Usable battery capacity

[londiniumperson]

I have been keeping enough detailed records for the past week to determine the usable battery capacity from the SoC at the beginning & end of each day as well as kWh usage via my home monitoring system & Ohme charger usage stats. Note that I have not been able to determine the losses other my Ohme charger which uses 0.2kWh/day on standby).

Assuming 0% loss of charge during each charge:

• 32.22 kWh
• 31.43 kWh
• 31.56 kWh
• 32.73 kWh
• 32.27 kWh

Assuming 10% loss of charge during each charge:

• 29.00 kWh
• 28.29 kWh
• 28.41 kWh
• 29.45 kWh
• 29.05 kWh

FYI - 28% was the lowest & 92% the highest charge state in the above calculations.

[Reuben80]

I remember that officially before the car was launched usable capacity was 32kWh but after Bjorn's test it went down to 28.5kWh.
I prefer to believe the first rumours of 32kWh than Bjorn.

[milligoon]

30 to 80% charge should make the calculations dead easy from in car limits to metered charge bothi AC and DC to give a better idea

[FDAD]

How much kwh/km are most people averaging?

[SwissChris]

Yesterday I did a 100 km drive on 60% highway (but slow speed around 90-110 km/h), 20% country roads (60-80 km/h) and 20% citydriving. Consumption according to board computer was 17.5 kWh/100 km. Outside temperature was 12°C - 14°C, heating was on (22°C, but only two bars). When calculating the remaining range, the algorithm to take into account heating is pretty basic. No matter if you set it to 20°C and one bar or HI and all bars, it always gives the same number as "saving" if you switch it off...

edit: corrected

[keithr]

Consumption according to board computer was 17.5 kWh/km.

You used about half the total battery capacity to travel 1 km! I don't believe it. Maybe if it indicated 17.5kWh/100km I would believe it, as that equates to about 3.55 miles/kWh.

[advance2020]

There is a lot more info on this topic under Keith's "Better Range than Expected", although that thread is getting long.
I have now clocked up 1000 miles and my AVG was 3.9m/KWh
Based on the details I keep from Journeys to date, and analysis of Battery % used per mile, cross-checked with the energy used for recharging,
I believe Usable Battery Capacity is 31.25KWh
This seems to be supported by Keith's data, and his Long Range test.

However, in practice, it's lower, because I doubt any of as want to drive until we reach 0% !

[londiniumperson]

There is a lot more info on this topic under Keith's "Better Range than Expected", although that thread is getting long.
I have now clocked up 1000 miles and my AVG was 3.9m/KWh
Based on the details I keep from Journeys to date, and analysis of Battery % used per mile, cross-checked with the energy used for recharging,
I believe Usable Battery Capacity is 31.25KWh
This seems to be supported by Keith's data, and his Long Range test.

However, in practice, it's lower, because I doubt any of as want to drive until we reach 0% !

Have you taken into account that there's an approximate 10% loss when charging using the 3pin or 7kW home charger?
So if you've hypothetically fed in 31.25KWh from 0-100%, that would actually be a useable battery capacity of around 28.125kWh.

[advance2020]

Have you taken into account that there's an approximate 10% loss when charging using the 3pin or 7kW home charger?
So if you've hypothetically fed in 31.25KWh from 0-100%, that would actually be a useable battery capacity of around 28.125kWh.
[/quote]

Yes, as you will see from snapshot from my Spreadsheet.
Column 6 shows "calculated" kWh Used - % of Battery Used x "My Usable Battery Assumption" - 31.25kWh
Column 7 is Actual Energy used by 3 pin Charger, measured at 3 pin Socket.
The figures seem to be consistent (there is more data) but this should be enough to make the point
for example, this is my biggest charge to date.

14 Sep Charged battery up by 55% - theory 17.19 kWh ( 0.55 * 31.25) - actual 19.1 (19.1 * 0.90 = 17.19)

Data from Public Chargers are less consistent.
And I actually managed to charge in Bridport, for a short while, trying using the USELESS ChargeYourCar App, and have never been billed!