Battery cells reset/rebalancing after erratic SoC readings

[Cogs79]

Quick update while leaving my Macan unplugged for the last 10 days. The car remained at 80% (what I charge to) for the first 5 days, and now dropped 7% (at 73%) in 5 days. That is the equivalent of driving almost 40 km for me in the summer! I haven't tried the rebalance procedure, and I honestly think it's insane that we need to do that. The car should be rebalancing when plugged in all on its own. I understand checking the app will "wake up" some systems in the car, but I am wondering if having the Porsche status in the iPhone Today View (right swipe) wakes up the car every time I check other app status there. I logged in to the app once in the last 10 days, but check the Today Status (for other apps) everyday.

Sponsored

 

[ChrisFromUK]

Quick update while leaving my Macan unplugged for the last 10 days. The car remained at 80% (what I charge to) for the first 5 days, and now dropped 7% (at 73%) in 5 days. That is the equivalent of driving almost 40 km for me in the summer! I haven't tried the rebalance procedure, and I honestly think it's insane that we need to do that. The car should be rebalancing when plugged in all on its own. I understand checking the app will "wake up" some systems in the car, but I am wondering if having the Porsche status in the iPhone Today View (right swipe) wakes up the car every time I check other app status there. I logged in to the app once in the last 10 days, but check the Today Status (for other apps) everyday.

Mines had this type of behaviour since delivery 12 months ago - my record is losing 13% over 14 days being parked up whilst on holiday. Doing the rebalancing doesn't fix this although it does help with other problems (like fast DC charging ability, range shown at low SoC, Sat Nav arrival SoC estimate). Car is in with Porsche dealer at the moment to look at the these SoC issues and some other minor problems. They are going to do a full battery health check. Not holding out any great hope for a fix this time but you've got to start somewhere.

 

[Cogs79]

Mines had this type of behaviour since delivery 12 months ago - my record is losing 13% over 14 days being parked up whilst on holiday. Doing the rebalancing doesn't fix this although it does help with other problems (like fast DC charging ability, range shown at low SoC, Sat Nav arrival SoC estimate). Car is in with Porsche dealer at the moment to look at the these SoC issues and some other minor problems. They are going to do a full battery health check. Not holding out any great hope for a fix this time but you've got to start somewhere.

Thanks for the information! This has only started happening to my 2024 Macan 4 (got it in December 2024) a couple of months ago. I would leave it plugged in at home, and then get in the car with 77% charge after sitting for a few days despite charging to 80%. I have driven 8023 km so I do not drive much. It just dropped another 7% in 4 days (not at 66%). I use about 8-10% for the 2 days-in-the-office commute! This power use is extra battery wear for nothing. Please let me know what your dealer tells you. I am still traveling but if there is anything I can test on on my car for extra troubleshooting, I will gladly support.

Cogs

 

[ChrisFromUK]

Dealer said they'd run some battery diagnostics but as soon as they plugged the car into their diagnostic tool it showed 7 software updates available including to the High voltage Battery. These are updates since the big 28.13 update in November. Note they said these updates don't show up in whatever system they normally check for available updates, only when the diagnostic tool is connected to the car.

They've installed these updates and given me the car back and want to see if it's made any difference to the SoC issue before investigating further which is fair enough. Car only came back yesterday evening so not been out in it yet.

I'm attaching a screenshot of the updates that have been applied.

 

[Fly4ever]

@ChrisFromUK what's the build date of your car? Mine is 18/09/2025 and my VIN also not showing any updates available in the dealership's online system so I wonder if my car ever connects to their diagnostic tool what will comes up!

 

[Wivenhoe]

My March 25 car developed range reporting errors - different between dash and Sat Nav and other issues. It went in for 5 days early May. It had previously had a post 28.13 update which may have caused at least one of the issues.

They installed 6 updates one of which was BM - they drove the car and charged it over 4 days and it’s exactly as it should be approx 1 month later. Also, this could be down to the previous drive history being wiped, the range is better than I saw last summer. Even with A/C on its returning 330+ miles and the charge amount is correlating to the % shown before charge.

 

[EVowner]

These optional updates are being released all the time. I was on that merry go round with service center just doing these updates every time they got a car. They always say that hopefully this one should fix all the issues. In my case it did absolutely nothing every time.

