Green / Eco-Friendly

solar panels at a remote cabin

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  • Apr 6th, 2010 10:14 pm
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[OP]
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Jan 28, 2009
1964 posts
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Calgary

solar panels at a remote cabin

Hi,

my family has a cabin in Northern Saskatchewan, right on the Churchill river. No electricity, no water, no nothing.

However, the cabin is wired for 8 lights (and 2 outlets). Generally, we run the generator at night to power the lights. I find this annoying and that it takes away from the peacefulness of nature.

I want to put some solar panels on the roof (which angles south) and charge a battery or something to run the lights at night. I only want it to run some lights... I could even change the 40W lights we have to LEDs if that'll help.

However, it needs to be either portable (and easy to set-up/take-down/transport) or very very very very weather resistant. It reaches -50'C in the winter.

Any thoughts? Is there a pre-packaged solution for me? How many watts do I need?

Help me shut that damn generator off.

Thanks,
34 replies
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Feb 9, 2003
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http://www.xurbia.ca/ is a good place for some info.

You could get a portable power pack from Canadian tire, and charge it with the generator. Or a DIY solution. Get a deep cycle battery and an inverter. You'd only need a 400 watt inverter to power 8x40w light bulbs. Use the generator's 12v posts to charge the batteries on arrival at the cabin, and before you leave, cause the batteries will last longer if they're stored charged.

Switching to LED is a no brainer, no matter what you end up doing. Without running the generator constantly, you'll need fewer batteries, less frequent charging, or a smaller solar panel with LED.

Assuming you switch to 7 watt LED bulbs, they'll take about 5 DC amps in total. A typical deep cycle battery should be enough to power the bulbs for about 10 hours. Since you should only run them to about half charge for the longest life, I'd probably get 2. They're about $150 each. Add a 100 watt inverter and you'll be able to run the LED lights. You can get a 1000 watt inverter for about $150 or so, so if you want to run other electronics.

If you want to go solar, you'll probably want 50-100 amp hours per day. 50 ah will let you run the lights for 10 hours, but there will be power wasted in the charging and discharging. You can double your planned needs to be safe, or you can budget low and use the generator for a half hour to top them up durng a day with heavy use. If you get 10 hours of daylight, you'll need 5-10 DC amps, which is 60-120 watts.
Sr. Member
Mar 7, 2009
780 posts
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Tell me how much you want to spend and I can give some suggestions. The panels can be mounted on the roof and left there. They will be ok in the cold. If you don't go in the winter, you could take the batteries home for the winter and put them in your basement.

Your best bet is to reduce your needs as much as possible because solar is expensive.

I am in the solar business and I have a client that wants us to build a portable battery pack that has some real power to it. This is exactly what you need. I envision a small box a bit bigger than a milk crate that has a 110v AC plug plus a 12 DC outlet. It would have lithium batteries and weight about 60-70 lbs. Maybe put it on a cart like a pressure washer. It could also have an input for solar charging. Unfortunately, the government does not want to provide funding to small compaines. We face the reality of limited time and money, so these things do not get developed.
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Dec 3, 2004
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Have you thought about propane lights?

A propane lantern will run for about 100 hours off of a standard barbeque tank (about $10 worth of propane). Might be cheaper in the long run than going and buying solar panels, batteries, inverters, etc.
[OP]
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Jan 28, 2009
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Calgary
Thanks for the replies guys.

WE have a propane lantern up there now, but don't use it all that much. Plus it seems less than safe to me. I think wiring the place for propane lights would likely cost as much as a few solar panels. I'll look into it though.

We only use the cabin for 2-3 weeks a year max. Therefore, I would be taking the battery home with me in between. All I would need the panels and batteries for is to run 8 lights for 6-10 hours a day. If I switch them to LEDs, I'm guessing that would be doable without a cart of batteries. (I hope).

