Battery charging

[Joss]

Hi thinking of changing my diesel XC40 for a hybrid petrol, can anyone tell me roughly how much it costs to charge the battery thx.

[Rockford]

It uses 10kWh or thereabouts, so it's 10x your electricity unit price.
If you switch to a tariff like Octopus Go, it's 5p per unit between 00:30 and 04:30, so you can charge for 50p.
If you charge at day rate, it will be more like £1.70.

[Greggspies]

I agree with that, except the Octopus tariff only gives you 4 hours of the 5 you need for a full charge at 5p so the rest will be at 17p making it 74p. I am currently battling to get a Smart Meter fitted to take advantage of the Octopus prices.

Bear in mind also that not all the electricity gets to the battery. Charging losses are generally reckoned at 9% or 10%. I've no idea what they are in the XC40, but if you want to be picky these costs are on the low side, but roughly right.

[Rockford]

If you charge via a dedicated car charging point (3.7kW) you will be able to get a full charge in the 4 hours.
The 13A 2.3kW 'granny charger' will take more than 4 hours, but I've only ever seen 4 hours 20 minutes as a maximum, plus the last bit of the charging session drops to 1.2kW, so it's a bit difficult to calculate the exact costs.
Somewhere between 50 and 55p is probably precise enough.

My consumption figures are at the socket, so will take into account losses in the charging unit and car itself.

[Greggspies]

Very good to know Rockford, and I'm happy to be corrected by your real world data. What are you using to measuring consumption at the socket?

[Rockford]

A smart plug, which I use to take advantage of the Octopus Go night rate (until Volvo fix their own charge timers).
Of course the smart plug is unlikely to be calibrated, but it seems to be very accurate in the limited comparisons I've done between smart plug and smart meter.

Should probably also address/add that this isn't technically recommended, but the smart plug is rated for 15A and the charger draws 10A. In the three months I've been using it so far there have been no issues at all - with heat or otherwise.

[Greggspies]

Interesting about the smart plug, thanks.

Volvo customer care told me on Wednesday that the charge timers should be in the app "within a fortnight". I've been battling to get a Smart Meter for months now with zero progress, so it may be a while before I'll be able to benefit from the timers..