Xantrex 4024 + solar + wind + grid = ??

Hi!
I am now in the process of building a grid tied system that is planned to consist of ~1.5 kW solar panels and ~3 kW wind generator. This is also going to be tied up to a grid. However, I am planning to use the grid only when solar+wind is not enough.

I read quite a lot about Xantrex inverters and those seem to be what will solve most of my problems, however tehre are some questions that I could not find definitive answeres to:

1. Is there a way to configure a Xantrex inverter in such a way that it gives say a 1/3 of the current to charge batteries (if they need to be charged) and the rest flows to my home wiring? If there is an excess of solar+wind power the batteries get more. If wind+solar is not enough get the rest from the grid.

2. Xantrex has a solar charge controller but there seems to be no specialized wind equipment that is able to block blades etc. Does it mean that I need to plug wind generator to AC2 mains on the inverter?

3. Where do I plug the dump load?

Thanks a lot in advance,

Comments

  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: Xantrex 4024 + solar + wind + grid = ??

    Xantrex has Grid-Tie inverters, and battery power inverters.

    Solar charge controllers are an additional box they sell.

    Wind generators need their OWN controller, and need to have a dump load at least 1.5x the size of the generator, WIRED into the controller. They don't "plug in".

    Generally, if you have to tie your hat to your head, you have enough wind to make it worth while. And it won't be pleasant to live in such a windy area.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • vomusvomus Solar Expert Posts: 31
    Re: Xantrex 4024 + solar + wind + grid = ??
    mike90045 wrote: »
    Xantrex has Grid-Tie inverters, and battery power inverters.

    Solar charge controllers are an additional box they sell.

    Wind generators need their OWN controller, and need to have a dump load at least 1.5x the size of the generator, WIRED into the controller. They don't "plug in".

    Generally, if you have to tie your hat to your head, you have enough wind to make it worth while. And it won't be pleasant to live in such a windy area.

    By Xantrex Grid-Tie inverter you mean GT 2.8/3.8 models? Who would do the programming logic that I described? I thought that Xantrex XW becomes a "central" point of the system to which I have to plug MPTT solar controller.
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: Xantrex 4024 + solar + wind + grid = ??
    vomus wrote: »
    Hi!
    I am now in the process of building a grid tied system that is planned to consist of ~1.5 kW solar panels and ~3 kW wind generator. This is also going to be tied up to a grid. However, I am planning to use the grid only when solar+wind is not enough.
    Solar and Wind are highly specific to where you live... I assume you are near the Black Sea (Russia)?

    For the XW system, the Solar PV just charges the DC battery bank.

    The XW hybrid inverter has two main operational modes. Grid Tied (any energy in the battery bank over >~52 volts (after the batteries have been fully charged) is pushed back into the home wiring (and the utility grid turning your utility meter backwards--if legal and your utility supports "net metering").

    So in GT mode, your home AC wiring and the utility are your dump loads.

    If your utility does not support Net Meter / Grid Tied inverters, I believe there is a mode where the XW can send power to your home but near Zero Watts out to the Grid (XW is complex and I am no expert).

    The other mode is Off-Grid... Just the usual pure sine wave inverter supplying 230 VAC 50 Hz (or whatever is common in your region) power to your local appliances.

    The XW inverter does have several AC inputs... One intended to connect to the utility grid, the second for a backup AC genset (usually ~230 VAC).
    I read quite a lot about Xantrex inverters and those seem to be what will solve most of my problems, however there are some questions that I could not find definitive answers to:

    1. Is there a way to configure a Xantrex inverter in such a way that it gives say a 1/3 of the current to charge batteries (if they need to be charged) and the rest flows to my home wiring? If there is an excess of solar+wind power the batteries get more. If wind+solar is not enough get the rest from the grid.
    First question is "what mode". Grid Tied or Off Grid?

