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

[SteveInKirkland]

I really hope you're right that keeping the car plugged into a charger will prevent the 12V draining to death.. but that still doesn't solve the issue of when/if the 12V fails due to age/defect. An ICE can simply pop the hood and just be jumpstarted and driven to a store to replace the battery. Don't understand why we have to go through a major hassle for the Macan as well.

"Third, the service manager at the dealership told me never to connect a trickle charger to the Macan EV and never to use an ICE "12v battery rescue charger" Did you then ask what to do in that situation then?

I have no confidence that I'm right. I am frustratingly relaying that I've been worried about this scenario since before purchase and no one seems to have a reasonable story about what should be done. I'm certainly going to FAFO, because I'm leaving the car for months at a time this summer.

This isn't my first Porsche. Like others, I know what the problems are with 12v batteries on ICE cars. ICE car 12v batteries are why I asked the question of the service manager during delivery of the Macan EV. But I can't read the engineers' minds for what they decided to do with this car ... which has a 100 kWh battery pack strapped to it and *should* almost *never* have this problem.

As for what they (Porsche dealer) recommend to use to charge the 12v battery using the exposed wires in the front bumper, they recommended a 4 amp 12v continuous sign wave power source but have asked Porsche for a part number recommendation for me. I still haven't received a response.

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[CandianPorsche83]

Your solution assumes that you can get into the car to "just zap the hood latch circuit on the driver's side left of the brake pedal", but how can you do this if the car is locked and can't be opened due to the dead battery?

 

[SimonEV]

As for what they (Porsche dealer) recommend to use to charge the 12v battery using the exposed wires in the front bumper, they recommended a 4 amp 12v continuous sine wave power source.

I wouldn't bet on this working. The System Battery is like a VW 000 915 105 DG that is a 12V AGM Lead Acid battery rated at 68AH 680A (380A DIN). I'm not sure Porsche would want you to charge it yourself, or worse still, start extracting power in an uncontrolled way from these exposed wires.

The purpose of connecting an external power source is solely for the purpose of powering up a module, so that you can then use the key fob to open the bonnet (in a controlled way) and certainly not to charge/maintain the battery. Normally the bonnet opens on demand but using this method it is unlocked and it's up to you to release the bonnet manually.

When you connect a 12V battery to these terminals, you use it to indirectly open the bonnet and it doesn't follow that it also connects directly to the System Battery terminals for charging. I'm not sure Porsche would want anyone to connect anything other than the recommended (normal, like a car's) 12V battery to these terminals.

A "4 amp 12V continuous sine wave power source" is the last thing you want to charge a 12V System Battery with e.g., commercial chargers like a CTEK Charger operate as a CC/CV charger and provides a regulated DC voltage. Unlike the interlock on the AC Charger you use to charge the HV Battery, there may be no safeguards to prevent you establishing readiness and driving off with a charger connected, so be careful.

 

[SteveInKirkland]

I wouldn't bet on this working. The System Battery is like a VW 000 915 105 DG that is a 12V AGM Lead Acid battery rated at 68AH 680A (380A DIN). I'm not sure Porsche would want you to charge it yourself, or worse still, start extracting power in an uncontrolled way from these exposed wires.

The purpose of connecting an external power source is solely for the purpose of powering up a module, so that you can then use the key fob to open the bonnet (in a controlled way) and certainly not to charge/maintain the battery. Normally the bonnet opens on demand but using this method it is unlocked and it's up to you to release the bonnet manually.

When you connect a 12V battery to these terminals, you use it to indirectly open the bonnet and it doesn't follow that it also connects directly to the System Battery terminals for charging. I'm not sure Porsche would want anyone to connect anything other than the recommended (normal, like a car's) 12V battery to these terminals.

