On Fri, 13 Jul 2018 16:41:57 +0100, Roland Perry
wrote:

In message , at 16:21:33 on Fri, 13
Jul 2018, John Williamson remarked:
On 13/07/2018 16:09, Roland Perry wrote:

What's important for the EV-charging scenario is that is if several
dozen houses are supplied by an 200A street main at 230v from the
local substation, how can more than a handful charge an EV overnight
at 50 amps?

The grid will eventually have to be upgraded, though for domestic use,
an off peak slow charge at 3 kilowatts is usually enough for a day's
use.

The problem with off-peak is that everyone is expecting to use it, so it
becomes just as much in demand as "peak".

3 kilowatts is double the normal average power consumption of houses.

The street main is usually 200A per phase, though.

Which if we believe grid figures that an average household is perhaps
1.5kW means it can feed (200/(1500/230))x3 = 90 houses.

Still wondering where even the level 2 Tesla chargers (80 amps at 230v)
will get their supply from.

The future is hydrogen.

--
jhk