EV's and 12 volt battery pitfalls - Taycan edition
10-07-2020, 04:45 PM
#31
RL Community Team
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You obviously don't know all the states the vehicle's systems were in when the 12V was be drained, i.e. you stated you left the vehicle unlocked & charging to go the bed.
There have been cases with other BEVs where the vehicle's 12V died after a charging completion, because the EVSE was left connected causing some ECUs to remain on.
Typically the 400/800V battery of an BEV only maintains the 12V battery when the vehicle is locked or in the run/ON mode.
There have been cases with other BEVs where the vehicle's 12V died after a charging completion, because the EVSE was left connected causing some ECUs to remain on.
Typically the 400/800V battery of an BEV only maintains the 12V battery when the vehicle is locked or in the run/ON mode.
Also, it looks like car locked / unlocked doesn't matter:
https://www.taycanforum.com/forum/th...-is-dead.2616/
Porsche has a real issue here. They know it, but they have no solution. There should be zero reason for the car to shunt to a safety mode because of a low 12v level while the car is plugged into a power source.
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daveo4porsche (10-09-2020)
10-07-2020, 05:22 PM
#32
Meh, I'm not buying this argument. You're saying that in order for the 12v battery to not die, I have to run out and unplug the car when it's done charging because otherwise the car won't power down in sleep mode? Nah, not buying that. That would be a really inconvenient thing for pretty much anyone who plugs their car in to charge over night. Which is what most of these manufacturers suggest you do. In fact, Tesla specifically states you should keep your car plugged in, even when at your desired charging goal.
Also, it looks like car locked / unlocked doesn't matter:
https://www.taycanforum.com/forum/th...-is-dead.2616/
Porsche has a real issue here. They know it, but they have no solution. There should be zero reason for the car to shunt to a safety mode because of a low 12v level while the car is plugged into a power source.
Also, it looks like car locked / unlocked doesn't matter:
https://www.taycanforum.com/forum/th...-is-dead.2616/
Porsche has a real issue here. They know it, but they have no solution. There should be zero reason for the car to shunt to a safety mode because of a low 12v level while the car is plugged into a power source.
e.g. it could be a home EVSE problem preventing the Taycan systems from entering their sleep mode.
10-07-2020, 11:43 PM
#33
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Thread Starter
so basically if the vehicle only works with porsche chargers your 12V might die if you’re using a non-porsche charger or public charger.
10-08-2020, 10:34 AM
#34
RL Community Team
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It's most recently happened on a public charger in the UK. So not simply a home EVSE problem.
From Dave's discussion with Porsche:
- Question: does checking the "connect" app causes this problem?
- Porsche Answer: it is a contributing factor, but can happen with or without connect app activity
- Question: does using non PMCC chargers cause this problem?
- Porsche Answer: non-PMCC chargers do not cause this problem, but create the circumstances where it is easier for this problem to occur.
- Question: does Porsche have a reproducible case for this problem?
- Porsche Answer: we are investigating some reports of 12V battery offline events and are aware this is a possibility with current vehicles.
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daveo4porsche (10-08-2020)
10-08-2020, 12:44 PM
#35
Burning Brakes
Actually I've read through all the threads on Taycan forum, and spoken to Dave offline who is dealing with this issue now. So while I have no idea what's causing it, I do have a pretty good handle on the issue. And I'm following this because Tesla Model 3's are having their 12v batteries die after about 2 years, sometimes without warning. A not similar, but seemingly possibly related issue. I wonder if Leafs, Bolts, etc. also have 12v battery issues?
The curious thing to me is that Porsche has been building e-Hybrid plug-ins for several years now - not to mention VAG in general has been building e-Golfs, e-Trons, etc. Did Porsche throw out all their institutional knowledge when doing the Taycan, and missed something in the process?
As an aside, the high trim version of the Gen 1 Leafs had a small solar panel on the rear spoiler that could trickle charge the 12V battery when parked in the sun. It would be interesting to know if in practice this helped prevent 12V battery issues or not compared to the lower trim versions. Somewhat telling is that the Gen 2 Leaf no longer offers the feature.
