Conext SW4024 - AC Support Performance

giawa · May 2018

Got it all up and running on a Netduino with ModBus and now I have a cool little LCD screen giving me real-time statistics on the SW performance. Now I just have to eagerly await my Amazon deliveries >.>

If you're curious about the hardware, this is a Netduino 2+ with a Gameduino shield attached. I'm using open-source C# code on the Netduino to interface with the Gameduino shield: https://github.com/giawa/gameduino4netduino Communication is over ModBus TCP, and everything is powered off the micro USB cable.

The plot on the left isn't showing anything interesting yet (I've adapted this display from another project). I'll probably get that to be able to swap between Solar/Grid/Battery/Load wattage or something.

Image: https://us.v-cdn.net/6024911/uploads/editor/wz/0h7xwe3yqk9n.jpg

Estragon · May 2018

I have nothing to add, but am curious about the hw and look forward to hearing how it turns out. Do share!

giawa · May 2018

Hey everyone,

It will still be a while longer before my double pole relay shows up, but I thought I would upload the most recent copy of my ModBus code in case anyone wants to try it out, or if anyone in the future looks at this thread trying to do something similar. I now have examples of writing data, and have successfully turned on/off AC Support, set AC Support voltage, etc over ModBus.

Cheers,

Giawa

Vic · May 2018

Hi Giawa,

WOW, that Netduino project looks stunning. Sure has been a lot of progress in these open-source computing devices.

You may know, but, on the MidNite Solar Forum, there is a Topic area for a number of the different computing boards. Here is a Link to the Arduino Topic. You might find it or some use, and bet, that the Forum would benefit from your input:

http://midniteftp.com/forum/index.php?board=35.0

Great work! Thanks, Vic

MrM1 · May 2018

Great work. Looks cool. Wondering though, when u say disconnect from AC you mean turning off AC support, or did you find a way to internally disconnect AC power.

Dave Angelini · May 2018

I am wondering the same thing and why you need a CB ? You should be able to control this with modbus internally.

giawa · May 2018

Dave Angelini said:

I am wondering the same thing and why you need a CB ? You should be able to control this with modbus internally.

Hi Dave,

Looking through the memory map for the SW in ModBus I couldn't find any way to control the internal switch. It could be this exists hidden somewhere, but their public documentation doesn't seem to include an ability to disable the AC input and run from the inverter only. If it is possible (or if you know someone who can point out that register) then that would be super helpful. There might be a way for me to fake it out as well by changing the AC min/max frequencies or high voltage/etc to have it disconnect the AC input.

Giawa

giawa · May 2018

MrM1 said:

Great work. Looks cool. Wondering though, when u say disconnect from AC you mean turning off AC support, or did you find a way to internally disconnect AC power.

My thought was to disconnect the AC input from the SW. This would force the SW to operate in inverter mode only. I can already easily control AC Support via ModBus (and am actively using this now).

Giawa

giawa · May 2018

Vic said:

Hi Giawa,
WOW, that Netduino project looks stunning.   Sure has been a lot of progress in these open-source computing devices.
You may know, but, on the MidNite Solar Forum, there is a Topic area for a number of the different computing boards.   Here is a Link to the Arduino Topic. You might find it or some use,   and bet, that the Forum would benefit from your input:
http://midniteftp.com/forum/index.php?board=35.0
Great work! Thanks,   Vic

Thanks! I've been having some fun with it. I'm hoping I can get some time this weekend to experiment with having the Netduino disconnect the AC input automatically. I'm already using it to control the AC support voltage, mode and to act as my quick reference and history for load/solar/etc.

I'll definitely check out that forum - thanks for the link! Cheers,

Giawa

MrM1 · May 2018

Post a link over here if you bounce over to MidNite Solar Forum plz

Dave Angelini · May 2018

There should be a way but I have only done this with XW. The reason I hire my friend is this programming stuff bores the heck out of me

giawa · May 2018

Dave Angelini said:

There should be a way but I have only done this with XW.

Ya, it looks like it is available in the XW memory map, but not in the SW.

Also, the SW forces a range of what it considers to be 'valid' values for the AC high/low voltage and frequency, so you cannot configure these values to be out of range. I was hoping I could set the AC high voltage to 110V and then have it unqualify the AC input, forcing it into inverter mode, but those Schneider engineers/programmers are just too clever for me.

