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Small Cabin Forum / Off-Grid Living / Mulling Power Options for Cabin - Little help please.
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LoonWhisperer
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# Posted: 4 Sep 2014 13:09 - Edited by: LoonWhisperer
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Hey folks,

We are in the process now of trying to run some power in our tiny 10x10 and hoping to get some help/suggestions from those who have "been there, done that"

Option 1 would a Renogy Solar kit - 100 watts with an inverter and 12v deep cycle battery (or 2 x 6v) in a power box.

Option 2 would be a generator

Ultimately we may end up with both but for the time being it has to be one or the other.

We don't need much juice, just enough to power laptops, small lights, a fan and 12v cooler/mini fridge. However I would like to run some power tools from time to time. Most, if not all, of whatever system we go with would come back with us each time.

My first question is, since the cabin has no wiring in place at all, what is the simplest solution to run either a cord inside or solar wiring without propping the door open? Is there specific inlets for either setup? Or something I could pop open and run a cord/wire through?

The cabin is sealed shut except for the pipe for the woodstove so it looks like some drilling out would be required. I am not very handy so a DIY disaster is very much a concern. The simpler the better

And for you solar folk, do I need to permanently mount the panel to the roof or is there a temporary option to keep it in place. The idea of drilling into my roof gives me shivers lol

Sorry for being so long winded and thanks in advance for any help with this.

groingo
Member
# Posted: 4 Sep 2014 16:59
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From what you mentioned means there is a wide range of power needs, power tools, mini fridge, fan etc.
Best advice would be to determine how much juice you will really need.
From what you already laid out the most cost effective solution would be a Honda 2000i inverter generator which would handle all of what you mentioned above and if later you want to take the solar plunge the Honda will always be a good backup just in case, either way a solid first step is the Honda.

suburbancowboy
Member
# Posted: 4 Sep 2014 17:48
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I agree with the above. Honda2000 generator if you are running any kind of power tools.
If only lights and 12v electronics, I would go with a harbor freight solar panel kit, with a harbor freight 200 Watt inverter and a power strip. Easy to set up easy to store and < 200 dollars plus battery.
Get a plastic storage bin at walmart to hold all the components. Cut a hole in the side of the bin and wall of cabin, run the power strip cord through the holes plug into the inverter and presto you have all the power you will need for a long weekend.
I ran a similar system for years at my cabin while I was building it.
Note the above mentioned will not work for running even small power tools.

MtnDon
Member
# Posted: 4 Sep 2014 17:48
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Quoting: groingo
Best advice would be to determine how much juice you will really need.


Correct. Nobody can plan a good off grid power system without knowing the energy needs.

You mention a 12 VDC cooler/fridge. Some of those are energy hogs, some are not. A DC meter that can measure actual use can be very helpful with that. I have a few of these GT Meters. They can give instantaneous reading as well as total up the watt hours used over a time period, like a day or a weekend.

