Triple Xantrex 6048 with Generac 22 kW generator, Grid connected

Folks

We are having devil of a problem with configuring our system. Our unit is a 9 kilowatt solar panel system on a 36 ft long goosneck trailer with 2500 amp hours (120 kilowatt hours at 48v), intended to run an entire Ranger station and associated housing at Yellowstone National park.

We have a 22kW generac liquid cooled generator and we are having a hell of a time figuring out whether or not the Generac transfer switch brings any benefit. With the demand curve of our system it is unlikely that it will ever discharge the batteries but we have to prepare for Murphy.

When the Grid goes down or does not exist, we have the Xantrex triple 6048 as the preferred output. The Generac is the backup to the Xantrex. The Generac unit is not compatible with the Xantrex auto gen start so from our literature search it seems that if the Xantrex dies from battery discharge that the generator then picks up the load after about a 20 second delay. The generator then powers the Xantrex battery recharge and also services the Grid (AC1).

Question

What happens when the Generator comes on and starts charging the batteries through the Xantrex? (our system configuration also includes three Outback MX-80 MPPT controllers at 80 amps each though the solar array is only capable of 184 amps of charge, don't ask it is a government thing).

We have a Generac transfer switch but it seems that if some of the other forum answers here are correct, that we don't really need that item as the Xantrex handles the load sharing until such time as the batteries recharge. What then happens to the Genset? How does it "know" to shut itself back down.

Thanks

Comments

  • Wildwood NJ ToddWildwood NJ Todd Registered Users Posts: 5
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected

    It seems like the only thing you would need the transfer switch for is if you had grid available, the ATS would allow you to switch from grid charging (if available) to generator charging.

    It seems like your recharge volts might be set too low to initiate charging. I've never set up an inverter for generator support, but the wiring diagrams from xantrex certainly don't show a transfer switch. From the installation manual it seems like its just a set of "dry contacts" that tells the generator to turn on. It does say you have to have a XW system control panel to configure generator start - do you have an XW control panel? The Xantrex xw6048 installation guide specifically lists Generac as one of the compatible manufacturers.
  • RCinFLARCinFLA Solar Expert Posts: 1,353 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected

    Depends on how your system is wired and breaker distribution.

    You probably don't need the generator transfer switch. You can run the generator into the XW's AC2in with the normal grid line on their AC1in.

    Since you don't have gen auto start you will have to start and stop the generator manually.

    When grid goes down the XW's will automatically, and within a cycle or two, pick up the ACout loads. I assume you have a breaker panel connected to ACout of XW inverters. You may have an original main grid breaker box. There would be a 60 amp breaker for each XW inverter going to AC1in. Most of the circuits should have been moved to breaker box on ACout from XW's. There should be an inverter bypass arrangement to take grid directly around inverters to aux breaker box. This is for inverter servicing. If you have the XW load center box accessory it has this inverter bypass switch breakers included in it.

    If grid is down and you are then running on batteries, you can start generator and the XW's will gradually align their ACout to be in phase with generator and close XW's internal switch to connect to generator. Again this is transparent to ACout without any power interruption. At this point the generator will be feeding the ACout loads and XW inverters will start recharging the batteries at the same time. There are settings on XW to avoid overloading generator and charging will automatically back down if more of the available generator power is needed for ACout loads.

    You may decide to keep running generator to supply loads through XW passthrough or shut generator down when batteries are charged up. If you shut down generator, XW inverter will pickup ACout load with no power interruption.

    If grid shows back up the XW will release from generator if it is running and realign the ACout to grid phase and close its internal relay to power from grid again. You can set priority control on XW to determine if generator or grid has priority to supply feed. Default is grid on ACin1 with priority to it.

    The generator autostart usually only works well with a diesel or propane based generator. Most generators can be modified for autostart capability. Gasoline generators have the issue of normally requiring choking which most autostart systems don't accommodate. The liquid cooled Generac 22kW does have autostart function. You may to modify the control wiring to take control away from its grid power loss detector and give control to XW generator module. You need to add the XW autostart module to control generator. XW has a periodic generator exercise feature. You can set XW to activate generator based on battery needing charging and/or based on heavy AC loads. You can even set a 'quite time' period during the night to prevent generator from startup up in the middle of the night, disturbing your sleep. It will automatically shut off generator when grid shows back up, batteries are fully charged, or AC loads lighten up.
  • DenniswingoDenniswingo Registered Users Posts: 16
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    It seems like the only thing you would need the transfer switch for is if you had grid available, the ATS would allow you to switch from grid charging (if available) to generator charging.

    It seems like your recharge volts might be set too low to initiate charging. I've never set up an inverter for generator support, but the wiring diagrams from xantrex certainly don't show a transfer switch. From the installation manual it seems like its just a set of "dry contacts" that tells the generator to turn on. It does say you have to have a XW system control panel to configure generator start - do you have an XW control panel? The Xantrex xw6048 installation guide specifically lists Generac as one of the compatible manufacturers.

