EVSE or dryer outlet?

[jim]

I fund this to explain it. ALSO I have an EVSE spy using that tells me the max amps even when my spark EV just pulls 12 amps.
QUOTE=Simply put, EVSE is a protocol to help keep you and your electric car safe while charging. Using two-way communication between the charger and car, the correct charging current is set based on the maximum current the charger can provide as well as the maximum current the car can receive.Oct 28, 2010

 

[Pushmi-Pullyu]

How does the EVSE know what size breakers are installed on the line?

I'm very far from being an electrician, but it seems pretty clear to me that the EVSE would have absolutely no way of knowing what the circuit it's connected to is rated for, in terms of continuous amp draw. That is, I think, the biggest reason why you need a licensed electrician to check out the circuit before you start using it to charge an EV.

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[jim]

I'm very far from being an electrician, but it seems pretty clear to me that the EVSE would have absolutely no way of knowing what the circuit it's connected to is rated for, in terms of continuous amp draw. That is, I think, the biggest reason why you need a licensed electrician to check out the circuit before you start using it to charge an EV.

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Right, Just look at the amperage of the breaker for the circuit you are using. Then get an EVSE that only pulls IE 28 amps or less. The car and EVSE communicate so you will be safe at less than the breaker. The i3 can take =he 2017 BMW i3 accepts up to 7.7 kW of charging power from a Level 2 charger. 7,700 / 240 = 32 amps a dryer is normally 35 amps. so 34 /80%=28 amps to be safe. So any EVSE that pulls 28 amps or less will work fine. That's 6.7 kW a lower power charge works great and will no kick on all the fans and cooling systems so it's more efficient. I used the Juice Box since I can turn it lower and cooler. I often charge at only 10 amps. 2.4 kW in the summer heat.
Note The Tesla is the only EV that you can adjust the power it pulls up or down right on the screen and it remembers it by location.

 

[Pushmi-Pullyu]

a dryer is normally 35 amps. so 34 /80%=28 amps to be safe. So any EVSE that pulls 28 amps or less will work fine.

Yes, I've picked that up just from reading comments to EV forums: That the circuit needs to be rated 20% over what the EVSE is drawing, in amps. That is, the rating for a circuit is given for normal use, not for hours-long continuous draw every day or night, like an EVSE draws. For that, the limit is 80% the normal rating.

Also, ideally it should be an isolated circuit, one without any other outlets attached to it, so nobody can overload the circuit by plugging something else into it while the EV is charging.

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