A "4 amp 12V continuous sine wave power source" is the last thing you want to charge a 12V System Battery with e.g., commercial chargers like a CTEK Charger operate as a CC/CV charger and provides a regulated DC voltage. Unlike the interlock on the AC Charger you use to charge the HV Battery, there may be no safeguards to prevent you establishing readiness and driving off with a charger connected, so be careful.

Yes. I'm sorry my cynicism about the process suggested by the dealer service manager didn't come across in that post. I tried to convey that I had no confidence in the information being presented to me.

 

[platypus]

I don’t get it… my car was not driven for 10 days, left with 50% charge, it’s been cold, no issue at all - and it was *not* plugged.

The 12V shouldn’t lose charge like that, there’s something else going on.
Don’t believe this is a thing that impacts everyone / every Macan.

Exactly my thought when reading this thread. A few days should definitely not cause a noticeable discharge, unless there is something actively draining the battery. A few months is a different issue. So as the manual indicates if you leave the car more than a few weeks, it's safer to plug it. That said, I've left my Macan EV more than once for three weeks unplugged, in an unheated parking garage with freezing outside temperatures, and everything worked smoothly when I restarted it.

 

[Fly4ever]

As far as there isn't a reaction officially made by someone from Porsche with any kind of hint or something, we must think on our own a probable cause and its likelihood solution. Won't be the first time...!
So, according to your knowledge, which could be the system(s) consuming electrical energy when the car is parked & locked? Like an alarm for example, or the Comfort Access feature, or something else entirely... What is it constantly needs 12V power? Is there a way for such systems to be entirely disengaged? What features concerning that matter the cars which their owners reported "no problem/everything normal" like @platypus have in common relatively to those who encountered the issue?
...C'mon, the tech guys at Porsche are waiting from us to do their job finding the solution again... Let's not disappoint them...!!

 

[Degenatron]

Jesus Christ! this thread is a vortex of assumptions and mis-information

Does anyone have a picture of the 12V battery in the Macan?

@JonoNZ We do here, it's a regular-sized AGM battery:
https://www.macanevowners.com/forum/threads/porsche-tech-claiming-the-car-is-shit.17598/post-266902

Wish it was that easy. This from Taycan forum:

1. Tools you will need:
   1. known good 12 volt power source - with "clamps"
   2. flash light
   3. possibly some copper wire with both ends exposed
   4. vehicle key
   5. 15-30 minutes in my experience
2. Goal: get the frunk open so we can "jump" the 12V battery power the vehicle’s main computer and let the car "recover" itself -it will then charge the 12V battery
3. You will need to open the doors to the vehicle, preferably the driver's door
   1. if the vehicle is locked - you'll need to extract the "emergency" key from the back of the key fob
4. Open the driver's door
5. place your light source in the driver's foot well and shine it on the plastic cover next the "dead pedal"
6. feel around and carefully remove the plastic mostly triangle shaped cover on the left of the dead pedal
7. removing this panel will expose the "fuse" panel for the vehicle
8. in the panel there is a "red" tab - carefully pull this tab out so that it extends beyond the fuse panel
   1. this red-tab has a graphic on it - that generally indicates the frunk "opening"
9. attach the positive terminal (red clamp) of your known good 12 volt power source to this red tab you just pulled out
10. attach the negative terminal (black clamp) of your known good 12 volt power source to any bare metal near by attached the car
    1. I used the door "latch" on the "B-pillar" since it's bare metal - my 12 volt negative cable was too short so I got about 2 feet of wire, stripped both ends to bare copper and "clamped" one end of the wire and wrapped the other end on the bare metal
    2. this wire is now part of my recovery “kit”.
11. fiddle with the 12 volt source and try and get it to provide "power" to the vehicle - in my case I had to place the 12volt booster I was using into "overload" mode
12. I hear the vehicle making some clicking noises
13. I used my key-fob to open the frunk
14. you are now done in the driver’s foot well - we’ll be moving on to the frunk area now
15. Now that the frunk is open you can access the 12V battery jumping posts (as notes in conversation do NOT attempt direct interaction with the actual 12V battery)
16. Remove the piece of black plastic covering the battery jumping post - there is a plastic trim piece below the windshield wipers, but above the frunk line
17. Once this piece of black plastic trim is removed - the 12V positive/+ jumping post is "under" the windshield wipers and you should see a "red tab" plastic tab
18. remove the plastic red-tab cover exposing the 12V positive/+ post for the vehicle
19. attach your known good 12V positve/+/red power source clamp/cable to the positive post for the vehicle
20. attach your known good 12V negative/-/black power source to the negative "post" which is bare metal sticking up near by the postive post
    1. it's about 1/2 way between the red-post and the passenger fender of the car
21. I had to place my 12V booster into overload mode, and after about 30-60 seconds the car "came" alive!!!
22. remove the 12V power source
23. the car should be good now and will recovery itself. Now that the car is alive again it should charge the 12V battery and normal operations can resume.
24. we’re done - your Taycan is back to functional.
25. Replace the pieces of trim you removed or leave them off for your dealer if you’re taking the car to service.

