Conext XW+ charging issue

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ZimInSeattle

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Aug 26, 2019
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Hi DIYers,

I have a message into Schneider about this issue, but have yet to receive a response. Wondering if anyone here might have an answer.

I have a 6848 XW+ connected to 14S7P Leaf module battery. I have Grid Support enabled and the Grid Support & Recharge voltage setting at 50 volts so that when battery gets down to that level it's supposed to go into charge mode. Inverter goes into AC Pass Through 0.5 volts above this setting and only a few watts is drawn from battery at this point thus it would take days for it to reach the 50 volt level. I have to manually change the Recharge setting to 50.5 volts to get charge cycle to start. On a seemingly related setting:

image_emwuxv.jpg


Grid Voltage Support is nowhere to be found in the manual. Not sure what this is supposed to do. I have tried several other tweaks involving load shed and sell to grid with no resolution. Any ideas on these issues would be appreciated. Thanks
 
I have had a few email conversations with Schneider support. It takes a couple days to get the first response. But once the email thread is started, they have always replied without 24 hours. A couple times it was less than 1 hour.


Do you have PV? AC or DC coupled?

Check PLS or peak load shaving.

For grid voltage support, search for the words in a different order. "Grid support volt" shows up on the manual for the XW pro.

On page 77, it also shows that you set grid support voltage above the recharge voltage. And notes that it will add 0.5 volts to your recharge setting for whatever reason...

Have you tried raising your grid support voltage?
 
400bird said:
I have had a few email conversations with Schneider support. It takes a couple days to get the first response. But once the email thread is started, they have always replied without 24 hours. A couple times it was less than 1 hour.


Do you have PV? AC or DC coupled?

Check PLS or peak load shaving.

For grid voltage support, search for the words in a different order. "Grid support volt" shows up on the manual for the XW pro.

On page 77, it also shows that you set grid support voltage above the recharge voltage. And notes that it will add 0.5 volts to your recharge setting for whatever reason...

Have you tried raising your grid support voltage?
Click to expand...
I'm AC coupled. 8KW into main panel and 2KW into critical load panel. I have tried the load shave settings and setting the above Grid Voltage Support to enable with no difference. I will try setting the Grid Support Voltage a little higher than the Recharge Voltage and see what happens. My manual only has 72 pages. :huh: Thanks for the help.
 
That's quite to PV system, nice!

Is your Conext between the main and critical loads panel? Using the internal transfer/disconnect switch?

I think you need the "owners guide" it is 148 pages long and goes into more detail about configuration and grid support settings.

This note (page 74) is of interest: "In grid support mode, the Conext XW+ should not draw a large amount
of current from the grid." That sounds to me like the symptom you have now. You want it to charge from the grid? It's not going to. Remember, the XW can't see your main panel or the PV connected to it, so that PV looks like the grid.

With the way I believe you have your system set up, I think all the XW is going to do is shoot for 0 kw passing through the unit. If the 2kw of PV in the critical load panel exceeds the demand from the critical loads panel it should charge. If it has battery capacity available, it will support the loads in your critical loads panel when load exceeds the PV capacity.
 
400bird said:
That's quite to PV system, nice!

Is your Conext between the main and critical loads panel? Using the internal transfer/disconnect switch?

I think you need the "owners guide" it is 148 pages long and goes into more detail about configuration and grid support settings.

This note (page 74) is of interest: "In grid support mode, the Conext XW+ should not draw a large amount
of current from the grid." That sounds to me like the symptom you have now. You want it to charge from the grid? It's not going to. Remember, the XW can't see your main panel or the PV connected to it, so that PV looks like the grid.

With the way I believe you have your system set up, I think all the XW is going to do is shoot for 0 kw passing through the unit. If the 2kw of PV in the critical load panel exceeds the demand from the critical loads panel it should charge. If it has battery capacity available, it will support the loads in your critical loads panel when load exceeds the PV capacity.
Click to expand...
Yes, @400bird XW+ is between main and critical load. I have the Rev. G hard copy of owners guide and it's broken out into chapters like 1-2, 1-3, etc. Probably 148 pages. However, the Rev. I of owners guide in PDF is only 72 pages. :-/

I'm charging from grid operating in grid support mode. Doesn't matter where the AC comes from when net metering taken into account. The main south PV array has Enphase M250 microinverters, 32 SW275 panels and is monitored via Enphase's Envoy. While the East/West array has the IQ7 inverters (incompatible with Envoy), 7 SW290 panels. This string AC coupled into critical load panel. IQ7's are better at handling frequency shift power curtailment in the event of an outage. But there's never been an outage here for more than a few seconds in the 7 years we've lived here. So my main purpose is mostly self consumption, running off of battery in the evening. No reason to put XW+ in Sell mode as all the excess PV already goes to grid anyway. I usually make $500+ a year from net metering plus no electric bill. If power outages were an issue, I do have a natural gas powered generator connected to AC2 input. Going to test that out today to see if XW+ likes the power quality. I monitor all this energy flow with Emporia Vue.