They come w/o connectors. I like the Anderson Powerpoles. Makes it easy to move the meter around from use to use.

~~~~

Then the next question is do you want or need 120 VAC power or just DC power? AC needs an inverter. There are many sizes and makes and there are also pure sine wave and modified sine wave. Some AC devices are not happy, and some won't work on MSW.

If you need some help on sizing list the devices, whether AC or DC, the watts or amps they use and the hours of use in a day, plus how many days of use desired before recharging the battery.

Many power tools run best off a generator, unless the inverter is big(ger) and the battery bank has sufficient capacity.

davestreck
Member
# Posted: 4 Sep 2014 18:56 - Edited by: davestreck
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I'll chime in just because my setup is very similar. I need to power a few LED light fixtures, charge cell phones/iPads etc., and run a small 12V fridge/freezer (this one).

I have good solar exposure, and the manufacturer of the fridge claims it can run on 85 watts of solar, so I installed 130 watts of solar, connected to a 315Ah battery bank. During the first 2 week test run of the system this year, I ran at a slight deficit over the course of the trip, although not so much that the system needed topping off with the genny. We had good sun most days, and we still hadn't hooked up any lights yet, so the system was mainly called upon to just run the fridge (which we set to 37 degrees F). Based on that experience, I've decided that the manufacturers specs were a bit unrealistic, and now I plan to upgrade to 230 watts of panels next year. Not a big deal, and we're really pleased with the way the system has come together so far, but it turns out I was a bit too optimistic when it came to the number of panels I needed.

My point is that you should be suspect of claimed power usage for your appliances, and factor your solar requirements accordingly. Don't just go by the label. Using a watt meter to measure actual real world power consumption before you design the system is a great idea.

LoonWhisperer
Member
# Posted: 4 Sep 2014 20:48 - Edited by: LoonWhisperer
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Thank you all for your responses. Very helpful. I plan to get a better assessment of our power requirements this weekend. Then I can list the devices and get your opinion.

The cooler we run is here:
URL

A lightweight compared to that bad boy davestreck is using.

We purchased the AC adapter for it so it is good to go on 120VAC.

A small genny as suggested might be the best way to go and this gets back to my first challenge... I have no clue how to get power inside the cabin (besides propping a door open that is).

Not a lot of experience wiring or running cable/wire through an exterior wall so any tips on this would be greatly appreciated. I googled till it hurt but nothing I found was dumbed down enough :p

If I go with a genny we really just need one outlet. I see those generator inlets from Reliance, Leviton etc but I have no idea what happens on the other side of them lol.. Can you wire an outlet to the back?

Much appreciated!

MtnDon
Member
# Posted: 4 Sep 2014 21:15 - Edited by: MtnDon
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Quoting: LoonWhisperer
The cooler we run is here:
URL


I would really want to measure the power consumption on that. It is a thermoelectric cooler, also known as a Peltier cooler. They do tend to use a lot of power. Once the outside temperature hits 80 F they run almost continuously. Of course it is nice to not have to deal with ice. However, that unit is likely to be the biggest power user, unless you want a microwave.

MtnDon
Member
# Posted: 4 Sep 2014 21:43 - Edited by: MtnDon
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Quoting: LoonWhisperer
have no idea what happens on the other side of them lol.. Can you wire an outlet to the back?


Yes, one of those inlets can be placed on the outside. Do not be tempted to use one of the ubsafe methods utilizibg a cord with male plugs on each end; called a suicide cord for good reason. Use a good quality inlet receptacle and cover plate. On the inside use a std. receptacle.

My first advise is to get a friend who is electrically savvy to help you with the installation. It's not rocket science but done wrong you or a family member could have a serious accident.

Second is... Have a look at this link...
http://www.familyhandyman.com/electrical/wiring-outlets/add-an-electrical-outlet/view -all

Photo 5 is really all you need. You would be basically installing two boxes, more or less as pictured in photo 5, and then connecting them with some Romex wire. All available at a big box store. Does any of that make sense? The white wire always goes to the silver colored screws, the black wire always to the brass colored screws and the bare or green wire to the green screws.

