Need help-remote cabin setup

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System
System Posts: 2,511 admin
in Solar Beginners Corner #1
I found this forum today and after reading for a couple hours I decided it would be wise if I got the opinion of the more seasoned veterans on this board.

My solar needs are many and money is limited so before I spend any more cash acquiring the gear I would appreciate any advice.

I decided to attack these needs in three stages as money provides. I will have three separate PV systems .



Currently I just have parts for #1 and some of #2



1st stage: Power for 12v RV pump, 32" lcd tv and DVD. Charging for AA batteries (All lighting is motion activated LEDs ran by AA batteries)

2nd stage: Submersible well pump power. Will purchase a Shurflo 9300

3rd stage: Energy Star rated frig 408KW year (Kenmore 20.6 )

I am living full time here and am currently using propane for the frig and generator power for the 240v well pump to fill a 200 gal. storage tank with the 12v RV pump pressurizing the cabin plumbing.

The parts I have already on hand for stage one are:

One evergreen 12v 200 watt panel
Two mk/dekka AGM 105s
One BlueSky 25w MPPT controller
One Xantrex RS 400 pure sine wave inverter

I haven't bought any fuses, breakers or a box yet. I was thinking of purchasing a Outback 60amp DIN for batteries to inverter a 30amp for controller to batteries and a 12amp for array to controller.

The parts I have for stage two are:

Unisolar 12v 64watt panel, two Dekka 105s wet cells, Morningstar 7amp controller (I only fill the tank once a week)

I have no parts for stage three and thought I would just copy the setup in stage one but use a larger inverter.

I also have a old Heart Interface 2000watt inverter which I don't think will run the new frig properly.

I have acquired these parts over time. The reason for the three separate PV systems is for system redundancy in case of failure since I am usually snowbound for weeks or more during winter.

Any thoughts?
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #2
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    Re: Need help-remote cabin setup

    You are on the right track here. Read all you can, here and other places. I would suggest that you get a very good handle on your loads as a first step. Do what you can to avoid the "ready, fire, aim!.

    I would consider leaving your big loads (water pumping, fridge etc) on the genny for a while. This will allow you to size your system up as you can afford to. For example, it might be cheaper to run the water pump off the genny at the same time you are bulk charging on a grey day. It might be cheaper to add a bigger storage tank, run the genny/pump once every two weeks than build the Pv for solar pump etc. (That said, I love the shurfloo 9300, but it comes at a cost and it pumps fairly slowly if you need a lot of water fast).

    Finally, while there is a certain attraction of a dual system, I would consider getting a good mppt controller now that you can grow into, add Pv as you can afford to. I might super size you battery bank assuming you are going to keep up with the charge with the genny. (Adding panels is easier than adding batteries to an existing system).
    I might also use multiple inverters for various uses to maximize efficiency, and these can be added in stages.

    I also would consider a good quality (Xantrex TC or Iota) charger, and a fuel efficient generator. (The new Xantrex 40 amp charger will run (I think) on a tiny Honda Eu 1000.

    Good luck, I'm sure there is more and others will chime in later. Welcome to the forum. There are some pretty smart, helpful folks here,

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
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    Re: Need help-remote cabin setup

    Also, add up your power usage... The 32" LCD TV will can a lot of power over all (120 watts * 4 hours = 480 Watt*Hours).

    That may take more power than the rest of your stuff (pump, DVD player, etc.) combined.

    For AC Power Measurements, the Kill-A-Watt meter is great for measuring energy usage (peak, average, kWatt*Hours, Power Factor, etc.).

    Sizing your battery bank to the loads is probably your first step. Typical rule of thumb, ~3 days of no sun (or generator usage) and 50% maximum discharge = 6x daily load.

    Also--since you are starting out... Many times, setting up a 24 or 48 VDC battery bank will help you when you loads exceed 1,000 watts or so. Helps keep the battery bank/bus DC current at a reasonable maximum (100-200 amps maximum). Above those levels, fuses/breakers, switches, and cabling get big and expensive.

    If you run many of your devices directly from an efficient AC inverter--then they are isolated from the effects of changing your bank voltage.

    A good charge controller (especially the larger ones) will include 48 VDC support, as well as 24 and 12 VDC. And the higher voltage allows you to put on more solar panels without getting a second or third charge controller at the higher back voltages.

    By the time you add an energy star fridge--you are getting close to the dividing line when a 24 VDC or higher voltage battery bank would be a good investment.

    Of course--your DC loads such as the pumps and inverter need to be changed out when you change bank voltage.

    Regarding the Unisolar panels--unless you have problems with "raining rocks" (vandalism)--your next solar panels should be standard poly or mono-crystalline glass panels (typically >100 watts in size). More efficient, longer lasting, and smaller in size for the same power output.

