Question

Load balancing does not work ok.

I have 3x20A fuses, Max power from the grid set to 20A and I'm on the latest FW v1.4.2.

If my house consumption is low and I start charging it charges full power 11kW. I can also see on the meter 16-18A (charging+house load) on each phase, everything ok.

Now if I start the oven, the charging stops and I can see on the meter L1 1A, L2 0.5A, L3 11.3A which is house load with the oven on. Offered current decrease to 9A (i see over OCPP) and if I monitor my tesla app I see max offered power 8A, still everything ok.

The charger now starts increasing current from 0 to 8A, but when it comes to 4 or 5A charging stops and starts from zero again to 4-5A. This repeats over and over again. I left it for 15 min and it was still doing the same thing, inc. to 4A and stops. If I stop the oven, offered power returns to about 18A, and then normal charging continues.

Something isn't right here.

Answer 1

Dear Rado, first of all, thank you for using our product.

We will need additional info to better understand the problem, what causes it and how can be solve it.

If you can, please provide the screenshots of the settings (both normal and installer settings) from the Teltocharge app.

What Tesla model are you using? US/EURO type charging port?

Is normal charging (without the oven on) is perfomed in 3 ph mode or in 1 ph mode?

Is smart charging enabled in the OCPP settings?

Is dynamic load balancing working correctly with lower load of the grid?

Will wait for furthers details.

Sincerely, Danielius.

Comments

@Danielius
I've installed the latest FW, but still not working as it should. Settings same as above. Now the offered current does not get lowered enough. 

and the current goes over the 20A limit.

As I understand none of the 3 phases should go over the 20 A limit.

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Dear @Rado , thanks for the feedback. Could you provide a screenshot of the installer settings or the troubleshoot file from diagnostics menu? By any chance, have you contacted support and provided those details? Something strange is happening. Just to be clear, are you using ocpp and dynamic load balance enabled? If ocpp is enabled, could you try dlb without the ocpp turned on? With the FW updated to the latest, in the case when oven is turned on, does Teltocharge show any warnings or some other relevant info?

Additional question. Is the phase sequence the same in the meter and charger? Is the phase 1 that is connected to the meter and after the meter goes into slot L1 in the charger, as well as phases 2 and 3? As we use a compensation method to evaluate how much current that the meter is showing is provided by that Teltocharge phase, the mixing of phases will introduce incorrect results which might be the case here. If you could, please check the phase order of the meter and the Teltocharge to be the same.

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@Danielius will try to gether the info over the weekend and let you know. Do I write it here or to support, where to? email?

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@Rado if you are able to, please write to vip help desk.

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Hey @danielszilagyi, thanks for the feedback. At first I was thinking about rounding issues for load balancing, however, the 7 A limit clears up a situation. Charging standard IEC 61851 says that the minimum charging current by PWM is 6 A. In our DLB algorithm, we set the current to 7 Amps. So in this case, if you set the current to 7 Amps, the PWM is 6 A / 0.6 = 11.667 -> 12 %. In this case the EV is drawing 5.8 Amps instead of 7 Amps, which seems to be the trait of the vehicle. 

Answer 2

@Danielius yes the phases were mixed up by the installer. I fixed the order and seems to all work correctly now. Need to do more testing. Sorry for the trouble.

Answer 3

nope, still an issue. OCPP on, load balancing limit set to 20A. House current usage before start L1 1.6A, L2 2.2A, L3 11.8A. Charging starts 0/8A ..when the charging current comes to 8A stops and starts over and over again. Then I disabled OCPP just using the app and seems to work ok. No more charging interruptions and the current stayed under 20A.

vip help desk? where it is?

Comments

@Rado, thanks for providing feedback. So if I understand correctly, dynamic load balancing seems to be working fine when ocpp is disabled, but when ocpp is enabled there is a constant turn on/off of charging. Is that correct? If that is the case, we will need to look into ocpp stuff as well.

If you're unfamiliar with the vip helpdesk, you should contact your sales manager.

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yes, you understand correctly. I'll test again on the next charging session and let you know if I find out anything else.

Answer 4

Hi, I did more testing this weekend and noticed isn't any difference if using the app or ocpp (at least this time). Settings same as above. House had minimal consumption 0-2A per phase. I started charging and everything was ok (went to 11kw), then I turned the oven which uses about 11A on L3. Charging stopped and switched to "one phase" charging on L2 offering 20A. I left it for some time and then turned the oven off. Charger continued to charge only on one phase with 20A. I had to stop charging and start it again to regain 3 phase charging, althought there were no load on other phases. I'm getting frustrated with this charger. This isn't load balancing.

I've downloaded the troubleshooting log file if can help you. Tell me where to send it.

Comments

@Danielius looking forward to the solar mode, but first fix basic load balancing.
By the way, did you discuss the option to add HTTP json endpoint to the charger? ..where charger and meter values could be read.

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Hi @Danielius,

Thanks for the OCPP power registers, I implemented it in software but now I no longer need it.

I made a long video which I then made timelapse so it’s only 3 minutes long which explains better the issue about the load balancing/limiting. It’s not solar related (time on the screen is AM) and not a really big issue, but the point is if the charging limit is set to 16A then the car would charge with maximum 14.8A, if limit is 17A it will charge with 15.7A and so on… not really annoying but I want to implement current limiting based on solar production in my home automation for the summer and 1A is not much but in this case this is not optimal.

Especially that with some values (13A) it works as expected. Video: https://youtu.be/CYT1_aSEejE

My car is charging on two phases only, maybe related?

By the way, after update to 1.6 I got an eeprom value out of range error in the app, but everything works as expected. I do not have vip helpdesk account, shall I contact the local reseller?

thanks,

Daniel

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Hey @danielszilagyi, thanks for the feedback. At first I was thinking about rounding issues for load balancing, however, the 7 A limit clears up a situation. Charging standard IEC 61851 says that the minimum charging current by PWM is 6 A. In our DLB algorithm, we set the current to 7 Amps. So in this case, if you set the current to 7 Amps, the PWM is 6 A / 0.6 = 11.667 -> 12 %. In this case the EV is drawing 5.8 Amps instead of 7 Amps, which seems to be the trait of the vehicle. 

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Hi Danielius,

Thank you for the prompt reply. No, I understand that the car probably stops charging at 6A (7A).

I did not want to make the car stop charging in the video, it was an error on my end as the slider is a bit hard to adjust amp by amp on the phone.

I wanted to show this difference (charging limit set to 16A, car drawing 14.8A / charging limit set to 17A, car drawing 15.8A) which is kind of a behavior, and wanted to ask if it is due to some rounding and if it could be improved (I would change the max current with an automation based on the solar inverter’s production and other consumption to make sure the charging is made from solar energy, but it’s a small difference so probably can just live with it)

Could you please answer the eeprom value out of range question?

thanks,

Daniel

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Hey Daniel,

we use 1 % accuracy, which, based on the equation from the charging standard would give a step of 1 / 0.6 = 1.667 Amp, so 1 - 2 Amp step for the vehicle.

Regarding the Eeprom value out of range, this flag/warning shows that new addresses of eeprom are used with the newer FW which were not used previously (or the limit of values for that address has changed and currently set value is out of the defined range). After the update, if the value for that address is out of range, a default value is set and "Eeprom out of range" flag is activated. A simple restart of the EVSE should clear the flag.