P8 Charging Question

Faults and Technical chat for the Volvo XC40
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qrt31
Posts: 172
Joined: Mon Aug 02, 2021 10:30 am

Post by qrt31 »

I noticed today when I was partially charging my new P8 that the charger was recording more KWhs than would have gone into the car. I was going from 70% to 90%, so 15 KWh. However, my home charger reported delivering 16.7 KWh. I noticed something similar with a short term rental electric car. Is this normal behaviour? Could it be related to difficulties related to charging in the higher % ranges - maybe requiring more energy to condition the battery or something?

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alanplum241276
Posts: 80
Joined: Sun Sep 29, 2019 6:47 pm
Location: Bristol, UK

Post by alanplum241276 »

There is always loss when charging through heat
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eugen61
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Joined: Sun May 10, 2020 7:33 am

Post by eugen61 »

To prevent heat loss some fast chargers include water cooling within the cable. There’s also loss through battery heating up during charging. You’ll always get less kW in your battery than what’s shown on the charger meter. Unfortunately, these things are not clearly explained to first time buyers of electric cars and unrealistic expectations are set in terms of real electricity cost per mile and real range (outside temperature impact, the 30-80% charging rule resulting in half the advertised range, etc). There’s an excellent channel with all kind of real life tests on electrical cars, your model included, worth taking a look at: https://youtube.com/user/bjornnyland
qrt31
Posts: 172
Joined: Mon Aug 02, 2021 10:30 am

Post by qrt31 »

Thanks. Very helpful. Indeed, none of the is mentioned by Volvo as far as I can see. I guess I will add 10% to my expectations for charging costs.
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