Preconditioning & charging planner

[Yves]

I have something to say about rebalancing, but I’m collecting a bit more information. I suspect there are some quirks that can be triggered with certain usage patterns that account for some charging issues people have posted. Nothing super surprising if you’ve followed Taycan forum info.

The reason I brought it up in context of preconditioning is because rebalancing can also be a fix for poor charging speeds. I don’t necessarily think the current implementation can rebalance a running vehicle, just an “it would be nice if” comment.

Interesting!
If you find something please let us know. Nice project you did with the data logger.

I guess rebalancing can only be done while charging, the high load you demand on the HV DC makes it in my option more complex to rebalance while driving, I think enabling that from a hardware perspective would be a costly endeavor as different cells will differ in voltage drop under load.

So hence all the cars I know do it when they reached there charging limit and start by either:
-Passive balancing, discharge higher voltage via resistors, that is the old way
-Active balancing, move charge from higher to lower via capacitors or inductors: more efficient less heat.

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[Yves]

Just a rough data point, I entered A ChargePoint close by when running some errands.
Ambient 12C battery 11C went up to 16C after 30 minutes so at ambient 12C it seems to gain 5C per 30 minutes.

I left the charge destination in the Nav and started pre conditioning in the App when at home… The battery is up to 19C … probably the thermal mass catching up with the sensors, but maybe Porsche has bug in the system

 

[TomekGnomek]

Here is an interesting test in winter conditions of Macan, Audi Q6 and Polestar 3:



They compared charging without preconditioning and turns out...

"With no pre-conditioning of the batteries, the Porsche Macan initially struggled, and achieved a disappointing charging speed of just 30 kW. The Polestar 3, limited by its 400-volt architecture, reached a peak charging speed of 80 kW. The Audi Q6 e-tron fell in between, and reached 100 kW."

Seems it's not only some people on this forum that complain about abnormally poor cold battery performance.

 

[sor]

It’s an interesting video and something to keep in mind. He says 17°C battery, which is really not cold at all, I think there’s more to the story. Indeed after watching the video they realized the charger wasn’t on its own circuit and got much better speeds after moving the Porsche to another charger. Timestamp 16:50, got 125kw right off.

I type this as I sit right now charging my car after a 2 hr drive in freezing temps. Not trying to be argumentative but just explaining why I personally don’t bother with precondition. I am not telling anyone else not to use it, nor that it’s worthless. Just don’t want to be called “ill informed” for saying that I haven’t found it to do much for me.

I went to pick up my skis from the tuning shop, it’s a little less than an hour away so I can drive there and fast charge on the way back closer to home.

Started the morning out at 30°F/-1C. Nothing special done to precondition. By the time I was getting close to the charger the outdoor temp was 37°F/3C and the battery temperature was 57°F/14C (lower than the video, they say battery is 17C!) just from driving. When I finally stopped I had a much lower SoC than the video at just 3%.

Just finished and pulled into another spot to finish up this post. The chargers were balanced and the station was packed, so I feel like it could have done better. Still I managed to go from 3%-73% in 22 minutes, peak speed I saw was about 206kw (probably due to balanced stations).

This is the sort of experience I’ve always had in EVs driving in winter, sometimes on 500 mile trips.

I noted that the battery jumped to 85°F/29C within the first four minutes of DC charging, and after ten minutes it was at 107°F/42C. So even if it just wasted a few minutes getting the battery temperature up to the sweet spot, no big deal for me.

 

[Yves]

I noted that the battery jumped to 85°F/29C within the first four minutes of DC charging, and after ten minutes it was at 107°F/42C. So even if it just wasted a few minutes getting the battery temperature up to the sweet spot, no big deal for me.

Well I watched it too and 123kw is what I see as well … as do others … so lucky you. The questions now is why do you see 200kw and others not?

I have done this test a dozen times at a station where I know I get 270kw and most of the time I’m the only one charging so we can eliminate the station.

When was your car build, did it had the software update, curious to see is they changed something in the meantime …
My car is one of the first and received the update …

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