    There is "grid" available, but there will be times when it is not and the system, which is on a trailer, is moved around (www.greentrailenergy.com for our wind and solar trailer, the solar is a new one coming out this week).

    So we want the Xantrex as the preferred source with our generator as the backup to the xantrex and the solar arrays. The solar arrays charge the batteries through the outbacks normally and the Xantrex charges them through the on board Generac generator. We have 6 kW Generacs with our existing systems and they work fine but supposedly there is some quirk that keeps the Xantrex autogenstart from working with this particular generator line.

    The Xantrex docs do show a Diversion load controller, which is functionally part of the transfer switch that is an option from Generac that we currently have installed and are preparing to power up for the first time. However, that diversion load controller is mostly for load shedding for priority loads (air conditioners) through this functionally as part of the transfer switch.

    We use the Auto gen start on our smaller systems and the Generac does have a CAN bus, but at this point we are slightly confused and need to understand how the Xantrex actually works with a local genset in AC2 and grid on AC1.

    Thanks for your reply!
  • DenniswingoDenniswingo Registered Users Posts: 16
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    RCinFLA wrote: »
    Depends on how your system is wired and breaker distribution.

    You probably don't need the generator transfer switch. You can run the generator into the XW's AC2in with the normal grid line on their AC1in.

    Since you don't have gen auto start you will have to start and stop the generator manually.

    When grid goes down the XW's will automatically, and within a cycle or two, pick up the ACout loads. I assume you have a breaker panel connected to ACout of XW inverters. You may have an original main grid breaker box. There would be a 60 amp breaker for each XW inverter going to AC1in. Most of the circuits should have been moved to breaker box on ACout from XW's. There should be an inverter bypass arrangement to take grid directly around inverters to aux breaker box. This is for inverter servicing. If you have the XW load center box accessory it has this inverter bypass switch breakers included in it.

    If grid is down and you are then running on batteries, you can start generator and the XW's will gradually align their ACout to be in phase with generator and close XW's internal switch to connect to generator. Again this is transparent to ACout without any power interruption. At this point the generator will be feeding the ACout loads and XW inverters will start recharging the batteries at the same time. There are settings on XW to avoid overloading generator and charging will automatically back down if more of the available generator power is needed for ACout loads.

    You may decide to keep running generator to supply loads through XW passthrough or shut generator down when batteries are charged up. If you shut down generator, XW inverter will pickup ACout load with no power interruption.

    If grid shows back up the XW will release from generator if it is running and realign the ACout to grid phase and close its internal relay to power from grid again. You can set priority control on XW to determine if generator or grid has priority to supply feed. Default is grid on ACin1 with priority to it.

    The generator autostart usually only works well with a diesel or propane based generator. Most generators can be modified for autostart capability. Gasoline generators have the issue of normally requiring choking which most autostart systems don't accommodate. The liquid cooled Generac 22kW does have autostart function. You may to modify the control wiring to take control away from its grid power loss detector and give control to XW generator module. You need to add the XW autostart module to control generator. XW has a periodic generator exercise feature. You can set XW to activate generator based on battery needing charging and/or based on heavy AC loads. You can even set a 'quite time' period during the night to prevent generator from startup up in the middle of the night, disturbing your sleep. It will automatically shut off generator when grid shows back up, batteries are fully charged, or AC loads lighten up.

    Thanks

    We do have an Xantrex system controller, which is needed for Xantrex configuration anyway, but at this time we do not have the autostart module, which we were told is incompatible with the 22 kW Generac. We would love to be able to use it as it is our preferred solution with our smaller generators and the single Xw6048 that are not grid connected.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected

    Please post the Generac model number, usually a 4-digit number, possibly followed by a dash with one more digit. The XW autostart needs a "running" signal as an input from the genset, and outputs 2 or 3 wire for the genset start if I remember right. Hooking up the wires to start the genset should be easy - usually just a matter of opening the panel and finding the wires running to the on/off/auto rocker switch. Cut the wire on the "on" side, connect it to the autostart, set autostart to latch on to run. Leave the rocker switch to "on". What might be the tricky part with your genset is finding the correct line to use as a "running" signal. Once I have the model number I'll try to find the service manual so I can study the schematics.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • RCinFLARCinFLA Solar Expert Posts: 1,353 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    Thanks

    We do have an Xantrex system controller, which is needed for Xantrex configuration anyway, but at this time we do not have the autostart module, which we were told is incompatible with the 22 kW Generac. We would love to be able to use it as it is our preferred solution with our smaller generators and the single Xw6048 that are not grid connected.

    There may be a relatively easy way to fake out the Generac autostart system without having to get in and bypass the Generac control module.

    You connect the XW AC output through a relay to the normal grid input on the Generac transfer switch (connections N1, N2 on transfer switch). The XW generator start module will control the DPDT relay to remove AC power supplied by XW inverter ACout to the Generac transfer switch grid input when the XW wants the generator to startup.

