You'll never guess what happened next! ... sorry.
I upgraded my garage's circuit to 40A (futureproofing) and installed a 16A caravan socket for my freshly arrived japanese import, and a 16A charger w/ caravan socket from OEMAudio.
It's been charging nicely over the last month. It goes up to 18.6A draw consistently, which I didn't really think anything of ("cool, faster charging!").
Turns out I should have thought a bit more about it because over the course of that month, those extra couple amps were melting the caravan plug and socket! One day I plugged it all in and noted a buzzing noise coming from it. Later in the day (I know, lack of thinking) I came back and the charger had stopped with a temperature error - it was at 74C. The plug was totally fused in the socket and I couldn't pull it out.
Sparky came the next day and got it out for me, he confirmed that the neutral pin on the charger's caravan plug had melted and fused with the socket. The circuit had a 40A fuse so the caravan socket effectively became the fuse in the circuit I guess :D
Now you might be wondering
- "why did the charger rated for 16A supply more than 16A and melt itself?"
- "aren't japanese leafs 16A max, I thought only UK leafs could be 32A, why is it accepting more than 16A?"
and those are good questions!
which I also have!
Supposedly there's a pilot signal that occurs between a charger and a car which negotiations what amperage to be used. According to this table it seems like both the car and the charger should be agreeing on 25% PWM to achieve a 15A continuous supply.
It's easy to point fingers at the charger here. After all, if you came along and plugged a 32A car in you wouldn't expect the charger to decide to self-immolate and try push 32A through.
But wouldn't the car also say "hey whoa there, stop at 15A buddy"? Which brings me to another question: how do I actually know what my car's onboard charger is? Supposedly only UK leafs have the 32A option (6.6kW charger) but this is a japanese import 916A / 3.3kW). It has two times on the dash but that doesn't seem very scientific.
Is there a piece of hardware on the car I can inspect or something?