these instructions were culled from the following threads:

https://www.taycanforum.com/forum/threads/my-car-died-overnight-12v.2501/
https://www.taycanforum.com/forum/threads/don-breaks-his-taycan-the-saga-of-the-12v-battery.1274/

@DHS That's for the Taycan, Macan is not at all that complicated:

To expand on @CandianPorsche83 instructions below, it doesn't look too difficult or require special tools:

Regarding the 12V battery drain: I've now successfully installed a dash cam with switched ACC-ish parking mode. It has quite a high drain of over 4W so it would fully deplete a typical 12V battery in less than a day I believe. I've been monitoring it and over a period of 4 days with the car undisturbed (no comfort access) the HV battery has been drained by at least 1%, all the while the camera has been recording uninterrupted.

So it looks like the car is topping up the 12V battery while idle - whether its on a scheduled interval or by monitoring the 12V voltage I cannot say. What's needed is to stick a 12V battery monitor on the car to see how it manages the 12V, then we can say for sure.

Both the Macan and Q6 manuals are lacking this info and conversely state that the 12V will simply become drained if left for a long time - a hang-up from ICE car manuals that has just been copy/pasted?

 

[SteveInKirkland]

Regarding the 12V battery drain: I've now successfully installed a dash cam with switched ACC-ish parking mode. It has quite a high drain of over 4W so it would fully deplete a typical 12V battery in less than a day I believe. I've been monitoring it and over a period of 4 days with the car undisturbed (no comfort access) the HV battery has been drained by at least 1%, all the while the camera has been recording uninterrupted.

So it looks like the car is topping up the 12V battery while idle - whether its on a scheduled interval or by monitoring the 12V voltage I cannot say. What's needed is to stick a 12V battery monitor on the car to see how it manages the 12V, then we can say for sure.

Both the Macan and Q6 manuals are lacking this info and conversely state that the 12V will simply become drained if left for a long time - a hang-up from ICE car manuals that has just been copy/pasted?

It likely matters which fuse your dash cam is using. It would be useful to add that to the documentation in the forum for others to work with. Also, did you use the factory pre-installed wiring harness or come up with another solution?

 

[SuperH]

My husband had this very issue on his Taycan a fortnight ago after leaving it for 5 weeks due to a combination of rain (he won’t take it out if its wet - annoys the hell out of me!) and a fortnight’s Christmas holiday. The RAC came out and got into the car, then took it to Porsche for them to replace the battery (just because the RAC man advised that as it was still under warranty - why not get Porsche to sort it!). Porsche advised that it should last 6 weeks, but clearly it didn’t!

