@whitequark
The real horror is that #EXI is used in an ISO 15118 sandwich on top of HomePlug AV (with broken encryption) and TCP (mostly with no encryption, but sometimes mixed with a wild PKI) to real-time control up to a Megawatt of electric power flowing into a car.
@whitequark
And to add to the horror, all of the cars and chargers are in the same physical powerline broadcast domain, so when another car is plugged in, it needs to broadcast ping and measure the response signal strength(*) to find out which charger it's connected to...
And once the data channel is up, you authorize the payment with the absolutely unforgeable and secret... *checks notes* serial number of your RFID card!
(*) SLAC (Signal Level Attenuation Characterization)
@ge0rg @whitequark yeah, I think one alternative had been “single wire CAN” over the control pilot pin, as used by Tesla Superchargers back then. 83kbps, bidirectional, the basics known by everyone in the industry, a pragmatic and completely sane solution for the problem of charging cars, with much future expandability to spare. Pretty much on point.
But then we came into the “design by committee” phase of EV charging, and now we have this fucking thing.
@vogelchr @ge0rg @whitequark Yeah, that's the part about EV charging that I never understood: What decisions resulted int using a standard derived from residential power line communications being used for vehicle-to-charger communications since
- It's not even powerline with the physical layer impairments that come with it
- They could have used CAN or single-pair ethernet
Was someone on that committee really destined to find new markets for their existing powerline communications protocol?
It's interesting how the DC charge protocols for cars and phones both have their roots in powerline communications, but shed the powerline part by the time they got widely implemented. Leaving us with PHYs that seem inappropriate for their current use.
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Ge0rG
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