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Small Cabin Forum / Off-Grid Living / Starting my solar journey
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NorthwoodsGuy
Member
# Posted: 8 Mar 2018 13:46 - Edited by: NorthwoodsGuy
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So, I think we are going to pull the plug on some solar. Our cabin is small (12x16), so I don't anticipate needing a ton of power. I am estimating 2-3kwh per day, and we are mostly weekenders at this point. I've got some beginner questions:

- I am leaning towards ground placement so I can reposition, but if I went with roof placement, how far away to panels need to be from the chimney? Other side of the roof? Is there guidance for this?

- Ontario Lakeside (if you are around, or Creeky)- In your original setup video you had one volt module, but it looks like you are adding more? It looks like I probably want 150+AH at 48v, so if I went the volt route, I would want at least 3, right?

creeky
Member
# Posted: 8 Mar 2018 17:47
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OL has two modules. for 100ah. That will easily handle 2-3 kw a day.
In fact, closer to 4.

If you have a 12x16 what are your loads that you need so much power? Fridge, induction cooktop? Cappuccino maker?

beachman
Member
# Posted: 8 Mar 2018 19:26
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After being on solar for a few years I have to agree with Creeky's comments about the need for so much power - 2 or 3 kWh per day. We have a 20 x 25 with a loft and provide for about 750 wh per day. We have a propane fridge and stove and wood heat and stay there weekends and about 6 to 8 weeks in the summer. Our power needs are small and simple. I highly recommend a Killawatt device to see what your needs really are before going down any road.

NorthwoodsGuy
Member
# Posted: 11 Mar 2018 15:57
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Thanks, I've been trying to figure out how much we need. I figure we want to be able to run 2 laptops, 2 cell phones, 6 LED lights, and the occasional hot plate or miscellaneous higher amperage device. We are CONSIDERING a small fridge but are also discussing propane or just not having one.

I'd like to be able to account for a couple of days of cloudy weather- we are next to the big lake, and weather can change pretty quickly. We get a lot of lake effect weather, which can mean a day or two of clouds.

Maybe I will start with a 1kwh system and build out if we need more?

Ontario lakeside
Member
# Posted: 11 Mar 2018 16:46
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Hey Northwoods

Like Creeky said we have two modules. we run a small fridge, lighting, charging of phones, computers, composting toilet fan etc. Last summer we never used more than 1/2 of our capacity and typically are fully charged again by 11am. Check out our Youtube channel, I have a few videos that might help you with your project.

https://www.youtube.com/channel/UCGuSGWaR9LgZwYVvaE3sXIA/videos

Best of luck

cspot
Member
# Posted: 11 Mar 2018 17:15
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What about having an inverter generator to run the misc high amperage devices and then just having a small solar setup for the lights and charging?

At our cabin which we use mainly on weekends we have a 50 watt panel and 1 deep cycle battery for storage. We charge phones and tablets off this plus we have 8 LED lights, a shurflo pump, and the fan on the composting toilet. Now we watch the light use as much as we can and in the evening we probably average 3 lights on at a time. We run everything off 12V. I have a 2000 KW generator to run anything bigger.

NorthwoodsGuy
Member
# Posted: 13 Mar 2018 13:18
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CSPot- Most anything SERIOUS ampage will probably be generator driven. Having some basic solar means I can run a low amp pure sine inverter for electronics and use a cheaper generator for tools and such. But I'd like to occassionally run an immersion blender or such.

We are trying to figure out if we want a small fridge or not and whether it will be propane. I am leaning towards starting small, and adding capacity if/when we want the refrigerator.

We both spend time at the cabin writing, so being able to power laptops for a good chunk of the day is important to us. Lighting will be LED for sure.

cspot
Member
# Posted: 13 Mar 2018 18:12 - Edited by: cspot
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Quoting: NorthwoodsGuy
CSPot- Most anything SERIOUS ampage will probably be generator driven. Having some basic solar means I can run a low amp pure sine inverter for electronics and use a cheaper generator for tools and such. But I'd like to occassionally run an immersion blender or such.

