Chademo vs SAE DC Technical Differences

[hbleaf]

Not sure if this is correct forum but I wanted to see if anyone here has answers to these ??s

Chademo is a current controlled specification as such its topology doesn't make voltage control necessary. Instead a large blocking diode prevents backfeed into charger and the power module is expected to come up to needed and asked for current request (via CAN).

From the SAE standard a Voltage control is needed. The SAE charger is expected to voltage match the pack voltage before contactors are closed to prevent in or outrush currents (ie stable v - v the same pack to charger).

These methods are very different and I'm wondering how charger manufactures will handle that in a combo device. I guess a charger could be made to do both and software mechanisms could decide which method to deploy based on which charge cord is selected by the user.

Steve

 

[garygid]

As part of starting up, the car asks Chademo to deliver a fraction of an amp after
the contacts are closed. It is up to the QC machine to match voltage and begin
to deliver the trickle of current as specified. Quickly, the car asks for more and
more current, ramping the current up to around 120 amps, or whatever the QC said
that it was capable of delivering.

The BIG difference between the two standards is the differential CAN communication
used by Chademo, and the proposed ground-referenced communication in SAE.