    Grid Tied, the system almost behaves like your car's electrical system. And the Grid is like a "giant/unlimited AC Battery Bank". Any extra Wind/Solar power is simply pumped into your home's wiring. And that energy is then used inside the home "first" and any excess is sent to the grid (turning your utility meter backwards).

    Off grid, a bit more complex. The Off-Grid inverter will supply whatever AC loads you give it... If the AC loads exceed the DC charging current, then the batteries will slowly discharge. If the AC loads are less than the DC charging power, then the batteries will be charged.

    In case of Solar PV arrays (solar cells), a charge controller can just reduce current flow, or even turn off current, from the solar panels to the battery bank (PWM or MPPT type charge controllers).

    With DC wind turbines, typically, you want to always have a load on them--to keep them from over-speeding in high winds (and no load).

    Normally what you would do is setup one (or one + backup) "Diversion/Shunt/Dump" controller on the battery bank. When the battery bank reaches ~59 volts, the dump controller "turns on" and dumps the energy to (typically) a simple resistance heater (some people use hot water tank heaters, or turn on a well pump, etc.).

    You could set something up that may turn on an AC load (XW Inverter output) and use it for optional loads (pumping water to holding pond, etc.).

    Remember, that this needs to be reliable and larger than your wind turbine output. If not, you will over charge the battery bank and can cause failure or even a fire.
    2. Xantrex has a solar charge controller but there seems to be no specialized wind equipment that is able to block blades etc. Does it mean that I need to plug wind generator to AC2 mains on the inverter?
    If the the turbine in 48 volt (or 24 volt) DC charging your battery bank, see above. The XW system has no specific control for wind turbines (that I am aware off).

    If the wind turbine is an AC Grid Type system... Then that would drive your AC house wiring instead. It is possible to drive the XW Inverter with a Grid Tied inverter and actually recharge the attached battery bank.

    The XW inverter (with new firmware) will change the frequency from 60Hz/50Hz to +1% or 2% which will cause the GT inverter (solar or wind) to shut down (for at least 5 minutes).

    For a Grid Tied Based Wind Turbine (120/230 VAC grid tied), I would expect the turbine to handle its own shutdown protocol.
    3. Where do I plug the dump load?

    I need more details on your planned wind/solar setup (DC, Grid Tied, Off-Grid with GT Wind Turbine, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: Xantrex 4024 + solar + wind + grid = ??
    vomus wrote: »
    By Xantrex Grid-Tie inverter you mean GT 2.8/3.8 models?
    Yes Those require 300-600VDC (high voltage) to run

    The XW line, is a special series, takes 24 or 48 VDC and inverts from that voltage.
    Batteries supply the voltage.
    Who would do the programming logic that I described? I thought that Xantrex XW becomes a "central" point of the system to which I have to plug MPTT solar controller.

    the programming is all done in the XW inverter, you set the Sell and shut off voltages in it, You need the System Control Panel ($) to do that .

    MPPT charge controllers can be of any brand. All they do is recharge the batteries, and the XW makes all the decisions based on battery voltage, if it's high enough to SELL or not.
    PV, wind, or hydro can all charge the battery, the inverter does not care.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • vomusvomus Solar Expert Posts: 31
    Re: Xantrex 4024 + solar + wind + grid = ??
    mike90045 wrote: »
    Yes Those require 300-600VDC (high voltage) to run

    The XW line, is a special series, takes 24 or 48 VDC and inverts from that voltage.
    Batteries supply the voltage.

    This means that in order to achieve this high voltage, I'd have to have quite a field of solar panels set in series, at least 15. So what you are saying basically is that I can either drive my home wiring from the Sun but I'd require a lot of panels or I have to do it all through batteries charging them from the Sun (I planned 8 panels) and inverting DC to AC through usual means. Is this correct?
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: Xantrex 4024 + solar + wind + grid = ??

    > inverting DC to AC through usual means

    But with a grid sync'd (Grid interactive/Tie) inverter
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: Xantrex 4024 + solar + wind + grid = ??