    If you leave the cabin for long periods of time--taking down the glass panels and using leaving out the Unisolar(s) to keep the batteries trickle charged would be a good use for them too.

    Assuming you are somewhere in the South West--You would need roughly 500 watts of solar panels just to run the fridge through the winter... You could go down to ~300 watts of panels if you work OK with using your generator some during the winter to make up for bad weather/low angles (if you have a reflective snow field in front of the panels--you may actually do very well with the lesser panels).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • System2
    System2 Posts: 6,290 admin
    #4
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    Re: Need help-remote cabin setup

    Thanks for the info guys. There is alot of stuff to think about.


    My power requirements are mainly the 12 RV pump and AA batteries charging.

    I only watch a dvd movie three times a week and use the laptop one hour a day.

    Everything else like shortwave and scanner, ham radios, computer chess game ect is AA powered.

    I figured my daily power usage not including the refrig or the well pump which is used only once a week is 400 watts.

    . I live in a area that gets sun 345 days a year with snow seven months a year, solar is a perfect means for power.

    I have three genneys.

    A gas sipping 1000watt yamaha. A 4000kw generac and a 7500 generac v-twin. I also have a 3 stage 40 watt charger.

    I use a 1200 watt APC line conditioner when using the small genney and the 40watt charger to charge the batteries.

    My goal is to be totally solar and use the generators for emergency backup only or when I have to run power tools.

    I made a mistake buying the 25amp charge controller. At the time I though that this controller would handle two 200watt panels. I didnt realize that each 200 watt panel needed 15amps. My plan was to upgrade to another 200watt in the future for a total of two panels.

    I should have found a 30amp controller instead.

    Live and learn :)
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
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    Re: Need help-remote cabin setup

    Sasq,

    You sound like we could be neighbours, climate wise at least,, although we don't have quite as many days of sun.

    Just FYI, we live with ~300 watts of panel, and we use on average 4-600 wh/day for all purposes. This includes water pumping for two, stereo (12vdc) sat radio, sat internet modem, 2 Mac lap tops going most of the day, asleep for much of the day, an average of 3-5 CFLs going, a couple of 15 watters, and a couple of 5 watters, fridge control (LP fridge) paddle fan(s) some small cordless tool charging etc. We treat ourselves to a "movie night" one or perhaps two nights a week, a bit more in the winter. We watch a DVD on the lap top and send the sound to the stereo,, pretty up town for us!. (No TV however)

    We manage our draw pretty carefully. For example after the evenings last shower or dishes, I will pull the breaker on the pump and wait until the sun is full to turn it back on. There is plenty in the tank for most uses then. We may run the laptops in the morning, but we often wait until the batteries have gone into absorb charge to charge them and the power tools etc. This way we limit the net draw on the batteries ( and ergo the required charge) while maximizing use. Usually, by first thing in the morning the Tri-metric is showing a net draw of ~30-40 ah (12vdc) ~350wh. We get 90% of that back by about noon, as our panels favour a south east and get full sun right after dawn in the winter.

    We almost never have to run a genny in the winter as the reflection off the snow is so good. Occasionally we will get 3-4 days of snow in a row in Dec-Feb and we will have to run the genny for a couple of hours, but that is pretty rare. Summer, because the dusk is so late, we have no need for lights until nearly 11pm the loads are less, and the sun is up by ~4 and on the panels by 5am.

    If I had to do it all over, knowing what I know, and seeing the current price of hardware, I would buy a good .5-75 kwh/day compressor fridge and get away from the Lp. Doesn't make sense now. I would also have gone with a bigger (better) controller as I am now on my third controller and I'm up against it's limit.

    As I suggested before, look carefully at your loads, and figure that they WILL increase with time. Buy you 3-5 year battery capacity now and count on keeping them up with the genny until you have enough Pv. I also suggest strongly a good battery monitor. I like the Tri-metric quite well.

    Good luck, keep working on your planning before you buy anything if possible,

    Tony
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  • System2
    System2 Posts: 6,290 admin
    #6
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    Re: Need help-remote cabin setup

    Icarus, thanks for the info on your usage.

    It looks that I am on the right track with PV- battery- usage needs.

    I also watch DVDs on my laptop when I don't want to fire up the tv. I mainly read by the woodburner with LEDs for light in the winter.

    I live in the Pacific North West. They call it "little Siberia" here. We get winter temps of 20 degrees below regularly. Even in the summer we go from the 80s during the day to the mid 30s at night.

    I love the cold and wish I could hibernate in the summer. My fingers are already itching to fire up the woodburner.

    My wife thinks I'm nuts!
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