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OpenEVSE / openevse_esp32_firmware

OpenEVSE V4 WiFi gateway using ESP32
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Difference between "Setpoint" and "Current" about 3 Amp #855

Open rpatricio122 opened 1 month ago

rpatricio122 commented 1 month ago

I have an Opel E-Corsa 2022 and when I try to charge my car there is about 3 amps difference between the Setpoint and Current. I'm sending via MQTT the Voltage topic to Openevse to improve the calculations but no improvements found. In addition if the Setpoint is about 8 Amp then because of this difference the car and openevse keep trying to close the contactor but then fails.

Please let me know if there is need to upload logs to provide more information.

Screenshot 2024-06-04 at 21 16 40

Dicion commented 2 weeks ago

So actual pulled current is determined by your onboard vehicle charger. It could actually only be pulling 7.3A even though it was told 10A was available. It could also be a calibration issue with the ammeter on the EVSE. It's not the best, and is generally 'close enough' for most purposes, but perhaps yours is way out.

What (measured) voltage and frequency are you actually running into the EVSE? 208/220/240? 50/60hz?

The only way to know for sure if it's a calibration issue on the EVSE or your car pulling less than it's being told is to measure the actual output with a calibrated clamp when it is charging, and see what it is actually pulling, 100% accurately. Then you can see if it's the car pulling low, or the EVSE saying its lower. If you don't know how to do this, you can ask any electrician.

Does your car show actual AMPS on it's display when it's charging? or does it only display KW or Miles gained per hour?

When/If you determine that it's the EVSE that is off, I believe you can use $GA and $SA to see and adjust the ammeter offset/cal factors in the controller.

If you want to pull your current settings to sanity check them, run $GA in the developer RAPI section and post the output

I haven't changed mine, and I get this:

< $OK 220 0^20

So I assume that's the default.

If you want to read about the syntax and output information for RAPI commands, it's documented here in the RAPI headers file.

https://github.com/OpenEVSE/open_evse/blob/master/firmware/open_evse/rapi_proc.h

pdhoogh commented 3 days ago

The on-board charger is master. It can be asked to pull 10A but it does not have to comply. That may be the case if the SoC is nearing 100% and the charger is reducing charge current while balancing the pack.

I have an e-208 and rarely charge to 100%. But when I do, I always see the current drop to 6A or even lower near the end. When SoC reaches 100%, the on-board charger terminates the charging, regardless what te OpenEVSE setpoint might be.

Another way to see this is when the charge is initiated. The setpoint may be 6A or so, but the current first jumps over 6A, then goes to 0.7 A for a while and then moves to the OpenEVSE setpoint.