In need of technicial advice

I am new to a company which we are designing a system we have not had very much practice with. This would be installing a 10kW Bergey Excel single phase 240VAC @ 60Hz grid-tie with battery back up on an SSL tower. The system will remain grid-tie with a battery backup only intended for emergency power outages lasting 24-48 hours, since power outages only happen maybe once a year. I was configuring to use the Xantrex XW6048 inverter C40 + display charge controller and DC250 DC disconnect. While using deep-cycle interstate batteries 48VDC @ an estimated 80Amp-Hours. We will also be using left over #2AWG which was left over in the shop.

If there is any knowledge from doing this kind of system the knowledge will be greatly appreciated.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: In need of technicial advice

    PC,

    Welcome to the forum. I am not familiar with the Bergey product--It looks like it is a wind turbine with a GT Inverter attached to it. So, pure AC grid. I would want to confirm what the system does when there is a wind storm and power outage (does the turbine furl and the GT inverter shunt/dump to a resistor load bank to keep the turbine from over-speeding?).

    What is your plan with the XW 6048 and C-40 charge controller?

    The XW appears to be too small to connect to the Bergey 10kW turbine in a "micro-grid" setup (XW hybrid inverter can make a local 120/240 VAC 60 Hz grid and work in tandem with the GT Inverter to support loads and even directly recharge the battery bank if there is excess wind power).

    Are you planning on solar power in the mix or just GT Wind? Will you have enough battery power to run the XW+loads for 24-48 hours without wind/solar/generator for backup power?

    At this point, this seems to be two different setups. A "standard" GT Connected wind turbine and a XW Hybrid inverter used as an off grid AC 120/240 VAC inverter. Battery bank would be recharged from the Grid Power? (if grid goes down, the wind turbine would not be able to recharge the battery bank in this setup). The XW 6048 is a hybrid inverter which is capable of both off grid operation and also as a Grid Tied system (solar/wind recharges battery bank, excess battery energy is fed to the grid in GT Mode).

    Note that I am not a big fan of small wind systems. There are few sites that have reliable wind--And many wind turbines have a relatively small "sweet spot" where they generate useful power (usually from around 12 mph to ~30-35 MPH).

    If you need backup power for more than a few days--Usually solar panels (or even gensets) are more useful for unplanned outages.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: In need of technicial advice
    BB. wrote: »
    Note that I am not a big fan of small wind systems. There are few sites that have reliable wind--And many wind turbines have a relatively small "sweet spot" where they generate useful power (usually from around 12 mph to ~30-35 MPH).

    If you need backup power for more than a few days--Usually solar panels (or even gensets) are more useful for unplanned outages.

    -Bill

    Totally agree with Bill on that one. Been there, done that, and ended up taking the turbine down and expanding solar. Just too bad I hadn't known enough to do that in the first place $$$$. But alas, I was taken in by all the sales hype over wind turbines, and had to learn the hard way. :cry:
  • program.coordinatorprogram.coordinator Registered Users Posts: 13
    Re: In need of technicial advice

    Bill-

    This is the problem we were trying to understand the bergey needs to supply the AC power and if the bergey is not meeting the requirements it takes from utility the battery bank will only be used in the instance of a black out and they should be charged by the begey.

    I am just trying to figure a way to use the powersinc II inverter that comes with the bergey or use a inverter that can support a grid-tie setup with battery backup

    Yes, the bergey excel 10kW does furl when the wind speed is critical and does dump the load.

    I have received a block diagram from xantrex that shows a system that takes out and uses the wind turbine to the DC Disconect then to the C40 charge controller which goes to a diversion load then the DC250 is also hooked to battery bank and the main to the inverter.

    I am just trying to incorporate the best plan to have the bergey power the AC when that is insufficinet the Utility takes over and the bergey charges the battery bank with the utility as a backup charging source for the battery bank and the battery bank be used only for an emergency.

    It would be idel to incorporate the PowerSinc II GT inverter that goes with the 10kW Bergey and incorporate another inverter and charge controller, but I have never had to do a wind system with battery backup.

