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Harold Halewijn avatar image
Harold Halewijn asked

EV Charger calibration issues

Hi, I'm using the EV Charger (old style) for 12 months now. Until now I didn't pay attention to the power calibration so I can't tell you if this was differently with previous firmware versions.

If I want to charge 3-phase cars, I have to set the power calibration setting to 0.8 to reflect real power. I can check this with smartmeters in my cabinet. But when I charge a hybrid-car (single phase) I have to change the calibration setting to 1 to see real power taken.

schermafbeelding-2023-08-18-105643.png

These pictures show the charging of single phase. You can notice the charge rate reported by EV Charger (2783) and the AC loads (4729, there are some small additional loads there).

schermafbeelding-2023-08-18-105730.png

Above picture is with power calibration set to 0.8

next picture shows right value after changing to 1.

schermafbeelding-2023-08-18-105747.png

If yoy want, I can supply the same pictures for a 3 phase car.

Why is this?

ev charging station
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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Hi, the power measurement is not very precise as we are only measuring the current and not the voltage. So the power displayed is just an approximation
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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
That's kind of a big oops for me as I'm using the numbers to do expenses every month.

Also, Harold is mentioning 0.8 and 1.0 to get his numbers matching from 3 to one 1 phase. That's a 20% difference whereas he most definitely never ever has a 20% voltage sag during charging.

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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
If you have a moment @Lucian Popescu (Victron Energy Staff) I think this thread is pretty important for some users including myself. I have also read the thread about users discussing the future/new reporting feature in VRM to charge their company or their employer. All of that is not realistic if the numbers are this far of.

For me there is no way to explain the 20% gap that Harold has experienced just because you don't know the voltage. If his numbers are showing up on other users dashboards as well, this is not "just a minor inconvenience". Specially because people don't even realise they actually have a problem to begin with.


If it's only the voltage that is missing and the current is pretty accurate, it would not be too difficult to "help" those users by writing a flow that sets the EVCS power calibration automatically based on the voltage you are using for your estimations (230 I presume) and the voltage taken from the grid meter or the inverter. This would not be 100% accurate and it will not cover power factor deviations during the start and stop process. But it will come closer than what you have now if charging at night with no wind energy (225V?) or by day if the whole neighbourhood is generating solar (235V and up)?

But all this does not fix nor does it explain the 20% gap.

I had a funny experience myself this afternoon. A friend had his M3SR set to 100% and at the end of the charge process the car was only taking 1kW for a long time. As the house was empty and almost everything is metered I know for a fact there were no other consumers with significance. The ac-load said 1.1kW spread over 3 phases, the car said it was taking 1kW, but the charger said 0W charging. Lasted for over 30mins if memory serves me well. This showed both on VRM and on the charger webpage.

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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ kudos50 commented ·


For me, it's pretty accurate, this is my charging session today.
If you have a meter installed where the EVCS is installed, and you see big differences, we can have a look.


1709055594696.png



1709055663407.png


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1709055594696.png (87.9 KiB)
kudos50 avatar image kudos50 kudos50 commented ·
I did. In fact, not knowing it only measures current I simply added an approved meter in between and charged 2 or 3 times to set the factor. The house ended up with 0,97 and 0,98 and the garage ended up with 0,81, 0,83 and later 0,89. For the same car, the same afternoon. An 8% difference that cannot be explained by voltage alone.

I don't have room to keep it metered all the time but I can connect it again some day to redo these tests. Both charger numbers are still off compared to the readings from the car. M3, MX and ID3.

Think this afternoon for the M3 the EVCS said 20 and the car only said 18 (with a 0,97 factor)

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kudos50 avatar image kudos50 kudos50 commented ·
Numbers with M3 are consistent with MX for this test. With calibration set to 1.0 I got 0,853 for the MX and 0,847 for the M3.

Will keep it connected and do it again with the ID3 this evening. From that I will try and change variables like charge current, wait for sun early next week etc etc..

For now not able to reproduce the constantly changing consumption numbers.

However. My MX is solely responsible for the odd charge current. A 12A setting on the EVCS has the following results in the EVCS power readout:

MX: 8400 (x 0,85 = 7140 with 224V = 10,6A = ~11A)

M3: 9500W (x 0,85 = 8075 with 225V = 12A)

I did re-run the CP calibration but the outcome obviously remains unchanged. The MX simply takes less power on the EVCS than it does on Elvi or TWC.

Will report the numbers for the ID3 as well this evening. Could be the 17kW unit from the MX just negotiates differently. I have the raven whereas your screenshot is palladium I think?

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