Giawa

MrM1 · May 2018

Post a link here if you bounce

giawa said:

... those Schneider engineers/programmers are just too clever for me.

Giawa

Yes I guess that's one way of looking at it.

giawa · May 2018

MrM1 said:

Post a link here if you bounce

I don't think I'll bounce out of this thread - but I'll definitely be reading up on some of the project that people in the other forum are working on.

Giawa

fasterski · July 2018

Thanks for the Shneider FAQ link. Now I understand why I could not get it running as per manual. What I did in my case is I used one phase 15 AMPs coming in on a Wink Compatible Smart light module. I can control it remotely when the sun in ablaze (On schedule and override as needed) Found the setup will work for most of the stuff in the house (except central vac and saws).

MrM1 · July 2018

@giawa, did you ever figure out a way to internally disconnect AC input on the SW? Or did you get it set up via a relay?

giawa · July 2018

MrM1 said:

@giawa, did you ever figure out a way to internally disconnect AC input on the SW? Or did you get it set up via a relay?

No. Trying to 'trick' it using settings for the AC input being out of range doesn't work either. They have some hard coded min/max values for those settings, and if you try to trick it by considering an AC under voltage at 130V it just ignores your command. They're being too clever for their own good.

The SW also doesn't support accessing/toggling the internal relay via ModBus, etc, so that's no fun. I talked with SE customer support and they don't seem to care. No timeline/roadmap for future firmware updates, no beta program, nothing like that. Darn. They *still* recommend AC support to me even though we've talked about how it doesn't work well. It seems their own customer support often aren't aware of their product limitations.

I ended up just using a controllable breaker in my main panel (the breaker that feeds the AC input of the SW). It seems to do the trick, although I need to work on automating it. Right now I just toggle it from my computer when the sun looks good. I'd like to get back into the Netduino stuff, but I've just been too busy these last few weeks. I'll update here if I get anything good going.

On a random aside, SE heavily suggested migrating to their own charge controller to "prioritize solar over grid". I ended up being able to effectively trade in my Morningstar ProStar for an MPPT 60 150. It had zero effect, except now I can see some nice plots of my PV energy generation (whereas before everything appeared to come from battery). "Prioritizing solar over grid" doesn't help when there's a fundamental limitation to the inverter in that it cannot perform AC support properly on unbalanced loads. When operating in island mode there is no difference, since the PV power is just PV power.

My new issue is that the SW does struggle with inductive loads on a single phase (when operating as an island). SE support is trying to help me track down why I am seeing AC output over voltage faults when a single phase inductive load is cycling. I don't think this inverter has the guts to pull it off, which I'm kind of 'meh' about.

The system works well enough for me to say that I've accomplished the goals I had. However, it wouldn't have worked as-is, regardless of how much configuration was attempted. The SW just isn't flexible enough (and I'm not convinced that the XW, at 3x the price, is flexible enough either). In my opinion the SW has some decent hardware and some awful firmware. Similarly, I've found the Combox firmware to be pretty awful.

To close on a more positive note. My average electricity consumption went from 30kWh/day down to 19kWh/day. My more recent days are looking even better (I just installed another 3 panels). I could probably cover another ~5kWh/day if I got a few more batteries. Right now I'm a wimp and don't like to discharge them more than 20% or so each day. From my energy provider, here are my last 7 days consumption:

Image: https://us.v-cdn.net/6024911/uploads/editor/lk/y9gh6skl096u.png

Giawa

giawa · July 2018

fasterski said:

Thanks for the Shneider FAQ link. Now I understand why I could not get it running as per manual. What I did in my case is I used one phase 15 AMPs coming in on a Wink Compatible Smart light module. I can control it remotely when the sun in ablaze (On schedule and override as needed) Found the setup will work for most of the stuff in the house (except central vac and saws).

Glad you found it useful! Their manual and marketing material are super misleading in my opinion.

Are you using the single phase switch to kill one of the AC input phases to get the inverter to operate in island mode? If so, that's a really cool solution! I didn't think of just killing a single of the two phases.