    Anymore advice?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: In need of technicial advice

    Ask Bergey. It's their product, they should support it. Including technical assistance for the PowerSinc II GT.
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: In need of technicial advice

    PC,
    This is the problem we were trying to understand the bergey needs to supply the AC power and if the bergey is not meeting the requirements it takes from utility the battery bank will only be used in the instance of a black out and they should be charged by the bergey.

    Then, this setup is not what you want/need. The Grid Tied wind turbine is (in my humble opinion) designed by marketing to get in on the renewable/green energy band wagon for the solar energy credits/rebates.

    While we can argue the cost effectiveness / usefulness of wind generated electricity--In this case it is the "wrong" setup for your needs.

    Normally, what would be done is to setup a Battery Bank with an AC inverter (if you need AC power). Your inverter choices would be like a UPS (Grid power with transfer switch to inverter+battery power if mains fail) or even a Hybrid Inverter which combines Off Grid capability (i.e., AC backup power) and any excess power charging the battery bank can be fed back to the grid and "turn the meter backwards" (of course, this depends on your utility and billing options).

    Now--Charging the battery bank. Solar Power is pretty easy. You just connect the panels to a charge controller and the charge controller to the battery bank. When the battery bank is full, the charge controller "turns off" the power from the solar array. (and with hybrid Inverter, the inverter takes the "excess" power and feeds it back to the utility--the panels continue to "charge" the battery bank and the GT Inverter acts like a "shunt" controller to feed excess power back to the grid and get some money back in your utility account--and a bit of return on your "investment" for solar power).

    With wind, this get a bit more complex. Horizontal Axis Wind Turbines (HAWT) need something to limit their maximum RPM. Nominally, this is done by always having a load on the turbine--I.e., charging the battery bank/running the loads. And in high winds/electrical failures, you should have at least two methods to limit RPM--Furling, mechanical brakes, feathering blades, etc. are all options. Many turbines will self destruct if not controlled correctly.

    So, now you have this "unregulated" power source tied to your battery bank. If this is a "hybrid inverter" based system, any excess energy is fed back into the grid (shunt load). The Hybrid Inverter / Grid Connection / Battery Bank should be large enough to manage the expected peak power from the turbine (otherwise, the batteries can over charge/over heat/melt down/etc.

    Generally, with shunt controller/loads, you should have a backup controller too... You can use a C40 type controller to dump excess power to a load back (a bunch of resistors/heaters) to keep the wind turbine loaded and the battery bank "safe".

    There are other ways to connect wind turbines to a battery bank... Basically a MPPT type wind rated charge controller is another. MPPT controllers can "optimize" the generator source to battery bank (i.e., a 48 volt wind turbine may actually produce more power at 100 VDC, the MPPT controller takes the high voltage/low current and down converts (switching power supply) to low voltage/high current as required by the battery bank).

    Midnite solar make such a setup, with load bank and shunt controller, for wind turbines... An MPPT type wind charge controller can significantly increase the yearly kWH harvest from a wind turbine. Obviously, not cheap.
    I am just trying to figure a way to use the powersinc II inverter that comes with the bergey or use a inverter that can support a grid-tie setup with battery backup

    To use the Bergey/Powersinc II, at the very least, you would need a Hybrid Inverter capable of >10kW of rated input power. They are probably available (Outback, Schneider, others???). But that is larger than the range of equipment we usually answer here.
    Yes, the bergey excel 10kW does furl when the wind speed is critical and does dump the load.

    Wind turbines, in my humble opinion, need lots of maintenance and should have at least two backup systems (ideally automatic, especially if unattended--somebody cannot "brake" before a storm) to prevent damage (throwing blades, turbine/tower collapses, nacelle fires are not unknown).

    A 10 kW wind turbine is not small--And you should be working with engineers (civil, electrical/power) that have lots of experience installing/maintaining such systems (check references/verify power generation kWH/month from actual installs).
    I have received a block diagram from xantrex that shows a system that takes out and uses the wind turbine to the DC Disconnect then to the C40 charge controller which goes to a diversion load then the DC250 is also hooked to battery bank and the main to the inverter.

