Tesla now logging AC waveform from charger

[Ingineer]

In the most recent software versions, (2.17.X) I've noticed Tesla has added a new function that records the AC waveform during charging. Here's an example of the data graphed:

The data is stored on the Gateway's 4G SD card located in the MCU. Each file appears to contain three 2.6k 16bit samples of approximately one cycle of the AC waveform.

It's not clear if these are being recorded when there is a disturbance, at regular intervals, or both. The files are named as hex versions of the UNIX timestamp and located in a directory called CHG_WVFM.

Pretty neat though!

 

[GlmnAlyAirCar]

Apparently an attempt to troubleshoot charging problems?

 

[Saghost]

Interesting. I wouldn't have assumed that the car had the right equipment to map and record the waveform - AFAIK that isn't a normal part of charger hardware.

 

[Ingineer]

The charger submodules all sample input voltage. All that has to happen is the gateway read these over CAN and record them to it's SD card. It doesn't need anything added except for software.

 

[Saghost]

The charger submodules all sample input voltage. All that has to happen is the gateway read these over CAN and record them to it's SD card. It doesn't need anything added except for software.

That makes sense - provided they are sampling the voltage at a high enough rate to show the curve shape (which you just proved they are, of course. In my ignorance I would have assumed the power was just rectified into DC and then smoothed and boosted to battery voltage, none of which requires such detailed sampling of input AC line voltage that I can see.

 

[AWDtsla]

Hopefully they can do some fancy stuff with it like arc fault detection, and not have current drop at a simple 8% voltage drop. Charging at 198V and 22A sucks.