Very slow DC charging

[Yves]

Just stumbled upon this post as I encountered the exact same issue this week in freezing upstate NY (-5°C)

My symptoms

• DC charging capped at 35kW despite preconditioned battery at 3 different chargers (2 EA and 1 Tesla Supercharger*)
• SoC jumped from 12% to 35% immediately when plugging in at EA
• SoC jumped from 22% to 33% after sitting parked for 20 minutes (unplugged)

Car was serviced at dealer one week prior with all latest software/recalls applied.

Partial progress
After letting the car sit overnight at ~20% SoC (unplugged), it charged at 65kW the next morning – not perfect but better than 35kW. Planning to complete the full rebalancing procedure (discharge to 20% → rest 12h → slow charge to 95% → rest 12h) once back home.

Questions for others

• Has anyone NOT been able to restore normal DC charging speeds even after rebalancing?
• Did anyone get any goodwill gesture from Porsche for this issue? Seems pretty unacceptable to me, although not that surprising.

* Sitting next to Cybertrucks that charged faster than me was a difficult moment.

Yes, but I can’t remember his name … so it is possible, I believe you need to be lower then 10% To balance bottom and above 95% to top balance and let it sit for 7 hours or so …

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[platypus]

Good to know. I’m at 11% but since I have another issue where the battery is dropping 1% per day, I’ll soon be below 10%

 

[ChrisFromUK]

My SoC loss seems to have increased to around 2 to 3% per day which is crazy. Arrived home yesterday after a 130 mile day trip at 37% and 24 hours later it is currently at 34% when I just checked in the car (app is useless as it doesn't update SoC). This isn't the only occurrence of very high SoC loss. Seems worse than usual after the recent software updates.

I'm going on holiday on Saturday for 2 weeks and will likely be leaving the car at about 25% so at this rate it will be dead and getting towed when I get home.

That should get the dealers attention.

 

[platypus]

@ChrisFromUK does it keep losing SoC after this initial drop? In my case there are definitely two things (correlated or not) going on between the consistent battery drain and the unreliable SoC because of the (apparently) unbalanced cells.

 

[Yves]

My SoC loss seems to have increased to around 2 to 3% per day which is crazy. Arrived home yesterday after a 130 mile day trip at 37% and 24 hours later it is currently at 34% when I just checked in the car (app is useless as it doesn't update SoC). This isn't the only occurrence of very high SoC loss. Seems worse than usual after the recent software updates.

I'm going on holiday on Saturday for 2 weeks and will likely be leaving the car at about 25% so at this rate it will be dead and getting towed when I get home.

That should get the dealers attention.

Maybe it is balancing and the drops will stop?

 

[ChrisFromUK]

Maybe it is balancing and the drops will stop?

The drops haven't stopped since took delivery in April at around 1% per day. Dealer doesn't seem interested, says it's just the way it is for Porsche. This seems like nonsense.

Anyway, I've just parked up and left it for 16 days and it's at 36%. If the daily drop is 'only' 1%/day then it should be around 20% when I get back to it. If the drop is how it's been since the recent software update then it could be anywhere between 20% max and at worst a dead battery and getting towed to the dealer - we'll see.

 

[platypus]

I’m wondering if we should start a shared Google spreadsheet with standardized data recording the daily battery drain issue across this forum.

If we have a consistent pattern across enough cars that we can share with Porsche, they may start caring a little bit more. Thoughts?

 

[mikestan]

Your dealer did a good job with the diagnosis and recovery.
Their diagnosis confirms my suspicion and the data from Car Scanner app that shows the issue is due to battery cell imbalances. It also means there is a bug in the Battery Management Module that lets the cells get to this state.
Next time you can solve it without a dealer visit by following the charging procedure mentioned a few posts above.

@Rocketair did you get your car back? If not you can point them to the post right above for the steps the other dealer followed.

Hi there,

I am having the same issue after leaving the car at home for 4 weeks, this past January 2026.

I forwarded the message from the xmlguy to my dealer and they are working on it.
Curious if you've had other instances after the fix where you left the car dormant for a while and the symptoms returned.

Thanks,
Mike
https://www.macanevowners.com/forum/members/xmlguy.657/

 

[chrisk]

Hi there,

I am having the same issue after leaving the car at home for 4 weeks, this past January 2026.