10-08-2020, 12:58 PM
#36
Actually I've read through all the threads on Taycan forum, and spoken to Dave offline who is dealing with this issue now. So while I have no idea what's causing it, I do have a pretty good handle on the issue. And I'm following this because Tesla Model 3's are having their 12v batteries die after about 2 years, sometimes without warning. A not similar, but seemingly possibly related issue. I wonder if Leafs, Bolts, etc. also have 12v battery issues?
It's most recently happened on a public charger in the UK. So not simply a home EVSE problem.
From Dave's discussion with Porsche:
It's most recently happened on a public charger in the UK. So not simply a home EVSE problem.
From Dave's discussion with Porsche:
and prevent other systems from entering sleep mode draining the 12V battery.
10-08-2020, 01:01 PM
#37
As I mentioned back in post #s 14 and 20, yes - early (2011 and 2012) Leafs and Volts did have some issues. In the case of the Volt, the 2013s contained some hardware improvements, followed by additional improvements in the Gen 2 (2016-2019) Volts. The Bolt EV incorporated what they learned when doing the Gen 2 Volt.
The curious thing to me is that Porsche has been building e-Hybrid plug-ins for several years now - not to mention VAG in general has been building e-Golfs, e-Trons, etc. Did Porsche throw out all their institutional knowledge when doing the Taycan, and missed something in the process?
As an aside, the high trim version of the Gen 1 Leafs had a small solar panel on the rear spoiler that could trickle charge the 12V battery when parked in the sun. It would be interesting to know if in practice this helped prevent 12V battery issues or not compared to the lower trim versions. Somewhat telling is that the Gen 2 Leaf no longer offers the feature.
The curious thing to me is that Porsche has been building e-Hybrid plug-ins for several years now - not to mention VAG in general has been building e-Golfs, e-Trons, etc. Did Porsche throw out all their institutional knowledge when doing the Taycan, and missed something in the process?
As an aside, the high trim version of the Gen 1 Leafs had a small solar panel on the rear spoiler that could trickle charge the 12V battery when parked in the sun. It would be interesting to know if in practice this helped prevent 12V battery issues or not compared to the lower trim versions. Somewhat telling is that the Gen 2 Leaf no longer offers the feature.
10-08-2020, 01:17 PM
#38
Burning Brakes
Actually I've read through all the threads on Taycan forum, and spoken to Dave offline who is dealing with this issue now. So while I have no idea what's causing it, I do have a pretty good handle on the issue. And I'm following this because Tesla Model 3's are having their 12v batteries die after about 2 years, sometimes without warning. A not similar, but seemingly possibly related issue. I wonder if Leafs, Bolts, etc. also have 12v battery issues?
It's most recently happened on a public charger in the UK. So not simply a home EVSE problem.
From Dave's discussion with Porsche:
It's most recently happened on a public charger in the UK. So not simply a home EVSE problem.
From Dave's discussion with Porsche:
Last edited by acoste; 10-08-2020 at 01:19 PM.
10-08-2020, 03:41 PM
#39
Rennlist Member
As I mentioned back in post #s 14 and 20, yes - early (2011 and 2012) Leafs and Volts did have some issues. In the case of the Volt, the 2013s contained some hardware improvements, followed by additional improvements in the Gen 2 (2016-2019) Volts. The Bolt EV incorporated what they learned when doing the Gen 2 Volt.
The curious thing to me is that Porsche has been building e-Hybrid plug-ins for several years now - not to mention VAG in general has been building e-Golfs, e-Trons, etc. Did Porsche throw out all their institutional knowledge when doing the Taycan, and missed something in the process?
As an aside, the high trim version of the Gen 1 Leafs had a small solar panel on the rear spoiler that could trickle charge the 12V battery when parked in the sun. It would be interesting to know if in practice this helped prevent 12V battery issues or not compared to the lower trim versions. Somewhat telling is that the Gen 2 Leaf no longer offers the feature.
The curious thing to me is that Porsche has been building e-Hybrid plug-ins for several years now - not to mention VAG in general has been building e-Golfs, e-Trons, etc. Did Porsche throw out all their institutional knowledge when doing the Taycan, and missed something in the process?
As an aside, the high trim version of the Gen 1 Leafs had a small solar panel on the rear spoiler that could trickle charge the 12V battery when parked in the sun. It would be interesting to know if in practice this helped prevent 12V battery issues or not compared to the lower trim versions. Somewhat telling is that the Gen 2 Leaf no longer offers the feature.