 

[fubar.droid]

Jesus Christ! this thread is a vortex of assumptions and mis-information


@JonoNZ We do here, it's a regular-sized AGM battery:
https://www.macanevowners.com/forum/threads/porsche-tech-claiming-the-car-is-shit.17598/post-266902



@DHS That's for the Taycan, Macan is not at all that complicated:


To expand on @CandianPorsche83 instructions below, it doesn't look too difficult or require special tools:

Regarding the 12V battery drain: I've now successfully installed a dash cam with switched ACC-ish parking mode. It has quite a high drain of over 4W so it would fully deplete a typical 12V battery in less than a day I believe. I've been monitoring it and over a period of 4 days with the car undisturbed (no comfort access) the HV battery has been drained by at least 1%, all the while the camera has been recording uninterrupted.

So it looks like the car is topping up the 12V battery while idle - whether its on a scheduled interval or by monitoring the 12V voltage I cannot say. What's needed is to stick a 12V battery monitor on the car to see how it manages the 12V, then we can say for sure.

Both the Macan and Q6 manuals are lacking this info and conversely state that the 12V will simply become drained if left for a long time - a hang-up from ICE car manuals that has just been copy/pasted?

4W is not a very high drain, that would be 48wHr per day.. a typical car battery has 420 - 900 wHr.

I'm not sure your experience of the HV battery draining 1% to recharge the 12V battery is necessarily accurate.

There is a ton of misinformation, though I don't think any of it is intentional, it's more due to lack of information from Porsche, but I feel like you're just adding onto that pile.

 

[Dragon Tourniquet]

My guess is (because that's all we can do at this point) is the phantom drain is because one of the computers isn't properly taking action on the power off command that will get sent out on the CAN bus when the car should go to sleep. Ideally the component that sends that command should watch for confirmation, but since it's a new platform that could be one of the things that has been forgotten (again).

 

[Degenatron]

It likely matters which fuse your dash cam is using. It would be useful to add that to the documentation in the forum for others to work with. Also, did you use the factory pre-installed wiring harness or come up with another solution?

I will update the thread once I can get some more pictures in the daylight to do it justice! The only ACC fuse slots I found were in the frunk fuse box, and I couldn't see how to run a fuse tap from there to the interior without removing the whole frunk unfortunately.

I shamefully used a wire tap on the rear 12V outlet, of which the power is cut 30 minutes after locking the car.

 

[Degenatron]

4W is not a very high drain, that would be 48wHr per day.. a typical car battery has 420 - 900 wHr.

I'm not sure your experience of the HV battery draining 1% to recharge the 12V battery is necessarily accurate.

There is a ton of misinformation, though I don't think any of it is intentional, it's more due to lack of information from Porsche, but I feel like you're just adding onto that pile.

Trying to clean up the pile! A 4W load would be 96Wh/day.

In the testing I did the battery was dropping to 11.8V after 1 day, 11.8V is approx 30% SOC for a 12V battery, 12.8 is 100%. 11.8V is the cutoff for the hardwire kit I have (Viofo HK4). However as I say its been recording continuously for the last 4 days which would suggest it is being topped up as at that rate it would hit 0% shortly after 1 day - you've swayed me confirm by doing some 12V logging!

 

[fubar.droid]

Trying to clean up the pile! A 4W load would be 96Wh/day.

In the testing I did the battery was dropping to 11.8V after 1 day, 11.8V is approx 30% SOC for a 12V battery, 12.8 is 100%. 11.8V is the cutoff for the hardwire kit I have (Viofo HK4). However as I say its been recording continuously for the last 4 days which would suggest it is being topped up as at that rate it would hit 0% shortly after 1 day - you've swayed me confirm by doing some 12V logging!

Ah derp on the math, thanks for correcting, but yes some data would be nice and I'm not discrediting you, we just need empirical data. Don't understand why a computer on wheels can't have this information readily available as well.

 

[tmrqs]

Jesus Christ! this thread is a vortex of assumptions and mis-information

There is a ton of misinformation, though I don't think any of it is intentional, it's more due to lack of information from Porsche, but I feel like you're just adding onto that pile.

This summarizes the current situation.

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