Terrific Charging Session: 283 kW charging yesterday

[SergeyIndy]

That

Higher amperage results in less loss - not more - but 48, 40, 32A, really makes little difference. My battery temp barely goes up when I charge at the 9.2-9.3 kW rate that it's running at.

Thank you for correcting me on the losses. My main point was that the EVSE cable does not get hot when I charge at 35Amps vs. 48Amps.

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[fubar.droid]

I do wish the Macan could be set to charge at a lower rate from within the car/app instead of having to do it from the EVSE.

 

[sor]

Generally speaking I don’t think people have a good grasp on what is “safe”. We hear 130°F and that sounds “hot” and get worried without really knowing what the chemistry and engineering supports. It is just a knee jerk reaction.

From what I can find this seems to be well within normal operating temperature for NMC batteries (up to 140F) and way below any dangerous temperature range, if a bit above the ideal range. It may cause excess wear to do this often - just like driving hard or other things we put the cars through for enjoyment and convenience.

 

[SergeyIndy]

Generally speaking I don’t think people have a good grasp on what is “safe”. We hear 130°F and that sounds “hot” and get worried without really knowing what the chemistry and engineering supports. It is just a knee jerk reaction.

From what I can find this seems to be well within normal operating temperature for NMC batteries (up to 140F) and way below any dangerous temperature range, if a bit above the ideal range. It may cause excess wear to do this often - just like driving hard or other things we put the cars through for enjoyment and convenience.

I guess you missed my point above, while battery temp may be ok to be that high, other components will not hold up so much, like fans.

 

[PrudentOcean]

That’s literally what the fans are designed for. I’d be more worried about the battery than the fans.

 

[jwatte]

I'd be a little worried if the charging wiring gets more than lukewarm, though -- that means either it's a weaker wire than it's supposed to be, or (frequently the case) the connector is getting very hot and wicking the heat into the wire. Connectors are where high currents go to make fire.

(This is why you should always tighten electric screws/connections hard enough, if you do your own wiring.)

As for components: I'd be more worried about the capacitors in the charge regulator than probably any other component... I'm sure they're automotive rated, but every 10C/18F means half the expected lifetime. And they're typically not cooled as well as transistors or battery cells.

 

[TomekGnomek]

This is my record on Ionity but honestly it doesn't hold this for long and overall the charging curve is something the EV industry fails to disclose to customers properly. In reality when travelling the amount of battery you can effectively use is 15-80% which translates to unimpressive range TBH. Below 15% it's too close in case something unexpected happens and above 80% charging is sloooow. Just the other week I was trying to charge to 95% on Ionity to be able to reach my destination @10% and above 90% it dropped to AC charging levels. One thing that works well and gives me comfort is the estimated SoC on arrival - it works well even when travelling 150 km/h on highway.

 

[krissrock]

I went to a 350w station today for the first time. Saw 285 kw rate and the battery never went above 131*
And it was 91* ambient

 

[byebye]

This is my record on Ionity but honestly it doesn't hold this for long and overall the charging curve is something the EV industry fails to disclose to customers properly.

The majority of the charging curves are public, and the indicator like « 10-80% in 21 minutes » is more than understandable for many of us, I guess.

https://evkx.net/models/porsche/macan/macan_turbo/chargingcurve/

 

[daveo4EV]

17% to 42% in less than 7 minutes - Coos Bay, OR

started at 250 kw

 

[krissrock]

on a 350, i went from 4% to 80% in 24 mins

 

[USMA81]

I was the OP, getting 283 kw peak on that recent charge. It took 19 minutes to go from about 19% to 80%. Under the right charging conditions, the charging performance is roughly as claimed by Porsche.

That session also took the battery to a peak 133 F (56 C). I expressed mild concern, more surprise, over the temperature. That generated many comments.

This article below states 35C (95 F) is best for maximum discharge temperature and that a peak charge temperature of 55 C (131 F) is OK.

https://blog.amphenol-sensors.com/blog/battery-thermal-management-systems-and-ev-battery-performance

This study below indicates peak charging temperatures of 60 C (140 F), when fast charging is done less frequently and when the elevated temperature is short-lived, doesn’t impact the battery’s longevity significantly (of note, after my fast charge, the BMS brought the battery temp down quickly).

https://www.osti.gov/servlets/purl/1977392

My conclusion: nothing to worry about.

 

[USMA81]

One more study:

https://findingspress.org/article/21459-impact-of-charging-rates-on-electric-ve-

C is the rate of battery charging or discharging. The C rate of charging affects battery longevity. At a maximum, my charge was from 19-80% in 19 minutes, and this translates into a C rate of 1.9. This is high, but it won’t affect my battery significantly; here’s why not. Assume I do fifteen C=1.9 charges per year. Not all DC sessions will be at C=1.9; assume 15 at lower C values (low speed DC charging), and 15 at C=1.9 per year. Those at lower C values won’t affect longevity much, and so let’s only count the fifteen at C=1.9. Let’s also assume that this will degrade performance (range) by 20% over 300 charge cycles. That means I should have 80% battery life remaining after 20 years (300/15=20 years). Lots of assumptions here, but it gives a ballpark idea of battery life.

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