Small Cabin

# Posted: 3 Feb 2013 11:37pm - Edited by: Dillio187
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Quoting: Rick004

Hi Dillio187 !! It sounds like You know your stuff !! I am building in the spring and would like to be off grid ! I am going propane with fridge , stove , tankless hot water heater , and woodstove for heat , but would like solar to run a few lights , very small flat screen tv , and the coffee maker in the morning . I am looking at 2 , 100 watt panels but wondering on what size charge controller and inverter and how many 6 volt cart batteries would be required ?

hi Rick.

You are headed down the right track, which is to use as little electricity as possible.

For a 12V system, you would need to use at least 2 6V golf cart batteries wired in series. Most of these batteries are right around 220ah (amp-hours) each, so in series you get a 12V, 220ah battery bank.

your 2, 100W panels will output about 12amps at best to your batteries. This really isn't enough to recharge a 220ah bank reliably, I would add another 100 watt panel to get you up closer to a 10% charge rate (18 amps into a 200ah bank is about 8%). With 18amps, you will want a 25-30 amp controller (build in some potential growth there). The Blue Sky 2512ix would be a decent place to start.

to run lights and a small TV, you don't need a very large inverter at all. The only thing you should be concerned about is the coffee maker, which uses electricity to heat the water. You will want to measure the amperage it draws using a Kill-A-Watt meter or similar device to ensure you size your inverter correctly. I highly recommend the Morningstar SureSine 300W, it will surge to 600W for up to 15 minutes I believe. You don't want a big inverter you will never use because the larger inverters draw more power at idle than smaller inverters.

If you want to see a similar system, check out my thread in the Project and Pictures area, there are a few pictures of it in there.

Let me know if you have any questions, I'm always happy to help out!

# Posted: 3 Feb 2013 11:37pm - Edited by: spencerin
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Quoting: Borrego

So you think with a system like yours, maybe an extra panel & battery, I could run my current loads? Add on later if need be??? And since I've been reading about the inverter issue, what would you get if you had it to do again?

Well, if you're running what I am (i.e. load and frequency), I wouldn't change it if you are trying to keep costs down.

I think I would have gotten the Whistler-Pro 1,600W interver - only few bucks more, a 100W more capacity, better ratings.

# Posted: 20 Feb 2013 01:04am
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I apologize for no pics yet. Two weekends ago it was raining heavily all day, so I couldn't take any pics with the digital camera. The rain also mudded up the "driveway" so much that I instead of driving *up* the driveway I drove *off* the driveway, lol, and had to get winched out, even with 4X4 and new tires! Ouch. And then I just forgot my camera last weekend. I'll get the pics as soon as I can, provided the battery charger for the camera works (a few months ago it went *pop* and smoke-sizzled a little bit because I accidentally switched the subwoofer adapter for the camera's battery charger adapter.....oops.)

Purplerules
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# Posted: 20 Feb 2013 09:28am
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spencerin - Thanks for all the great info. I will be looking forward to the pics when you can post.

# Posted: 20 Feb 2013 09:38am
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agreed, I always like seeing solar setups at cabins doing their thing. Mud? We haven't seen unfrozen water here in 4 months

Just
Member

# Posted: 21 Feb 2013 08:38am
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Borrego
the trick is to lower your usage,
3 way =you can now buy a led. 3 way
tv =make sure your tv has a adjustable back light
vacuum =i found a small shop vac 600 w .broom 0 watts
ceiling fans and bathroom fans burn a lot of watts not many small cabin owners can use them ==.put a high up window in the bath , get a stove powered fan for winter and high windows in the cabin for summer ventalation
buy 2 inverters a very small pure sine [300 w] for the electronics and lights and a larger one 1500 watt or larger for occasional use .
JUST my thoughts ..

# Posted: 21 Feb 2013 05:48pm
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Just,

Good advice. There are options available to lower power draw for a lot of items. Just gotta do a little research on the options.

# Posted: 2 Mar 2013 06:57pm
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Well, my digital camera is now worthless.....but, I did find 2 pics from last summer that show the solar panel setup and the battery box. I'll try to get a pic of the inverter once I get a working digital camera.

Anything else anybody wants to see?

Solar Panel

Battery Box

# Posted: 3 Mar 2013 09:26am
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thanks for the pics. What/where did you get your battery box, is it a garden style box? Looks like it works great for the batteries.

You can tell the sun is starting to get higher in the sky now, around noon yesterday I was getting 15 amps into my batteries from my system. Gotta love this time of year, cold panels and good sun = happy batteries.

CabinBuilder
Admin

# Posted: 3 Mar 2013 01:05pm
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spencerin,

I would make 2 suggestions:

1) Make U-shape wire bends between cabin and battery box walls, and between box wall and the battery - so if wire gets wet, the water would drip down instead of traveling down the wire to the battery terminal.

2) Seal holes with sealant where wire goes through the cabin and box walls, to prevent water seeping in.

Hope this helps.

# Posted: 3 Mar 2013 02:02pm - Edited by: spencerin
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Yes, that is a garden box. It came with the place when I bought it, so for free, it worked perfectly. You can get them $50-$60 on Amazon if you're interested, or maybe find them on Craig's List for cheaper.

