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Small Cabin Forum / Off-Grid Living / Any one use GoalZero Portable solar?
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LakeSuperior5
Member
# Posted: 6 Oct 2011 14:37
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We have been researching various solar options for our Shabin. We actually use very little power but then again, when a little is all that is available, you tend to conserve. Our needs are lighting periodically, we use battery laterns most of the time. Recharging batteries would be nice. Our biggest use would be a water pump for the shower.

Currently we have a generator that is used during the building process. Will upgrade to a quieter Hondai when they old one stops running.

Goal Zero has some small portable units that I like as we could move the panel into the best sun possible as seasons change.
Wondering however if I am thinking to simple and if anyone has experience with their durablility over a few years?

kevhead101
Member
# Posted: 6 Oct 2011 14:58 - Edited by: kevhead101
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I just saw the video for the Extreme 350.....looks awesome!!!

Extreme 350 Adventure Kit Video Demo

LakeSuperior5
Member
# Posted: 6 Oct 2011 16:23
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And they say you can add onto them. We discovered them because my husband was looking for something to take on a mission trip they do in Haiti. The portability looks good, small, moveable, but we want something that will last and have not found anyone who has one yet.

razmichael
Member
# Posted: 6 Oct 2011 21:28
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As nice as the Extreme kits look, I would really consider what your needs are. You are paying a big premium for portability which may not be what you need in a cabin. The price of their 30 watt panel will get you a 95 or more (with controller) that could be mounted on the roof and more than make up for the lack of ability to move it around (and why do you want to worry about moving it anyway). Do a good assessment of your actual power needs and then size the panel accordingly (you can always add more panels later). Add a good deep cycle battery that also meets your power and cost budget and you are good to go for lights, pump and other 12v devices. Add a small inverter and you are ready to run small 120v devices (lots of possible discussions on the inverter selection criteria is possible!). Obviously you could get far more complex than this but it sounds like this would be all you need (and if you start off right you can expand later). Long rambling post mostly to say that the extra cost for portability may not be the best choice if you really do not need to move it around.

trollbridge
Member
# Posted: 6 Oct 2011 22:00
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I am wondering how those of us who have cabins in northern climates where there is heavy snowfall keep the solar panels free enough from snow to get a charge? Is mounting the panel flat on the wall the best thing to do?

razmichael
Member
# Posted: 6 Oct 2011 22:57
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Normally the best thing is to have them on the roof facing south. A wall mount will seriously reduce the exposure/power. If you use the cabin in the winter you will need a long brush to pull snow off (no different than our home/microfit systems). It is surprising how much power will still be provided even through a fair amount of snow. if you are not using the cabin much there will likely still be enough power to trickle charge and maintain the batteries (which should stop them from freezing). If you are not living in the cabin then bring the batteries home for the winter.

trollbridge
Member
# Posted: 6 Oct 2011 23:13
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I know the roof would be best but our roof is way up there. I'm thinking if it was mounted on the wall at a little angle it might be better than sitting with a foot of snow on it? But then in the summer months that wouldn't work well at all-almost need two locations depending on the time of year. I would say that in the winter we only get to the cabin about 1 time a month. Thoughts?

razmichael
Member
# Posted: 7 Oct 2011 07:32
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My thoughts (not really knowing your complete situation) is that the summer is your main use so mount the panel on the roof in the best position. If you power budget is fairly small, use a good quality REAL deep cycle battery and case for the summer. In the winter you can either leave the battery up there and see how well it stays charged with the snow covered panels (risky if it does freeze) or bring the battery home and back with you the 1 time a month you go up (assuming you need power for a pump etc). I know that some people add a small panel that could be stuck anyway (the ones you see for use in a boat or car) that could be put anywhere to trickle charge the battery. All of this depends very much on how permanent you want the setup, what size, how much you are willing to spend etc. A really good site to read up on solar systems (focussed on RVs but this is likely more applicable to cabins than not) is at URL . To ensure a full disclaimer, my experience with solar is home and Pop Up trailer. I redesigned the electrical system in my Pop Up trailer in such a way that the complete system will eventually be lifted from the trailer and moved to the cabin (when it is finished). Obviously I will need to add the wiring and fixtures but the core system is ready.

trollbridge
Member
# Posted: 7 Oct 2011 09:44
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Thank you for your help. We have been so busy with building our cabin that we really haven't poured ourselves into the solar set up yet. We do want to go that route though so that we are not running our generator so much. Right now we charge our 1 battery when the generator is on and that provides a few lights at night and the ceiling fans all night too. I think you are right about going with the roof cause that is definitely when we use the cabin most(Summer). The battery we do have we bring home anyway during the winter and take back with us when we do go. Thanks for getting me thinking!

