Advice on adding wind to my off-grid system...

tuckersnocattuckersnocat Registered Users Posts: 7
Hi All,

I'm new to this forum and am hoping that someone can give me some advice about adding a wind turbine to my small off-grid cabin system. It's high in the mtns of SW Colorado. I'm there intermittently throughout the year but access can be challenging in the winter, I'm not complaining, I like the adventure . In the summer we usually have adequate power but I have to run the generator quite a bit in the winter and would like to decrease that. I've had the current system running for some time but I'm no expert and would appreciate any advice.

I've got an opportunity to buy a good used 3.2 kW wind generator (Proven). It produces 3 phase AC variable voltage power (200-225 Vac 3 ph). Nothing else would come with it so I'd have to purchase all of the other components needed to use the power. I'm thinking that I could rectify that output to DC variable voltage (240-300V dc) which would then go through a load diverting charge controller into my 24V battery bank. I'll probably heat water with the diverted power. Is there anything wrong with that general concept? Any suggestions for the charge controller?

The rest of my system consists of:
-720W of PV through an Outback MX60 charge controller.
-24V microhydro generator which is used with a Morningstar load diverting charge controller in the summer.
-SW Windpower 24V 300W wind turbine which we really just put up to get a sense of how much wind we have - the answer is not a tremendous amount but it's nicely complementary to the PV. It's usually either sunny or windy at 11,000 feet in the mountains.
-Outback 2500W FX Inverter
-Outback AC and DC Enclosures
-Generator

I would appreciate any advice!
Russell Hill
La Plata, NM

Location: Four Corners

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,923 admin
    Re: Advice on adding wind to my off-grid system...

    I would suggest looking at Midnite's MPPT Wind Controller system (with the "Clipper" dump load system)... It will offer you the best output to battery bank for your system (MPPT charge controllers can allow the wind turbines to operate at higher voltages/lower current and efficiently down convert to lower battery voltage/higher current). A good MPPT controller has been reported to increase output approximately 2-3 times.

    Otherwise, with your "high voltage" turbine, you will either have to charge a higher voltage battery bank or use step-down transformers on the three phase AC side to get an efficient energy transfer to your 24 volt battery bank.

    You will probably have to contact our host or Midnite directly (or their forum) and see if their controller would be a good match for your turbine as presently wound.

    Otherwise, yes, you could run water heater elements directly from your wind turbine (with some sort of dump load)--It will be less efficient than a MPPT controller--However, it will cost less in electronics.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    Thanks Bill, that does look like a good option. I'll check with NAWS and Midnite on the details. Maybe the Classic 250 w a 4000W AC Clipper? It looks like that should contain everything that I need, including the rectifier.

    Russell
  • BB.BB. Super Moderators, Administrators Posts: 32,923 admin
    Re: Advice on adding wind to my off-grid system...

    My concern is the very high voltage for your wind turbine--It may be too high for the Midnite controller (they can probably program it to run at a "safe" voltage though--just slightly less efficient).

    Another option would be a (high voltage) grid tied wind inverter back driving a OG TSW inverter (over 3.2 kW rated). The correct OG Inverter will actually charge the battery bank with excess power from the wind turbine+GT Inverter.

    However--For a small cabin--This is getting some pretty big hardware. May be over size/too costly to justify.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    Thanks Bill. We're discussing it now on the Midnite forum. Sounds like it should work with the AC Clipper/Classic Controller but still under discussion. The setup suggested by Proven does involve a control box w rectifier into a Windy Boy GT inverter but since I'm going to use it solely to charge my battery bank I'd like to find a cheaper, simple, reliable alternative.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Advice on adding wind to my off-grid system...
    Hi All,
    I've got an opportunity to buy a good used 3.2 kW wind generator (Proven). It produces 3 phase AC variable voltage power (200-225 Vac 3 ph). Nothing else would come with it so I'd have to purchase all of the other components needed to use the power. I'm thinking that I could rectify that output to DC variable voltage (240-300V dc) which would then go through a load diverting charge controller into my 24V battery bank. I'll probably heat water with the diverted power. Is there anything wrong with that general concept? Any suggestions for the charge controller?