So I will see later this afternoon if setting Grid Support Volts at 50.1 volts while Recharge is at 50 volts gets the charge cycle going. Thanks again for your help.
 
So it turns out XW+ still goes from Grid Support to AC Pass Through 0.5 volts above Recharge Voltage of 50 volts with Grid Support volts set at 50.1. Also my generator test failed as XW+ did not qualify power after 10 minutes of running generator. Voltage and frequency within parameters set. So another issue to figure out down the road.
 
When it switches to AC pass through, which way is current flowing? Is the solar on the critical loads panel producing excess current over the load?

I hope Schneider gets back to you soon and can help you out!
 
400bird said:
When it switches to AC pass through, which way is current flowing? Is the solar on the critical loads panel producing excess current over the load?

I hope Schneider gets back to you soon and can help you out!
Click to expand...
Makes no difference on the current flow. This last cycle it happened at night. No AC from solar. I am changing out my ComBox to a Gateway and then Schneider should be able to log into system remotely to see what's going on. There has to be other people experiencing the same issue.
 
I finally got a response from Schneider:

Hello John,

I attach the XW+ users guide where you can see in page 3-26 all the grid support modes and in figure 3-6 how the different features can work.

You have to put Grid support volts always upper than recharge volts (at least 0,5VDC my recomendation test 1 or 2 VDC it has an 2VDC hysteresys as maximum) because this feature prioritize charging batteries from the MPPTs and just in case the AC grid drops or you limit the ACgrid input ( with AC Amps in AC settings) and the loads are bigger than this limit, the DC batterie value will drop until recharge volts. and just only in this case the batteries will do a complete charge cycle. This is because you prioritize PV panels instead of grid .

Depending on your battery capacity and you loads and pv panels but my recommendation is grid support around 50VDC and recharge volts no less than 48-49VDC. But you can play with depending on your needs.

On the web site you can also find some recommended configurations and their explanations too.

https://solar.schneider-electric.com/product/conext-xw-hybrid-inverter/

inside of technical publications : load shedding and enhanced support modes.

Regards
Ivn Domnguez | Schneider Electric | Solar Technical Support

And my response:

Thanks, Ivan, for your response. My solar is AC coupled. I have 8KW coupled into main panel and 2KW coupled into critical load panel so no MPPT's. I have tried playing around with all the Recharge Voltage and Grid Support settings, load shaving, disconnecting solar, etc. The problem is always the same. Inverter exits Grid Support 1/2 volt above Recharge Voltage setting and goes into AC Pass Through as if it's in Load Shave mode. There's no documentation that I can find about this behavior either in the manual or online FAQ's. If I leave it in AC Pass Through, battery charge remains about 1/2 volt above Recharge Voltage setting basically forever requiring me to manually start charge cycle. It appears there's no combination of settings that will allow inverter to stay in Grid Support mode until battery depleted down to Recharge Voltage setting. And there is no setting for limiting the AC input amps other than in Load Shave mode which is supposed to exit to AC Pass Through 1/2 volt above Recharge setting. For self-consumption on an AC coupled system, it would seem that there should be settings to enable grid support all the way down to Recharge voltage. Thanks.

The bottom line is, I think I'll have to wait for the Gateway to show up and then utilize the CAN bus port to have my Watchmon control when to charge battery.
 
Well, that response from Schneider was less helpful. Hopefully they respond quickly. With more info that applies to your actual set up, not DC coupled.

Once you switch to the gateway I believe you could add a RS485 energy meter at the main panel. The Conext (in grid support mode) should then work to keep this meter close to 0kw and charge when excess solar from the main arrays would otherwise go back to the grid.

The energy meter seems more desirable that just recharging from the grid whenever the battery runs low. You won't be paying for the juice to change the battery, the battery would charge from both arrays based on your entire production and energy use.
 
400bird said:
Well, that response from Schneider was less helpful. Hopefully they respond quickly. With more info that applies to your actual set up, not DC coupled.

Once you switch to the gateway I believe you could add a RS485 energy meter at the main panel. The Conext (in grid support mode) should then work to keep this meter close to 0kw and charge when excess solar from the main arrays would otherwise go back to the grid.