I posted it already in another thread. Issue with SoC loss is most likely this:

It fits all symptoms reported by multiple owners experiencing this perfectly. If Porsche tries to tell you BS that this is normal it is not. There is ongoing FB poll here: Is your Macan EV losing SoC (battery charge) while parked? Similar to poll on this forum there is 0% SoC drops being reported by very high majority of owners.

If you are experiencing this constantly it just means that there is most likely something wrong with either BMS or battery in your particular car with car trying to fix itself and failing over and over again. If service center is not willing to diagnose and says this is expected ask for official Porsche engineering statement on where exactly 0.95kWh/day (1% SoC) is being used when car is parked, why this behavior stops when car reaches 30% SoC and why was this not happening on your car before. Feel free to also ask why other owners are not experiencing this normal expected behavior. If service center is not willing to provide you with the answer call Porsche costumer support (number for your country is in the app under Account > Contact and help) and demand those answers there alongside with fix.

We paid premium for a car that is obviously broken, so I don't see any reason to give them any slack moreover with them pretending that issue does not exist.

 

[byebye]

These optional updates are being released all the time. I was on that merry go round with service center just doing these updates every time they got a car. They always say that hopefully this one should fix all the issues. In my case it did absolutely nothing every time.

I posted it already in another thread. Issue with SoC loss is most likely this:

It fits all symptoms reported by multiple owners experiencing this perfectly. If Porsche tries to tell you BS that this is normal it is not. There is ongoing FB poll here: Is your Macan EV losing SoC (battery charge) while parked? Similar to poll on this forum there is 0% SoC drops being reported by very high majority of owners.

If you are experiencing this constantly it just means that there is most likely something wrong with either BMS or battery in your particular car with car trying to fix itself and failing over and over again. If service center is not willing to diagnose and says this is expected ask for official Porsche engineering statement on where exactly 0.95kWh/day (1% SoC) is being used when car is parked, why this behavior stops when car reaches 30% SoC and why was this not happening on your car before. Feel free to also ask why other owners are not experiencing this normal expected behavior. If service center is not willing to provide you with the answer call Porsche costumer support (number for your country is in the app under Account > Contact and help) and demand those answers there alongside with fix.

We paid premium for a car that is obviously broken, so I don't see any reason to give them any slack moreover with them pretending that issue does not exist.

100% true.
My particular car loses 1% per day since October 2025, after one year without this behavior.
40 watts 24/7 is a huge consumption assuming the car is off.
350 kWh wasted per year is an aberration.

 

[superv]

Had this SOC issue while on a short 800 mile road trip. My account also defaulted to user during this time so I'm not sure if that also added to the problem.
Came back into town and drove around until I was down to 0%/limited power. Parked and 2 hours later, SOC jumped to 15%. Drove around until 40 miles drained/1%. Waited few hours and no changes so charged up to 100% overnight. Added 94Kw.

 

[Fly4ever]

@superv even though not 100% confirmed as related issues (SoC erratic behavior and 1%/day loss) you'll definitely see way better and stable SoC readings now.Also, your average consumption readings will now be harmonized with % SoC as well and your displayed % remaining you'll see will be the actual one.

 

[minsc]

I’ve just completed the x2 discharge to 5% and charging to 100%. Let’s see how it goes. I’m also noticing almost 8 to 10% battery loss over the period of just over a week. I’ve absolutely no idea what’s going on in that time I didn’t use the app to login. Cant understand the energy loss. My MY26 Tesla remains rock solid

Will be back to the london dealership later this week yet again

 

[superv]

@superv even though not 100% confirmed as related issues (SoC erratic behavior and 1%/day loss) you'll definitely see way better and stable SoC readings now.Also, your average consumption readings will now be harmonized with % SoC as well and your displayed % remaining you'll see will be the actual one.

This should also help with faster DFCF charging on 350kW pedestals. I was previously getting 230+ and on the recent trip, only maxing out at 150kW. Have an upcoming 5000 mile road trip and taking the Macan (still under EA free charging) instead of the Rivian.

 

[superv]

Had this SOC issue while on a short 800 mile road trip. My account also defaulted to user during this time so I'm not sure if that also added to the problem.
Came back into town and drove around until I was down to 0%/limited power. Parked and 2 hours later, SOC jumped to 15%. Drove around until 40 miles drained/1%. Waited few hours and no changes so charged up to 100% overnight. Added 94Kw.

3 hours later, plugged back in and added another 1.5kW, pack is maxed now.

Sponsored