You would wire the inside and outside units up brass - back - brass, etc. New present day receptacles use different terminals that don't even need curving the wire ends like shown. Just strip the straight end, insert and tighten the screw.

For use with a generator up to the 2000 watt size you can get away with 14 gauge wire and 15 amp receptacles and plugs. 12 gauge wire and 20 amp wall receptacles is theoretically better, but not really a must for what you are doing, IMO.

If the walls inside are paneled / drywalled the inside box would be as shown in photo 5. The outside could possibly use the same. Depends on how the exterior wall is built. Outside an outdoor weatherproof box may be better. Can't say from here w/o knowing more.

Lastly if any of this sounds like Greek, get help.

MtnDon
Member
# Posted: 4 Sep 2014 21:47 - Edited by: MtnDon
Reply 


Back to the ? about panels on the roof. The wires can drop over the eve and enter through the wall. A drip loop is needed and the hole well caulked. Secure wires so they don't flap in the breeze.

You could have a ground mount and store the panels in the cabin when absent, unless the batteries are left on site. They do self discharge with no use, no charging by PV panels and a charge controller.


What about the battery or batteries? Is the plan to haul them back and forth or leave them on site? With typical flooded lead acid batteries transporting requires some caution to prevent acid spills and burns as well as deadly short circuits across terminals.

With PV panel(s) and a CC they can be left, even through a winter.

LoonWhisperer
Member
# Posted: 4 Sep 2014 22:07 - Edited by: LoonWhisperer
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Quoting: MtnDon
I would really want to measure the power consumption on that. It is a thermoelectric cooler, also known as a Peltier cooler. They do tend to use a lot of power.


I am curious too. Now that I think about it, it ran down my powerpack (Xantrex 400 Plus) pretty quickly. Need to track down the specs and see what it draws.

Quoting: MtnDon
Have a look at this...[/url] Photo 5 is really all you need.


Link is down MD but I will definitely check it out. I do follow what you are saying and seeing the pics will really help. Thanks!

Quoting: MtnDon
What about the battery or batteries? Is the plan to haul them back and forth? With typical flooded lead acid batteries that requires some caution to prevent acid spills and burns as well as deadly short circuits across terminals.


Yes, the plan was to truck them back with us. Great point about the flooded batteries. I guess sealed AGM would be the better choice or leave them there connected to the panel. Just worried about theft as we are not up there as often as I would like.

And thanks for the info on the wiring install with the loop. That is exactly what I needed to know.

I really appreciate your help with all this.

MtnDon
Member
# Posted: 4 Sep 2014 22:34
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I messed up the link this is IT

will fix the first one

groingo
Member
# Posted: 5 Sep 2014 11:52 - Edited by: groingo
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As far as the cooler all (compact fridges Peltier or compressor type) will have a minimum pull of 75 watts at 120 volts, after a few minutes it will usually settle down to about half that but it is the initial startup and every time it comes back on to maintain temp is where you will get the power spikes.

As far as wiring, this again will be based on need (how much juice) but for the most part for what you are talking about just keep it simple but first and foremost get a KillaWatt power tester, thy are about $29.00 and something you may find yourself using a lot because not only is is useful but fun to use!

My best advice no matter what you do is kept it simple, do your homework and whatever you think you need.......DOUBLE IT!

MtnDon
Member
# Posted: 5 Sep 2014 14:31
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Quoting: groingo
As far as the cooler all (compact fridges Peltier or compressor type) will have a minimum pull of 75 watts at 120 volts,


groingo and all, If you look for a fridge that uses a Danfoss compressor you will have the most efficient electric fridge on the market. The Engle, ARB and some others like Novakool and Truckfridge use them. Ours has never drawn more than 50 watts on a start up. I'm not certain but I believe they ramp up. Their speed is also variable.

Just for the heck of it I test ran it here at home for a few days with a 5 amp ATO fuse on 12 VDC.

CaptCanuck
Member
# Posted: 5 Sep 2014 22:06
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How long are you planning on being at the cabin at a time?

LoonWhisperer
Member
# Posted: 6 Sep 2014 11:16
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Quoting: MtnDon
I messed up the link this is IT


Perfect! Thanks. So I guess it's a matter of running a short run of wire from the back of the inlet to a plug, correct?

Quoting: groingo
My best advice no matter what you do is kept it simple, do your homework and whatever you think you need.......DOUBLE IT!


