Charging Multiple Cars... Simultaneously

[jamie94bc]

Here in the UK, the majority of our homes have 100amp connections to the National Grid, however some only have 60amp connections.

In a future where we all charge our cars at home, for homes with multiple electric cars that may need charging simultaneously, theoretically 2x 7.4kW chargers (7.4kW, single phase AC @ 240V draws ~30amps) could exceed your connection's max power draw - and that's assuming you don't have anything else in your house which has a high power draw.

Perhaps in the future we will see wall boxes which can charge multiple cars, but limit the power (ie. not charging each car with a full 7.4kW)?

I presume this is what the OLEV meter readings are being used for anyway - surely it would be a fairly big task to upgrade connections to exceed 100amps?!

 

[AndyW]

It's a good point - mine's only a 60A supply, so my wallbox has been knocked back to half-rate. I'm getting my supplier to change my main fuse to 80A or even 100A if my local substation will allow it, but then I have the problem of changing the narrow-gauge cable from the middle of the house, under the house & patio, across the garden to the garage where the wallbox is!

Either way, I'm going for maximum power, as I can see more electric vehicles in our household in years to come...

 

[jamie94bc]

It's a good point - mine's only a 60A supply, so my wallbox has been knocked back to half-rate. I'm getting my supplier to change my main fuse to 80A or even 100A if my local substation will allow it, but then I have the problem of changing the narrow-gauge cable from the middle of the house, under the house & patio, across the garden to the garage where the wallbox is!

Either way, I'm going for maximum power, as I can see more electric vehicles in our household in years to come...

Does your service cable have a large enough gauge to support 60A?

I've seen somewhere online there's a possibility of 200A connections - which would largely solve the problem (unless of course we get more powerful chargers).

Did you have a 30A connection already to your garage?!

 

[AndyW]

I'm not sure exactly what size the current cable to the garage is, only that it wasn't enough to supply the car with 7.4kW (even if the house supply was increased from 60A) so they had to knock it back with a resistor to half that. When I get the house supply bumped up to 100A and get thicker cable to the garage, then I'll be able to put the right resistor in & have the full 7.4.

 

[littlebitinlaurel]

As I'm from the US I can't speak on how you charge in the UK but I can tell you that having two electric cars really doesn't present any problems. My husband and I have a 2013 Honda Fit EV and a 2011 Nissan Leaf. The Fit can charge from empty to full in about 3 hours although the Leaf takes about 7 hours. The Fit has a 6.6 charger where the Leaf has a 3.3 charger. I drive the Fit much more than my husband drives the Leaf so we usually never need to charge them at the same time. I love driving electric and I'm looking forward to test driving the i3 when it comes to one of our BMW dealerships.