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Schneider XWPro Primary/Secondary Pass-through

FullMoonSolar

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Joined
May 22, 2022
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13
Hello All,

We have helped friends install several XWPro systems in the past but this is the first dual (Primary/Secondary) system that we have operating.

The system is wired according to the installation manuals and AC and DC wiring has been checked several times. The supply wire is larger than the recommended (2awg thhn/thwn vs 6awg). The system is setup as a residential backup power source in a hurricane zone. It is a 240v split phase AC system with a 48v LFP Battery bank with Schneider BMS. There is no MPPT.

The good:
Both inverters work as advertised when in stand-alone or Operating/Standby modes.... AC passthrough, DC Charging, and Backup. There isn't any issue with any of these regardless of which Inverter/Charger is in Operating and which is in Standby.

The bad:
The issue only occurs when we enable Operating/Operating mode. As you may know, there is a 9 second delay after the 2nd unit Operating mode is Enabled. The instant the relays pull in on the switched Inverter/Charger, the line voltage separates by 8 to 12 volts. The XWPro dual system switches to Invert mode almost immediately and begins the qualification check. It qualifies AC as expected and switches back to AC-passthrough where it immediately detects the line voltage split again - then back to DC/Qualification/Transfer to Passthrough. The cycle continues.

Both Inverter/Chargers are set, and confirmed, to be Grid Code IEEE-1547-2003. The local power company requires the same.

We have talked to Schneider Tech support and Schneider Engineering but we don't have any recommendations. We have documented many voltage measurements in all states and taken video of the Insite Home screens but they seem not to be of any help to identify the cause.

As a result, we have been operating in Operating/Standby mode for the past 6 months. We alternate Inverter 1/2 in Operating mode each month.

We have no idea what to check next. We think our options are to take the system out and install something else, or setup a second independent backup load panel.

Does anyone have experience with Schneider dual XWPros? Any ideas?

We will track down any recommendation. Thank you for your support.
 
Couple of ideas - things to check:

- Are the "AC SYNC" connections on each XW-Pro cabled together.
(Page 17 XW-Pro multi unit design guide, 990-91373C Sept 2022)

- Was the calibration procedure performed?
(Page 64)

 
I have dual XW Pro running off grid
What firmware are you running?
In the Schneider Commissioning guide for XW pro it has some steps that need to be followed. Did you follow the Commissioning guide?
If you have a insight device you can calibrate the voltage output without the configuration tool.
 
You'd be getting an error if the sync cable wasn't installed when they're in Primary/Secondary, so I think that's probably okay.

Are you using a PDP? Both inverters need to be connected together through breakers on both the AC1 input sides, and through breakers on the Load sides. This can be a challenge to accomplish correctly without a PDP so I am curious what you've got here.

The calibration needs to be done between them as pvdude said. You no longer need the commissioning tool for this, that has been deprecated and is possible to do in Insight v1.18 and running XW Pro v2.04.00 build 29.

It is under "AC Advanced Settings" in the XW Configuration/Advanced page.
The password is XWproGridCodes and is case-sensitive.

Refer to page 26 of the attached Guide under the section "Commissioning (Single/Split-Phase without BCS or External Contactor)" and follow those steps to synchronize the voltage of the two inverters. You'll need a good digital multimeter to perform this procedure.
(For reference, my Primary XW Pro is 32900 and the Secondary is 32888)

After that's done, you may fin it necessary to offset the voltage values of several parameters in the configuration for each inverter according to the slight variations all units have between each other. Particularly picky here is Grid Support Voltage, which if imbalanced will always cause one inverter to be favored over the other. You can tell what that variance is by looking at the Status panel in Insight, and evaluate your settings by watching the load kW LEDs on the XWs to see how they're sharing the work.
 

Attachments

Hello All,

We have helped friends install several XWPro systems in the past but this is the first dual (Primary/Secondary) system that we have operating.

The system is wired according to the installation manuals and AC and DC wiring has been checked several times. The supply wire is larger than the recommended (2awg thhn/thwn vs 6awg). The system is setup as a residential backup power source in a hurricane zone. It is a 240v split phase AC system with a 48v LFP Battery bank with Schneider BMS. There is no MPPT.

The good:
Both inverters work as advertised when in stand-alone or Operating/Standby modes.... AC passthrough, DC Charging, and Backup. There isn't any issue with any of these regardless of which Inverter/Charger is in Operating and which is in Standby.