    No other connections is made to the Generac transfer switch. (E1, E2, and T1, T2 will have no connections) Instead, the main Generac power breaker output (E1, E2 on Generac main breaker) is connected to XW inverter AC2in input.

    I am guessing the transfer switch solenoid coils on the transfer switch are powered by their respective AC source. Grid connect solenoid is powered from grid side input so DPDT relay would have to carry the current of a momentary solenoid coil current, maybe 10 amps. There would be no need for the generator side solenoid to operate so you don't need generator output power to be routed over to transfer switch.


    The other possiblity is to use the Generac manual/test start mode switch. A relay would have to be wired in to act as the manual start switch function. The relay is controlled by XW generator start module.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    RCinFLA wrote: »
    You connect the XW AC output through a relay to the normal grid input on the Generac transfer switch (connections N1, N2 on transfer switch). The XW generator start module will control the DPDT relay to remove AC power supplied by XW inverter ACout to the Generac transfer switch grid input when the XW wants the generator to startup.

    No need to use the transfer switch at all, you can feed the utility sensor wires directly into the genset.
    I am guessing the transfer switch solenoid coils on the transfer switch are powered by their respective AC source.

    This is true. I had to rewire the utility-side solenoid in my transfer switch so I could remotely control my switch and genset during an outage. Now both solenoids get their supply from the genset.
    The other possiblity is to use the Generac manual/test start mode switch. A relay would have to be wired in to act as the manual start switch function. The relay is controlled by XW generator start module.

    This is what I was describing in my last post, which is what I did for remote control. However, his genset may have another option, the high-temp sensor. While the oil pressure sensor causes the system to shut down permanently until a manual reset, the control board will restart the system once the temperature sensor has reset. So, you can cut one of the wires running to the temp sensor and add in the autostart system in series. No need for an extra relay, the autostart system is just a bunch of relays itself. Leave the genset on "on" and it will just think it is an overtemp condition until the autostart latches closed.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • RCinFLARCinFLA Solar Expert Posts: 1,353 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    techntrek wrote: »
    No need to use the transfer switch at all, you can feed the utility sensor wires directly into the genset.

    The reason for this is the generator's grid voltage sensor will be connected to this point. The purpose is the make the generator controller think grid power has been lost and returned to get it to start and stop the generator.
    techntrek wrote: »
    However, his genset may have another option, the high-temp sensor. No need for an extra relay, the autostart system is just a bunch of relays itself. Leave the genset on "on" and it will just think it is an overtemp condition until the autostart latches closed.
    I would not mess with this. Definately could be used to void warranty.

    In my opinion, wiring a control relay into the manual start/test switch is the best solution. But it requires modifying the control panel switch which might be used as a warranty issue.

    Faking the generator to start and stop via the grid line input only accesses the area and connections that are normally accessed for regular installation. You must disconnect the wires from the generator internal main breaker to the transfer switch so it does not feed into the XW ACout connected to grid line input. The only reason I brought up the solenoid is because the one that flips transfer switch back to grid side will still be powered and the contacts on the added relay controlled by XW gen start module will have to carry its surge current when grid input is repowered to shut down the generator. You probably could disconnect the wires to this solenoid to avoid its activity.

    There might even be a trickle charger for the starter battery tied on the grid input which will be powered by the XWout when generator was off.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected
    RCinFLA wrote: »
    The reason for this is the generator's grid voltage sensor will be connected to this point. The purpose is the make the generator controller think grid power has been lost and returned to get it to start and stop the generator.

    Exactly, we are talking about the same thing. But you want to leave the transfer switch in place, only using it as a connection point for the N1 N2 utility sense lines. So take the transfer switch out the picture.
    In my opinion, wiring a control relay into the manual start/test switch is the best solution. But it requires modifying the control panel switch which might be used as a warranty issue.

    Yes, modifying the wiring either behind the control switch or the temperature sensor could lead to warranty issues. But doing the first option requires opening up the control panel, the second option does not. So it is easier and ultimately achieves an identical result. It is also easier to modify back later if warranty will be called into question or if the unit will be sold. Personally, I opened up my control panel to extend the on/off switch, I was just giving an easier option to him.
    There might even be a trickle charger for the starter battery tied on the grid input which will be powered by the XWout when generator was off.

    True, usually N1 and N2 are attached to a transformer which in turn powers a trickle charger, but so many Generacs have crappy trickle chargers it would be better to ditch it and get a good aftermarket charger (many on a Generac forum I visit have done this).
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • DenniswingoDenniswingo Registered Users Posts: 16
    Re: Triple Xantrex 6048 with Generac 22 kW generator, Grid connected

    Guys, I just want to say thanks for your help in this.

    We still had a bugaboo with the third inverter but so far the system is working ok. Lots of interesting things they don't tell you about on that inverter!

    Here is a picture of the system before we shipped it to Yellowstone.

    Also, as a post facto, we are not using the Generac transfer switch, the Park bought the Xantrex AGS module and are not worrying about the Generac warranty.

    It works fine.
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