Battery Charge Drain

[JoeH]

I have owned a 2020 4S since late 2020. Overall, the experience has been positive, though there have been a number of problems that needed to be addressed resulting in trips to the dealer for service. Among other issues, following a yellow "maintenance required" warning message the vehicle was in the shop for about three months in late 2023 - early 2024 eventually resulting in the replacement of a battery module. In the last month or so I have noted a significant drop in battery charge/range, including having the displayed charge percentage drop from 80% to 50% over a week and a half while the car sat idle in my driveway. In the past nearly five years of ownership I have never noticed any even modest drainage (if I charged to 80% and left the car for weeks it would still be at 80%). I took the vehicle to the dealership (Herb Chambers - Burlington, MA) to have the battery charge issue looked at along with getting tires replaced and a number of outstanding recall notices cleared. Last Friday, they told me all was fine, but I needed to leave the vehicle for the weekend as they were waiting for a tire. I was skeptical that all was fine and asked that they note any battery drain over the weekend. I got the following message today:

"I believe Friday at the end of the day it was 70 miles. Four days later it was 58 miles. We don't have any faults. Porsche is still fully analyzing the vehicle analysis log we sent to them as part of the recall. The range it depleted in four days is normal according to the technician. The battery is always trying to maintain a certain temperature. Even with the vehicle not running, sometimes it may be required to heat and other times required to cool."

And after I expressed my continued conviction that something is wrong and that I would like it figured out before I collect the vehicle:

"I do understand what you are saying. However at this time we are not finding anything diagnostically to go off of. Porsche is reviewing the log to check the battery cells. According to the technician if there were any problems with the battery or charging systems, we would have thermal event faults. The diagnostic log is clean."

I am concerned and would appreciate any thoughts/guidance anyone can share.

Thanks.

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[anonymouse]

You are right that Taycans have very little battery drain when idle. You are also right to measure this using the % indicator rather than the “miles” guess-o-meter which has other factors.

Was it a one-off or do you think it is repeatable? Could be some software issue keeping the car awake?

 

[Tooney]

Here are links to 3 older threads about unusual battery drain:
https://www.taycanforum.com/forum/t...ty-range-dropped-overnight.23737/#post-362228
https://www.taycanforum.com/forum/t...re-overwhelming-an-otherwise-great-car.16987/
https://www.taycanforum.com/forum/threads/once-again-the-battery.19571/

 

[bastaycanturbo]

Any timers active maybe?

 

[tophamn]

Any timers active maybe?

Dashcam?

 

[ovonrein]

You may be worrying about the wrong battery. The 12v recharges from the HV battery, and the alarm etc drain the 12v.

 

[ct14garage]

HV battery is leaking

 

[JoeH]

HV battery is leaking

That what I'm thinking. The dealer is still waiting to hear back from Porsche. I don't know what the diagnostics the dealer did that apparently showed no problem entailed, but am troubled that they didn't identify anything given what to me seems to be an obvious battery issue.

 

[JoeH]

Dashcam?

No dashcam, no timers set, no precool/heat set, and gave up Porsche Connect so don't do anything remotely. I've had the vehicle nearly 5 years and have gotten to know it pretty well. I'll be pretty surprised if this is anything but a battery issue, whether HV or 12V I have no idea. How it works is above my pay grade - I'm just a driver who hopes and expects the service guys and Porsche to figure it out. But it does seem they need a bit of a push sometimes to root out the issues.

 

[JoeH]

Just wanted to give an update on this in case anyone is interested. Despite initially insisting all was well and the unusual battery drain I observed was normal, Porsche eventually determined there was a problem and that 14 modules needed to be replaced. I finally collected the vehicle in mid-December (almost exactly 4 months after bringing it in during which time I put about 4,000 miles on a Macan loaner) and all seems fine since then. Copy of the invoice work description attached. Given I previously had failed module #3 replaced in 2023 (another 3 months in the shop), I don’t have enormous confidence going forward, but still have nearly 3 years left on the battery warranty and an extended service contract that lines up with the battery warranty. Really enjoy the car when I have it and would love to drive it forever, but basically looking at it as having an eight year lifespan.

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