MikeD wrote:Ingineer: Care to comment on advisability/effectiveness of AFCI detection especially if you are correct that worn-out plugs/inlets are inevitable? Or do you think the best approach is that worn-out/damaged plugs/inlets are able to be routinely repaired/replaced? I am concerned about the possibility that a worn-out/damaged public charger plug could spread damage to car inlets (and vice versa)...
I have not tested AFCI's for this application. On a standard Leaf charging at only 16A, I just don't see this happening, but when we start getting up to around double that, the chances of problems go up markedly.
The right thing to to is for the software in the on-board charger (OBC) to be modified to detect things like this and issue a warning. On the CHAdeMO port, they have a thermistor to detect problems like this, but this is because there can be well over 100 amps of high-voltage DC flowing (Arcing would be disastrous!). Obviously the addition of a thermistor to the J1772
port would also go a long way toward detecting these kinds of failures.
I would design the algorithm to reduce charging power and alert the owner in the event of a high resistance (sagging voltage) or arcing event.
Keep in mind, if a public charger gets a failed contact like Tony's, I seriously doubt it will "spread". It will kill one hungry EV, then be damaged too badly to be used again.
It's obviously prudent to at least take a glance at the condition of J1772
handle connectors before blindly inserting them into your EV. Report any apparent damage to the station owner so they can fix it.
It's too bad the J1772
pins were designed so thinly. They are about the same cross-section as a #12 AWG wire (3.6mm), which nobody would not consider sending 70 Amps though, let alone 30, but someone decided it was ok.