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Conext XW+ charging issue
#11
(07-12-2020, 03:56 PM)400bird Wrote: 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.
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. Smile 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.
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#12
Were you able to get the gateway installed? Any help from Schneider?
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#13
(07-24-2020, 11:40 PM)400bird Wrote: Were you able to get the gateway installed? Any help from Schneider?
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. Big Grin
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#14
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.
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#15
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.
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#16
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 .
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#17
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.
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#18
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
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#19
(Yesterday, 03:26 PM)clyleadams Wrote: 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.
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. Doesn’t matter where the AC for charging battery comes from. I’ve just been manually bulk charging every few days. I’m pretty sure Batrium will be easy to integrate as they’ve 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 shouldn’t 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 doesn’t really matter where the AC is coupled though except in the case of grid outage which never happens here.
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