The energy meter seems more desirable that just recharging from the grid whenever the battery runs low. You won't be paying for the juice to change the battery, the battery would charge from both arrays based on your entire production and energy use.
Click to expand...
When you have net metering, the grid acts as a battery. The only drawback of charging at night is that XW+ in AC Pass thru mode during charge cycle so energy stored in Leaf battery not being used at that time to power loads. This is why I will have charge block for nighttime hours once recharge is automated. I'm essentially moving energy between one really large battery, the grid, and my Leaf battery bank and then using that stored energy at night. Right now solar is powering my whole house plus putting about 4KW to the grid. :) XW+ is just idling waiting for critical loads to exceed solar input and/or the sun to go down. In the end, it's a near zero sum game.
 
400bird said:
Were you able to get the gateway installed? Any help from Schneider?
Click to expand...
Yes, it finally showed up the other day. Was on back order with my supplier. ComBox for sale on Ebay. Haven't done anything other than get it installed. Still need to wire in the CAN bus to the Watchmon but I'm not in a hurry anyway. I'll let Batrium know they can use my setup for testing. Battery is perfectly balanced and I only have to do manual recharge every 2 or 3 days.

The technician from Schneider wasn't very helpful. He was saying Grid Support doesn't do anything without having Load Shave and/or Sell to Grid also enabled. Wrong! XW+ with Grid Support enabled supplies 90+% of the power to the panel. I copied & pasted the paragraph out of the manual to the tech. I also explained to him that Sell to Grid is irrelevant in an AC coupled system as all excess PV goes to grid anyway and load shave should not be used in AC coupled setup. Everything works perfectly except it doesn't deplete the battery down to the Recharge Voltage setting. It goes into AC Pass Through 1/2 volt above Recharge Voltage. This is supposedly to allow the MPPT controllers time to charge the battery from solar. Well, in AC coupled system, no MPPT controllers. All I want is when AC coupled enabled, the 1/2 volt offset is disabled. I told the tech I can't believe Schneider has not come across this issue elsewhere. The tech was telling me I could use the AUX output to disconnect the AC by relay blah, blah blah and I'm like that's ridiculous. I need to talk to their engineering. Anyway, Batrium will be integrated soon and I'll just have it initiate charge cycle when XW goes into AC Pass through. :D
 
Well, now I have to go back through all my research and see if I still want to use the Schneider XW Pro. It's basically the same thing as the plus, but is compliant with the California rule 21 and Hawaii Heck.

Maybe Barium will be quicker than I expect and build your integration (would work for me too). That would be perfect.
 
ZIM, Have you solved this problem yet? I have a 6848pro AC coupled with a solar edge inverter. I sure would like it to charge the batteries when the AC OUTPUT side is positive (greater than the load). I've changed every setting that can be changed and it just hangs out at .5V over recharge volts. I have tripped the AC1 breaker but the solar edge inverter outputs too much much power for the Conext which goes into curtail mode which shuts the Solar Edge shuts off with a high freq fault. Also, the power seems to get abnormally flaky with flickering lights and lots of chattering in the Conext. It sure seems like the Conext should be able to automatically charge the batteries to the bulk voltage setting when there is excess power on AC OUT.
 
I'm hopeful that Zim will get batrium in on it and batrium can force the Context to do what it should.

I also had an email exchange with Schneider support. Basically, AC coupling works only as an emergency back up. They suggest adding a relay and forcing the context "off-grid" to get it to act like it should, charge the battery when production exceeds demand.

My emails with Schneider:

Me:
My system is AC coupled with the existing PV inverter connected in the critical loads panel.

As load and solar output change throughout the day, will the Context XW Pro switch back and forth from inverting (battery power to support loads) to charging (when there is excess solar output) throughout the day?

It looks to me like the specs and set up options are centered around a DC coupled system and require the battery to reach the "recharge voltage" before the XW Pro will start charging the battery

Schneider:
First question: Do you really need grid support? i mean, do you need sell to the grid or load shaving? If not, the best option in AC coupled systems is disable grid support mode. And the system will do all you need.

Second: If you really need sell mode or load shaving(you should enable grid suppor to do that) and you only have AC coupling the only solution to achieve a proper operation is installing an external contactor in AC1, commanded with a relay with Aux port ( with low battery trigger) just to tell to the system there is AC grid present when this AC contactor is closed (triggering with low battery signal)

Me:
With grid support disabled, what will the XW do? Back up, in case of grid failure?

