Conext XW Modbus registers to control sell to grid/charge from grid

[Consumerbot3418]

I'm trying to adapt to the Schneider Conext XW Pro 6848, coming from Victron gear. I was used to setting a single modbus register with a positive or negative number to indicate the targeted power to be drawn from or backfed into AC1. It seems to be a whole different paradigm with Schneider. I'm trying to work out how to get the XW to charge or discharge the battery by a specific amount. I found the EPC setting/register (external power control?), but it didn't seem to behave as anticipated...

(below discussion snipped from another thread)

What is the does it do and what are you expecting when you send to EPC charge?

I see it update on the Insight, so I know I'm writing the address correctly, but it doesn't always respond by charging or discharging at the rate selected--most of the time, it seems to just ignore it.

I'm sure there are dependent settings and variables I'm missing, and I'm just struggling to figure out what the prerequisites are for charging or backfeeding (selling). It looks like, for selling:

• AC1 needs to be connected (duh)
• battery voltage/SoC needs to be over the threshold
• "Sell" needs to be enabled
• "Grid Support" switched on??
• need to be outside a "Sell Block" window

But, if I want to switch to charging batteries from the grid, now I need:

• battery forced to bulk?
• "Sell" disabled?
• to be outside a "Charge Block" window
• ???

What are the questions? What data do you need to make the decisions? What does each answer make you do?

I really appreciate you sharing that overarching description of your system, the obstacles, and thought process to get there. I'd seen your "mega thread" before, and it actually me inspired me to get the XW, after previously writing it off as being incapable of manual control. I doubt I'll end up going the PLC route, but between Home Assistant, Node Red, or maybe even Arduino, I'm confident I'll be able to make things work... once I figure out which registers I need to set! To summarize, your PLC is initiating charge with a forced bulk in the morning, controlling throughout the day via charge current, and then stops based on "Sell Block" time.

I only bother stopping the charge if the AC coupled Grid Tied solar falls to where the AC output of the XW-Pro starts consuming power.

How, exactly, do you stop the charge process?

As long as the XW-Pro is still charging at just 5%, it can't pull battery power to feed loads.

This was a little tricky to understand, but I think I get it...

I didn't like seeing it jumping around too quickly and certainly didn't like ever seeing it overshoot the desired current.

Looks like a pretty good application for a PID loop. Not sure how easy that is to implement in the PLC world, but I'll likely end up using one when trying to settle on my "target".

 

[400bird]

I'm trying to adapt to the Schneider Conext XW Pro 6848, coming from Victron gear. I was used to setting a single modbus register with a positive or negative number to indicate the targeted power to be drawn from or backfed into AC1. It seems to be a whole different paradigm with Schneider. I'm trying to work out how to get the XW to charge or discharge the battery by a specific amount. I found the EPC setting/register (external power control?), but it didn't seem to behave as anticipated...

(below discussion snipped from another thread)

I see it update on the Insight, so I know I'm writing the address correctly, but it doesn't always respond by charging or discharging at the rate selected--most of the time, it seems to just ignore it.

I'm pretty sure the EPC discharge command is an upper limit. If you command 5,000 watts but only have 1,000 watts of load, no change. So, this only seems useful to limit the inverter output, but I haven't played with it enough to fully understand how it works.

If you want to command selling to the grid, I wrote to Maximum Export (Sell) Sell Amps.
This means the XW will support loads on the output and then try to sell to the grid with your sell amps setting.

EPC charge won't start a charge cycle or override your charger current limit set elsewhere. But if the charge cycle is already going, it will limit the charger down to you command it watts. My charger lives set at 100 amps and EPC handles updating charge wattage to absorb excess PV instead of sending it to the grid.

I'm sure there are dependent settings and variables I'm missing, and I'm just struggling to figure out what the prerequisites are for charging or backfeeding (selling). It looks like, for selling:

• AC1 needs to be connected (duh)
• battery voltage/SoC needs to be over the threshold
• "Sell" needs to be enabled
• "Grid Support" switched on??

Yes, grid support and grid sell are related.

• need to be outside a "Sell Block" window

But, if I want to switch to charging batteries from the grid, now I need:

• battery forced to bulk?
• "Sell" disabled?

I don't think so. I switch back and forth in the middle of the day by just sending a no float command and the XW will support loads, sending a bulk charge command switches it back to charging.

• to be outside a "Charge Block" window
• ???

Yeah, I'm sure there is something else that isn't coming to mind.