razmichael
Member
# Posted: 7 Oct 2011 10:23
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I'd rather be in your shoes - finishing the cabin and then working on power, water etc! I have my power setup done, I've got my water setup done (hot and cold) but I likely will not be starting the cabin until next spring. I have some photos of the wiring although it does focus on how I bypassed and modified the built in trailer converter. I built my system on an inverter that incorporates a control panel, auto switch (for plugging in a generator when/if needed), 3 way battery charger etc). Along with two deep cycle 6 volt batteries (trojan T105), I was able to get a week or more of use easily including LED lights, water pump, occasional furnace fan, charging up the odd electronics and my wife insisting on using a hair dryer every once and a while. Although I rarely used the inverter's 120v output, it is nice to have available. I later added a 90 watt panel so I did not need to bring up a generator every once in a while to charge the batteries up. link at Link to Electrical System

LakeSuperior5
Member
# Posted: 7 Oct 2011 10:39
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Thanks razmichael for your thoughts. We are sort of in the same shoes as trollbridge. Permanent mount may not be the best for us in the fall and winter, not like we are there as often however during those times. Northern Minnesota.

I guess more reading is required. I didn't realize there was a premium on the portability because the systems we had looked at prior seemed to be running around $2500. So I actually thought this was a less expensive option. hmmmmmm. More reading

razmichael
Member
# Posted: 7 Oct 2011 12:20
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I'm not against these portable systems - I have one (a canadian tire eliminator). You pay for the convenience of a complete package in nice looking box with lots of connectors that is great to take with you for all sorts of things. For a cabin or other more static requirement, you lose the ability to pick and chose component sizes and specifications that best meet your needs and you pay more. For example, looking at the specs of the Extreme 350 (selling for almost $800), you get a very nice looking (and likely well built) portable system but the specs are not great if you want to do much else than power a couple of lights and charge some electronics (which is really all they claim it is for). The battery is rated at 350 watt hours - something like 30 amp-hrs - this is not much. The inverter is 400 watts max - so don't expect to power much from that (nor power anything for long). You can stack them but now you have paid $1600 for about 60 amp-hrs of power and spending money on more connectors and inverters. But again - it is a convenient package with lots of connectors available easily and you do not need to put it together.

For $800 you could put together a much more capable system that would provide way more power and value if you only need a fixed system at the cabin. A couple of hundred dollars or less will get you a great deep cycle or (not so great) hybrid marine battery with 3-4 times the capacity. Spend a bit more if you need to and go with 2 6v deep cycle batteries and you end up with 7-8 times the capacity. $200 will get you a decent inverter (not true sine wave but likely more than good enough) with 1000 watt capacity or more. Another $200 will get a 60 watt solar panel with controller. Final $200 for cables, fuses etc. You can end up with a very capable cabin system where you can wire in some lights and plugs and have basic power for other things - and you can easily expand it later on if you wish.

bhebby
Member
# Posted: 7 Oct 2011 15:45
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Raz you seem to know your stuff. I just bought 5 40 watt LED bulbs at Home depot for 8 bucks a piece,2 deep cycle 12v rechargable marine batteries from Interstate(ask for reconditioned) 35 bucks a piece. I am in the market for an affortable solar battery trickle charger. DO you have any opinons on a good one so I dont have to truck those batteries back and forth from home?thanks-Brett

trollbridge
Member
# Posted: 7 Oct 2011 16:15
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Wow-whoa-wow...I just took a peek at your link and whoa-WAY over my head :o Yikes! This is probably somewhat over my husbands head too but he would have to look at this. I don't know much about what we did but I do know we ran wires in our walls just like you would for normal electricity(in case we ever go that route). There are basically 4 lines that run on the same "fuse"or circuit so to speak. They each have a plug on the end that goes into a power strip. The power strip plug goes into the generator using an extension cord for now. Then there is a battery charger that charges the battery whenever the generator is running. There is also an inverter somewhere in there and at night we unplug one line and it gets the battery power to run a few lights and two ceiling fans if we need them. Did that make any sense??? I"m sure I butchered the description on that!!! It does work nicely for now it seems. It fits nice and neat under our stairway. What is this about venting batteries? When is that necessary? He will have to explain it better to you.

What are you planning on building in the spring for your cabin? Do you have your design figured out? It will be a real exciting time for you. Have you ever built a cabin before?

trollbridge
Member
# Posted: 7 Oct 2011 16:27
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lakesuperior5,
What have you been working on lately? Are you enjoying the wonderful weekend weather we have been having? It's been beautiful but today the winds are so strong. It must really blow up at your cabin? Going up this weekend?

bugs
Member
# Posted: 7 Oct 2011 17:01
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I saw a wall mounted pv unit and it worked quite well. The people had it mounted on a hinge along the top. In the winter when the sun is very low the panel was adjusted to 10 degrees or so off the wall. This essentially eliminated snow build up. Through spring and summer the panel was adjusted periodically to increase the angle to catch full sun. Worked slick I thought.

