulated battery box that's easily removable or removable lid when it's not cold. Or has vents you can open when it's warmer outside or a small computer fan on the case that you clip the leads on a battery when it's hot out.

I think you missed the part about a remote cabin out in the wilderness that's vacant most of the year?

quote:

Originally posted by jimmy123x:
The higher the DC voltage of the battery bank, the easier it is to charge faster and less conversion losses. 48V banks are common.....which is just 4 12 volt batteries wired in parrallel.

Series. Four 12VDC batteries wired in parallel would still be 12VDC. And, yes: A 48VDC battery system is what he's looking at.

He has a EE degree. We're both experienced computer geeks.

quote:

Originally posted by jimmy123x:
Make the insulated battery box that's easily removable or removable lid when it's not cold. Or has vents you can open when it's warmer outside or a small computer fan on the case that you clip the leads on a battery when it's hot out.

The higher the DC voltage of the battery bank, the easier it is to charge faster and less conversion losses. 48V banks are common.....which is just 4 12 volt batteries wired in parrallel.

I believe that would be in series, positive to negative like in your flashlight.

quote:

Originally posted by Krazeehorse:

quote:

Originally posted by jimmy123x:
Make the insulated battery box that's easily removable or removable lid when it's not cold. Or has vents you can open when it's warmer outside or a small computer fan on the case that you clip the leads on a battery when it's hot out.

The higher the DC voltage of the battery bank, the easier it is to charge faster and less conversion losses. 48V banks are common.....which is just 4 12 volt batteries wired in parrallel.

I believe that would be in series, positive to negative like in your flashlight.

Yes, you both are correct. Series. Even though I deal with battery banks on a regular basis I mix those 2 terms up.

Put a fan on the insulated case with a thermostat.....over 90F the fan comes on. Underground, I'd be afraid of flooding from a heavy rain.

quote:

Originally posted by jimmy123x:
Yes, you both are correct. Series. Even though I deal with battery banks on a regular basis I mix those 2 terms up.

Easy ways to remember:

Series: Front-to-back, one following the other, voltage (pressure) additive.

Parallel: Side-by-side, like connected to like, amperage (quantity, volume) additive.

Or: Series is like hoses connected together, vs. parallel is like them connected side-by-side: In the former: Pressure is higher. In the latter: Volume.

quote:

Originally posted by jimmy123x:
Put a fan on the insulated case with a thermostat.....over 90F the fan comes on.

Then there'd need to be an air inlet. But something to consider.

quote:

Originally posted by jimmy123x:
Underground, I'd be afraid of flooding from a heavy rain.

Good point. Don't know as that would be an issue at this particular location, but it's a thought.

quote:

quote:
Originally posted by HRK:
Wonder if there is some kind of cellular service up there where he could get a notice of power outage to the battery.

Certainly, but I'm not sure what would be the point?

Just an alert system that he's got issues, batteries failing or falling below a specific charge, requiring some service or attention.

If he's using it to maintain a low temp in the cabin to keep pipes from freezing and bursting or to alert him that he's going to have issues with a dead battery wall when he drives up in the spring.

More of adding capability to monitor the location through an application was the thought, since its remote and not visited often.

Nothing like driving up in the spring to a dead battery pack and a solar system that's not functioning, burst pipes, or missing because someone decided they wanted his system...

quote:

Originally posted by HRK:

quote:

Oringinally posted by ensigmatic:

quote:

Originally posted by HRK:
Wonder if there is some kind of cellular service up there where he could get a notice of power outage to the battery.

Certainly, but I'm not sure what would be the point?

Just an alert system that he's got issues, batteries failing or falling below a specific charge, requiring some service or attention.

Could be useful, I suppose.

quote:

Originally posted by HRK:
If he's using it to maintain a low temp in the cabin to keep pipes from freezing and bursting or to alert him that he's going to have issues with a dead battery wall when he drives up in the spring.

He's more likely to find he has a dead system come fall. It's mostly a hunting cabin

The cabin is winterized in late fall. Thenceforth, until next spring, it's a hand pump for water that gets primed each time they go up, and a brick shithouse. (Yes, it really is brick. Well, a brick façade--just because he could .)

Cabin is heated primarily with a wood stove, with supplemental propane.

The solar system will primarily be used to run the lights, TV, and microwave, chargers for mobile devices, the WLAN I'm going to design, and, in the warmer months, the well pump. And surveillance system, if we put it in. Battery chargers for the ORVs, I suppose. Electric power tools on occasion.

Is his property in the former Abitibi Paper Company land? Cellphone service is spotty on the main roads in parts of Northern Michigan.

ensigmatic, I sent you an email.

David

We've been living offgrid for 15yrs, installed everything myself. Installed several offgrid systems for others.

Seasonal cabin solar systems are tough to design. Use lots of power for short periods of time. System sets for the rest of the time. Probably no idea how much power he'll use. "Not much power" is not an answer! Having a 24/7 load with the surveillance system on a seasonal cabin, I would not do that, believe you're asking for problems. You could have a quality generator auto start when the battery voltage drops to a set level. I would be concerned about the generator starting at -20 though.

Electronics or "Power Panel" inverter/charge controller... look at Outback Power. Outback is fairly easy plug and play. Solar panels, for the most part they are really all the same. I have Canadian Solar panels. My panels and every offgrid system I've installed are on adjustable angle ground mounts. Much easier to install, easier to clean off snow, adjust for winter sun angle, snow slides off... For a seasonal cabin would put the panels at 60+ degrees for winter. If space is available and have a good sun window/no shading from trees, ground mount!! Batteries, Concorde Sun Xtender. Insulated battery box with a power vent.

Suggest to find a local dealer to buy all the stuff. You probably won't know all the little things you'll need until you are 20 miles down that two track road!

Lithium would be the wrong choice for batteries in a cold climate. They can be ruined if they are exposed to temps below about 20 degrees. Lithium batteries that have to operate in cold temps need a heat source to keep them above the low temp threshold.
The most basic/cost effective battery source is lift truck batteries. These coupled, as suggested in a earlier post,with a generator (diesel)with auto start might be an alternative.
Not being there in the Winter and having the solar panels covered in snow or many overcast winter days will drain the battery bank at very low temps.
The batteries are your biggest expense, they MUST be protected or they will be ruined.

quote:

Originally posted by armored:

The most basic/cost effective battery source is lift truck batteries. These coupled, as suggested in a earlier post,with a generator (diesel)with auto start might be an alternative.

Lift truck batteries are nothing more then a bunch of "industrial" 2 volt flooded lead acid cell in a steel case. Lift batteries are nothing special. The problem with lift batteries is they are often extremely heavy, making moving them a challenge. I've installed several sets of 2 volt FLA banks. Mostly these, about as heavy as I want to deal with. https://ibe-inc.com/.

A flooded lead acid battery would not be a good choice for a seasonal cabin. FLA batteries ideally should be equalized/watered every 60 days to get the best life. An AGM battery would be a better choice.

Takes over 10" of snow to make my array slow down production. But they are only powering 2 chest freezers and a fridge. 6 solar batteries and 4 230 watt panels. I clean them off when there is more than 12" on them. Really don't know how much they could really power. Highly recommend Outback Power though. Mine will generate 230 volt although I haven't gone that way with it yet, still working on the system.

I would verify the construction of the pole barn first to confirm it’s strong enough to hold the panels on the roof in addition to the weight of the snow that falls. Good luck with the project.