I think I cut the cables too short to put some decent U-bends in them. That being said, the backside of the box is covered by an eave and everytime I've checked the box it's been dry. But, I should probably seal the hole anyway - I put a tight grommet in there, but there are still a few, small holes.

kdrtk
Member

# Posted: 5 Mar 2013 02:12pm
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My one panel system, run lights and older travel travel trailer. Before picture, used to bring up a charged battery each time, now I just flick the on/off switches, nice.

Panel is a Kyocera 135, controller is a Xantrex C-12.

DSCN4884.jpg

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DSCN5082.jpg

# Posted: 3 Jun 2013 09:31pm
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spencerin
You mention that this system works for you even in winter. would you mind sharing your location? I live in northern Manitoba. I am wanting to do something similar exept i have been told that these charge controllers should not be left in sub zero conditions. I thought for the the batteries I might be able to make a small wooded box lined with some good styrafoam. my primary use would be a 120v fan running off of an inverter. I would be using ruoughly 4-5 amps on the 12v side per hour and only for night time use. On a good AGM battery i would be able to get 2-3 nights of use before needing charging. I am looking at putting up a 100w panel for charging. Thanks for any input.

# Posted: 3 Jun 2013 10:14pm
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Silverfox71,

Central Indiana.

I didn't have any problems with my system this winter, and there were a several times where temps were always below freezing for several days consecutively. But, as you know, northern Manitoba and central Indiana are at rather different latitudes.

I don't know much about insulation in the sense that, if you keep the box outside, won't the contents eventually reach the temperature of the ambient environment regardless without a heat source inside the box? Won't the insulation only slow down the rate of the temperature change in the box? I think you'd need a heat source inside the box during the deep winters.

Is your fan going to be used daily?

# Posted: 4 Jun 2013 08:24am
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spencerin

This location is only used for weekend use for the most part with the exeption of hunting season. The fan would only be used during these times. There are periods where we are not there for a month at a time.

I had been thinking about putting a small 12v light bulb in the box to keep the ambient temp of the batteries up in winter.....but I havn't done the math to see if 1 - a bulb would keep the box worm enought and 2- would the solar system handle this load. perhaps if I would set a thermastat in the box and hook the buld to It, it would only need to cylce on when it drops down to a point that the light would come on. I would probalbly use one of those old mercury thermastats (no power required).

I was going to store the batteries inside and use a single AGM battery. Now that I am thinking of putting these batteries outside in a insulated box, I will probably go with 2 standard deep cycle batteries to keep the cost down.

Any further input would be appreciated.

Thanks
Silverfox

# Posted: 4 Jun 2013 06:39pm
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Well, a solar system can handle any reasonable load you put on system, as long as you design the system right. For example, running only a fan for a day or 2 once a week would not require a 100W panel (though having one would be a good idea if you want to expand later on) because the panel would charge the battery back up during the times you are not using the fan (and charges it *while* you are using the fan, assuming there is sunlight). But, adding a heat source to the box would draw more power over time, and may necessitate such a panel.

What it comes down to really is power draw over time. All electronic devices tell you what watts / volts / amps they draw, so you need to find out what your potential heat source draws (sounds like you know what your fan will draw). Then, you can size your system from there.

# Posted: 5 Jun 2013 09:23am
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I wouldn't worry about leaving your charge controller, panels, inverter etc in extreme cold. My cabin is in central Minnesota, and I'm sure it's frequently -20 in there, and my stuff is fine. Keep in mind that lead acid batteries lose much of their capacity the colder it gets.

# Posted: 9 Jun 2013 08:08am
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Dillio187,

That is very helpfull. I hope to get all that I need in the next week or so. I am thinking of going with either Canadian tires Group 31 deep cycle or maybe Walmart Everstart Maxx deep cycle. For my solar panels i will be going with 145W. This should be able to charge 2x what I am currently planning on running. It also alows for adding a few things along the way.

Thanks,
Silverfox

razmichael
Member

# Posted: 9 Jun 2013 08:56am
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It always depends on budget but if you can, don't scrimp on the batteries. Many of the box store deep cycle batteries are actually hybrid or marine - if they provide a starting rating of any sort then they are hybrid. Doesn't mean they will not do the job but you will not get the performance from them that you would with dedicated deep cycle batteries. Dilio mentioned previously two 6V golf cart batteries - trojan t105s are an example. I noticed last time I was in Costco (in canada) they are now selling "golf cart" batteries along with the hybrid, marine and starter batteries. I did not do a good look at the specs but I think they are 12v at 110 amp-hrs. Two of these in parallel will provide 220 amp-hrs. I have no idea on the true manufacturer or quality and they may be limited to a few stores only. Not sure on price either.

creeky
Member

# Posted: 9 Jun 2013 09:43am
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i'll echo razmichael about the batteries.
don't know where you're located, but check for a Total Battery location. when I bought for my offgrid solar system they had the best battery for the price. i went with Crown over Trojan (which TB also carries). three years now and going strong.
(in fact the sun is shining and the morningstar is "equalizing" the batteries today. It's 9:41 and the batteries are at 14.63 heading for 15.5.)

rmak
Member

# Posted: 10 Jun 2013 08:24pm
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I'm reading this thread with a great deal of interest (and a great deal of ignorance).

