Apparent discrepancy between metering systems

[sathornlover]

9 hours ago, lom said:

 

I blame the discrepancy you have from the way your  inverter measures power,  it seems to me that it counts the import correctly during night when there is no PV (ie no export) but fails in the day when there is PV and export.

It can't get it right when there is export and import at the same time?

 

 

 

 

 

Heureka, wow, that's it, now I've finally understood it, thank you very much for the patient, small-scale curve discussion, please forgive me for my clumsiness, lack of solid basic knowledge of electrics, last night when I read this I found it very difficult to accept what you were asking me to do, but after a good night's sleep everything is fine. and I also agree with your assumption that the Huawei software unfortunately omits this necessary import and export,-(

[sathornlover]

9 hours ago, lom said:

Ok, your graphs had no time markings so I guestimated the time and missed half an hour and I did not count the short morning 

 

Sorry for that!

 

[sathornlover]

On 2/4/2025 at 11:51 AM, lom said:

Have it connected in 3-phase mode so that you can use your own produced electricity from all 3 phases instead of buying electricity from PEA!! You are selling blue and yellow phase power to PEA at a lower price than what you pay for the import from them on the green phase.

I will most likely ask my PV system installer to do this job. If I have understood you correctly, which you have taken so much trouble to explain to me, I think we can now expect the following from this three-phase upgrade of the charger: 

 

Firstly, the car will actually be charged predominantly with solar energy, 

 

secondly, logically, the previously necessary export imports should then at least be significantly reduced, 

 

thirdly, the charging costs should then logically be lower in the most favourable case, at least with this charger, if I adjust it manually or with the help of software with corresponding compatible electricity meters, actually charging almost 100% with solar energy! 

 

Fourthly, the discrepancy between the electricity meter from the power grid and the Huawei. electricity meter will decrease considerably. 

 

However, I assume that this discrepancy will remain in the one to lower double-digit range if the assumption is correct that the Huawei software at the top level does not correctly represent the actual exports/imports in the event that one phase requires more electricity than the solar system can supply, while at the same time the other two phases or even just one phase exports excess electricity at the same time. 

However, I think I could live with this outcome. 

 

Such an upgrade should:

reduce the charging costs where the electricity can be sold to the electricity supplier by at least 50 % and otherwise by at least 66 %, 

This could mean that the upgrade would pay for itself in between one and a half and seven years ...

 

Unfortunately, I first bought an electric car for which I was given a single-phase device including installation as a free extra. It was only six months later that I decided to have the PV system installed and then another six months later that I received the three-phase ABB as a free extra with my second electric car. 

From what the Huawei app and also the website on the top level showed me, I stupidly assumed that we would charge both our cars mainly with solar energy. Another six months later, almost a year and a half after the PV system was installed, the electricity provider finally installed the digital electricity meter and the rest is history...

[UWEB]

3 hours ago, sathornlover said:

I will most likely ask my PV system installer to do this job. If I have understood you correctly, which you have taken so much trouble to explain to me, I think we can now expect the following from this three-phase upgrade of the charger: 

 

Firstly, the car will actually be charged predominantly with solar energy, 

 

secondly, logically, the previously necessary export imports should then at least be significantly reduced, 

 

thirdly, the charging costs should then logically be lower in the most favourable case, at least with this charger, if I adjust it manually or with the help of software with corresponding compatible electricity meters, actually charging almost 100% with solar energy! 

 

Fourthly, the discrepancy between the electricity meter from the power grid and the Huawei. electricity meter will decrease considerably. 

 

However, I assume that this discrepancy will remain in the one to lower double-digit range if the assumption is correct that the Huawei software at the top level does not correctly represent the actual exports/imports in the event that one phase requires more electricity than the solar system can supply, while at the same time the other two phases or even just one phase exports excess electricity at the same time. 

However, I think I could live with this outcome. 

 

Such an upgrade should:

reduce the charging costs where the electricity can be sold to the electricity supplier by at least 50 % and otherwise by at least 66 %, 

This could mean that the upgrade would pay for itself in between one and a half and seven years ...

 

Unfortunately, I first bought an electric car for which I was given a single-phase device including installation as a free extra. It was only six months later that I decided to have the PV system installed and then another six months later that I received the three-phase ABB as a free extra with my second electric car. 

From what the Huawei app and also the website on the top level showed me, I stupidly assumed that we would charge both our cars mainly with solar energy. Another six months later, almost a year and a half after the PV system was installed, the electricity provider finally installed the digital electricity meter and the rest is history...

What for EV's do you have, are they 3 phase charging capable? I have the same setup like you want to have with 3 phase power supply, 3 phase Solar and installed ABB Charger as 3 phase, but when charging the Car the Charger uses always the same phase as my Seal has 1 phase charging only. From the charging experience I have I can charge on a sunny day with a rate of up to 5.5 kwh before the Charger starts using additional Grid Power.

