A2. Last thing you want is 24 volts and is quite foolish. With 2820 watt sof panels would require two very expensive Charge Controllers. It also requires a lot larger more expensive wiring. At 2820 watts is a 48 volt Battery system with one single 60 Amp MPPT Charge Controller. Use the Morningstar TS-MPPT-60. I would even consider the Morningstar MPPT-600-60 a 600 volt controller. That will allow you to wire your panels 6S2P which means no requirement for expensive Fuses or Combiners, and nice and small inexpensive wiring between panel and controller. If you go with a 150 Voc controller like you have listed, you are looking at 3S4P panel configuration and a quite expensive Combiner, Fuses, and 1/0 feeder cable. That is a lot of money. At 600 volts no combiners or fuses, and using 8 or 10 AWg wire.
Hey Sunking - wouldn't even a 6S2P require a combiner box? I am asking because I consider 24 panels, and I had in mind 2 ground mounts of 12 panels - all in series with each a Conext MPPT 600-80. But having 12 panel in series can be slightly problematic with shading thus the 6S2P is interesting for me also, but not necessarily having a combiner box.
Thanks!
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Tiny Off-Grid system my ass. 2820 watts is a monster sized system.
A1 NO. Forget the Wind Turds. A complete waste of money. They are not called Wind Turds for nothing.
A2. Last thing you want is 24 volts and is quite foolish. With 2820 watt sof panels would require two very expensive Charge Controllers. It also requires a lot larger more expensive wiring. At 2820 watts is a 48 volt Battery system with one single 60 Amp MPPT Charge Controller. Use the Morningstar TS-MPPT-60. I would even consider the Morningstar MPPT-600-60 a 600 volt controller. That will allow you to wire your panels 6S2P which means no requirement for expensive Fuses or Combiners, and nice and small inexpensive wiring between panel and controller. If you go with a 150 Voc controller like you have listed, you are looking at 3S4P panel configuration and a quite expensive Combiner, Fuses, and 1/0 feeder cable. That is a lot of money. At 600 volts no combiners or fuses, and using 8 or 10 AWg wire.
A3. Surge arrestor is optional. TVSS is a Passive device and does not interact with anything.
A4. Generator has to be sized to operate all loads plus charge the battery as fast as possible at C/6 to minimize fuel burn. With 2820 watts of panels suggest your battery capacity is 28 Kwh and peak load is 2 Kw which works out to about a 8 Kva genny. Again this is where 24 volts is not possible. With your panel wattage of 2820 watts minimum battery AH capacity is around 1000 AH which would need a 175 to 200 Amp 24 volt Battery Charger. Good luck finding one. They do exist in the Telecom market. At 48 volts you are looking at 75 to 100 amps, a whole lot less expensive. Dump the 24 volt battery idea.
A5. Battery capacity is determined by your daily Kwh load for 5 day reserve capacity giving you 3 days autonomy. It is also has to meet minimum and maximum charge current requirements of no greater than C/6 in your case with Forklift batteries and no less than C/12. With a 48 volt battery means they must be no smaller than 450 AH and no larger than 900 AH. If you use 24 volts, foolish, double those capacities from 900 to 1800 AH. Last word on batteries DO NOT USE PARALLEL CONFIGURATION. Since you are willing to spend the bucks on Fork Lift Batteries, there is a better option which is slightly less expensive and will last longer than FL batteries, Trojan makes an Industrial Line, no better battery can be found. Cell capacities are perfectly aligned so you WOULD NOT have to use PARALLEL configuration. Capacity starts at 454 AH up to 1850 AH. Take care of them and you are looking at a 10 to 15 year battery. Fork lift and you may get 5 to 7 years.. What is not to like? Less expensive and last longer.
Follow my advice and you save $10,000 to $15,000 and will work a lot better than your plan. I only charge 15% for the money I save you.Last edited by Sunking; 05-05-2017, 12:14 PM.Leave a comment:
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The generator size is supposed to be large enough to :
Run expected normal loads
Charge batteries at C/10 rate ( if its a 600ah battery, it needs to be able to drive the charger at 60A ) Some of the larger inverters have a mode where you can feed AC into them and they function as a battery charger, yours might have this feature,
Under both conditions above, still have about 30% reserve capacity at rated continuous load (not peak capacity)
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Wind
very problematic, Wiring, Dump loads and Controller need to be really robust, they are the only failsafe against turbine overspeed and gernadeing, sending shards into your house
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Combiners
Check the boxes made for combiners by Midnight Solar. Use DC breakers, not fuses.Leave a comment:
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Tiny solar off grid cabin Northern Michigan
Hello everyone, great forum and I have enjoyed reading it for system design info.
Let me start by saying that electric grid from the power company is simply not an option where I am located.
The system below will be full time use, connected to ultra efficient 200 sq ft cabin. Lights are LED, 24 Volt DC chest fridge, DC shower pressure pump, tiny AC washing machine with pulse motor, DC electric teapot, 2 laptops, wifi router and last mile internet equipment are pretty much all our electronics. In the fall we also run a Sedona dehydrator, and I plan to add movie projector in the future (most efficient I can find). Lets say total ~3000 watt hours per day of electric used.
Equipment:
12 x Canada Solar CS6P-235 235 Watt 24 Volt, Vmp 29.8. Imp 7.9A, Voc 36.9 Isc 8.46A
Outback MX60 CC
Outback FlexMax 80 CC
Magnum 4024 24 volt inverter (I know that 4000W is too big inverter for 24volt battery bank, don't plan to ever use it to it's full rating)
2 x Windmax 24v Y-400 Watt turbines, one on 20ft tower, one on 60ft tower
24 Volt forklift battery
I'm planning to set it up like this:
6 x 235 Panels on MX60 CC
6 x 235 Panels on FM80 CC
Both wind turbines connected directly to the battery with a MorningStar TS60 acting as a dump load controller + Dumpload heating element
I have no misconceptions about my wind generators, I know that the best I'll get out of them is couple amps, I plan to upgrade to a proper turbine in 3-5KW range once I can afford it.
I'm looking at couple lightly used Honda generators locally to connect one to my MS4024 to charge the batteries when it's cloudy for too long
My next steps are to get breakers, lightning arrestors, gen auto-start, combiners boxers, wiring and to start the assembly.
Couple questions to which I would appreciate an answer:
- Is there a better way to connect wind generators then directly to the battery + dump load? I know about Midnite Classic and Clipper, but it's not worth it for this toy turbine.
- For my 24 Volt DC loads, do I run those from the battery bank or is the inverter involved?
- Do I need lightning arrestor for each combiner box? What makes the combiner box compatible or incompatible with the Lightning arrestor?
- How do I size the generator for this system? I've seen a lot of generator info on this forum, but not much on sizing.
- Does sizing the battery differ in any way if I'm using a forklift battery since it has thicker plates and higher charger rate?
Looking forward to getting some input.
Leave a comment: