Schneider Conext XW

[fafrd]

Sort of. The resolution of the XW-Pro is 1% steps, but the minimum is 5%. The maximum charge current is 140 amps, so it starts at 7 amps and has 1.4 amp steps above that.

Got it. So 7A / ~350W minimum and then 1.4A / 70W steps above that.

I had thought about using 3 or 4 chargers. If you get a 2.5 amp, 5 amp, 10 amp, and 20 amp then you could do binary count and get any current from 0 to 37.5 amps in 2.5 amp steps.

In my case, I’ll have a maximum of 764W I’m trying to absorb, so just using a pair of ~320W chargers would get me there…

Even in Winter, the off peak to peak rate swing is still a 55% jump for me. Until I know how long my batteries will last, it makes it tough to calculate how much I am saving or is it wasting? At this rate, I will break even if the cells last 5 years, and they might make 7 years. In the Chevy Bolt, they are warrantied for 10 years, so I am hopeful.

Ouch! Yea, for +55% I’d at least delay my discharge to begin at 4pm.

My AC charger has an efficiency of 90% and my GTIL inverters are only 90% efficient, so charging from AC to discharge from 4-9pm is hardly worth it (even at +55%).

As it is, my winter 4-9pm rate is only +7% higher, so charging from grid would be a losing proposition…

Of course, my utility has just requested a +18% rate increase, so we’ll see how that breaks down in terms of peak-vs-offpeak and winter-vs-summer…

 

[400bird]

Sort of. The resolution of the XW-Pro is 1% steps, but the minimum is 5%. The maximum charge current is 140 amps, so it starts at 7 amps and has 1.4 amp steps above that.

I'd just like to point out that that applies when using charge rate to actively control charging.

There's also the option to use EPC to control charging. I've got the ability to control charging in single watt steps down to about 20 watts. I don't remember the exact minimum threshold, but it's pretty low. It will accept 1 watt in the register or configuration option, but the 140 amp charger doesn't seem to have the resolution to charge at 0.25 amp.

 

[keepsake]

Isn't the EPC stuff ONLY for S/E approved battery systems ?
I mean can I use EPC at all if I built my own bank of cells ?
It would be gratious if S/E would not clutter my screen and settings areas with stuff I can't use.

 

[fafrd]

I'd just like to point out that that applies when using charge rate to actively control charging.

There's also the option to use EPC to control charging. I've got the ability to control charging in single watt steps down to about 20 watts. I don't remember the exact minimum threshold, but it's pretty low. It will accept 1 watt in the register or configuration option, but the 140 amp charger doesn't seem to have the resolution to charge at 0.25 amp.

What is EPC and is it more complicated / restrictive to use than the approach GXMnow is using?

And another question for the two of you: what is the granularity to which export power can be controlled?

If the charger can be controlled to consume power in steps of 1W or 1.4A / 73W above a starting power of 20W or 360W, what are the minimum steps to control export power and how many Wats of export is the minimum that can be pushed out the AC input?

 

[GXMnow]

The "Sell to Grid" current in the XW-Pro is set in milliamps. I have not tested to see the lowest it can go, but I have seen it working at just a few watts, and it does seem to respond to single milliamp changes. 1 milliamp at 240 volts is only 0.24 watts. I have not bothered to put any minimum range limiting on the value other then it won't set negative (if calculated less than 0, set to zero), and at the top I have it limited to 16,000 milliamps or 16.000 amps as that is the safe limit to push back through the 20 amp breaker in my main panel. The XW is now feeding back through the same 120% rule limited 20 amp breaker as my original grid tied Enphase solar setup. One of the very good features of the XW-Pro is how it handles the AC coupled back feed. If I set the XW to sell at 3 amps, and the Enphase is already putting out more than 3 amps, it goes to idle and does not push any current. If the Solar was pushing 2 amps, it would only push 1 more amp to get to the desired 3 amps. The sell to grid current is the maximum it will allow back to the AC1 grid input. The only time it will be higher is when the AC coupled solar on the output is higher than this setting. Too bad they didn't add "Smart Charge" like the SW has. If it did, it could know to switch into charge mode to limit this back flow current, but it just can't do it with the current software. Adding the PLC allows me to make it do that with external commands.

We are having clouds again today, and it has gone in and out of charging a couple times.