I forwarded the message from the xmlguy to my dealer and they are working on it.
Curious if you've had other instances after the fix where you left the car dormant for a while and the symptoms returned.

Thanks,
Mike
https://www.macanevowners.com/forum/members/xmlguy.657/

Yes It happened again at least twice. The fix is easy.
Charge to 95%, unplug and let the car parked undisturbed for at least 10 hours. That helps rebalance the battery cells. I have taken measurements via Car Scanner which confirm the battery degrades to big cell voltage imbalances and this process restores the balance and the DC charge speed for my car every time.

 

[mikestan]

Thanks for reply, do you mind sharing info on the Car Scanner, brand, model ...
Much appreciated!
Mike

 

[chrisk]

Thanks for reply, do you mind sharing info on the Car Scanner, brand, model ...
Much appreciated!
Mike

Car Scanner is a mobile app I bought from the app store. It connects to the car via a Bluetooth OBD2 device you can buy from amazon like this one https://a.co/d/07erJJxy

When in the app, I look for the cell with highest and lowest voltage. Ideally they should be the same, but sometimes they get more than 3% off and that's when the DC charge is slow and the range estimate is usually off.

 

[SergeyIndy]

Thanks for reply, do you mind sharing info on the Car Scanner, brand, model ...
Much appreciated!
Mike

You can follow any advice you prefer, but I would like to share what we know works for Taycan and Macan:

OBD that is known to work is https://www.amazon.com/dp/B088LW211V
CarScanner is a free app, but upgrade to Pro is a few dollars one time cost and optional

Rebalance: The advice of charging to 95% and waiting 10 hours may work, but that is not the official Porsche TSB procedure if we are being precise about it. The official procedure calls for a little bit more discipline to allow the car to go into deep sleep at which time it will do the rebalancing when totally undisturbed:

- Measure your SoH before starting using OBD/CarScanner (optional)
- Run down your SoC to low with 2-3% ideal
- Lock the car and leave it undisturbed, no app use, no key close by, for at least 6.5 hours (overnight is suggested)
- Charge the car on a home charger (slow but not too slow) at about 35Amp to 100%
- Lock the car and leave it undisturbed, no app use, no key close by, for at least 6.5 hours
- Measure your SoH after this is done using OBD/CarScanner (optional)
- Rebalance is complete. Note the difference in SoH readings before and after.

 

[ron_b]

The OBD II reader that I have been using since I got my Taycan in 2020 is this one, https://a.co/d/0b2D28uV a bit more bulky but works fine. Used it in the past with Torque Pro on an Android phone then switched to Car Scanner Pro on an iPhone. Used it to test many vehicles from the Taycan, BMW i4, 2000 Town & Country. Very handy tool.

 

[Doggo]

You can follow any advice you prefer, but I would like to share what we know works for Taycan and Macan:

OBD that is known to work is https://www.amazon.com/dp/B088LW211V
CarScanner is a free app, but upgrade to Pro is a few dollars one time cost and optional

Rebalance: The advice of charging to 95% and waiting 10 hours may work, but that is not the official Porsche TSB procedure if we are being precise about it. The official procedure calls for a little bit more discipline to allow the car to go into deep sleep at which time it will do the rebalancing when totally undisturbed:

- Measure your SoH before starting using OBD/CarScanner (optional)
- Run down your SoC to low with 2-3% ideal
- Lock the car and leave it undisturbed, no app use, no key close by, for at least 6.5 hours (overnight is suggested)
- Charge the car on a home charger (slow but not too slow) at about 35Amp to 100%
- Lock the car and leave it undisturbed, no app use, no key close by, for at least 6.5 hours
- Measure your SoH after this is done using OBD/CarScanner (optional)
- Rebalance is complete. Note the difference in SoH readings before and after.

When you charge to 100%, do you unplug the charger, or leave it in? Does it make a difference?

 

[SergeyIndy]

When you charge to 100%, do you unplug the charger, or leave it in? Does it make a difference?

You unplug, as the car has to be totally undisturbed to allow it to go into deep sleep that triggers the rebalancing sequence. The key is to be sure you do NOT use App, shut it down, and make sure the Key is far enough and cannot reach the car for any communication or that would disrupt the deep sleep.

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