[lom]

You would at least reduce your import and pay less to PEA by wiring the charger for 3-phase and hopefully it will also correct the metering discrepancy. I still don't get how a big player like Huawei can do that kind of mistake which if true ought to be a software bug.

Ask the guys from the PV installer to also confirm that you have 3 external current transformers (CT) which measures current flow to/from the grid and that all consumers are installed behind the CT's so that there is no consumption hidden from them.

Your graphs of the 3 phases says that you have them but have the installer confirming it.

[lom]

14 minutes ago, UWEB said:

What for EV's do you have, are they 3 phase charging capable? I have the same setup like you want to have with 3 phase power supply, 3 phase Solar and installed ABB Charger as 3 phase, but when charging the Car the Charger uses always the same phase as my Seal has 1 phase charging only.

Good point! That the car may only have single phase charging was something I didn't think of.

 

14 minutes ago, UWEB said:

From the charging experience I have I can charge on a sunny day with a rate of up to 5.5 kwh before the Charger starts using additional Grid Power.

Hmm.. You have such a high power inverter that it can deliver 5.5KW on a single phase?

[sathornlover]

24 minutes ago, UWEB said:

What for EV's do you have, are they 3 phase charging capable? I have the same setup like you want to have with 3 phase power supply, 3 phase Solar and installed ABB Charger as 3 phase, but when charging the Car the Charger uses always the same phase as my Seal has 1 phase charging only. From the charging experience I have I can charge on a sunny day with a rate of up to 5.5 kwh before the Charger starts using additional Grid Power.

Also the Seal 2023, thanks for the tip, I had almost feared that too, everything points to that. BYD itself has not commented further, specifically about the onboard charger, at least as far as AC charging is concerned. As far as I remember, all the Thai versions of the car are 7.5 kW and thus significantly devalued, and the fact that BYD gave away the actually really great charger with only a one phase breaker speaks for itself...

[UWEB]

37 minutes ago, lom said:

Good point! That the car may only have single phase charging was something I didn't think of.

 

Hmm.. You have such a high power inverter that it can deliver 5.5KW on a single phase?

I have 2 x 10 kw Deye Hybrid Inverter and a total of 21 kwp installed.

[lom]

20 minutes ago, sathornlover said:

Also the Seal 2023, thanks for the tip, I had almost feared that too, everything points to that. BYD itself has not commented further, specifically about the onboard charger, at least as far as AC charging is concerned. As far as I remember, all the Thai versions of the car are 7.5 kW and thus significantly devalued, and the fact that BYD gave away the actually really great charger with only a one phase breaker speaks for itself...

Does the ABB charger allow you to set a charging limit? If it does then you can set it so it is below what your inverter can produce from PV and charge for a longer period instead to avoid import. Start charging earlier in the day if you can, charge less but charge every day if you don't do that already.  Or buy a 3-phase DC charger for home....

[sathornlover]

9 minutes ago, lom said:

Does the ABB charger allow you to set a charging limit? If it does then you can set it so it is below what your inverter can produce from PV and charge for a longer period instead to avoid import. Start charging earlier in the day if you can, charge less but charge every day if you don't do that already.  Or buy a 3-phase DC charger for home....

yes, it works with this charger, and that has tended to be my charging strategy, but so far I have orientated myself according to what the Huawei app has led me to believe...

[UWEB]

29 minutes ago, sathornlover said:

yes, it works with this charger, and that has tended to be my charging strategy, but so far I have orientated myself according to what the Huawei app has led me to believe...

If you really want to use Solar Power for charging your Car you have with the ABB Charger the option to install a Smart Meter, but that comes with a price and the problem that it's almost impossible to find  a Company to install this one for me. Fortunately I have not really a clue about electrical Systems, so I will not touch my installation.

I have an ABB Installation Guide for it, but it's a PDF File which I can't attach here.

[sathornlover]

26 minutes ago, UWEB said:

If you really want to use Solar Power for charging your Car you have with the ABB Charger the option to install a Smart Meter, but that comes with a price and the problem that it's almost impossible to find  a Company to install this one for me. Fortunately I have not really a clue about electrical Systems, so I will not touch my installation.

I have an ABB Installation Guide for it, but it's a PDF File which I can't attach here.

Yes, I am aware of the option and I have already hinted at it slightly in my comments, but it is very interesting to see what else you have written about it. My PV installer suggested that I implement a corresponding Huawei charger as a solution, certainly at a certain price. I then referred to my similarly well-equipped charger. But unfortunately, this great feature doesn't get me out of the annoying BYD single phase limitation either 

[UWEB]

59 minutes ago, sathornlover said:

Yes, I am aware of the option and I have already hinted at it slightly in my comments, but it is very interesting to see what else you have written about it. My PV installer suggested that I implement a corresponding Huawei charger as a solution, certainly at a certain price. I then referred to my similarly well-equipped charger. But unfortunately, this great feature doesn't get me out of the annoying BYD single phase limitation either 

At least you wouldn't import any power from the Grid to charge your Car when installing a Smart Meter, off course that would not change the max. 7 kw charging limit of the Seal.