    The 3.2 Proven will be severely de-rated at your altitude due to air density. That being said, I don't think it is suitable for battery charging on a 24V system. Not that it can't be done with the right combination of step down transformers, rectifier and Classic controller. Just that it's not practical. I think I would either look at setting up a mini-grid with it (with a GT inverter AC coupled to a battery based GT inverter), or use it just for water heating with a three-phase delta wired array of off-the-shelf water heater elements.

    The main problem with it is that it runs at too high of voltages to be practical for battery charging, and the losses in stepping that down, plus the de-rate losses due to thin air at higher altitude will more than likely yield less than impressive results. Direct driving resistive heating with it will be pretty efficient if you can match the resistance of the heater array so the turbine runs at the right tip speed ratio.
    --
    Chris
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Advice on adding wind to my off-grid system...

    you did not tell us about the battery bank, make and size
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    Ah yes. Eight Crown 6V Lead/Acid 390 Ah batteries, set up in 24V configuration.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Advice on adding wind to my off-grid system...
    Hi All,

    . In the summer we usually have adequate power but I have to run the generator quite a bit in the winter and would like to decrease that. I've had the current system running for some time but I'm no expert and would appreciate any advice.

    The rest of my system consists of:
    -720W of PV through an Outback MX60 charge controller.
    ..............
    -Outback 2500W FX Inverter
    -Outback AC and DC Enclosures
    -Generator

    I would appreciate any advice!
    Russell Hill
    La Plata, NM
    Location: Four Corners

    Looks like you have about a 10% charge rate and a usable (50%) 9,360W
    So what happens to your PV in winter? How low does it go (%) ?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    If I start with a fully charged battery bank and leave my electronic equipment on (satellite internet, computer, cameras - about 150 watts) in the winter months it slowly drains the battery bank down to the point where the inverter shuts down. That happens over a period of about 5-6 days. Faster if it's cloudy, snow covers the panels, etc.

    In practice I just don't leave anything on in the winter, I disconnect all loads but don't turn the inverter off, mostly because there's usually a lot of snow to dig through to get into the bldg where the inverter is and I want to power things up right away when I get there, (Email is my only way to communicate, it's sometimes an adventure-filled, dangerous trip up and my wife wants me to let her know right away when I arrive....) The system is usually at about 24.5V, 60% charged. I'd like to leave the electronics on so I can monitor things remotely but I don't want to discharge the batteries to the point where they might freeze - it's happened. When I get into the electonics bldg I fire up the generator and leave it on until the batteries are fully charged or I leave.

    I'm hoping that adding the wind generator will give me enough additional power to leave the electronics on all the time. 150 watts isn't much of a load but it's 24/7. Sometimes it's impossible or too dangerous to get to the cabin for several weeks at a time in the winter and I'd like to be able to monitor things from afar.
    westbranch wrote: »
    Looks like you have about a 10% charge rate and a usable (50%) 9,360W
    So what happens to your PV in winter? How low does it go (%) ?
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Advice on adding wind to my off-grid system...

    I was thinking also about where the panels are , how high, winter angle, snow height, etc...
    what about a remote switch for the inverter? Does it have a sleep mode?

    I did some quick calcs and your batteries should last ~ 3 days to 50 % DoD, so I'm thinking that your estimation is off a bit or there is a silent load you are not aware of.???

    There was another poster some years ago high up in Colorado I think and he had some ingenious erector-set stuff to get his PV sway up over the snow, I'll see if I can find it later...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.BB. Super Moderators, Administrators Posts: 32,923 admin
    Re: Advice on adding wind to my off-grid system...

    Can you use a smaller inverter with lower "tare" loss (idle current)?

    Taking your batteries down that far is not good for them in the long term--The fact that they are very cold is probably helping you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    The panels are high enough that the snow on the ground doesn't cover them, but if it's "sticky" enough it does stick to the panels and block some light until it melts

    Finding a small very efficient inverter that would supply maybe 250 watts to run what I need to while I'm gone is a thought. I don't think the Outback inverter is that inefficient though. The issue isn't really with the current draw while idle, if I leave everything off I don't have any problems. What I need to have is that 150 watt output all the time, as efficiently as possible to run what I'd like to run.

