Economy 7 rates

[DSLiverpool]

I spoke to NPower today about this and from 12 midnight to 7 am we pay 7.3p / KW much cheaper than standard.

to put it in perspective how do you know what a car will draw? does it say anywhere from empty it needs 50kw etc ?

Edited by DSLiverpool on Tuesday 3rd February 09:56

[DSLiverpool]

Found this -



Charging Times

To understand how charging times come about we need to consider some basic electrical theory, as follows:

Power (Watts) = Current (Amps) x Voltage (V)
Charge Time (hours) = Battery Capacity (kWh) / Power (kW)
In a three-phase system the power is simply three times the single-phase power. In Europe the Voltage is the standard supply voltage of 230V – this is true for our purposes whether it’s a domestic single-phase supply (as used in the home) or the phase voltage of a commercial three-phase supply (as used in a public fast charge station).

The nominal battery capacity of the Zoe is 22kW. Using the various power options gives us a table as follows:

CHARGING TYPE
PHASES
CURRENT (A)
VOLTAGE (V)
POWER (KW)
CHARGE TIME (HOURS)
Domestic socket 1 10 230 2.3 9.5
Wall charger - standard 1 16 230 3.7 6.0
Wall charger - high power 1 32 230 7.4 3.0
Fast charger 3 32 230 22 1.0
Quick charger 3 63 230 43 0.5
Some points to note:

All values are approximate.
All systems are assumed perfect, in fact power loss in the charging process means that charge times will be longer than these theoretical values, by perhaps 10%.
The fast charge time of half an hour is for about 80% capacity, as discussed above, because the charging process must slow down as the battery fills up.