    You do have other options too... There are several companies (Enphase is one) that make "micro" GT inverters. Basically one inverter per ~200 watt solar panel.

    Mount one inverter to each solar panel, and run your 230 VAC circuit to the roof and connect to the output of each micro GT inverter (usually somewhere around a maximum of ~15 inverter per branch circuit).

    The Enphase inverters also use a small network computer that talks to the inverters and lets you download (some data) to your computer (and/or to the Enphase web server).

    Otherwise the micro inverters have pretty much the same operational characteristics as the larger central inverters.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vomusvomus Solar Expert Posts: 31
    Re: Xantrex 4024 + solar + wind + grid = ??
    BB. wrote: »
    Solar and Wind are highly specific to where you live... I assume you are near the Black Sea (Russia)?
    Yep. I can see Taganrog bay from my window. :-) Strictly speaking Black Sea is a little bit further south: it goes like this Taganrog bay -> Azov Sea -> Black Sea.

    For the XW system, the Solar PV just charges the DC battery bank.

    The XW hybrid inverter has two main operational modes. Grid Tied (any energy in the battery bank over >~52 volts (after the batteries have been fully charged) is pushed back into the home wiring (and the utility grid turning your utility meter backwards--if legal and your utility supports "net metering").

    So in GT mode, your home AC wiring and the utility are your dump loads.

    If your utility does not support Net Meter / Grid Tied inverters, I believe there is a mode where the XW can send power to your home but near Zero Watts out to the Grid (XW is complex and I am no expert).

    The other mode is Off-Grid... Just the usual pure sine wave inverter supplying 230 VAC 50 Hz (or whatever is common in your region) power to your local appliances.

    The XW inverter does have several AC inputs... One intended to connect to the utility grid, the second for a backup AC genset (usually ~230 VAC).

    First question is "what mode". Grid Tied or Off Grid?
    The mode I seem to need is not really a grid tied, it could be called "grid supported" (I have seen this term in this forum) where the grid basically takes in when alternative sources are not enough. The reason I am doing all this is because grid power could be unreliable at times especially during winds. Local power company tells me they have some regulation that makes them turn the grid off when wind speed hikes to around 10 m/s. They say it is because line wires hang in air and wind can shorten them.
    Off grid, a bit more complex. The Off-Grid inverter will supply whatever AC loads you give it... If the AC loads exceed the DC charging current, then the batteries will slowly discharge. If the AC loads are less than the DC charging power, then the batteries will be charged.
    From the post of mike90045 I see that driving home wiring from the Sun directly does not seem to be an option because Xantrex GT will require a high DC input which in turn will require a field of panels and I can accomodate only about 8 of them on my roof. The alternative is to simply charge batteries from solar panels and get AC from them.
    If the wind turbine is an AC Grid Type system... Then that would drive your AC house wiring instead. It is possible to drive the XW Inverter with a Grid Tied inverter and actually recharge the attached battery bank.

    It seems that only wind turbine can drive my home wiring directly because I wanted to get an AC system. From what I gather so far, I'd have to plug it (through its own controller) to a second pair of mains on the Xantrex XW and program it to be a priority in comparison to the grid.
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: Xantrex 4024 + solar + wind + grid = ??

    Vomus,

    Are Grid Tie Solar PV inverters illegal for use with your utility?

    Many people have asked for a "Grid Support" mode and I have not seen anybody really claim that they have it.

    The Xantrex XW, I think, is close to that but I am not sure it would be legal to connect to a "no GT" utility. You probably would have to contact Schneider (aka Xantrex) to find out the details and talk with your utility.

    The other way to do this would be to have a straight forward Off-Grid inverter with the battery bank powered by solar+wind power. And run a separate AC battery charger that can recharge from the AC line if the battery state of charge gets too low (~75 to 50% state of charge recommended).

