external meter with Deye instead of CT

[mateusz1945]

whatever Deye cloud ( and home assistant using deye data) calculates is is off by like 2kwh a day. (pea meter spinning disc meter showing more consumption)
i wonder if its worth to add meter like chnt ddsu666 (seen on aliexpress for like 15$)
- would it calibrate deye calculations? also i dont want to look outside at the meter every couple of days , neighbor looking at me funny 

* i already tried to change CT ratio settings  to calibrate it up and down and still error is the same,

[Crossy]

The Deye CTs are horribly inaccurate.

 

You can improve that accuracy by using an external meter, but there are only a few that work with the Deye (check your manual), doing this certainly improves the zero-export accuracy. This meter (not cheap) definitely works with the Deye 

https://www.lazada.co.th/products/i4470648921-s18041805611.html?

 

We also have a number of Hiking DS238-2 energy meters monitoring various stuff. These have RS-485 for remote reading, sadly they don't talk to the inverters.

 

In reality, the only meter that actually matters is the PEA one, the others are purely an estimate unless they are calibrated and certified.

[Bandersnatch]

2 hours ago, mateusz1945 said:

whatever Deye cloud ( and home assistant using deye data) calculates is is off by like 2kwh a day. (pea meter spinning disc meter showing more consumption)
i wonder if its worth to add meter like chnt ddsu666 (seen on aliexpress for like 15$)
- would it calibrate deye calculations? also i dont want to look outside at the meter every couple of days , neighbor looking at me funny 

* i already tried to change CT ratio settings  to calibrate it up and down and still error is the same,

 

I am quite happy with my Zemismart sensor, it seems pretty accurate as far as I can tell, but I don't have a PEA meter to compare it with.

 

I have started a discussion about smart home kit:

 

 

 

[lom]

5 hours ago, mateusz1945 said:

i already tried to change CT ratio settings  to calibrate it up and down and still error is the same,

The Deye inverters uses grid power themselves and that is not included in reported grid import, I guess they have their internal CT's in the wrong place..😉

I have 0.3 KWh grid import a day according to Deye but PEA's smart meter says 1KWh a day.

I can get rid of the ghost import if I run off-grid but it comes back as soon as I switch to on-grid mode which activates the grid relay in the inverter and I guess that is what is responsible for the ghost import.

 

[KhunLA]

On 11/1/2024 at 8:30 PM, lom said:

The Deye inverters uses grid power themselves and that is not included in reported grid import, I guess they have their internal CT's in the wrong place..😉

I have 0.3 KWh grid import a day according to Deye but PEA's smart meter says 1KWh a day.

I can get rid of the ghost import if I run off-grid but it comes back as soon as I switch to on-grid mode which activates the grid relay in the inverter and I guess that is what is responsible for the ghost import.

 

Mine is also about 0.3kWh a day, as PEA bill shows 9-10kWh a month, and we don't use it for anything, except the MG wall charging cable, which is rarely used, and the only thing on the grid.

[lom]

I have had my external CT's disconnected for a few days while moving them one notch closer to the incoming grid, they were placed after an incoming grid electronic voltage/current/frequency/phase fault detector which must draw something even if very little.
I have therefore, without external CT's also changed my setting from "no export to ct" to "no export to load". The ghost import is still the same 1KWh/day according to PEA, 0.3KWh according to Deye.

I have looked at the "purchasing power" graph in SolarMan and have disabled display of other graphs in order to get a good  resolution. There is according to SolarMan a constant import between 0-20W but also a couple of quick but higher peaks (100-300W) during the day and they all seem to be related to Deye power tracking.

Example:

1. A high peak in consumption causes a high peak in import even though there is enough panel or battery power available to handle that consumption peak without importing from the grid.

2. A quick drop of panel power (a cloud arrives) causes a high peak in import even though consumption is low (1.5 - 2.5KW) and there is enough battery power available.

3. Rapid variations on the incoming grid causes a high peak in the import, slow variations in grid voltage doesn't do that but may be what is responsible for the up to 20W consumption.
The PEA meter did not move at all when I for weeks ran the inverter in off-grid mode and the inverter did then of course not record any import either.  

So my conclusion is that the inverter resorts to import if it can (has grid connection) when it sees sudden changes in incoming grid, in consumption, and in production.

 

My OCD still want's to know where the other 0.7KWh is going though...

[mateusz1945]

UPDATE:

finally bought and installed Eastron sdm-230 meter (the one without CT)
tested for the whole billing cycle and here are results:
before Eastron : ~ 20% mismatch with PEA meter  ( underestimate consumption- bill higher that deye numbers would suggest)
after    Eastron   :   2-3% underestimate PEA meter

so i would say accuracy improved by 10 fold. meter from PEA likely is slightly biased towards overcharging than losing money for utilities so it is acceptable.
meter itself is not very useful to look but at least data collected from inverter either to deye cloud or home assistant is reliable and could be useful for correct calculation and statistics.