I was looking at a couple options on the costco.ca website:

1) http://www.costco.ca/Browse/Product.asp ... lang=en-CA

2) http://www.costco.ca/Browse/Product.asp ... =C&topnav=

I would be mounting them on the tin roof, facing south. They would be in partial shade for most of the day, receiving only 4-6 hours of direct sunlight. This makes me worry about whether they would get enough of a charge to top off the battery/batteries.

Another option just occurred to me. I could simply take a battery or two, fully charged, up with me, and clip it into the system. Would it be feasible for a battery to run 8 LEDs for 6-10 hours a day for a week? If necessary, I could run the generator and charge the battery. I might not even need the solar solution (although I still think it would be good to be completely silent up there).
Deal Expert
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Jun 14, 2003
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canehdianman wrote: Another option just occurred to me. I could simply take a battery or two, fully charged, up with me, and clip it into the system. Would it be feasible for a battery to run 8 LEDs for 6-10 hours a day for a week? If necessary, I could run the generator and charge the battery. I might not even need the solar solution (although I still think it would be good to be completely silent up there).
This is the option I wanted to suggest but you figured that out already.
Solar panel is expensive. I would worry about it being stolen.
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[OP]
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Jan 28, 2009
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The expense is definitely a consideration.

It getting stolen isn't much of one though. This is one heck of a remote cabin. There is no road to it, you have to launch a boat to get there.

But I get your point. I'll look into the straight battery idea.
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canehdianman wrote: Thanks for the replies guys.

WE have a propane lantern up there now, but don't use it all that much. Plus it seems less than safe to me. I think wiring the place for propane lights would likely cost as much as a few solar panels. I'll look into it though.

We only use the cabin for 2-3 weeks a year max. Therefore, I would be taking the battery home with me in between. All I would need the panels and batteries for is to run 8 lights for 6-10 hours a day. If I switch them to LEDs, I'm guessing that would be doable without a cart of batteries. (I hope).

I was looking at a couple options on the costco.ca website:

1) http://www.costco.ca/Browse/Product.asp ... lang=en-CA

2) http://www.costco.ca/Browse/Product.asp ... =C&topnav=

I would be mounting them on the tin roof, facing south. They would be in partial shade for most of the day, receiving only 4-6 hours of direct sunlight. This makes me worry about whether they would get enough of a charge to top off the battery/batteries.

Another option just occurred to me. I could simply take a battery or two, fully charged, up with me, and clip it into the system. Would it be feasible for a battery to run 8 LEDs for 6-10 hours a day for a week? If necessary, I could run the generator and charge the battery. I might not even need the solar solution (although I still think it would be good to be completely silent up there).
The 60 watt solar systems you linked to are not enough to power those lights for 10 hours with only 5 hours of sunlight per day. The bulbs themselves use 56watts, and you want to run them for twice as long as you can charge them, and there's power wasted in the charging, discharging, and inversion.

If you wanted to run the lights off the batteries for that long, you'd need about one battery per day. So unless you want to bring 7 charged batteries, you'll need to charge them with the generator or with sunlight.

Next time you go up you should take an electric usage meter:

http://www.amazon.com/P3-International- ... B00009MDBU

They're available all over the place. Change all the lights to LED, and see how much power you actually use in a week.

Once you know your real usage, buy one or two deep cycle batteries. Use the generator to charge them each day, and see how long the charging takes. If you can live with the generator running for that long, then you don't need to get a solar panel. You might find that your real usage is low enough to use a system from costco.
Newbie
Apr 3, 2009
36 posts
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First, are you only using your cabin in summer/warmer weather (say above -10C) and/or heating it when you are there? If so, you could just go compact flourescent with the present wiring. It would be easiest. Go with smaller ones, say 7watts, and you are only looking at say 60 watts. Hence a 200watt inverter is going to give you enough power for anything you need and run a radio as well or something similar.