 

[fafrd]

The "Sell to Grid" current in the XW-Pro is set in milliamps. I have not tested to see the lowest it can go, but I have seen it working at just a few watts, and it does seem to respond to single milliamp changes. 1 milliamp at 240 volts is only 0.24 watts.

Wow, well that’s that then. Sounds as though the XW Pro is more finely able to control output power versus input power (battery charging).

I have not bothered to put any minimum range limiting on the value other then it won't set negative (if calculated less than 0, set to zero), and at the top I have it limited to 16,000 milliamps or 16.000 amps as that is the safe limit to push back through the 20 amp breaker in my main panel.

The whole 120% limit on older main panels thing is interesting when you have an energy meter / monitor involved.

The idea is to never have more than 120% of panel backplane rating glowing into opposite ends of the panel (100% from grid input at the top + 20% from solar+hybrid input from the bottom).

I’m planning to connect my hybrid in through an existing subpanel which is already connected into the top of the main panel through a 50A breaker.

So strictly following the rules, even inputting 20A at that location would be unsafe.

But since my brain will be monitoring grid input, it will be easy to assure I never have more than 100A coming into the top of my mains panel. I just need to assure that inverter output never exceeds 100A - measured import current.

So I can leave my 50A breaker where it is and I can use a 30A or even 40A breaker on the input of the Conext XW into the subpanel…

The XW is now feeding back through the same 120% rule limited 20 amp breaker as my original grid tied Enphase solar setup. One of the very good features of the XW-Pro is how it handles the AC coupled back feed. If I set the XW to sell at 3 amps, and the Enphase is already putting out more than 3 amps, it goes to idle and does not push any current. If the Solar was pushing 2 amps, it would only push 1 more amp to get to the desired 3 amps.

This is exactly what I am trying to do, but I’m hoping to do so by directly telling the inverter how much power to export (so that the total export power remains at 3409-3500W whenever possible).

The sell to grid current is the maximum it will allow back to the AC1 grid input. The only time it will be higher is when the AC coupled solar on the output is higher than this setting. Too bad they didn't add "Smart Charge" like the SW has. If it did, it could know to switch into charge mode to limit this back flow current, but it just can't do it with the current software. Adding the PLC allows me to make it do that with external commands.

I’m still getting comfortable with the idea, but once I’ve bitten the bullet and decided to add a customized PLC or RPi-based ‘brain’ / monitor / controller to the system, seems as though I might as well use it to achieve as much as possible through direct control of the inverter as I can…

We are having clouds again today, and it has gone in and out of charging a couple times.

I think that on overcast / cloudy / rainy days like today, I’ll want my system to maintain near-zero overall export and absorb as much AC and DC-coupled energy as possible to charge the battery. Come as close as I can to 0W of total (not net) import…

At my winter rates, wholesale value is $0.06 /kWh and NBCs on an imported kWh total to about $0.03/kWh. So not exporting 1kWh for wholesale credit and instead using it to offset 1kWh of consumption is worth a minimum of $0.09…

 

[GXMnow]

It basically comes down to your comfort level with the coding. If you can deal with it, it gives you a ton of options. For me, the hardest part is toning it down to what I really need it to do. The way my brain works, I keep thinking of all the cool stuff I can make it do, but in the end, I need to decide on what I can actually code and make work properly, rather than be buried in too many possibilities. So I programmed it in steps. Step one was just to make it start charging when the PV Solar was making enough power. At first, it just set it to 10 amps of charge current at battery voltage from when the Solar was making at least 5 amps at 240 volts. Once that was working, then I added charge current control by only watching the current going out of the AC1 grid side of the XW-Pro. I had it raise current until the grid export was under 1 amp (240 watts), and then it would lower current if it fell below 0.5 amps (120 watts). At that point, it had no idea how much was being used in the main panel.

