Select how many kW to charge at?

Select how many kW to charge at?

I'm curious. Right now I have at home the main braker at 400V 16A. My last months electricity usage was 730kWh or about 23 kWh/day or ~1 kW per hour. Now I don't have electric heating or what not therefore the nightly usage is about the same as daily usage. However the daily usage should probably be peaky with the use of electric ovens etc while the nightly usage is more uniform (computers and what not running steady). So all-in-all I use on average about 9% of the peak capacity of the main breaker.

So my main question is, would I be able to put a separate 16A 400V breaker that feeds off the main one for the EV charging and charge the MS from that. However I really wouldn't want the MS to hog the 100% capacity up to 16A because it's likely to kick out the main breaker then. Can I specify that it charges not at 11kW rate, but at say 8-9 kW rate? I'd still get 40-45 km per hour of charging and a full tank overnight as well as being able to waive all costs of additional ampers and just swap the current typeF connector to a type-II connector with new cable and breaker (basic electric work, likely costing no more than a few hundred euro). However it requires the charge rate to be configurable from the car.

Or actually how the heck does the car know what amount is available? What do I need to install at home to make sure the car doesn't overreach itself without kicking the breakers.

RZippel | September 2, 2013

Max. Amps. to charge can be selected in the car.

mario.kadastik | September 2, 2013

@RZippel: I wonder how that's accommodated in a 3-phase connector :) And can this be programmed per location where I charge so that at home it would be limited and at public charging stations that have 400V 32A 22kW chargers I could go all out?

pebell | September 2, 2013

From what I have gathered so far: the manual charge rate settings are stored in the car together with GPS information, so that next time you charge at the location where you set the speed, it remembers it.

However, when you connect to "charging stations" instead of plain electrical outlets, there is a protocol where information is exchanged between software in the car and in the charger, telling each other how much current can be drawn. How this protocol relates to the manual settings, and which overrides what, I hope someone else here more knowledgeable than me can fill in the blanks. | September 2, 2013

The manual charge rates for each kind of connector are stored so you don't have to keep programming them in each time.


mario.kadastik | September 2, 2013

omarsultan: yes, but if the connector is the same at various locations :) Then I'd like it to be GPS based :) But if I can tune it at home and the chargers use some protocol to agree on the max rate, then that should be fine. Also, this means that I probably don't need to rebuild my whole electrical system :)

GeekEV | September 2, 2013

It is GPS based...

Brian H | September 3, 2013

GPS based, with max set by the connection itself.