10-08-2020, 05:35 PM
#40
RL Community Team
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I didn't investigate this issue yet. Just a comment. BMW's first V8 turbo engines kept killing the 12V batteries in the US to the point that BMW decided to replace the battery at every oil change. The combination of high load from consumers and the short distance commutes wore out the batteries fast. (it was used for mild regen as well)
Give me a break.
Don't believe that there was really mild regen, moreso that the alternator would declutch under engine load to prevent parasitic loss, and then engage only on the over-run.
10-08-2020, 05:44 PM
#41
Rennlist Member
Thread Starter
my issue here is EV's are different than ICE's - in the case of the ICE when the battery dies there is no other power source available to "save" the battery
so far in the case of the Tin-can 12V issue - there has been ample power sources - even going so far as to being plugged into "shore power" with ample power resources on tap to prevent the 12V from being fully discharged - and yet the vehicle is allowing the 12V to die even when the main battery has ample power, and there is an existing external power source…
the vehicle is not lacking resources to save the 12V battery when this occurs…
it would be one thing if the battery was at 5% or less, and the car has been parked in a parking complex at the airport for 2 weeks- that's a different situation
in all cases the vehicles so far to date have had ample main battery power, plugged into charging source and has happened "overnight" when the vehicle was used/functional less than 24 hours before…in-excusable comes to mind.
so far in the case of the Tin-can 12V issue - there has been ample power sources - even going so far as to being plugged into "shore power" with ample power resources on tap to prevent the 12V from being fully discharged - and yet the vehicle is allowing the 12V to die even when the main battery has ample power, and there is an existing external power source…
the vehicle is not lacking resources to save the 12V battery when this occurs…
it would be one thing if the battery was at 5% or less, and the car has been parked in a parking complex at the airport for 2 weeks- that's a different situation
in all cases the vehicles so far to date have had ample main battery power, plugged into charging source and has happened "overnight" when the vehicle was used/functional less than 24 hours before…in-excusable comes to mind.
10-08-2020, 08:12 PM
#42
Burning Brakes
10-08-2020, 08:13 PM
#43
Burning Brakes
It's easier to find a problem in a car in service when there is a continuous retry instead of a time out.
10-09-2020, 10:32 AM
#44
RL Community Team
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No. But two wrong's don't make a right. BMW's situation, IMO, is more egregious given their position in the automotive world. You seem to continually think I'm hoisting Tesla on some kind of pedestal. I've publicly acknowledged that their service sucks, so can we stop this tired trope?
Regen braking implies significant braking force due to the drag caused by the electric motor. In my drives of various 550's and M5's, and I drove maybe 6-8, I never detected any more off-throttle rolling resistance than in my 535. How much retardation did this alternator on demand actually supply?
Regardless, the overall point is clear.
Regen braking implies significant braking force due to the drag caused by the electric motor. In my drives of various 550's and M5's, and I drove maybe 6-8, I never detected any more off-throttle rolling resistance than in my 535. How much retardation did this alternator on demand actually supply?
Regardless, the overall point is clear.
10-09-2020, 11:36 AM
#45
Burning Brakes
No. But two wrong's don't make a right. BMW's situation, IMO, is more egregious given their position in the automotive world. You seem to continually think I'm hoisting Tesla on some kind of pedestal. I've publicly acknowledged that their service sucks, so can we stop this tired trope?
Regen braking implies significant braking force due to the drag caused by the electric motor. In my drives of various 550's and M5's, and I drove maybe 6-8, I never detected any more off-throttle rolling resistance than in my 535. How much retardation did this alternator on demand actually supply?
Regardless, the overall point is clear.
Regen braking implies significant braking force due to the drag caused by the electric motor. In my drives of various 550's and M5's, and I drove maybe 6-8, I never detected any more off-throttle rolling resistance than in my 535. How much retardation did this alternator on demand actually supply?
Regardless, the overall point is clear.
Not a lot of regen since the battery (and the alternator) is small. But it raised the alternator's output voltage under deceleration. 100A x 14V = 1.4kW. If you compare that to how much power you need for accelerating a car, you see this is very little.
Last edited by acoste; 10-09-2020 at 11:38 AM.