    Yes, that would work--You would need at least 5-6 of those C-40 diversion controllers+load to "manage" a 10kW wind turbine. I am sure there are larger dump controllers out there (again check references/designs--There are "400 Amp" diversion controllers that appear that they would melt down with ~100 amps of load current).
    I am just trying to incorporate the best plan to have the bergey power the AC when that is insufficient the Utility takes over and the bergey charges the battery bank with the utility as a backup charging source for the battery bank and the battery bank be used only for an emergency.

    Back to "knowing your loads"... If you are after 24-48 hour backup (or even up to a week)--Then an inverter+battery bank+optional backup generator (diesel, propane, etc.) is going to be a much better solution.

    If you do not go with "grid tied" (aka Hybrid Battery based AC inverter), for 364 days a year you are simply spinning a turbine into a dump load (or having solar panels collecting dust).

    Is this for a remote Cell/Communications site? The standard "in town" type cell sites I have seen are pretty large energy hogs (5kW * 24*7 power usage). To install a solar/wind RE backup power system that would keep a large cell site running for any length of time would require a huge installation and a very large battery bank).

    Solar, at least, you know will be there most days (except for bad weather). Wind tends to be more variable and expecting to have useful wind when there is an outage is a roll of the dice (yes, you may loose power during a wind storm--But many turbines shut down in >~40 MPH winds for safety--so they are not available either).

    In either case, I would assume you will still need a backup genset (either on site, or can get there before the battery bank is emptied) if you have a 99.999% reliability target for your power needs.
    It would be ideal to incorporate the PowerSinc II GT inverter that goes with the 10kW Bergey and incorporate another inverter and charge controller, but I have never had to do a wind system with battery backup.

    Anymore advice?

    Just to rethink your design/load requirements. I would start with battery+inverter system, backup genset, then look at how to keep the battery bank charged (solar/wind direct to battery bank).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: In need of technicial advice

    Regarding wind, here was a relatively popular wind turbine with lots of Mfg. support (SkyStream ~ 2kW turbine GT connected) monthly history (post #216):
    There was one Skystream owner (blog.keepturning.com website long since abandoned) (near Lake Erie?) during the good months, as I remember:

    JANES HOUSEHOLD SKYSTREAM kWh RECORD





    JAN

    FEB

    MAR

    APR

    MAY

    JUN

    JUL

    AUG

    SEP

    OCT

    NOV

    DEC

    Total



    2007

    n/a

    n/a

    n/a

    n/a

    n/a

    n/a

    n/a

    n/a

    n/a

    175

    225

    0*

    400



    2008

    98*

    292

    308
    246
    228
    153
    92
    84
    97
    164
    246
    472
    2,480


    2009

    265
    348
    244
    371
    182
    86
    90
    84
    250
    100
    194
    131*
    2,345


    2010

    101
    130
























    * December, 2007 - Skystream shut down from software problem with cold and would not restart.
    * January, 2008 - Skystream down until the 27th. Produce 98kWh in the 5 days remaining in the month.
    * December, 2009 - Skystream shut down several times and would not restart on it's own, production very low for wind speeds.
    * January, 2010 - Production very low for wind speeds.
    * February, 2010 - Production very low for wind speeds.

    Don't know if Bergey will be better or worse in performance--But I have seen very few sites that supply year over year verified/actual data for their wind sites. And even this one (a true wind supporter) appears to have abandoned the website (if not the install).


    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • program.coordinatorprogram.coordinator Registered Users Posts: 13
    Re: In need of technicial advice

    Bill,

    Thank you very much for the information. At the moment we have installed one turbine on site grid-tie using the bergey 10kW SSL tower with powersinc II Inverter. However the second turbine needs to support fans for a hog farm if power ever fails. So I am going to increas the battery bank to have a better atonomy.

    I am in contact with Xantrex and Outback, unfortunally Bergey does not want to give any suggestions

    Thanks,

    Grant
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: In need of technicial advice
    I am in contact with Xantrex and Outback, unfortunally Bergey does not want to give any suggestions

    That is a bad sign. :blush:

    Anyone want to risk designing an AC coupled wind turbine system?
    Normally the turbine would feed grid directly and any back-up power would be had through stand-alone PV/batteries, but it is theoretically possible to have the turbine back-feed a battery-based inverter to provide additional AC power and recharge batteries. The battery inverter would have to be a Xantrex XW, Magnum, or Sunny Island that could handle the turbine's power output and shift frequency to drop the turbine GT inverter as needed. Where the extra power would go then ... :confused: Not sure I'd trust furling alone.