    An alternative would be to use an AC Transfer switch that switches you from Off-Grid inverter (with low battery bank) back to the Main Grid power. This would be more efficient (no AC->DC->AC conversion--that will save upwards of 30 to 40% conversion losses. And if the AC mains fail, you can fail over back to the off-grid inverter.

    If you have critical loads (such as a computer)--I would use a small UPS to power it... All of the transfer switches probably are not quick enough to keep a standard desk top computer (DVR, etc.) from rebooting.

    One of the problems with doing this type of "grid support" system is that you do cycle the batteries quite a bit which can shorten their life over pure standby usage--And this adds your over all cost of power (replacing batteries every 5-10 years or so).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: Xantrex 4024 + solar + wind + grid = ??

    You can use an XW inverter, and just turn SELL off, can't you? If the grid goes down, it then acts like a UPS for the circuits wired into it, and when grid returns, it recharges the batteries.

    And you can add on any other battery chargers you like - generators, wind, solar, hydro, the XW only cares there is voltage in the battery for it to run.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • vomusvomus Solar Expert Posts: 31
    Re: Xantrex 4024 + solar + wind + grid = ??
    BB. wrote: »
    Vomus,

    Are Grid Tie Solar PV inverters illegal for use with your utility?
    At this point the law does not say it is either legal or illegal. :-) That's one of the reason I wanted this kind of "grid support" system: take what I want from sun+wind and the rest, if needed, from the grid. If there is an excess in sun+wind I'd charge the battery and dump the rest (another question where to).
    Many people have asked for a "Grid Support" mode and I have not seen anybody really claim that they have it.

    The Xantrex XW, I think, is close to that but I am not sure it would be legal to connect to a "no GT" utility. You probably would have to contact Schneider (aka Xantrex) to find out the details and talk with your utility.

    The other way to do this would be to have a straight forward Off-Grid inverter with the battery bank powered by solar+wind power. And run a separate AC battery charger that can recharge from the AC line if the battery state of charge gets too low (~75 to 50% state of charge recommended).
    You mean the same battery?
    An alternative would be to use an AC Transfer switch that switches you from Off-Grid inverter (with low battery bank) back to the Main Grid power. This would be more efficient (no AC->DC->AC conversion--that will save upwards of 30 to 40% conversion losses. And if the AC mains fail, you can fail over back to the off-grid inverter.

    If you have critical loads (such as a computer)--I would use a small UPS to power it... All of the transfer switches probably are not quick enough to keep a standard desk top computer (DVR, etc.) from rebooting.

    One could use supercapacitors for that. They could flatten out shortages when switching from one line to another but they are not prone to cycling exhaustion as regular batteries.
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: Xantrex 4024 + solar + wind + grid = ??
    vomus wrote: »
    At this point the law does not say it is either legal or illegal. :-) That's one of the reason I wanted this kind of "grid support" system: take what I want from sun+wind and the rest, if needed, from the grid. If there is an excess in sun+wind I'd charge the battery and dump the rest (another question where to).
    For solar PV (panels), you do not need to dump excess power anywhere... It is OK to turn off current from panels without any damage (that is what the solar charge controller does).

    For wind, generally you need a dump load (larger than the wind turbine output for reliability) to absorb excess energy. You need to look at the particular Wind Turbine for their installation requirements.
    You mean the same battery?
    Yes, use your Grid Power to recharge the battery if sun/wind is not enough and you have, for example, AM power and PM outages.
    One could use supercapacitors for that. They could flatten out shortages when switching from one line to another but they are not prone to cycling exhaustion as regular batteries.
    Believe me, super capacitors are not going to be the answer for off-grid power. At least for the next 10 years (guess).

    When you look at the specifications in detail, you find that they will not even last as long as a set of cheap deep cycle golf cart batteries. SupCaps are typically rated for around 2 years of power on life. At this point, they only make sense in very limited industrial situations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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