Schneider:
Sorry for the misunderstanding, just disabling the grid support and no more, yes you will have only back up in case of grid failure because the system always detect grid in AC1. The only way to prioritize PV energy with only AC coupling PV field is installing an external contactor in AC1 commanded with a relay with aux port (with low battery trigger) in this way , you only connect the AC1 in case of low battery trigger , it will work as a AGS for AC1 .
 
Thank you 400Bird. That is pretty much what I have been experiencing. I have an AC coupled Solar Edge 10K inverter putting out over 8K watts with a XW pro 6848. The 6848 can't handle the Juice the Solar Edge is putting out and it shuts off the Solar Edge with over freq fault. I'm confident I could be off grid with grid as backup/charging but I probably have to get a second XW pro to handle the power but I\m not too sure that will work the way I want it to either.
 
You might try disconnecting from the grid before the solar ramps up. If the context has time to frequency adjust it might do better. It don't think it will use all 8kw for charging, but it should be able to limit PV production by frequency shift. That just takes more time. If a large load cycles on/off (like the AC) the conext probably can't keep up with adjusting PV output quick enough.

Also, with 8kw of solar you're probably pushing the internal transfer relays to the max
 
clyleadams said:
ZIM, Have you solved this problem yet? I have a 6848pro AC coupled with a solar edge inverter. I sure would like it to charge the batteries when the AC OUTPUT side is positive (greater than the load). I've changed every setting that can be changed and it just hangs out at .5V over recharge volts. I have tripped the AC1 breaker but the solar edge inverter outputs too much much power for the Conext which goes into curtail mode which shuts the Solar Edge shuts off with a high freq fault. Also, the power seems to get abnormally flaky with flickering lights and lots of chattering in the Conext. It sure seems like the Conext should be able to automatically charge the batteries to the bulk voltage setting when there is excess power on AC OUT.
Click to expand...
No, clyleadams, I have not resolved the issue. I still need to wire in the Batrium. In my situation with net metering, grid acts as battery so all excess PV goes to grid. Doesnt matter where the AC for charging battery comes from. Ive just been manually bulk charging every few days. Im pretty sure Batrium will be easy to integrate as theyve already done the code for CAN bus from Watchmon to the Conext Bridge. Conext Bridge has been superseded by Conext Gateway which also has CAN bus interface. Are you grid tied & do you have net metering? So you have 8KW AC coupled into critical load panel? My understanding is you shouldnt have more than the 6.8KW output rating of the XW Pro coupled into the load panel. I have 2KW into load panel & 8KW into main panel. It doesnt really matter where the AC is coupled though except in the case of grid outage which never happens here.
 
ZimInSeattle said:
clyleadams said:
ZIM, Have you solved this problem yet? I have a 6848pro AC coupled with a solar edge inverter. I sure would like it to charge the batteries when the AC OUTPUT side is positive (greater than the load). I've changed every setting that can be changed and it just hangs out at .5V over recharge volts. I have tripped the AC1 breaker but the solar edge inverter outputs too much much power for the Conext which goes into curtail mode which shuts the Solar Edge shuts off with a high freq fault. Also, the power seems to get abnormally flaky with flickering lights and lots of chattering in the Conext. It sure seems like the Conext should be able to automatically charge the batteries to the bulk voltage setting when there is excess power on AC OUT.
Click to expand...
No, clyleadams, I have not resolved the issue. I still need to wire in the Batrium. In my situation with net metering, grid acts as battery so all excess PV goes to grid. Doesnt matter where the AC for charging battery comes from. Ive just been manually bulk charging every few days. Im pretty sure Batrium will be easy to integrate as theyve already done the code for CAN bus from Watchmon to the Conext Bridge. Conext Bridge has been superseded by Conext Gateway which also has CAN bus interface. Are you grid tied & do you have net metering? So you have 8KW AC coupled into critical load panel? My understanding is you shouldnt have more than the 6.8KW output rating of the XW Pro coupled into the load panel. I have 2KW into load panel & 8KW into main panel. It doesnt really matter where the AC is coupled though except in the case of grid outage which never happens here.
Click to expand...
Today my system started charging all on its own! I turned off all of the advanced features on the conext except grid support, put a charge block on until 8:30AM, and I set grid support volts and recharge volts at the same value.... 47.50 volts. apparently, we had a nice 120A battery draw at the perfect time and it lowered the battery volts below recharge volts long enough for a charge cycle to begin. If this works consistently, I will be completely satisfied with it operating in this manner. I will be able to use the battery at night and get a charge started after the battery is depleted in the AM.
 
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