    Otherwise you have the nightmare of trying to adapt an AC generating turbine to supply DC charging for batteries to run a large hybrid inverter. That is also not a welcome situation.
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: In need of technicial advice

    Grant,

    A genset will be much more cost effective over time than a wind or off-grid solar system to power your fans (for emergency use).

    You have the genset (capital costs, not too much), just setting except for weekly/bi-weekly check runs (not much fuel) then running for a few hours/days a year for actual outage.

    Off grid solar power, when used 9+ months of the year is around $1 to $2+ per kWH (including battery bank/equipment replacement every X or XX years).

    You can go hybrid, and from my back of the envelope costs go down to ~$0.45 per kWH (GT feeding back to utility most of the time)--But you may still need a backup genset anyway (do you have days/week or more of heavy clouds?).

    Another thing to worry about--Fans and other material moving devices (like water pumps) can be highly inefficient, or if well designed/using newer type motors/electronics, can be much more efficient--Reducing your power needs and costs--both grid and for emergency backup.

    In California, GT connected RE systems have pretty good billing options from our major utilities... For commercial operations, the costing does not usually work out as well (at best, many plans only reduce the bill by the avoided cost of power by the utility--usually only ~50% or so of the power bill).

    Adjustable air flow (cool nights/seasons/etc.) can help reduce power usage too (although, I am sure you know way more about farm equipment than I--Just trying to cover all the bases).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • program.coordinatorprogram.coordinator Registered Users Posts: 13
    Re: In need of technicial advice

    Bill,

    This system would be done if I could interpret solar and use the PV array to charge the battery bank or even use a generator but I have to install to a clints needs. So I do agree this systme could be a lot easier and a lot more cost effecient. I think I'm going to expand my battery bank go with the powersinc II inverter for the utility connection throw in a manal throw and connect to the AC load center with using the Xantrex XW6048 and a charge controller with the proper dump load I think this can be acomplished, but I still have to talk to Xantrex or possibly go with Outback since they are the only ones that offer this option other than Sunny-Boy but at that rate the price will be out of range.

    The other possible option was to run the powersince II inverter after the Diconnect with a manul throw for when the power goes out then connect to the meter, ac load center and utility grid and then hook up the VCS II controller also from the disconnect to turn the AC power from the turbine connect to an Outback mppt controller then to the battery bank, I should not have to worry about a dump load at that point because the mppt controller should take care of it the next step would to correctly size the battery bank. So it would be two seperate systems in one but not sure this is really possible it sounds possible but unsure if the utility would aprove of this design

    Let me know what you thank of this,

    thanks,

    Grant
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: In need of technicial advice

    Grant;

    From what I can tell the Powersinc II is a straight GT inverter meant for back-feeding only. It has no batteries. When the grid goes down it will produce nothing.
    The only way it can be utilized without grid power is to sync it to a battery-based inverter like the XW as I mentioned before. This presents its own set of problems.

    Sometimes it's best to tell a customer it can't be done the way they want to do it and walk away. The risk of trying to cobble something together is not insubstantial.
  • program.coordinatorprogram.coordinator Registered Users Posts: 13
    Re: In need of technicial advice

    Well I changed the idea of AC coupling and messing with the Bergey and just going to connect to the grid as intended. I will though be putting a system together hooked up to the utility,transfer switch, breaker box, AC disconect, critical load panel and an Outback 3648, along with a three day atonomy battery bank. It Will be close to a backup generator system but just using the batteries as backup when or if the utility cuts out.

    So I think this will work a lot better than trying to configure a piece of equipment that was not inted to be configured. Thanks for all the advice and knowledge if you have ever done this let me know what you think
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: In need of technicial advice

    I think that's a wise decision. Rather than look at the wind and batteries as a single system, I think it's better to evaluate them separately as a battery backup and a grid tied offset of electricity expenses, because in the case of a power outage you cannot depend on the wind generator producing enough power to keep your system running. Some will say, in fact, that you cannot depend on the wind generator for anything at all.
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