Locked out - another 12v saga

[kailifish]

i've had the same issue happen to me less than two weeks ago, same situation, but left the car a bit longer (2.5weeks).

i had to apply quite a bit of force to unlock the door, not sure if I held on for 5 seconds. It took several tries, and I was afraid of breaking the key's small plastic dimple.

called the dealership, and they didnt know anything as well.

Now I'm thinking if I should buy a 12V booster and keep in my garage.

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[Windpower]

Thanks, can only see support for lead acid on the spec sheet though?

This device can be used as a 12v source to both unlock the frunk and jump (boost) the 12v lithium ion car battery. It cannot be used as a trickle charger for a lithium ion battery.

 

[batteredhaddock]

This device can be used as a 12v source to both unlock the frunk and jump (boost) the 12v lithium ion car battery. It cannot be used as a trickle charger for a lithium ion battery.

Yeah, saw it was a booster. But just can’t see anywhere mentioned if its ok to boost a Li battery with it? I’ve seen a few booster brands explicitly state to not use with a Li 12V so a bit cautious on what to buy as a contingency option.

 

[Windpower]

But just can’t see anywhere mentioned if its ok to boost a Li battery with it?

It’s been awhile since I looked, but with Tesla’s Li battery, you just need a 12v source to kick start the car. Once the car is back up, it can properly charge the 12v Li battery. The procedure keeps the 12v booster connected for only a few seconds. I believe the same procedure is specified in the Taycan manual.

 

[BigBob]

Do you have a decent mobile phone reception where you live? I think if it's poor the car can drain itself trying to repeatedly contact the mothership. Also, did you have the Porsche app open on your phone while away. I understand that can also cause the car to stay awake for a chat.

As you point out. How on earth a little battery attached to a device that is 50% a giant battery can't keep itself charged up is beyond me!

 

[rb33gl]

Do you have a decent mobile phone reception where you live? I think if it's poor the car can drain itself trying to repeatedly contact the mothership. Also, did you have the Porsche app open on your phone while away. I understand that can also cause the car to stay awake for a chat.

As you point out. How on earth a little battery attached to a device that is 50% a giant battery can't keep itself charged up is beyond me!

Porsche Connect uses Vodafone, the same as my mobile. That has a good reception around here, but the car was in my garage so that might’ve a factor.

I didn’t open the app while I was away - there didn’t seem much point in Antigua!

 

[MTGBUK]

People using iPhones should also turn off location access when car is not in regular use. Occasionally I get a pop up on my phone saying “Myporsche has accessed your location X times in X days”. I think default is always on.

 

[simcity]

It’s been awhile since I looked, but with Tesla’s Li battery, you just need a 12v source to kick start the car. Once the car is back up, it can properly charge the 12v Li battery. The procedure keeps the 12v booster connected for only a few seconds. I believe the same procedure is specified in the Taycan manual.

It’s only very recent Tesla’s that have a 12V lithium battery. All the older ones including my current one, were wet-cell lead acid 12V.

I’d be very careful about using something like a NOCO booster (I have several for tractors and machinery) on a Lithium chemistry 12v battery.

I have only ever trickle charged Lithium ferrous phosphate (LiFePo) batteries with either an Optimate or CTEK lithium specific chargers. Never dared boost charge them due to the differing voltage / chemistry and (on some) their BMS

 

[Windpower]

I’d be very careful about using something like a NOCO booster (I have several for tractors and machinery) on a Lithium chemistry 12v battery.

Agreed. You can’t charge a Li battery with a non Li charger. But …
In the case of both the Tesla and Taycan, usually the 12v battery is not ‘dead’ but it’s voltage has dropped. Once the 12v voltage drops below a certain voltage, the car electronics puts itself to sleep to avoid damaging the batteries and electronics. You use the NOCO booster to ‘wake up’ the cars electronics, and once awake the car can properly recharge the 12v Li battery from the high voltage battery.
The NOCO booster is not charging the 12v Li battery but just kick starting the cars electronic system. In the Taycan manual there was a reference to using a 12v battery to kick start the electronics.You never actually touch the 12v Li battery, just the jumper terminals under the frunk.
The root cause is most likely a software issue and should get solved over time.

 

[satchurator]

Plugging in the charger to the main battery doesn’t do anything either.

@rb33gl Can you clarify - did you have your car connected to an L1/L2 charger while you were away?

Re: “Germany fiddling with some of the Connect settings” - They might be referring to the ONA5 OTA update and related backend changes.

 

[rb33gl]

@rb33gl Can you clarify - did you have your car connected to an L1/L2 charger while you were away?

Re: “Germany fiddling with some of the Connect settings” - They might be referring to the ONA5 OTA update and related backend changes.

No it wasn't connected while we were away.

The OPC wasn't particularly clear about how to charge the 12v Li battery other than taking it for a drive or connecting it to a 12v Li charger.

They said plugging in a charger for the main battery wouldn't recharge the Li one, but I understand this does happen if the voltage of the Li battery falls to a level where it shuts down. When you reactivate the 12v, it kicks back all the systems and (AFAIK) the main battery will top it up.

