Re:Investors conclude that Tesla is a carmaker, not a tech firm
by giobox on Thursday January 05, 2023 @12:54PM
(#34263683)
As battery charges its pretty common to taper the charge rate to improve health of the battery. To my knowledge, no EV today will sit at 350kw for the full 10 to 80 percent even if it can draw this. You still get faster charge times as the full draw can usually happen at close to empty, but charge rate will taper as battery fills. 181kw average is still pretty great - there are many EVs on sale that still max draw at 50 (looking at you VW...).
Re:Investors conclude that Tesla is a carmaker, not a tech firm
by jefftk on Thursday January 05, 2023 @01:00PM
(#34263779)
If the peak current draw were 350kW then I'd agree the specs were fine.
I'd thought they were advertising a 10% to 80% charge because that's the period over which they can charge at max speed? Looking now, it seems like they start tapering at 50%, and it's peak draw is 235kW? https://www.arenaev.com/kia_ev6_crowned_the_best_charging_ev...
(I agree this is very good, but it's still wrong to quote 350kW if they never draw this much.)
DC Fast Charge Time (10-80% @ 350 kW via Electric Vehicle Supply Equipment) Level 3 Charger: Approx. 18 min.
and
Drive Battery Energy: 77.4 kWh
The battery is 77.4 kWh. This implies the battery is charging at 180kW.
If it were taking in the full 350kW and losing 170kW as heat that would be one (inefficient and dangerous) thing, but it doesn't sound like it actually draws 350kW?
For comparison, they say 73min for charging at 50kW, which implies the battery is charging at 45kW. If we figure that same 10% loss, then to charge at 180kW it's probably drawing 200kW from the charger.
[1] https://www.kia.com/us/en/ev6/specs
[2] 70% * 77.4 kWh * (60min / 1h) / 18 min = 181 kW