We are trying to figure out if we want a small fridge or not and whether it will be propane. I am leaning towards starting small, and adding capacity if/when we want the refrigerator.

We both spend time at the cabin writing, so being able to power laptops for a good chunk of the day is important to us. Lighting will be LED for sure.


We are torn about what to do with the refrigerator. Right now we use coolers with ice. Thinking about going propane, but from my understanding those can take a while to get cool if just using on the weekend. The other downside is the initial cost of them.

As far as the laptops, I think there draw is pretty minimal so you shouldn't have much issue powering them.

How much would you be running the blender. If it was minimal use, I wouldn't think it would be that hard to account for that and still stay with a basic system.

I was originally going to put in an inverter, but ended up doing everything 12V. Made the system simpler. I put in a couple of charging stations that have USB hookups and a cigarette lighter to plug in chargers. They make small inverters that I could plug into the cigarette lighter if I wanted to charge a laptop on 120V.

creeky
Member
# Posted: 13 Mar 2018 19:48
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I paid 400 for my 10 cu ft electric fridge. I sold my propane fridge for 1200. I have since saved over 2k in propane costs.

For small camps I have some 24v systems I'm building. They should be ready next week.

NorthwoodsGuy
Member
# Posted: 17 Mar 2018 12:48
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Creeky- Yeah, I see a lot of advantages to the electric fridge if we go that route. It can be an energy sink when we are away, and we could keep things cool between visits. Plus, I feel safer with electricity than with propane (mostly because I have more experience wiring than plumbing).

I think we will start smaller and build out if we need more. I'm leaning towards 2 24V panels and a single volt cell for now.

beachman
Member
# Posted: 17 Mar 2018 13:38
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Creeky makes a good point about an electric frige not having to lug and pay for propane, as well as a lower cost for the appliance itself. We have a propane frige that I start up in May and turn off in September and it works great. Never think about it when not there. But, if going down that road now, I would seriously consider electric with a beefier solar set up to accommodate it.

Bancroft bound
Member
# Posted: 17 Mar 2018 20:27
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We got a 4.4 Danby at Princess Auto, scratch and dent for $120?
50 watts when running. Amazing how much stuff can fit in there! Load up when you arrive, clean out when you leave! Full frig only, kinda wished I'd looked a little closer that didn't have freezer...oh well.
200ah @ 12v with panels.... you're set! Full charge by 10 ish with full sun.

Borrego
Member
# Posted: 17 Mar 2018 20:48
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We got a Danby 10 CF to run off our new solar...296 KWH/Yr
We leave it on during the week when we are gone.....will clean it out and turn off during the summer...

creeky
Member
# Posted: 18 Mar 2018 13:46
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One thing, with lithium you can run high draw appliances as long as you have the inverter for it.

So your immersion blender needs a good 800w invert er. Or a lower cost 1500.

Couple of general points for all.
* Think about starting with 48v. Gives you more upgrade room.
* anything propane you can replace with solar saves big long term. And by long term I mean 2-4 years. With the fridge of course, you save immediately. Just put the cost difference towards your solar budget.

I had another point. But i'm old and I have forgotten it.

NorthwoodsGuy
Member
# Posted: 20 Mar 2018 12:30
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Any recommendations on the inverter front? We will also be charging 18v cordless tool batteries, but that will affect Ah, not inverter size.

socceronly
Member
# Posted: 27 Mar 2018 16:18
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Quoting: cspot
We run everything off 12V. I have a 2000 KW generator to run anything bigger.


I think a 2 Megawatt generator should suffice.....

Borrego
Member
# Posted: 27 Mar 2018 21:57
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Quoting: cspot
We are torn about what to do with the refrigerator. Right now we use coolers with ice. Thinking about going propane, but from my understanding those can take a while to get cool if just using on the weekend. The other downside is the initial cost of them.


I thought about this A LOT and decided on the typical fridge running on solar. Couldn't be happier....an extra panel and a couple batteries..... a true no-brainer IMO

You just need to make this decision, and the rest will fall into place....

creeky
Member
# Posted: 28 Mar 2018 19:43
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NWG, You can charge anything with even a small inverter. Like 350w. The switch mode chargers don't care. I still prefer pure sine 'cause I burned out a couple of older rechargeable batteries with a modified sine and that cost me the drill.