Cheers,

Giawa

MrM1 · July 2018

fasterski said:

Thanks for the Shneider FAQ link. Now I understand why I could not get it running as per manual. What I did in my case is I used one phase 15 AMPs coming in on a Wink Compatible Smart light module. I can control it remotely when the sun in ablaze (On schedule and override as needed) Found the setup will work for most of the stuff in the house (except central vac and saws).

Yes I am not fully understanding what you are doing. I am curious though. Anything to make it work better would be awesome.

MrM1 · July 2018

@giawa

I did come up with a "sorta" fix for charging and who the charger terminates absorb way too early to get a full charge (although I recall you not needing the charger?? Cant remember)

Anyway. The charge block feature!!!! It occurred to me a month or so ago. just set absorb volts and float volts to the same voltage and set the charge block to kick in at whatever time you want the charge to end. Works like a charm. Not perfect, but then at least you can stay in "absorb" (all-be-it via absorb / float ) for several hours rather than the 20-45 minutes I had been experiencing before the charge would terminate and go to float based on 2% or more of battery amp hour. You could skip charge block, but then you have to really monitor the charger or it charges until you remember to turn it off. hours, days, weeks ... yikes.

giawa · July 2018

MrM1 said:

@giawa
I did come up with a "sorta" fix for charging and who the charger terminates absorb way too early to get a full charge (although I recall you not needing the charger?? Cant remember)

Very cool! I'm glad the charge block feature did the trick for you. I never use the charger built into the SW, and instead rely upon the MPPT charge controller. The charge controller seems to do a decent job with my GC2 batteries. I checked specific gravity shortly after receiving the XW MPPT and it did a reasonable job. I haven't tried equalizing with the new charge controller yet, so I'll learn more at that time I imagine.

Dave Angelini · July 2018

You can get around the balance limitations of a small inverter by stacking them. That is what one would do offgrid

giawa · August 2018

For anyone looking to improve their AC support performance (the title of this post) I suggest you take a look at this post here: http://forum.solar-electric.com/discussion/comment/389558#Comment_389558

MrM1 had pretty good success with balancing L1 and L2 by using an autotransformer! Definitely check out his posts and the results (pictures/data included in that thread). Cheers,

Giawa

b. ecologìcAll · September 2018

any solution to this problem? that is for the SW to automatically use full sun power to avoid manually turning on and of AC in

fasterskii · December 2019

For anyone ever searching forms for modbus support via combox i was able to achive that with no additional hardware.

As mentioned by giawa combox runs modbus over TCP/IP on port 502. Navigation in web brower is Settings -> Modbus Communications - > Enabled ->TCP Port

Once you plug those in your software of choice (I used HomeAssistant platform) you can get the values. Here are home assistant configuration.yaml file entries.

This brings it to the next level in terms of automation of dump loads etc. when sun is plenty, notifications etc, monitoring, etc. Sky is the limit

I hope I save some folks some time. It took me a while to get this figured out (I was a modbus noob before got educated by some folks here and elsewhere on the www )

# Example ModBus Combox
modbus:
name: ComBoxS
type: tcp
host: xxx.xxx.xxx.xxx
port: 502

sensor:
#Combox Sensors
- platform: modbus
scan_interval: 60
registers:
    - name: "Solar Battery Current"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: AMPS
      register: 156
      data_type: int
      scale: 0.001
      offset: 0
      precision: 2
    - name: "Solar Current"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: AMPS
      register: 142
      data_type: int
      scale: 0.001
      offset: 0
      precision: 2
    - name: "Solar Battery Volts"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: Volts
      register: 152
      data_type: uint
      scale: 0.001
      offset: 0
      precision: 2
    - name: "Solar Battery Temp"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: °C
      register: 154
      data_type: uint
      scale: 0.01
      offset: -273
    - name: "Grid W"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: W
      register: 82
      count: 1
      data_type: uint
      offset: 1
    - name: "Solar Input W"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: W
      register: 68
      count: 1
      data_type: uint
      offset: 1
    - name: "Load W"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: W
      register: 98
      count: 1
      data_type: uint
      offset: 1
    - name: "Solar Today"
      hub: ComBoxS
      slave: 201
      unit_of_measurement: kWh
      register: 308
      data_type: uint
      scale: 0.001
      offset: 0
      precision: 2

Conext SW4024 - AC Support Performance

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