    I could also add more PV, or add a tracker. I think that a tracker would help quite a bit but I've never tried to use one and I'm not sure how temperamental they are when left unattended in extreme environments. It does bother me to see bright sunlight streaming over the horizon with my panels pointed in an entirely different direction.

    Another option is to get a generator set up on autostart to bump up the system when necessary, that would solve the problem. I do have a nice Onan 2.5 kw propane generator that I bought with that in mind and I will try to get that done this year. That seems like admitting defeat though and I'm going to try to get the system to work sans fossil fuel as much as possible. That's part of the challenge and the fun IMHO.

    The MidNite forum discussion leads me to believe that the Proven turbine coupled with a 4000W AC Clipper and a Classic 250 controller will work, though maybe less efficiently than going with a high voltage GT inverter. I'm leaning towards giving that approach a try.

    I do appreciate all of the suggestions and thought!
  • BB.BB. Super Moderators, Administrators Posts: 32,923 admin
    Re: Advice on adding wind to my off-grid system...

    For a cabin, the MorningStar 300 watt TSW 12 volt AC Inverter is difficult to beat... besides being very rugged, it also has two features that make it really nice for small systems. First it has a "sleep mode"--Just turns on for 1 cycle every second to look for >6 watt AC load. And second, it has a remote on/off switch (12 volt signal level voltage--connect it to a mechanical twist timer--i.e., 1-x hours of AC power then auto off for charging cell phones, laptop, etc.). Can save you a lot of idle losses on a small system but still leave it easy enough to use without confusing everyone in the house.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Advice on adding wind to my off-grid system...

    I'm well familiar with the 'dig out the door ' issue in heavy snowfall areas...

    If all you want right away upon arrival is lights, the smaller inverter that powers a separate sub panel , for lights, would get you started till you finish digging... you could run more off it if needed, leaving the heavy loads for the big unit.


    If it were me I would do a cost analysis of more (currently cheap) panels , bigger battery vs the cost of getting the turbine up, CC'ed, Clipper'd, tower, etc. factoring the issue of maintenance for both too...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • NorthGuyNorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: Advice on adding wind to my off-grid system...
    Another option is to get a generator set up on autostart to bump up the system when necessary, that would solve the problem. I do have a nice Onan 2.5 kw propane generator that I bought with that in mind and I will try to get that done this year. That seems like admitting defeat though and I'm going to try to get the system to work sans fossil fuel as much as possible. That's part of the challenge and the fun IMHO.

    I don't think it's ever possible to do without fossil fuels. Cloudy period can always be darker and longer than you anticipate, and the wind may not be there to help you.

    If you design your system well, you may need to run your generator very rarely for very short times just to charge your batteries. But you always have piece of mind that if your batteries won't discharge too much because the generator will come up if needed.
  • toothytoothy Registered Users Posts: 29 ✭✭✭
    Re: Advice on adding wind to my off-grid system...

    I've been accused of reinventing the wheel on more than one occasion, but here goes.

    BB. mentioned a timer, why not leave the inverter on and use a timer to kick on your monitoring stuff for an hour twice per day?

    The Midnite Classic monitoring software is pretty easy to get along with also.

    Wade
  • tuckersnocattuckersnocat Registered Users Posts: 7
    Re: Advice on adding wind to my off-grid system...

    That's a good idea Wade. Ideally I want it up and running all the time but if I might give that a try while I'm accumulating power sources....

    The MidNite 4000W AC Clipper and Classic 250 have been ordered, I'll let y'all know how it works out!

    Russell

    toothy wrote: »
    I've been accused of reinventing the wheel on more than one occasion, but here goes.

    BB. mentioned a timer, why not leave the inverter on and use a timer to kick on your monitoring stuff for an hour twice per day?

    The Midnite Classic monitoring software is pretty easy to get along with also.

    Wade
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