But apparently the newer switch mode chargers are better for that. Don't take my word for it tho.

That, and the new pure sine inverters are so cheap. Its like MPPT. Used to be MPPT was expensive. But now you get MPPT in a $100 solar controller. So to get 30% more power from your panels. You'd be crazy not to get MPPT.

Now you get pure sine for cheap. Might as well get the extra efficiency out of your devices (esp. motors like a fridge/micro/etc).

Tech really has improved. And costs have dropped. Huzzah!

caducus
Member
# Posted: 28 Mar 2018 22:17
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Following this closely. I'm trying to design my first system for a 14x20 cabin. Similar power needs. Looking to run a true sine wave inverter for a laptop, lights, phones, makita charger, and maybe a fridge.

I was gifted a bunch of 12v lead acid batteries. some 100 ah, some 50ah, some 40ah. How much did I save on the whole setup? not sure how much battery cost plays into a design.

NorthwoodsGuy
Member
# Posted: 1 Apr 2018 16:55
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OK, pulled the trigger on a Volt battery. I'm going to start with one pack for 2.3kWh for now. We can add capacity if we need it. Probably 2 300W or so panels, trying to decide on make.

creeky
Member
# Posted: 1 Apr 2018 19:42
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Nice. For the solar panels it doesn't really matter. the newer ones, poly or mono, are more efficient than the older ones.

I go by the cost per watt. Cheaper is better. The "better" mfct do usually have stronger frames.

But I would keep my money for a better inverter. that's where you'll get the best bang for longevity.

NorthwoodsGuy
Member
# Posted: 3 Apr 2018 22:00
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Panels (2 @ 300W) and charge controller (Victron) ordered. Inverter is next- will probably go with 800W, the 1200 and 1500 ones get pricey fast.

creeky
Member
# Posted: 6 Apr 2018 10:58
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This is one of the reasons I so tout the "don't get carried away with the inverter size".

A smaller inverter is all most folks need. And you save overhead. Both idle draw and cash.

Thx for reminding folks of this. (and me)

NorthwoodsGuy
Member
# Posted: 8 Apr 2018 20:25
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Picked up all the lighting fixtures today. Man LED is amazing. Every light in the cabin, if all turned on, will draw 70.5W. That's 6 fixtures in total, including a 3-bulb chandelier.

NorthwoodsGuy
Member
# Posted: 13 Apr 2018 18:32
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Hmmmm. I may be leaning back towards 1500W. Trying to decide between the Victron 800 and the Cotek 1500.

creeky
Member
# Posted: 13 Apr 2018 20:32
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The Cotek is nice. But the Victron has programmable settings for LVD. And bluetooth monitoring.

If you're going lithium battery you may want to program a lower than 21v lvd. low voltage disconnect.

Cotek is good brand. But the Victron is cheaper and has better features. .02

I did get a Victron 800 back. The customer wants to go 2000w so he can run a tablesaw. So the 800 runs everything but the table saw. Initially he said he wanted to save some money on the inverter and would run his table saw off the genny. But after working (this is a job site system) without genny noise the guys find starting the genny more and more annoying.

Btw. They're building an off grid "passive house" (just passed the blower door test. .57/changes per hour). The "home" solar system is up and running (with PowerWings of course) and they love running all the tools off the sun.

NorthwoodsGuy
Member
# Posted: 16 Apr 2018 17:56 - Edited by: NorthwoodsGuy
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Good point. Maybe at some point I'll go that far. I like what you say about the Victron, ordered one. The price difference between that and a 2kw inverter is enough to justify one of those new li-ion table saws...

creeky
Member
# Posted: 16 Apr 2018 18:20
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Ha. That's what I thought too.

I looked online. I think the Victron 1200 is around the same price as the Cotek 1500.

NorthwoodsGuy
Member
# Posted: 16 Apr 2018 21:04
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I had trouble finding the Victron 1200 in stock- and I needed to order soon, as project is approaching.

creeky
Member
# Posted: 17 Apr 2018 22:21
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Exciting times

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