Serious Design Flaw - No easy access to vehicle if 12v battery is very low

[SimonEV]

The manual is quite helpful about the System Battery (see below). Keeping the car plugged in to charge the HV Battery and also the System Battery would seem to prevent issues - unless there is a fault.

The reference to System Battery discharging is nothing new to ICE car owners, as there is a lot going on in modern cars, but the "What I have to do?" is not simply copied over from an ICE Manual.

The "Charge the vehicle electrical system battery approx. every 6 weeks" would seem to depend on what you expect the car to do when it's not being charged regularly.

I have the Comfort Access option - but I wouldn't want to keep it enabled if I had to leave the car for too long (a week or two) because it can be switched off and the additional battery drain seems something that can be controlled by the User.

Vehicle electrical system battery care

What do I want to do?	What do I have to do?
Putting the vehicle out of operation for prolonged downtime	Keep the doors, lids and bonnet of the vehicle closed. Switch off readiness for operation. To trickle charge, connect the high-voltage battery to the mains supply

(I) INFORMATION
The vehicle electrical system battery discharges even while the vehicle is not in use.

• To maintain its function, charge the vehicle electrical system battery approx. every 6 weeks or connect it to a CC/CV or pure CV trickle charger suitable for electrical system batteries.

Sponsored

 

[Grumpy]

I don't have comfort access intentionally as we have a high theft problem in the UK with this system.
My concern is I often leave a car at the airpot for 2/3 weeks should I risk the Macan? or do I take a ICE car

 

[Fly4ever]

...So,if I get it right the 12V battery will discharge anyway at some point in time if the car remains unused.If you do nothing of what @SimonEV describes above and just leave it there unplugged the battery will be dead in 2 weeks.If you take all the above preventive (according to Porsche) measures and additionally switch off Comfort access system - if you have it as a feature - you'll loose the battery after 6 weeks.Therefore the 12V battery will be gone anyway.There're preventing actions only to prolong the time period it'll remain alive.Should this time pass the battery will be saved only if the car will be plugged in for some time by someone or even maybe someone worthtrust takes care of it for as long we're away.
@Grumpy most likely it seems that without the Comfort access feature to continuously drain the battery it will be ok for up to 6 weeks according to Porsche manual.Therefore you seemingly must be o.k.However as this thing concerning this system isn't 100% confirmed officially,don't bet everything on this yet.Maybe there's something hidden depleting the battery.

 

[Grumpy]

The sad case is that I think my previous Macan S diesel was a better car, for me anyway.. I would be brave to leave this one at the Airport, I can hear my wife now!

 

[ChrisFromUK]

I'm not convinced this problem will be due to Comfort Access - surely this will switch off after a few days of the car being parked up. Certainly my wife's EV (not Porsche) does this and we've left her car for 7 weeks without issue although you do need to use the fob buttons wake it up and unlock it. If my Macan 4, when it arrives, can't be left in a car park for 2 to 4 weeks while I'm on holiday then I'm going to be having some very strong conversations with Porsche.

 

[dgkhn]

Vehicle electrical system battery care

What do I want to do?What do I have to do?Putting the vehicle out of operation for prolonged downtime

• Keep the doors, lids and bonnet of the vehicle closed.
• Switch off readiness for operation.
• To trickle charge, connect the high-voltage battery to the mains supply

(I) INFORMATION
The vehicle electrical system battery discharges even while the vehicle is not in use.

• To maintain its function, charge the vehicle electrical system battery approx. every 6 weeks or connect it to a CC/CV or pure CV trickle charger suitable for electrical system batteries.

Porsche creates the pile. How is one truly to understand what this means? Does "connect[ing] the high-voltage battery to the mains supply" trickle charge as this clearly states? If so, why would you need to charge or trickle charge the electrical systems battery? Or, does this mean that trickle charging the small battery is the alternative to leaving the HV battery plugged in? Who writes/reviews these manuals? Why doesn't Porsche just clearly explain this?

 

[Fly4ever]

I'm not convinced this problem will be due to Comfort Access - surely this will switch off after a few days of the car being parked up. Certainly my wife's EV (not Porsche) does this and we've left her car for 7 weeks without issue although you do need to use the fob buttons wake it up and unlock it. If my Macan 4, when it arrives, can't be left in a car park for 2 to 4 weeks while I'm on holiday then I'm going to be having some very strong conversations with Porsche.

I'not sure either and certainly could be other factors lurking in there as well.Even in @ChrisFromUK assumption that the Comfort Access system is shutting down after a while, could be somekind of malfunction preventing it from doing so, therefore depleats the battery remaining operational for much longer than originally designed.
When in my wife's car we had to deal with it couple of years ago the battery was completely drained in only 3 weeks.After we've been told to disengage the "Comfort Access" (don't remember how Renault calls it) in similar occasions we did so but then we were away for 6 weeks resulting in a second battery dead in 1half year time!It was then I was personally informed by a fellow tech guy with expertise in modern car electrical systems and electronics to completely remove the positive terminal.Now we're doing so everytime we leave the car and even after 3-4 months it remains sparkling and brand new every time I reconnect it.
There's obviously something here going on which certainly needs clarification and only Porsche themselves are(?) capable providing a clear explanation plus an acceptable solution. Otherwise we can only speculate and if a solution is to be found it will be out of pure luck.

