Taycan Dead After Vacation

[whitex]

After using the GB20 to get the frunk to open, you are going to have to charge the 12V battery enough to get it operational if you want to continue on with whatever recovery you are tasked with.

You only need sufficient current (more then 5A, but not for long) to power-on Taycan's electronics and close the HV contactor. After that, the HV battery charges the 12V battery via DC-DC converter.

In simpler terms, this is very similar to jump-starting an ICE engine, momentary large current to start the engine, after that the alternator takes care of the 12V charging.

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[simcity]

You only need sufficient current (more then 5A, but not for long) to power-on Taycan's electronics and close the HV contactor. After that, the HV battery charges the 12V battery via DC-DC connector.

In simpler terms, this is very similar to jump-starting an ICE engine, momentary large current to start the engine, after that the alternator takes care of the 12V charging.

That’s correct. There’s no point popping the hood/bonnet open - and strapping on a 12v battery charger - it won’t work. I tried on a severely depleted 12v. No dice.

Need something with enough oompah to also wake up the “dead” 12v from its slumber - that is close the safety relay /contactor inside the 12v battery.

If you use a booster it will wake up the dead battery and also juice up the electronics to open the main daddy 800V to 12V system and take over the 12v charging duties, that it had previously abdicated ??

Porsche power electronics engineers need some lessons from Tesla on how this should be done. Are you listening lads!!??? ?

 

[whitex]

Porsche power electronics engineers need some lessons from Tesla on how this should be done. Are you listening lads!!??? ?

Actually, it has worked very similar on all 4 of the Model S'es I've owned. I'm not sure if Tesla ever got rid of the 12V battery completely and replaced it with just a tap from the HV battery (which was not interrupted with the main contactor). Did they?

 

[simcity]

Actually, it has worked very similar on all 4 of the Model S'es I've owned. I'm not sure if Tesla ever got rid of the 12V battery completely and replaced it with just a tap from the HV battery (which was not interrupted with the main contactor). Did they?

I never had a problem when we used to go to Australia for a month or two. The main HV as long as it was sufficiently charged just kept topping up the 12V…

Porsche / Audi is designed to stop after 8 recharge cycles. Then you’re on yor ownsome. Not a great idea, especially if the car has higher vampire drain than the engineers calculated when coming up with this grand plan.

 

[whitex]

I never had a problem when we used to go to Australia for a month or two. The main HV as long as it was sufficiently charged just kept topping up the 12V…

Porsche / Audi is designed to stop after 8 recharge cycles. Then you’re on yor ownsome. Not a great idea, especially if the car has higher vampire drain than the engineers calculated when coming up with this grand plan.

I am not sure they still have 8 cycle limit. I've had a 24/7 dual channel dashcam running on my Taycan which increases the 12V drain of course, but I haven't lost 12V battery yet, even leaving it at the airport for a week at a time (or sometimes leaving it plugged in at home for a few days). The dashcam does use the official Porsche pre-wire, perhaps they check if the pre-wire constant power fuse is installed (car came without a fuse in that slot) and remove the 8 cycle limit, or increase it?

I used to run the same dashcam setup on all my Teslas, but there the 12V battery is topped off every 4-10hrs depending on outside temperature and main battery SoC. This is because Tesla uses the 12V to cool/heat the main battery when the car is parked. On more than one occasion, when tinkering with the Tesla and disabling the 12V recharging (which happened if I removed the main infotainment, as it controls the 12V charging), I managed to drain my Tesla 12V battery from full to zero in as little as 4 hrs, had to jump start it after replacing the infotainment so that the 12V would recharge. Tesla 12V batteries had about 2-3 year lifespan for me - changed them as often as wiper blades (cars garage parked, not doing a lot of miles, but 12V was always exercised even when parked).

 

[simcity]

I am not sure they still have 8 cycle limit. I've had a 24/7 dual channel dashcam running on my Taycan which increases the 12V drain of course, but I haven't lost 12V battery yet, even leaving it at the airport for a week at a time (or sometimes leaving it plugged in at home for a few days). The dashcam does use the official Porsche pre-wire, perhaps they check if the pre-wire constant power fuse is installed (car came without a fuse in that slot) and remove the 8 cycle limit, or increase it?

I used to run the same dashcam setup on all my Teslas, but there the 12V battery is topped off every 4-10hrs depending on outside temperature and main battery SoC. This is because Tesla uses the 12V to cool/heat the main battery when the car is parked. On more than one occasion, when tinkering with the Tesla and disabling the 12V recharging (which happened if I removed the main infotainment, as it controls the 12V charging), I managed to drain my Tesla 12V battery from full to zero in as little as 4 hrs, had to jump start it after replacing the infotainment so that the 12V would recharge. Tesla 12V batteries had about 2-3 year lifespan for me - changed them as often as wiper blades (cars garage parked, not doing a lot of miles, but 12V was always exercised even when parked).

I don’t think a week is long enough to test the bounds of the recharge algorithm. For various reasons I had the car sat since mid-September and I know when the 12v died - around 2 weeks ago when the Vodafone/Porsche tracker spat the dummy. It had been fine up until that point.

I’ve variously had our model X idle for 6 weeks whilst away travelling and the key thing was to leave the HV battery around 80% and not be tempted to check the app. That 12v lead acid lasted me 5 years and 80K miles when I preemptively replaced it.

To be replace a Porsche 12v LiFePo is an astounding £1k. Tesla was £120 installed by a ranger. Think this will be my last electric Porsche.

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