April to August, you can count on at least 4 peak sun hours for a fixed panel installation (but can clarify if I know the exact area) and it may be higher. What that means is that if you have a 130watt panel, you can get about 520watt hours out of the panel. We usually at a 0.75 factor for variable weather, etc. so you can count on about 400 watt/hours per day (ON AVERAGE). To power 60 watts of lights, you need about 80 watts into the average cheap inverter. So if you run everything, those panels will give you about 5 hours a day. Odds are you are going to run less, but keep in mind that inverter is drawing about 6 watts just sitting there (depends on the model). If you can turn it off, the it only draws when using it. Hence if you rewire for 12volt lighting with LEDs, you can get your draw down some more.

A 130 watt panel will run you $600-900 depending on who you get it from. They are guarenteed to give 90% power for 10 years, 80% for 25 if you get name brand, i.e. Sharp, BP, etc.

Lets say you are going to draw about 40 watts for 6 hours per day or 240 watt-hours. Generally for a solar system, you want several days of backup. If you run winter and it must work, 7-8 days may be speced. For your needs, 4-5 days is likely enough, so having on the order of 1000 - 1200 watt hours is enough. If you are going to be using them when its cold, the batteries need to be sized even larger. It is best not to run the batteries too low, so add another 25% to the size. 1200 watt-hours is about a 100Ah 12V battery. For your requirements, I would suggest a good AGM (Absorbed Glass Mat) battery designed for solar usage. If you had two, you would have a pretty good reserve.

You will need a good charge controller, I would suggest Morningstar with Maximum Point Power Tracking (MPPT) which gets the most out of your panel. Call it $150.

So:

130 watt panel = $800
2 * 100Ah 12V AGM battery = $400
200 watt inverter = $100
Charge Controller = $150


You will need mounting hardware, cables (suited for the weather), fuses, a good battery box (insulated would be best), etc. You are likely looking at $2000 minimum. Keep in mind you should have a licenses electrician wire in 120V. That i my disclaimer.
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Nov 5, 2001
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From the feeling of the OPs post, $2000 is WAY too much to budget for some lights a couple of weeks out of the year.


2 things we can do, reduce the wattage used, and increase capacity. Also, you can keep the generator for charging the batteries when you first arrive, and to run major appliances. Combine all this and you have a great system.

First, the 60W kits you mention are too small for what you need. Plus they don't even include the batteries. Don't bother with them at the prices you posted. If you find an end of summer deal, say under $200, then go for it.

Next, go to 5w or 7w CFLs for your lights. Much cheaper than LED bulbs, and almost as efficent. If you can find a deal on them in the future, upgrade to LEDs. For now, a 12 pack of CFLS will cost you under $20.

130 Watt panel is more like $400 to $500 US. This would be the ideal start to the system. My advice is to buy in the US from a supplier. Warranty and shipping is a bit more, but you'll save a bundle compared to buying in Canada. If budget is really a concern, go with a 60 watt panel or kit. Under $200 is a good price.

Batteries are a fickle item. On a budget, a couple of good deep cycle batteries will do just fine. Even standard 12V or 6V golf cart batteries will work. You might even luck out on some cheap cast off forklift or utility batteries if you hunt around, more than enough for a few low wattage lights. Bank on $100-$150 each for dedicated 'solar' batteries. In any case, I wouldn't bother toting one or two back and forth. Hooking up the generator to a charger for the first 3-4 hours you are on site should be all you need to do.

Then, you need the charge controller, inverter, and wiring, fusing and switches. A 60 Watt controller will set you back $50 or so. $100 and up for something more powerful. 300 Watt inverters go on sale at Canadian tire for $20 to $30 often. More than enough to run lights, radio, tv, coffee maker, etc. Just don't run a hair dryer or microwave off the inverter and you'll be ok. For wiring, stick to 8 guage or better and you'll be fine. About $20-$30 for wiring.

Now, here's where it gets a little more complex: If you want to set up the generator to charge the batteries when you first arrive, hardwire in an AC/DC charger as well. $50 for a decent one.


Now for setup. My advice is to NOT roof mount the panels, unless tree coverage makes it ABSOLUTELY necessary. The best solution you could build is a wood frame and mount the panels to that. Give yourself a little more cable length at a heavier guage to compensate.