 

[Vercingetorix]

From NOCO:
Carefully read and understand the vehicle owner's manual on specific precautions and recommended methods for jump starting the vehicle. Make sure to determine the
voltage and chemistry of the battery by referring to your battery owner's manual prior to using this product. The GB40 is for jump starting 12-volt lead-acid batteries only.
Before connecting to the battery, verify that you have a 12-volt lead-acid battery. The GB40 is not suitable for any other type of battery.

 

[Windpower]

The GB40 is for jump starting 12-volt lead-acid batteries only.

Once again, you're not jump starting the EV. Unlike an ICE car, there is no starter motor or alternator which you need to power. Instead with an EV. you're providing 12v power to the electronics so that the car will wake up. Once the car is back up, the car will take care of properly charging the 12v Li battery.

If the use of this device makes you uncomfortable, don't use it. Instead get a 12v lead acid battery to kick start your EV in the case of a problem. That's what the AAA trucks use.

 

[02bluesuperroo]

I wonder if putting the car into privacy mode could prevent these issues at all. I'm about to leave my car sit for 8 days and I'd rather not have to deal with anything like this.

 

[daveo4EV]

this problem was more common prior to the latest updates (circa 2021) - I never expect Porsche to eliminate these problems that's impossible - just make them less frequent. My personal experience post update is that the 12V problems are far fewer and far between but still possible (as this post indicates). The recovery procedures are the same regardless of why your 12V battery is "offline", you simply need to provide power to the vehicle via the 12V jumping post in the frunk and the vehicle will cover itself…

the reason as to why the 12V drains itself are elusive and most likely software related to systems being allowed to run that should be "asleep" - this will get better over time as Porsche fixes more software bugs but the core problem can never be 100% fixed, there will always be corner cases where the software system can mistakenly keep the vehicle's systems "awake" and therefore place demands on the 12V system - causing a drain to low voltage which when reached will cut-off the 12V battery…

I am highly dubious of any 12V trickle charger mattering here for the following reasons:

• if there are no Taycan software faults the 12V tickle charger is un-necessary
• if there is a software fault keeping Taycan systems awake and draining power the power drain of Taycan systems will greatly exceed the 12V trickle charger's abilities and therefore still drain the 12V battery until it trips "offline"
  • once the 12V battery has dropped "offline" the trickle charger can not bypass the relay that has tripped and the 12V battery is effectively disconnected - therefore no power will ever reach the 12V once it's in this condition.
    • you must provide sufficient 12V power to the jumper posts to wake up/power the main computer in the Taycan for it to be alive and and reset the 12V relay
  • the fact that a 12V trickle charger is insufficient is trivally demonstarted by the fact that once the Taycan is in this state a 12V trickle charger like the CTEK doesn't provide enough power to "wake up" the Taycan's main computer
  • 12V trickle charger is nearly pointless for EV given my reasons above
• any 12V "booster" is sufficent to wake up the Taycan - and the only method other than an actual 12V battery for recovering the vehicle
  • there is _NO_ issue with lead-acid vs. liOn booster and what not - 12V power is 12V power is 12V power - and properly used the booster is only involved for 90 seconds or less…once the main computer has woken up the Taycan will recover itself - and you disconnect the 12V booster as once the vehicle is "alive" it is no longer necessary.
• The issue as to 12V boosters and the risk of using them is _NOT_ to the Taycan's systems, it is to the booster - as when the Taycan wakes and begins charging the vehicle's 12V battery that power will also flow "into" the 12V booster - potentially overwhelming the booster - in extreme circumstances that could cause problems for the booster's battery being overloaded and outcomes are "unpredictable" and potentially dangerous
  • if you're not comfortable using a booster don't use one.
• I for one have no issues using the booster and only leave it connected long enough to wake up the vehicle - I've no no issues to date.

this is little new information in this thread - other than proof the Taycan's software systems are not yet perfect at managing 12V power drain - this is unsurprising…and never a reasonable expectation for it to be otherwise. I do believe at this time Taycan is no worse (and actually better) with regards to 12V dead-battery scenarios than any ICE vehicle I've ever owned. And given the actual frequency of 12V problems it's not an issue in terms of overall quality.

nothing by the way can be done for an actual "bad" 12V battery - and they do go bad and need replacing - again this is no different that any ICE vehicle's 12V battery - they are not lifetime items, they are subject to wear/tear/age and will eventually fail and need to be replaced.

a 12V trickle charger for nearly any EV is an excellent elephant defence mechanism - i.e. the system you deploy in your home to protect you from elephant attack - I have one of these and my home as never been attacked by elephant…so it must be working. But then again no elephants have ever tried to attack my home - so we really don't know now do we? Same thing with the Taycan - the 12V battery drain is software fault that drains the 12V in a matter of hours (sometimes less than an hour) - once the Taycan's software systems are in this state _NO_ 12V trickle charger can keep up with the power demands and the 12V battery will be drained and trip offline…at which point you require a 12V booster (or actual 12V battery) to power the vehicle's systems to wake it back up…at which point the car will reset itself and Taycan will use the big battery to charge the little battery.

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