 

[DHS]

Porsche creates the pile. How is one truly to understand what this means? Does "connect[ing] the high-voltage battery to the mains supply" trickle charge as this clearly states? If so, why would you need to charge or trickle charge the electrical systems battery? Or, does this mean that trickle charging the small battery is the alternative to leaving the HV battery plugged in? Who writes/reviews these manuals? Why doesn't Porsche just clearly explain this?

 

[DHS]

I called Porsche (1-800-PORSCHE) and talked to a person in their EV department. I was told that if you are leaving your car for an extended period of time, the only thing you need to do is to connect the high-voltage charger to the car before you leave, making sure that the amount of the charge is limited to 80%. The high-voltage charger will provide a trickle charge to the 12-volt battery. They are connected. The only time you need a trickle charger is when your car will not be able to be connected to a high-voltage charger while you are away.

That seems to answer the question. Of course, this won't work if your leaving your car at an airport parking lot for an extended period of time, which I suggest is not a good idea. It also means that we should monitor the health of our 12-volt batteries and replace them sooner rather than later. If we do that and if we follow the above advise from Porsche, it looks like problems like I had can be avoided.

 

[tmrqs]

I called Porsche (1-800-PORSCHE) and talked to a person in their EV department. I was told that if you are leaving your car for an extended period of time, the only thing you need to do is to connect the high-voltage charger to the car before you leave, making sure that the amount of the charge is limited to 80%. The high-voltage charger will provide a trickle charge to the 12-volt battery. They are connected. The only time you need a trickle charger is when your car will not be able to be connected to a high-voltage charger while you are away.

That seems to answer the question. Of course, this won't work if your leaving your car at an airport parking lot for an extended period of time, which I suggest is not a good idea. It also means that we should monitor the health of our 12-volt batteries and replace them sooner rather than later. If we do that and if we follow the above advise from Porsche, it looks like problems like I had can be avoided.

But… but… why would you call Porsche to get the question answered…?

There were only 6 pages of frustrated (angry?) posts about made up steps to access the Macan battery, explanations about why Porsche engineers are dumb dumbs… there could have been so many more with wild theories!

Oh well… guess people will have to move on to the next thread to get upset about something else!




(and thank you for calling Porsche!)

 

[SteveInKirkland]

But… but… why would you call Porsche to get the question answered…?

There were only 6 pages of frustrated (angry?) posts about made up steps to access the Macan battery, explanations about why Porsche engineers are dumb dumbs… there could have been so many more with wild theories!

Oh well… guess people will have to move on to the next to get upset about something else!




(and thank you for calling Porsche!)

I've had 5 conversations with Porsche about this and received 5 different answers. I'm still skeptical about all of the answers and look forward to reports of people trying it.

 

[Wivenhoe]

This problem is prevalent on EV’s and hybrids. Apparently all of the manufacturers decided that on EV’s & Hybrids they could reduce the size and weight of the 12v batteries as it is has a very limited use - the hybrid and EV battery do most of the work.

When I was locked out of my Lexus RZ I was told to run the car for 20 minutes every couple of days to be sure. I pointed out that I couldn’t do that when abroad so they gave me a solar panel to put on the dashboard and plug in the OBD port and provide a trickle charge - I pointed out that wouldn’t sort it if parked in a multi-storey car park !

My tracker monitored the 12v battery and when it showed amber I knew it was time to start the car. Ridiculous on a $ 90k car but a widespread issue that I understand can’t be sorted by a software upgrade. Lexus said no point replacing the battery as it wasn’t deficient once charged - it was an inherent hardware problem that couldn’t be currently resolved as it would need a physically bigger battery and there was no available space.
I hope Porsche have a better resolution than plugging in a solar panel.

 

[SergeyIndy]

I've had 5 conversations with Porsche about this and received 5 different answers. I'm still skeptical about all of the answers and look forward to reports of people trying it.

We still do not know how this works on the Taycan after manuals and tech recommendations, with some having no problem leaving the car for weeks and months and others leaving for 10 days to find a dead 12v. The original issue was that HV battery would only charge the 12v 8 times (plugged into mains or not) when the car is parked, but then we were under the impression that this was fixed with a software update, but to this day cases still coming up.

Somehow, we need an answer from the mothership on the logic under what conditions HV battery maintains 12v health. However, we know this will not be easy, as we cannot get the mothership to tell us why US Macan EVs are limited to 40Amp/9.5kWh charge rate.

 

[SergeyIndy]

The next best thing would be a TSB describing on how to "really" do it if going by the example below, where it clearly states that manuals are not clear and most likely a cut and paste from other models. This is to prove @SteveInKirkland point that reading the manual or listening to a 1800Porsche person reading from most likely the same incorrect sources is not going to give us on how it really works.

Taycan TSB example: https://www.taycanforum.com/forum/attachments/mc-10182251-0001-pdf.10661/

 

[Fun TC Driving]

As a few other new models of other brands have found out the hard way, we are seeing more premature (sometimes as little as a month or two), complete 12V battery failures that we used to, e.g., initial 12V battery manufacture performance quality issues.

As SergeyIndy asked above, do we have 100% confidence that if we treat our main batteries property (and they do not have their own issues), that the main batteries will “trickle charge” or equivalent the 12V one?

Sponsored