Ha... isn't that always the way! Thanks for the input.

Quoting: CaptCanuck
How long are you planning on being at the cabin at a time?


At most we would stay is 3 nights, it's too small to stay for any extended time.

LoonWhisperer
Member
# Posted: 6 Sep 2014 11:19 - Edited by: LoonWhisperer
Reply 


Not sure if I am on the correct path here but after doing some research, someone asking a similar question was told to use one of these to bring power in their cabin:

110 Volt MALE plug

Sound about right? The generators I have looked at seem to all have just the standard outlets (2) and a 12v. Not the 30amp connection. So I guess this is what I need.

Sucks not knowing anything lol

Cheers!

CaptCanuck
Member
# Posted: 6 Sep 2014 13:12
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For three nights, why not just get a high end cooler like an Engel or a Yeti? My Engel 65 quart cooler keeps ice up to a week or so.

We went through all the same discussions for our similar sized cabin, and solar and all that goes with it just wasn't worth the trouble. We have a honda portable generator but only really use it for building and maintenance tasks.

VTweekender
Member
# Posted: 6 Sep 2014 15:01 - Edited by: VTweekender
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As captcanuck mentioned, I use the cooler and ice method. The Engel is great, I freeze water in 4 half gallon empty milk jugs and use for my ice, everything in the cooler is still cold 3 days later, even in very hot weather, also if I need more fresh water then I have 2 gallons always sitting in the cooler.

I have both solar and generator. I put together an inexpensive 45 watt solar system for $250 total. 45 watt panel, morning star 10 amp controller, a 400watt continuous / 800 watt surge inverter, 25 ft. Solar panel wire and finally a 160AH marine 12V battery from Advance Auto Parts. I run a 15" flat screen TV with a digital antenna up in a tree - 5 channels, a light with 25 watt CFL bulb, a small radio, and charge cell phone on this solar system for weekend stays with no problems. Each device running average about 4 hours a day, the system recharges easily by the time I go back for another weekend. The plug ins you need are built into the inverter already. The solar panel wire that you need to feed into the cabin to your controller, just drill a 3/8 hole in the floor or wall and run the wire in , set it up then silicone around the wire in the hole.

I also have a Champion 4000 watt generator at the cabin to run my power tools etc..outside. Bought that genny used in almost new condition off Craigslist for 175, been working perfect for 2 years. All in all I spent 425 and have everything I need for juice on weekends. Its nice to have the solar for the TV and radio without a genny running.

LoonWhisperer
Member
# Posted: 8 Sep 2014 11:53 - Edited by: LoonWhisperer
Reply 


Thanks Capt. and VT!

I think initially, the plan will be to add a deep cycle 12v battery to a MinnKota power centre and add an inverter to run a few small things for the few days we are there.

Next, add a small solar kit like the Renogy ones on Amazon (under $200 for 100 watt)then the genny for outdoor work.

And for anyone interested, I found this site had some helpful info on inverters. The usage calculator further down the page is pretty handy too.

Inverter FAQ

LoonWhisperer
Member
# Posted: 10 Sep 2014 12:06 - Edited by: LoonWhisperer
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So a local retailer has some Deka Unigy Batteries on sale and I am wondering if this looks like a good choice for a single 12v setup

It is a 150 amp hour agm battery. The manufacture date was summer 2013 and they are on a float charge. Here are the specs:

Deka Unigy UPS HR5500

I understand Deka is made by East Penn. Retail is around $160.

Thoughts?

Thanks!

VTweekender
Member
# Posted: 10 Sep 2014 12:56
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Does look like a decent battery, 107 LBS wow, I would use it for sure.

LoonWhisperer
Member
# Posted: 10 Sep 2014 13:00
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That's what I'm thinking VT, it's a beast! But after doing some reading, I see where people suggest UPS batteries are not designed for constant charging and discharging and may not be a good fit.

MtnDon
Member
# Posted: 10 Sep 2014 14:29
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Where is that 150 amp hour rating coming from? I do not see an amp-hour rating given at the 20 hour rate in that brochure link. That is the std method of rating a battery capacity for RE uses. That battery would likely fail early when used in a RE PV system, IMO.

LoonWhisperer
Member
# Posted: 10 Sep 2014 15:11
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Not mentioned on the brochure (which is odd imo) but comes from the Deka dealer in the area. I would definitely verify this if I was going to buy one. Upon further research however, I am going another direction.

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