As for your connection into your main panel, what you have is not safe. The whole idea of the 120% rule is to make it safe no matter what could possibly go wrong. It is a bit more limiting than it really needs to be, but it is safe and has good reason behind it. At the very least, you should move the sub panel breaker to the other end of the panel. If the main breaker and the sub panel breaker both end up feeding into the panel, you never want the two currents to be able to add together in the bus bars. Feeding from opposite ends eliminates that possible problem. If something in the middle of the panel is failing and pulling too much, it might still be able to pull 150 amps with your 100 amp main at the top, and a 50 amp back feed at the bottom, but no length of bus bar is having to carry more than 100 amps. With your sub panel feeding to the top, you could have 150 amps in the bus bar flowing down into the panel. It does not matter how good our code is, devices can fail, and code can crash etc. We always want the breakers to trip before anything goes too far wrong. I have thought of bumping my breaker to the XW-Pro up to a 30 amp, but if I do, I would also change my main down to a 90 amp to keep it legal for the 120% rule in the panel. Going to a 50 amp is not going to happen for me without upgrading my panel. Being able to push 16 amps back to the panel has been plenty. The only way it becomes a problem is if I move more large loads into my backed up panel. Right now, if I had no charge left in the battery, and all the breakers in the backup loads panel were maxed out, it would be trying to pull 40 amps from the main panel. Oops!! As long as I have charge in the batteries, the XW will supply up to 28 amps of additional power, and any solar production also adds. My worry would only be at night after the battery runs out.

 

[fafrd]

It basically comes down to your comfort level with the coding. If you can deal with it, it gives you a ton of options. For me, the hardest part is toning it down to what I really need it to do. The way my brain works, I keep thinking of all the cool stuff I can make it do, but in the end, I need to decide on what I can actually code and make work properly, rather than be buried in too many possibilities. So I programmed it in steps. Step one was just to make it start charging when the PV Solar was making enough power. At first, it just set it to 10 amps of charge current at battery voltage from when the Solar was making at least 5 amps at 240 volts. Once that was working, then I added charge current control by only watching the current going out of the AC1 grid side of the XW-Pro. I had it raise current until the grid export was under 1 amp (240 watts), and then it would lower current if it fell below 0.5 amps (120 watts). At that point, it had no idea how much was being used in the main panel.

That sounds like a very effective approach (incremental coding).

I believe you said you could hook up as many Modbus-capable energy meters as you wanted to your PLC,correct?

Does it also have a few channels for analog inputs?

I’ll go back to read the specifications at the link you provided, but I’m starting to think a PLC-based controller will be easier for me to manage than an RPi-based one…

 

[400bird]

Does it also have Bowie a few channels for analog inputs?

Typo? Or do I need to research something ?

I’ll go back to read the specifications at the link you provided, but I’m starting to think a PLC-based controller will be easier for me to manage than an RPi-based one…

I'm sure the PLC would be easier to source right now. Raspberry Pi available has been rough for something like 18 months now.

 

[fafrd]

As for your connection into your main panel, what you have is not safe. The whole idea of the 120% rule is to make it safe no matter what could possibly go wrong. It is a bit more limiting than it really needs to be, but it is safe and has good reason behind it.

This is a wise input, and I should have thought things through more carefully and detailed the several options I have to skin that cat.

At the very least, you should move the sub panel breaker to the other end of the panel. If the main breaker and the sub panel breaker both end up feeding into the panel, you never want the two currents to be able to add together in the bus bars.

That alone won’t add much of a safety factor, since 20A from solar .+ 40A from Conext XW Pro on one end plus 100A from grid can total to much over 120%…

Feeding from opposite ends eliminates that possible problem. If something in the middle of the panel is failing and pulling too much, it might still be able to pull 150 amps with your 100 amp main at the top, and a 50 amp back feed at the bottom, but no length of bus bar is having to carry more than 100 amps. With your sub panel feeding to the top, you could have 150 amps in the bus bar flowing down into the panel.

I’m probably never consuming over 50A of load, so (as you mention below), reducing my main breaker from 100A to 80A would be the best way to add safety.

With an 80A main breaker and the Conext breaker reduced to 20A, it won’tmatter whether the sun panel is connected at the top or the bottom…

It does not matter how good our code is, devices can fail, and code can crash etc. We always want the breakers to trip before anything goes too far wrong. I have thought of bumping my breaker to the XW-Pro up to a 30 amp, but if I do, I would also change my main down to a 90 amp to keep it legal for the 120% rule in the panel. Going to a 50 amp is not going to happen for me without upgrading my panel. Being able to push 16 amps back to the panel has been plenty. The only way it becomes a problem is if I move more large loads into my backed up panel. Right now, if I had no charge left in the battery, and all the breakers in the backup loads panel were maxed out, it would be trying to pull 40 amps from the main panel. Oops!! As long as I have charge in the batteries, the XW will supply up to 28 amps of additional power, and any solar production also adds. My worry would only be at night after the battery runs out.