There are huge advantages to this:

1. You can relocate the panel once or twice a day to take advantage of morning/afternoon sunlight.
2. You can relocate the panel at different times of year for different paths of the sun.
3. You can move the panel in bad weather. (sudden hailstorm or windstorm)
4. You can put the panel inside at the end of season, reducing winter weathering.

Also, to reduce the noise pollution from your generator, build a baffled wooden box for it at least 50-100 feet away from the cabin. Vent it away from the building, and use a heavier guage cord to cover the extra distance. Maybe $75 for the cord and the enclosure.


With some electrical handywork, turning off the lights when not in use, and some bargain hunting, I would bet you could set up a decent system for under $700.
[OP]
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Jan 28, 2009
1964 posts
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Calgary
Thanks for the great advice guys!

$2k is definitely out of the price range that I'm interested in. I might wire it a little more powerfully later on, but for right now, all I would be interested in is a couple of lights. I enjoy it nice and rustic.

One more question regarding leaving the batteries up there over winter. Would they be ok? The temperature gets down to -40 or -50 for much of the winter, and I wouldn't want the batteries to get wrecked.
[OP]
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Jan 28, 2009
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Calgary
Well, my vacation just got cancelled, so looks like I have another 12 months to plan this :)
Sr. Member
Jan 20, 2007
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canehdianman wrote: Well, my vacation just got cancelled, so looks like I have another 12 months to plan this :)
If you want to keep the 'feeling' of the cabin in the woods, why don't you just go to bed when it's dark? :o ) j/k

I would either go with an old school oil lamp from a 100 years ago for style or a propane 'coleman' torch for price..

Bringing the battery for the few days would also be an option, but the good thing with the oil/propane options is that you can leave it there and forget about it.
Newbie
Aug 19, 2009
9 posts
the cabin sounds great. i think solar panels would be a perfect fit. let us know if/when you get this set up and post some pics!
[OP]
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Jan 28, 2009
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Calgary
Unfortunately, it will be next summer before I go up there and have a chance to install anything.

Given how quickly prices are dropping I have decided to hold off buying anything until next year. There is a manufacturer's rebate on the 60W system at costco right now (down to $349.99 I think?), but I don't want it cluttering up my apartment for 11 months.
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Nov 5, 2001
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Yeah, I'd wait until next year unless you come accross the right deal.

I actually helped a buddy set up a ghetto system for his fifth wheel last week.

A pair of 60 watt panels he got for nothing thru work, a 15A charge controller, and 4 retired heavy duty farm batteries.

We were worried about the batteries not holding a full charge, so we fully discharged/drained them, balanced the fluid levels, and ran a full conditioning cycle with my battery charger

Couple this with the cheapo 500 Watt Canadian Tire Inverter and about $25 in cables and connectors and he has a kick ass system that lasts him for 2-3 days of light use when fully charged. The main problem is the solar panels are way underpowered to fully charge the batteries in a day. He expects he'll get another 3-4 panels from work as they retire them this winter, and we'll add them when time allows. In the meantime, 5 weekdays of charging should have the batteries ready to go for the weekend...
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Jan 4, 2007
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I think stick with Propane, and get a queiter generator...unless you start using the cabin more... for 2-3 weeks i couldnt justify the money and work to implement that.
Sr. Member
Jul 21, 2003
952 posts
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You could also run the lights direct off the batteries w/ no inverter required by switching your lights to DC type. DC (12v) cfl's would prob cost a little more but would remove the need for any type of AC->DC inverter. You would only need to run the generator then to charge your 12v batteries or when you wanted to run something heavy duty, tv etc. You could in theory run the TV off your 12v batteries w/ an inverter but that would nuke them pretty fast.

I'm not too experienced in this area but i think this would reduce the overall complexity of the system, solar pannels charge batteries, generator could be used to charge via a charger when required, lights run off 12v.

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