But look at post#54I am a little confused by all of this. First there are no public chargers, unless you count DC fast charging like the tesla supercharger, CHAdeMO or the DC combo plug. These are kind of like chargers in that the vehicle communicates with the permanently installed, land based charger, tells it what DC voltage and DC current it can accept, and then the equipment provides it. I am not sure about the Alta’s wiring and battery pack, but it doubt that it could accept the lowest level of current/power these devices can provide. These are high power (50-125kw) DC sources that would probably overwhelm our poor little Alta. Plugging into 50kw would give you a 6-7 minute charge time from completely empty. They do ramp the power and current down at the end of the charge cycle, so it may work, but they are not designed for this small a battery pack and you would need the vehicle communication equipment to tell the charger what to do.
J1772 equipment is not a charger, it is more appropriately called EV Support Equipment (EVSE). It is a source of power for the charger already installed in the vehicle. For safety it will not turn on until it is plugged into a vehicle, or a box that simulates a vehicle. Once it communicates with the vehicle, and finds the right signals, all it does is energize a large contactor to connect 120 Vac (Level 1) or 240 Vac (Level 2) to the box or vehicle. You can find the J1772 specs here on Wikipedia. J1772 should work fine with an SM that is enabled for 240Vac power, as long as you have a converter box that will accept the J1772 plug and tell the EVSE to close the contactor. Once the EVSE closes the contactor, it is just like plugging into a wall socket at home. The only issue would be that most public EVSEs are Level 2 (240 Vac) so you would need the firmware upgrade to enable that on a SM. The SM charger would still communicate with the Alta, just like it does when you charge at home, you would just be receiving power from the public EVSE instead of your house. Public EVSEs will do nothing for an EX or MX since it doesn’t have an onboard charger. To charge an EX or MX you would have to pack the charger with you (heavy).
I have installed J1772 on my 300ZX that I converted, and it is just a small board to provide the enable signal (about $50) and the J1772 female plug (about $100). It is easy to install and works good, but all it does is power the charger I have installed in my vehicle.