daveo4porsche

as I have noted in several historical posts EV's while having 400V/800V batteries with oodles (oodles is a technical term meaning a lot) of power - they can all be undone by a simple 12V battery failure - yep your fancy EV can be rendered inert by a simple and common 12 volt battery failure - this has been true for Tesla, Bolts, and other EV's for a while now - an apparently the same is true for the Taycan

I post this for informational purposed and zero judgement - I simply find it amusing how modern devices from all manufactures carry with them legacy limitations due to engineering practice and supply chain issues - this is not bashing the Taycan but simply pointing out how in many ways the more things change the more they stay the same…

https://www.taycanforum.com/forum/th...-battery.1274/

the good news here is once identified we all know it's easy to jump/replace a 12 volt battery.

apparently the car is at the dealship now and Porsche is analyzing it as to "why" the 12 volt battery went dead.

apparently another Taycan owner has had a similar issues - that alone wouldn't be interesting but 2 similar failures for the very very few number of units in the wild might be interesting. Porsche will get to the bottom of this - I'm guessing software fix - maybe the 1st OTA update ever will resolve the issue for current owners - it would be a good use of that type of system.

daveo4porsche

NOTE: I've had 12V battery issues with _ALL_ the EV's I've owned - I personally find it very amusing that a low-maintenance very reliable EV drive train (again all EV's to date seem to have this basic design) can be rendered inert by a "dead" 12 volt battery which needs replacing/jump starting to bootstrap the car to running off the "big" battery.

daveo4porsche

problem is now reproducing - owner is hoping to get Porsche a reproducible case so they can fix it - but this appears to be an issue.

Nelson Paiva

I had similar issues in my Tesla as well, and had it replaced twice. The same being true in the Taycan hopefully won't affect all cars.
ICE vehicles were also deemed unusable when 12-volt batteries were dead. Indeed, the more things change, the more they stay the same.
Hope your car is back and running well soon.

various cheeses

Yeah when I had my beater Prius, I read dozens of weird issues on the forums could be cleared up just by replacing your 12V battery. You'd think they'd figure out a better solution for it by now.

Needsdecaf

There is now a recall out to replace the grounding pin on the charging connector.

r553

FWIW so you can tell your service department the recall is WLB3 – Replace ground point for external power connection.

daveo4porsche

the ground pin recall has not fixed @Louv charging problems - investigation continues…

aCayenneFan

If memory serves, when the Prius is started from being shutdown (when the Start button is pressed), the ICE on the Prius is started by the 12 volt battery, not the hybrid battery...

Whoopsy

Not exactly unheard of.

In the 918, it also has a little tiny 12V lithium battery. it's buried in the middle of the car but accessible from the bottom. The 'design' was that the hybrid battery will be responsible for keeping the little guy in working order. As long as the car charger is plugged in, the hybrid system will top off the 12V. Same system is used in all their hybrids. I don't believe Porsche developed another system just for the Taycan, they should still be using the same one.

In a few select cases, I have seen one case in person (not my car) and heard of another, that the voltage regulator/distributer is defective and didn't do it's job to maintain the 12V. End result is a dead 12V lithium battery and that bricked the whole car.

Replacement cost for that tiny little thing that weights next to nothing? ~$12,000. The 12V in the Taycan will of course be a lot cheaper.

Antigravity

Well this might be an opportunity for Antigravity Batteries. Actually I don't know anything about the Taycan's Battery or its issues, but I do have a Tesla Model 3 that I have been testing our Group 51R RE-START Battery in. All has been well for the last 3 months, and I have not bricked the car, so that part of testing has not been attempted yet but maybe in a few more months. But our battery has a built in RESERVE that we usually use for Jump Starting in an ICE vehicle, but I am assuming that would work for the Jump Start that is normally required.

Interestingly we are the supplier to Tesla's Roadside Assistance Department, they buy our MICRO-START XP-10s for their Jump Starter for the Teslas Roadside service worldwide, which is cool for us. More interestingly is I've never bothered to talk to them about it, they just started ordering direct about 5 years ago and they said it worked great so I left it at that. Now that I've owned a Tesla for about a year or so and have not required a jump start, I still wanted to try to put our Group 51 in there and test so that is what I'm doing. We'll see where it goes but it might have promise.

I have found is that the Tesla Charging profile is quite odd for the Lead Acid Batteries they put into the Car it basically just an on and off thing... just kick the voltage up, , then turn it off to a lower voltage then off again... then kick it on again, where as its usually for a lead acid battery you will see a more mild raise then drop during charging.

Anyway, not adding a lot to the conversation, but maybe we will learn something and we can have a Lithium option for the Tesla and Taycans.... don't know what size the Taycan is using. Last I"m not sure why they don't go with a Lithium Battery also for this power supply type battery, unless they want more Service options to make the Customer pay for because a Lithium battery can offer twice the Cycles... Don't think it has anything to do with the cold really but might. They might assume they don't want a Lithium in below freezing for long periods, or it could be and expense thing.

tnikolov

Is there an easy way to see if my 12V battery is OK?

r553

You can display 12V battery voltage on the instrument panel.

whiz944

Prius-like drivetrains don't have a traditional starter motor nor an alternator. They use one of the big motor/generators instead. (Prius, like my Volt, has two MGs.) The MGs are connected to the high voltage battery pack via digitally controlled inverters. So the initial role of the 12V battery is to simply boot any computers and whatnot, then actuate the contactor (big relay) inside the battery pack to make the high voltage power available outside the pack. A MG can then spin the ICE up as needed. Also once the high voltage system is turned on, a DC-DC converter provides 12V power to all the 12V stuff (and maintains charge on the 12V battery) - as an alternator would in a traditional car.

A BEV doesn't have an ICE of course. But the other roles of the 12V battery for 'booting' the car and turning on the high voltage pack are the same. And again, once the HV pack is turned on, the DC-DC converter supplies the 12V power.

The end result is that the 12V battery can be much smaller than in a traditional ICE car because it doesn't have to spin a starter motor on the ICE. Some Volt owners carry a small handheld Li jump battery in their cars just in case the 12V battery fails. It is enough to get the car booted so that the HV pack can take over. I think it was more an issue with the early (e.g., 2011-2012) Volts, as I know that GM improved the charging algorithms (e.g., when and how often) over time.

Antigravity

We make a bluetooth device called the Battery Tracker, you can connect to any 12v battery including the Teslas... that will give you the real time voltage as well as 31 days of Historical voltages.... it send all the information to you phone so you don't actually have to check the battery or turn on the car to see the realtime voltage. It all goes to your phone.. Above you can see the picture of the graph that is ONE DAY in the Historical area of the App you use. It would allow you to monitor you batteries charge level at all times. But it wouldn't TELL you if you cars battery was bad being that take a load tester, and it DOES have a starting tester on the App for regular cars that would give you a good indication of your Batteries condition... but on and electric vehicle you don't have to "Start" the vehicle so you don't get that higher load to test with. But another good indication is the battery not holding a charge well, and the Battery Tracker can show that.