We are likely a bit more rustic than some as we don't have a stove in our shack. We found we use our solar setup/electricity for appliances ie microwave, kettle, in the spring and fall (Our shed is 3 season) so we don't have to cook outside in the dark and cold.

As mentioned above unless you have lots of snow a 45 degree angle on the panels keeps most of the snow off. At least that is what we are finding.

We have 3 deep cells in our setup and we leave them in the shack throughout the winter with no ill affects. (We got down to -40C last winter.) They are connected to the panels so there is a trickle going on via the regulator. We keep the inverter turned off through the winter tho as they supposedly don't like the cold.

suburbancowboy
Member
# Posted: 7 Oct 2011 17:26
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Get the small harbor freight solar kit for 149.00. I have three and I have only ran out of power once when I was running my 1600 watt halogen lights one night when building.

razmichael
Member
# Posted: 7 Oct 2011 21:59
Reply 


Trollbridge, the diagrams look more complicated than they really are and keep in mind they include integrating a trailer converter in (while bypassing the converter functions other than circuit breakers and fuses). Also, the fact that I wnated to design it so that I could pull it out from the trailer, restore the trailer to original, and move the system into the cabin added some complexity. For a cabin, the system can be very basic. It sounds like you have already done a lot of work. When it comes to wiring there are two trains of thought - wire for 120v and use an inverter for everything - or wire for mostly 12v and only use 120 for occasional use. Inverters have a loss due to inefficiency (often around 15% loss) and will draw some power even when just sitting there, so make sure you can turn it off when not needed or it could drain the battery by itself given enough time. Inverters are not all born equal so check the specs. The inefficiency needs to be accounted for in your power budget. The alternative is wire things for 12v (or 24). The down side to this is that the wire gauge may need to be larger to handle the added loss for DC current over any distance - thus more cost. Not sure this is much of an issue in a small cabin. Another factor is the lots of stuff is easily available for 120V AC while 12V stuff tends to be more expensive. My plan is to use DC for lights and basic functions (fan, pumps etc) but also have 120 available when needed. If you watch wire length and guage, you can use 120v wiring but run 12v over it thus enabling you to wire once and change over in the future if desired. Be careful with this to ensure sockets etc will not be mixed up (and it may depend on building codes if this is an issue).

My cabin plan is a 16x16 with an additional 8' deck and overhanging loft. Plans are all ready - just sorting out some other issues. I've never built a cabin but how hard can it be!!??

Bhebby, I don't have a suggestion for a trickle charger. If I was you I woulonsider getting a smallish panel and charge controller (as mentioned by suburbancowboy, these are not expensive and then you are really charging the batteries rather than maintaining a full charge. A trickle charger will not handle a run down battery or replace daily use. Panel size would depen on your power budget and the actual capacity of your battery bank.

trollbridge
Member
# Posted: 7 Oct 2011 22:10
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Hinged on the wall would be easier to tend to for us. The best portion of roof for solar panels at our cabin would be the roof over our loft dormer. It would get the most sun there but is very difficult to access. We don't have a high demand for electricity since we do not have utilities, but like you said, in the winter it is dark so early that lights are more necessary.

suburbancowboy, are the panels on your trailer the ones from H.F? They look very large to me-approximately what are the dimensions?

BTW Bugs, if you don't go to your cabin all winter, what wonderful pictures of wildlife am I going to get to look at???!!
This side face mostly south
This side face mostly south


LakeSuperior5
Member
# Posted: 10 Oct 2011 13:32
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Such good information, thank you everyone. Many possibilities.

The weather is great for Minnysnowta right now. Working on two walls for what will be the bathroom, then time to move indoors and work on wiring and insulation. Fingers crossed that maybe we can move into it by next summer.

trollbridge
Member
# Posted: 10 Oct 2011 23:45
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My fingers are crossed for you :) How often are you able to get up north to your place?

LakeSuperior5
Member
# Posted: 12 Oct 2011 11:20
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We go "north" almost every weekend from May-Oct. Winter months are snow dependent and we do not have heat installed in the Shabin yet.

Bathroom walls are coming along, one more to go and door to install. Our bathroom is located outside on the deck allowing for more space inside the Shabin.

Got a nice deal on used oak flooring. Need to remove the nails which is taking a bit of time away from other projects. However we need to be able to stack the flooring until we are ready to use so sometimes you have to switch gears. Heard the word snow flurries today. arrrrghhhhhh

trollbridge
Member
# Posted: 12 Oct 2011 12:54
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snow flurries...oh say it isn't so!!!

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