Octopus Drive Pack

MeteredOut

QrizB said:

MeteredOut said:

... granny charger losses can be 20%+.

And

Reed_Richards said:

I measured mine ... that's a 10% loss.  Maybe I'm just lucky?

ADAC did a comparison a few years ago. How's your German?

https://www.adac.de/rund-ums-fahrzeug/elektromobilitaet/laden/ladeverluste-elektroauto-studie/

Edit to add: it seems that Germans tend to have three-phase wall boxes, hence the 11kW (or 22kW)  rating. Makes our 7kW single phase ones seem a bit wimpy!

And I'm jealous of the photographed three-phase extension reel ...

Thanks, using the built-in translator from my browser, that seems to confirm my findings of nearer 20% losses in some circumstances, and that higher power leads to lower losses.

That article also highlights that there are losses in delivering to the car, and then storing that energy in the battery (AC->DC). I'm not sure at which point the car measures the delivery, but I suspect its the latter.

(I've not mentioned that even proper wall box charges also have losses, and Octopus should make clear if those customers will also be credited with the measured-at-car kWh and not the actual pull from the grid)

matt_drummer

MeteredOut said:

QrizB said:

MeteredOut said:

... granny charger losses can be 20%+.

And

Reed_Richards said:

I measured mine ... that's a 10% loss.  Maybe I'm just lucky?

ADAC did a comparison a few years ago. How's your German?

https://www.adac.de/rund-ums-fahrzeug/elektromobilitaet/laden/ladeverluste-elektroauto-studie/

Edit to add: it seems that Germans tend to have three-phase wall boxes, hence the 11kW (or 22kW)  rating. Makes our 7kW single phase ones seem a bit wimpy!

And I'm jealous of the photographed three-phase extension reel ...

Thanks, using the built-in translator from my browser, that seems to confirm my findings of nearer 20% losses in some circumstances, and that higher power leads to lower losses.

(I've not mentioned that even proper wall box charges also have losses, and Octopus should make clear if those customers will also be credited with the measured-at-car kWh and not the actual pull from the grid)

It is clear.

Your ev charger is not your ev.

QrizB

MeteredOut said:

Thanks, using the built-in translator from my browser, that seems to confirm my findings of nearer 20% losses in some circumstances, and that higher power leads to lower losses.

As mentioned in the article, some of the "losses" are a constant power used during charging to run certain of the vehicle electrical systems. These will vary between manufacturers, between models, and between generations of vehicles.

Imagine a car that loses 5% in the conversion process but also has a constant 300 watt draw for the electrical systems. And imagine that you want to add 10kWh gross to the battery.

1. Granny charger, 2kW. Takes 5 hours. Losses are 0.5kWh for conversion plus 1.5kWh for electrical systems. Total loss 2kWh, 20%.

2. Home wall box, 7kW. Takes 1.4 hours. Losses are 0.5kWh for conversion plus 0.43kWh for electrical systems. Total loss 0.93kWh, 9.3%

3. Public mode 2 charger, 22kW. Takes 0.45 hours. Losses are 0.5kWh for conversion plus 0.14kWh for electrical systems. Total loss 0.64kWh, 6.4%.

In this hypothetical example, faster charging is less lossy simply because it takes less time. A car where the onboard electrical systems only draw 200 watts would, under the same circumstances, have losses of 15%, 7.8% and 5.9% respectively.

ASA201

So what’s evident thus far is there’s no consensus on what you will be charged for with one of these drive packs