You are correct that multiple shorts that are sufficient to max out load breakers without tripping them is the corner case to be concerned about. My subpanel is rated for 200A, so another avenue I have to add safety is to gut my main panel by moving all 120VAC loads and breakers to the subpanel. The electric oven only consumes 3kW through a dual-pole 20A breaker, so I could limit the main panel consumption to 50+20=70A max (meaning I could have a 20A breaker at the bottom of the main panel and a 30A breaker on the inverter in the subpanel).

But just downgrading the main breaker to 70A seems easier.

Bottom line is you were right and I was wrong - I should make sure I’m respecting the 120% rule no matter what failures occur…

 

[fafrd]

Typo? Or do I need to research something ?

You’ve got to watch this interface like a hawk! No idea how that slipped in. I probably clear up ~10 Autocorrect / Autoinsertion ‘typos’ per post, but every so often a rager like that slips through…

I'm sure the PLC would be easier to source right now. Raspberry Pi available has been rough for something like 18 months now.

And then there is that. I saw than Home Assistant actually has a crowd-funded RPi platform in the works, but not skated to arrive before mid-next-year.

Trying a PLC-based brain first is starting to sound like the most sensible first attempt…

 

[400bird]

Ok, well no Bowie then. I guess that would make it too expensive ?

That sounds like a very effective approach (incremental coding).

This is exactly how I did it, I had never heard of modbus before wading into this and my python coding was very limited. Think "hello world" level stuff.

.I saw than Home Assistant actually has a crowd-funded RPi platform in the works, but not skated to arrive before mid-next-year.

I've tried Home Assistant a couple times and feel like I'm just missing something in the programming language/user interface/documentation. I'm not quite sure what it is, but I'm missing something, it just hasn't clicked yet.

Are you talking about Home Assistant Yellow? I thought those were already shipping to early backers. A quick Google, says maybe...

 

[GXMnow]

An RS-485 bus has a theoretical limit of 254 slave devices and one master. But in reality, there are signal level and current restrictions. With the PLC and cheap power meters. 20 devices should not be a problem. Do you think you would ever want to monitor that many?

My system technically has 4 strings of batteries. I was thinking if I ever do get the PLC to serve a custom web page, I might have it show the current and state of charge of each string to make sure they are sharing evenly. So that would be 4 more devices. Then I could have one monitor the Enphase output, and one on the DC charge controller. 2 more devices. Maybe add a good proper bidirectional meter on the grid input, 2 more?

That still only has me reading 10 devices on the Modbus RTU serial bus. Reading all that data at just 9600 bps does take a little time though. To make sure I don't stomp on a reply, I had to add a small delay function when I rea the second PZEM power meter. And I can see it pause the 1/2 second steps in the ladder. So my update rate is actually a little slower than every 5 seconds. I found it interesting that the free run time pulse actually halts when it is stuck running a basic routine in a ladder output. But in a way that is a good thing. You know for sure the previous ladder function is complete before it can trigger another one. If the loop time was a critical timing issue, you can have it reference the real time clock, but I think this is better for what we are doing.

Here is the site where I bought my PLC.

Low Cost Ethernet Programmable Logic Controllers | TRi PLC

High-end features included standard on a low cost, small foot-print board. Modbus TCP Client/Server, RS485/RS232,Analog & Digital I/O, HSC/Interrupt/Stepper/PWM

triplc.com

Mine is the little Nano-10
If I was going to do it again, is it worth the money for the Fx1616-BA? It has a lot more I/O and supports the hardware LCD screen too. The prices have gone up a little since I got mine. The Nano-10 is now $279 for the starter kit with the full software license etc. Adding the RTC clock module with battery backup is $67

Moving up to the FX1616 is $569 with the full starter kit. Add $46 for the LCD screen. Not sure if you need the extra RTC module, might need it for battery backup to keep time during power off.

 

[fafrd]

An RS-485 bus has a theoretical limit of 254 slave devices and one master. But in reality, there are signal level and current restrictions. With the PLC and cheap power meters. 20 devices should not be a problem. Do you think you would ever want to monitor that many?

