Have been running a Axpert King with Solpiplog to ingest data via MQTT and onto Node-Red where the heart of the system lives.

However, the issue, not a problem I have is that Solpiplog doesn't extract the battery Watts as what is displayed on the Inverter panel. I can calculate this myself W = Battery V x Battery Discharge Amps

But the slight inconvenience I have is that the Discharge Amps aren't in decimal, so I can never 100% calculate the exact watt usage at a given interval. Would this perhaps be a display firmware related issue that is preventing the Battery Watts shown on the inverter to be ingested via MQTT, OR, am I needing to find an alternative way to calculate?

Or perhaps there is a better ingestion program like Solpiplog?

TIA
Grant

19 minutes ago, grant.cpt said:

Have been running a Axpert King with Solpiplog to ingest data via MQTT and onto Node-Red where the heart of the system lives.

However, the issue, not a problem I have is that Solpiplog doesn't extract the battery Watts as what is displayed on the Inverter panel. I can calculate this myself W = Battery V x Battery Discharge Amps

But the slight inconvenience I have is that the Discharge Amps aren't in decimal, so I can never 100% calculate the exact watt usage at a given interval. Would this perhaps be a display firmware related issue that is preventing the Battery Watts shown on the inverter to be ingested via MQTT, OR, am I needing to find an alternative way to calculate?

Or perhaps there is a better ingestion program like Solpiplog?

TIA
Grant

Sadly this is a constraint, the battery current is exposed on RS232/USB protocols (QPIGS) as whole integer only, so the resolution is 1 ampere. I am surprised that the display reads a higher resolution, as the acquisition accuracy of the inverter inferring the battery current is already  low. 

The only alternative is to read the battery metrics from your bms, that is if you have one. 

EDIT: it could be that if your bms is already connected to the inverter, that the inverter displays thr bms metric, but the QPIGS protocol still only can provide 1A resolution. 

If i am not mistaken there is a QBMS command on later models/firmware. We will have to ask @Coulomb if he knows more. 

 

 

Edited December 31, 20222 yr by BritishRacingGreen

1 hour ago, BritishRacingGreen said:

Sadly this is a constraint, the battery current is exposed on RS232/USB protocols (QPIGS) as whole integer only, so the resolution is 1 ampere. I am surprised that the display reads a higher resolution, as the acquisition accuracy of the inverter inferring the battery current is already  low. 

The only alternative is to read the battery metrics from your bms, that is if you have one. 

EDIT: it could be that if your bms is already connected to the inverter, that the inverter displays thr bms metric, but the QPIGS protocol still only can provide 1A resolution. 

If i am not mistaken there is a QBMS command on later models/firmware. We will have to ask @Coulomb if he knows more. 

 

 

Thank you so much for your detailed response. And for confirming my suspicions. Currently the PylonTech bank is connected to the inverter, but will need to take a look at how I can ingest the information from the BMS as well via Solpiplog. I know it is possible, but not sure what cable should be used

Above is what I get back from the QBMS query from the inverter.

089 is the battery percentage, but I'm unsure about the other numbers

13 hours ago, BritishRacingGreen said:

If i am not mistaken there is a QBMS command on later models/firmware. We will have to ask @Coulomb if he knows more. 

As of Axpert King display firmware version 02.66 (the one that I have best commented), the values returned by QBMS are:

      ; a: BMS DISconnected
      ; b: BMS SOC %
      ; c : BMS force charge
      ; d: BMS stop discharge
      ; e: BMS stop charge
      ; f: BMS CV voltage in tenths
      ; g: BMS float voltage in tenths
      ; h: BMS cutoff voltage in tenths
      ; i: max charge current
      ; j: max discharge current
      ;

So: only values supplied by the BMS, not stuff related to what the inverter is doing.

Edited January 1, 20232 yr by Coulomb

On 2023/01/01 at 9:12 AM, Coulomb said:

As of Axpert King display firmware version 02.66 (the one that I have best commented), the values returned by QBMS are:

      ; a: BMS DISconnected
      ; b: BMS SOC %
      ; c : BMS force charge
      ; d: BMS stop discharge
      ; e: BMS stop charge
      ; f: BMS CV voltage in tenths
      ; g: BMS float voltage in tenths
      ; h: BMS cutoff voltage in tenths
      ; i: max charge current
      ; j: max discharge current
      ;

So: only values supplied by the BMS, not stuff related to what the inverter is doing.

Thank you for the information. I agree, the information isn't much useful in what I'm looking for.

How best would I perhaps be able to get a more decimal amps value (discharge) or the Battery Discharge Watts displayed on the inverter (if you have any idea)?

 

19 hours ago, grant.cpt said:

How best would I perhaps be able to get a more decimal amps value (discharge) or the Battery Discharge Watts displayed on the inverter

As a quite long shot, you might be able to duplicate the inverter's calculation of battery watts, knowing for example that it typically uses 0.93 as an efficiency figure. You could use that to compute battery current using the battery voltage. and compare that with displayed current in whole amps. Note that they usually truncate, not round to nearest, for all displayed values. If that seems to line up, then you'd have confidence in this method. I can't recall off-hand if it takes into account idle self-consumption; bug me for details later if you need this and can't guess it.