The bad:
The issue only occurs when we enable Operating/Operating mode. As you may know, there is a 9 second delay after the 2nd unit Operating mode is Enabled. The instant the relays pull in on the switched Inverter/Charger, the line voltage separates by 8 to 12 volts. The XWPro dual system switches to Invert mode almost immediately and begins the qualification check. It qualifies AC as expected and switches back to AC-passthrough where it immediately detects the line voltage split again - then back to DC/Qualification/Transfer to Passthrough. The cycle continues.

Both Inverter/Chargers are set, and confirmed, to be Grid Code IEEE-1547-2003. The local power company requires the same.

We have talked to Schneider Tech support and Schneider Engineering but we don't have any recommendations. We have documented many voltage measurements in all states and taken video of the Insite Home screens but they seem not to be of any help to identify the cause.

As a result, we have been operating in Operating/Standby mode for the past 6 months. We alternate Inverter 1/2 in Operating mode each month.

We have no idea what to check next. We think our options are to take the system out and install something else, or setup a second independent backup load panel.

Does anyone have experience with Schneider dual XWPros? Any ideas?

We will track down any recommendation. Thank you for your support.
See signature below.
With grid tied dual XWpros each of the 60 amps relays will not switch at the same time. If you can’t guarantee that loads will always be below 60 amps then you really should be using the BCS200.

I am full house backup on a 200 amp service. Getting the 2 XW pros into Master/Slave was the easiest part.

NB. Make sure the Device name for each XWPro is different. Bus ID and Device ID are documented. The unique naming is not documented but is required.
 
Wow.... thanks for the great suggestions. we think we can answer most but maybe not all of the questions. First the easy items.

Yes - we are using a PDP. I am attaching 2 pics so that perhaps someone can identify a mistake somewhere.

As James Bertok mentioned, we should be seeing a fault code if the sync cables were not installed. Each of the XW came with their own cable while only one is required with a 2 unit setup. As you probably know, there are two sync ports on each inverter/charger although only one on each is required for a 2 unit setup. We also confirmed with tech support that no terminator is required in the empty port. In all we have tried multiple cables with the same results.

The calibration procedure was followed as Mr. Bertok pointed out. That actually went exactly as described in the manual. We reviewed the results with Tech Support and our guy from Schneider agreed it was set appropriately.

Gttnsun asked if we followed the commissioning guide... yes - forty seven times. Every manual and procedure was followed as we understood them. This is a grid-tie rather than off-grid system. Off-grid functionality works fine. transferring from AC to DC and back work fine... with either single unit.

GRMRC mentioned the 60A relays. The issue we have occurs even with a 400w or 500w load as well as a 1200w or 1400w load. Not even close to 60A anywhere. Each single inverter works great alone.

The breaker arrangement in the PDP (Bypass, Incoming, Output) has been double checked but that deserves another go. If in fact we did something wrong with one of those, or we don't have them torqued properly, maybe there is something there. I think it is a remote, but reasonable overlook.

Thank you again for your replies. We are about out of ideas, as is Tech support, and Engineering.
 

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I just saw this in another thread, maybe it will help
I figured I would share the reason my XW6048 was deemed defective in case someone else has the same issue. It only took the technician about 2 minutes to diagnose the problem making me feel like it might be a common issue. The insight home read AC1 128.9 volts and 126.7 volts causing the XW6848 to go into Passthrough mode. He told me to put a multimeter on the AC1 inputs (grid) and they read 121.8 volts and 121.5 volts. So he said the XW6848 was reading the voltage incorrectly. So I asked him if he could adjust the reading and he said no, it would require a replacement. He said any voltage reading above 125 volts will cause the XW6848 to go into passthrough mode.
 
And that measurement was on the AC1Grid terminals (3 middle terminals). He said the voltage cannot be adjusted on the grid in.
 
Looking at the photos, I see your Neutrals are on the AC1/Grid input. I'm not sure if this raises an issue, but the documentation specifies to connect the Neutral to the Load terminal block on the left.
It's hard to tell in the second photo - are you using the terminal block at the top of the PDP for a Neutral Bus? I am looking for Neutrals in the PDP and not seeing them.
 
Would not hurt to reset your InsightLocal (InsightHome)to factory settings, and re-enter settings.
 

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