My system technically has 4 strings of batteries. I was thinking if I ever do get the PLC to serve a custom web page, I might have it show the current and state of charge of each string to make sure they are sharing evenly. So that would be 4 more devices. Then I could have one monitor the Enphase output, and one on the DC charge controller. 2 more devices. Maybe add a good proper bidirectional meter on the grid input, 2 more?

That still only has me reading 10 devices on the Modbus RTU serial bus. Reading all that data at just 9600 bps does take a little time though. To make sure I don't stomp on a reply, I had to add a small delay function when I rea the second PZEM power meter. And I can see it pause the 1/2 second steps in the ladder. So my update rate is actually a little slower than every 5 seconds. I found it interesting that the free run time pulse actually halts when it is stuck running a basic routine in a ladder output. But in a way that is a good thing. You know for sure the previous ladder function is complete before it can trigger another one. If the loop time was a critical timing issue, you can have it reference the real time clock, but I think this is better for what we are doing.

Here is the site where I bought my PLC.

Low Cost Ethernet Programmable Logic Controllers | TRi PLC

High-end features included standard on a low cost, small foot-print board. Modbus TCP Client/Server, RS485/RS232,Analog & Digital I/O, HSC/Interrupt/Stepper/PWM

triplc.com

Mine is the little Nano-10
If I was going to do it again, is it worth the money for the Fx1616-BA? It has a lot more I/O and supports the hardware LCD screen too. The prices have gone up a little since I got mine. The Nano-10 is now $279 for the starter kit with the full software license etc. Adding the RTC clock module with battery backup is $67

Moving up to the FX1616 is $569 with the full starter kit. Add $46 for the LCD screen. Not sure if you need the extra RTC module, might need it for battery backup to keep time during power off.

I’d found that site and the starter kit.

For power meters, 2 on the grid hots is the minimum and if I ever wanted to add more, it would probably be on the AC-coupled solar input so I could calculate load.

I see that there are 2 analog inputs with 12-bit precision over 0-5VDC, so I’m thinking I should be able to hook up a 100A / 100mV shunt on combined DC-coupled output to measure DC power to ~ 1.22A / 33W precision. Probably need to be careful to use shielded cable like is done for CT sensors, but it should be possible.

So I’m starting to seriously think about jumping on one of these. Since my house battery is 24V and pretty much always available, I’m not seeing any real benefit to the RTC with battery backup.

Sounds as though just the learning would be worth the ~$300 bucks to me .

I’m still not clearly understanding whether on of these can directly communicate over Modbus with a Conext XW Pro (or Victron MPII) or whether some sort of communication gateway is also required…

 

[GXMnow]

For whatever reason, I have not gotten the analog inputs to return a value other than zero, and yes, I did apply a small voltage on the pin to get it above zero. I am not using any analog in, so it has not been a priority to figure out why it does not seem to work. My guess is I need to do something in the initialize script to turn on the A to D converter. If I find it, I will let you know.

If I want to add DC power metering, I will just use another Modbus meter at under $20. Not only does it measure voltage and current, it comes with the shunt, and calculates watts and kilowatt hours, even while not being read, it will keep counting up the energy in and out. That is why I may get them to monitor the batteries.

The real time clock might not be essential, but it is nice that it will survive a power down and still know when it is 4 pm to stop charging.

For the Schneider XW-Pro, I an using ethernet to the Gateway. Is there a chance it could talk straight to the Xanbus??? The physical interface of Xanbus is the same as RS-485, and Xantrex, who created Xanbus, also did create Modbus. I would expect the protocol to be close. But talking to it via Modbus TCP over the ethernet port to the gateway works great. Even limited to 100 Mbps it is way faster than 9,600 bps half duplex serial. All my data requests from the XW-Pro are basically instant, and the ethernet switch handles the data and eliminates any issue with data collisions. On the RS-485 serial bus, every device is n the same wire pair sharing the 9,600 bits per second, The PLC and Gateway talk to each other over a 100 MPS switch, which then talks to the rest of my system on a gigabit router and switches.

 

[fafrd]

For whatever reason, I have not gotten the analog inputs to return a value other than zero, and yes, I did apply a small voltage on the pin to get it above zero. I am not using any analog in, so it has not been a priority to figure out why it does not seem to work. My guess is I need to do something in the initialize script to turn on the A to D converter. If I find it, I will let you know.

