Simple Solar Set Up Recommendation

jpedjped Registered Users Posts: 8 ✭✭
I am brand new to Solar and I am wanting to buy a simple solar set up for a my remote small cabin. (usage would be minimal - basic lighting, clock radio, maybe charge cordless drill if possible.)
The more I research, the more complicated it seems. Does it need to be that complicated?
From what I've read, I think I could get a 140-200W Panel (mono or poly?), Charge Controller, 2 - 6V Golf cart batteries and an Inverter to suit my needs.
If someone could help me out as to any recommendations/comments without getting too technical, it would be appreciated.
Also, is there a big difference in Brands. I don't mind spending the extra money on quality. Just wondering how much of a difference it makes. (Kyocera, Hanwha, Canadian Solar)
I'm in Canada so shipping from the States is usually not worth it due to the high cost.

Would a Kit be the way to go or buying each piece individually?

Here's a couple of links to comment on. Thanks.

http://solarenergydc.com/products/200w-solar-panel-kit

http://www.amazon.ca/Grape-Solar-GS-...rape+solar+kit

http://hespv.ca/residential-solar-en...d-solar-panels

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    jped wrote: »
    I am brand new to Solar and I am wanting to buy a simple solar set up for a my remote small cabin. (usage would be minimal - basic lighting, clock radio, maybe charge cordless drill if possible.)

    A "classic clock radio" is probably not a good idea. The typical AC inverter frequency is not "accurate enough" time keeping (off minutes per day or more).

    Getting a battery powered LCD clock+Alarm, good start. Or get some sort of small MP3 player/use your cell phone is usually better (lower power, uses its own crystal oscillator for time keeping).
    The more I research, the more complicated it seems. Does it need to be that complicated?

    Talking about solar system design "in general" can be very complicated and confusing. Designing a system for your needs, is usually less confusing (difference between looking for a 4 door car vs understanding everything from a motorcycle to an 18 wheel semi with refrigerated trailers--A huge undertaking).
    From what I've read, I think I could get a 140-200W Panel (mono or poly?), Charge Controller, 2 - 6V Golf cart batteries and an Inverter to suit my needs.

    Very reasonable small cabin system. Mono or Poly crystalline panels--Usually a don't care for your needs (mono panels are slightly more efficient and are slightly smaller than poly crystalline panels--Poly panels are generally less expensive--Mono panels are sometimes worth the extra money if you have a small place to install panels--top of an RV, boat, etc.).
    If someone could help me out as to any recommendations/comments without getting too technical, it would be appreciated.
    Also, is there a big difference in Brands. I don't mind spending the extra money on quality. Just wondering how much of a difference it makes. (Kyocera, Hanwha, Canadian Solar)
    I'm in Canada so shipping from the States is usually not worth it due to the high cost.

    Do the paper design first (the general battery size, solar array size, charge controller size, ac inverter, etc.). After you have those requirements worked out, then start picking hardware to buy (based on what is cost effective for your location). Kyocera and Canadian Solar are good brands of solar panels... I just don't know anything about Hanwha (I am not in the solar business anyway--So I don't have that knowledge to start with).

    I like to start with loads--A solar system that is too small, not useful. A solar system that is too big--An expensive white elephant. Using a kill-a-watt type meter is great for 120 VAC appliances. A DC Amp*Hour/Watt*Hour meter is nice for smaller DC loads. You can also get a DC Current Clamp DMM (digital multi-meter) to do some estimates of your power needs (links are starting points for your research/reference).

    Basically we need to know your average power needs (Watts, or Amps @ xx volts), and energy used per day (Watt*Hours, Amp*Hours @ xx volts, etc.).

    You gave two 6 volt @ 220 AH golf cart batteries as your battery bank... So lets see what they can do. First, for an off grid cabin, 2 days of storage (bad weather) and 50% maximum discharge (longer battery life) is a good start for our rules of thumbs.
    • 12 volts * 220 Amp*Hour battery bank * 0.85 AC inverter eff * 1/2 days storage * 0.50 maximum discharge = 561 Watt*Hours per day
    That is a "small" amount of power for a typical cabin. Generally enough for lighting (use LED fixtures/bulbs). Charge a cell phone, battery powered tools, laptop for a few hours of use per day, Even a small DC RV type water pump (if needed).