I decided to go solar on our weekend cabin. It's on our property. I have a step-son and an adopted son with disabilities, so we are hoping to use the cabin to get away a little but still be close enough to home if we're needed.

Anyhow, I mention this because I don't think I'll need much electricity. Just lights and a fan or two. We are going to cook and make coffee on a Coleman, and take out a cooler. We were thinking of a woodstove and a small propane heater as a backup.

I was going to have electricity run from out house, but the distance and the size of the wire due to the power drop over that length makes it cost prohibitive.

I will have to cut some trees that shade the cabin now. That will break my heart.

I've been talking to a guy at a company named AltE. He's very helpful, but his kits look like I'll be in the $2,500-$3,500 range. I'm glad to read here that others do it for less.

I'd really need someone to talk me through the whole thing. I don't even know where to begin. Does anyone know of a book or pamphlet that would get me started?

Any, repeat, any advice or suggestions would be appreciated. My cabin is a 12 X 16 and I live in NE Ohio. Thanks.

# Posted: 11 Jun 2013 08:18am
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rmak,

It sounds like you are going to be using the same amount of power that I am looking at. For this do what these guys have mentioned and use 2- t-105 batteries and tie them together to make 12v. You can choose as much solar as you wish to pay for. If you are using small fans on a 120v inverter and 12v lights, I would imagine you would get 2 days of use out of those batteries without recharging. If you are only using the fans over night you might get 4 days. I have selected a 145 watt system from ebay whitch gives you everything that you would need (not including the batteries).

Silverfox

# Posted: 11 Jun 2013 09:42am - Edited by: Dillio187
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Here's my take on a 'small' cabin system. It's very similar to my own.

Panels: Solar Cynergy 140watt 2 pack

$360

Charge controller: Blue Sky 2512ix

$212, if you can wait the new Rogue Tech unit will be the cats meow I'm sure.

Inverter: Morningstar Sure Sine 300W

$242

Batteries: 2 GC batteries from your local Sam's Club etc.

$175 depending on location

wire: use 4 or 6 gauge from the batteries to the inverter. 6 or 8 gauge from the charge controller to the batteries. Install fuses on any positive wire leaving the battery bank.

Maybe another $300 or so for wire, fusing, and panel mounting, junction boxes etc.

Total, around $1300

The Morningstar inverter is highly recommended as it has a very, very low idle draw, pure sine wave, and will surge to 600W for 15 minutes. It does not have a plug on it, so you will need to either hard wire it into your cabin wiring (as I did) or install a piggy back with an outlet.

There are pics of my setup in action here: My place in the woods

Other than putting distilled water in the batteries, it's been totally trouble-free.

rmak
Member

# Posted: 11 Jun 2013 11:39am
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Thanks, folks!
Is it a good idea to buy a bigger system at the start assuming that I will want/need more power as I spend more time in the cabin?

Or is it better to just get what I need now and add on to the solar system as I need it?

# Posted: 11 Jun 2013 11:59am
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adding onto solar systems is usually a bad idea. Buy what you envision for the future now.

Rossman
Member

# Posted: 11 Jun 2013 12:28pm
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Yeah, some stuff you can add on, like additional panels, but you will want your key components like inverters/charge controllers/etc to be sized for what you imagine would be the final system size. These items are expensive and it doesn't make any sense to buy them and then re-buy them when you need more capacity!

creeky
Member

# Posted: 28 Jun 2013 10:20am
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batteries and inverter are your sticking points in expansion.
while a charge controller will typically handle a variety of voltages your inverter is designed for the battery pack. so if you want to add battery capacity at say 24 volts instead of the 12 you have now, you need a new inverter.
and batteries being linked together are as strong as the weakest link. if you add new batteries to a three year old battery pack your new batteries will quickly age to three years old.
that said. i have expanded my system successfully twice, selling the original equipment for what I paid for it in the first place. i actually saved money as the new mppt charge controller had dropped substantially in price ...
I would like to expand my current 12v at 1200 amp hr battery pack to 24 at 800 a/hr. but I'm making myself stick with the original equipment because, well, it works perfectly well. and sometimes you wonder if you just have "two foot itis" (a boating disease where you always want the boat that's two feet longer)

rmak
Member

# Posted: 28 Jun 2013 06:32pm
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Ha, ha! I guess I have to have two feet itis before I buy. My difficulty seems to be that I continually think of what's a "necessity". I just hauled a rug down to my cabin and after looking at it I thought, "Man, I'm going to need to vacuum that thing." (it's funky) Now I have to refigure my power usage or find out what a non electric sweeper is going to cost. So much I take for granted at home! That's why I'm considering over estimating my usage and taking the financial hit up front, rather than being underpowered. I guess I could haul the rug back home for cleaning, but if I have to add a bunch of other duties and chores, I'm not accomplishing what I wanted a cabin for in the first place namely a quiet place to go to and enjoy.