If I want to add DC power metering, I will just use another Modbus meter at under $20. Not only does it measure voltage and current, it comes with the shunt, and calculates watts and kilowatt hours, even while not being read, it will keep counting up the energy in and out. That is why I may get them to monitor the batteries.

Understandable if those are available for only $20. You’re talking about something like this, right: https://www.amazon.com/PZEM-017-Communication-Interface-Voltage-Consumption/dp/B08TTTXNM7

Locally translates the analog signal to RS485, so no need to worry about signal noise over a long wire. Makes much more sense.

The real time clock might not be essential, but it is nice that it will survive a power down and still know when it is 4 pm to stop charging.

With an essentially unlimited source of 24V supply, I don’t think I’ll ever need to worry about the PLC getting depowered. Everything else will disconnect itself from the 24V battery first and the ‘last man standing’ during an extended power outage will be the PLC…

For the Schneider XW-Pro, I an using ethernet to the Gateway. Is there a chance it could talk straight to the Xanbus??? The physical interface of Xanbus is the same as RS-485, and Xantrex, who created Xanbus, also did create Modbus. I would expect the protocol to be close.

Got it. Seems as though the inverters themselves do not directly support Modbus (Victron is the same). $500 for a ‘gateway’ is painful, but looks as though there is really no alternative…

But talking to it via Modbus TCP over the ethernet port to the gateway works great. Even limited to 100 Mbps it is way faster than 9,600 bps half duplex serial. All my data requests from the XW-Pro are basically instant, and the ethernet switch handles the data and eliminates any issue with data collisions. On the RS-485 serial bus, every device is n the same wire pair sharing the 9,600 bits per second, The PLC and Gateway talk to each other over a 100 MPS switch, which then talks to the rest of my system on a gigabit router and switches.

I don’t currently have Ethernet in my basement where the inverters are, but seems like it’s a minimum ante to plunge into this world of advanced power control.

I’m still on the fence between Conext XW Pro and moving to 48VDC or Victron MPII and sticking with the 24VDC I have currently.

Found this on Victron’s website: https://www.victronenergy.com/live/ess:ess_mode_2_and_3

‘1.3 - Mode 3

Customer self implements their control loop and grid measurements, and uses the MultiPlus and/or Quattros as simple, remote controllable, bidirectional inverter/chargers that can be set to either charge or discharge an x amount of Watts.’

Once one has built a PLC-based energy monitor and is controlling registers on the inverter/charger to import or export a particular amount of power, that is a pretty accurate description of what is going on…

 

[GXMnow]

It would be nice if they just had either Ethernet or a Modbus RS-485 port directly on the inverter, but NOPE! So they get to sell you a box to translate. If you have several devices, it makes it no big deal, but to only talk to one device, really?

Lack of Ethernet might not be a big problem. My router is not too far from the gear in my garage, but the WiFi all the way to outside the house at the far wall was lousy. The Enphase Envoy kept dropping offline. So I just got a Linksys WiFi extender, and installed it in the front of the garage where it get's a goof WiFi signal from the house router. IT is talking to the house on the 5gig band. It then has an ethernet port which I ran to a 5 port switch for the Schneider Gateway and the Tri PLC. And the Enphase now connects to the 2.4 gig WiFi of the extender. It works great, no signal drop issues. And I can now get WiFi from the far end of my driveway in the car.

 

[GXMnow]

I looked at the linked Victron Page.

Mode 3 does look like it would work very well with the PLC. The address and the data format are coded a bit different, but it seems easy enough to do. It is interesting that it uses a single number, with the sign bit telling it import power vs export power. And it looks like the power set point has a 1 watt resolution to 32K watts in or out. Using just a single 16 bit word. Nice. It shows separate modbus registers for each phase L1 and L2 for split phase, and even L3 for 3 phase systems. I assume that would be if using a separate inverter per leg. While on grid, the XW-Pro only pushes 240 volts across L1 to L2, so the balance is actually done out by the utility transformer for the whole block. When it transfers to off grid mode, it then ties the transformer enter tap to the neutral. They do this to ensure the XW transformer is not trying to correct any imbalance in the grid feed in. Having separate synced 120 volt inverters would not have that issue, and each one could independently zero the power on each leg.