    Next, solar panels. Generally suggest 5% to 13% rate of charge. 5% is OK for a seasonal/weekend cabin. If you are going to be "full time", you should be looking at 10% or more rate of charge:
    • 14.5 volts charging * 220 AH * 1/0.77 panel+controller derating * 0.05 rate of charge = 207 Watt minimum array
    • 14.5 volts charging * 220 AH * 1/0.77 panel+controller derating * 0.10 rate of charge = 414 Watt nominal array
    • 14.5 volts charging * 220 AH * 1/0.77 panel+controller derating * 0.13 rate of charge = 539 Watt "cost effective" maximum array
    Next, what size array based on where you live/seasonal needs. Lets say you live in Winnipeg Canada. Using PV Watts for fixed array, tilted to 50 degrees from horizontal:
    Month      Solar Radiation (kWh/m2/day)
    1      3.45     
    2      4.48     
    3      5.51     
    4      5.57     
    5      5.84     
    6      5.77     
    7      5.89     
    8      5.79     
    9      4.64     
    10      3.82     
    11      2.69     
    12      2.96     
    Year      4.70
    

    Toss the bottom three months (use genset/shut down for winter), 3.82 hours of sun for October would be your 'break even' month (may need a genset or not--on average). Using 561 Watt*Hours of AC power per day, the minimum solar array would be:
    • 561 Watt*Hours per day * 1/0.52 end to end system eff * 1/3.82 hours per day minimum average sun = 282 Watt solar array minimum (based on October sun)
    So, it would look like a minimum solar array of 282 watts would meet the battery bank capability. And if you where there full time (weeks at a time), then a 414 to 539 Watt array would be nicer (note, "exact numbers" are used so you can follow math/where they are used. Anything within ~ +/- 10% is pretty much "close enough" for solar).

    What should you expect for power from a 220 @ 12 volts Golf Cart flooded cell lead acid battery bank:
    • 12 volts * 220 AH * 0.85 inverter eff * 1/20 hour discharge rate = 112 Watt average load--5 hours per night, two nights, 50% maximum discharge
    • 12 volts * 220 AH * 0.85 inverter eff * 1/8 hour discharge rate = 281 Watt load for ~4 hours (50% max discharge)
    • 12 volts * 220 AH * 0.85 inverter eff * 1/5 hour discharge rate = 449 Watt load for minutes to an hour or so
    • 12 volts * 220 AH * 0.85 inverter eff * 1/2.5 hour discharge rate = 898 Watt maximum surge (starting water pump, etc.).
    So--Ignoring actual equipment/brand names/etc... Does the above system do what you need? What size solar array? Small array (weekend use, reduce chance of theft)? Nominal or larger array (more daytime power, full time living--roughly 9 months a year)?

    The above system--I would be suggesting a MorningStar 300 Watt TSW 12 VDC inverter. Includes remote On/Off switch & "search mode". Not common for smaller AC inverters. Very nice for 12 VDC based power systems. And, not bad for running LED/CFL lighting (sending 12 VDC power any distance is difficult--Lot of heavy copper wire, and many time 120 VAC lighting is cheaper than 12 VDC lighting).
    Would a Kit be the way to go or buying each piece individually?

    Size the system first.... Many kits really do not fit your power needs (battery bank, solar array, etc.). However, it does not hurt to compare kit prices.

    Sometimes, it is nice to buy a prewired kit or "E-Panel" for more complex systems. For smaller systems like this, not so much need.

    One way to tackle the problem that seems to work well--Get a piece of 4 foot x 4 foot 1" plywood subfloor and build your solar power system (inverter, charge controller, breakers, etc.) on the panel and get it working at home. Then disconnect the battery bank+solar panels and haul it to the cabin. Very easy to reconnect and not have to worry about one or two missing parts at the cabin.
    Here's a couple of links to comment on. Thanks.

    Once we have a better idea of what size system you would need--Then we can start picking hardware to meet those needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Sign In or Register to comment.