I would need to study this guide in more detail, but I don't think it would be a problem to make it work using the cheap power meters.
Mode 2 also looks like it could be made to work, and it might even be less coding as the Victron gear ends up doing a lot of the repeating loop math. You just put in set points and it appears that the Victron gear will adjust charge/sell to maintain the desired grid side current. My only question is if it can read external CT's, or would "we" need to tell it how much power we need to have sent to the main grid side panel to cover local loads and net zero to the grid? That is the function that made me need to use the external CTs on the XW-Pro.

 

[fafrd]

I looked at the linked Victron Page.

Mode 3 does look like it would work very well with the PLC. The address and the data format are coded a bit different, but it seems easy enough to do. It is interesting that it uses a single number, with the sign bit telling it import power vs export power. And it looks like the power set point has a 1 watt resolution to 32K watts in or out. Using just a single 16 bit word. Nice. It shows separate modbus registers for each phase L1 and L2 for split phase, and even L3 for 3 phase systems. I assume that would be if using a separate inverter per leg.

Yes, if I go the Victron route, I’d have a seperate 2.4kW Multiplus II on each leg. So no sharing of power capacity between legs but that is not a priority for me (and it also means zero export means no power being exported on either leg, whether my meter is intelligent enough to detect export in one leg offsetting import on the other leg or not).

While on grid, the XW-Pro only pushes 240 volts across L1 to L2, so the balance is actually done out by the utility transformer for the whole block. When it transfers to off grid mode, it then ties the transformer enter tap to the neutral. They do this to ensure the XW transformer is not trying to correct any imbalance in the grid feed in. Having separate synced 120 volt inverters would not have that issue, and each one could independently zero the power on each leg.

Yes. The cost is that the split-phase inverter has less peak power available when off-grid, but that is a non-concern for my priorities

I would need to study this guide in more detail, but I don't think it would be a problem to make it work using the cheap power meters.

That’s what I’m thinking as well. Victron only provides the register map by email (and probably only to actual customers), so it’s going to be more difficult that I’d like to be certain I can make it work as easily and effectively as you have with the Conext XW Pro. But it looks promising enough that I think I need to look into it.

Mode 2 also looks like it could be made to work, and it might even be less coding as the Victron gear ends up doing a lot of the repeating loop math. You just put in set points and it appears that the Victron gear will adjust charge/sell to maintain the desired grid side current. My only question is if it can read external CT's, or would "we" need to tell it how much power we need to have sent to the main grid side panel to cover local loads and net zero to the grid? That is the function that made me need to use the external CTs on the XW-Pro.

The issue with the external CTs is that from what I’ve understood, there would be no way to use DC-coupled power generation to govern export (up the cap). If you can directly calculate the amount of power you want to export based on DC-power being generated (hopefully being directly from the SCCs using Modbus), it would be the most direct way to achieve what I’m aiming for.

Once DC-coupled power + AC-coupled power hits my 3.5kW export cap, I just calculate the amount of inverter export that brings total export to just under that cap and DC-coupled battery charging begins to ramp up).

So partly stimulated by your suggestion (of considering DC-coupling for my additional array instead of AC-coupled), I’d actually never make use of the the inverter / charger’s AC battery charger.

The inverter just exports as much DC-coupled power as it can during daylight hours and then used energy stored in the battery to offset nighttime consumption for as long as the battery lasts…

 

[keepsake]

Hoping someone has tackled this ...

I have beautiful communication between python code and the Insight Home with modbus. Got it down the a 100% reliable science.
I still have a ComBox that I wish to use and thought it should be easy-peasy to use almost identical modbus code to do so. I had no trouble going from gateway to Insight home and back again.
What does the ComBox expect that is different than the later Insight/gateway boxes ?
Is it port number, id= number, something to do with a slave parameter ?
I cannot even get to ComBox for the device name at address 0. Yet the gateway responds.
Yes, both boxes are two different IP addresses. And I have two totally different XanBus's to the respective inverters.
fyi - the new stuff is xw6848 Pro and the old stuff I want with the Combox is xw4548.
Both Combox and gateway work fine on their respective local webpages. So I have no issue with config'ing 'em all.
Thanks.