Don Breaks His Taycan - The Saga of the 12v Battery

[chrisk]

I'll quibble with this one slightly - the vast majority of 240 volt circuits "are" dedicated - they are typically installed to support a single and particular appliance - this is because the circuit is typically sized to exactly "match" the appliance it's being install for - there are few if any "shared" load use cases for 240 volt circuits, other than sub-panels.

but I see your point.

There are several dedicated 240v circuits in US garages for dryers that several people use. Some of them are wired with #10 or #8 wire and have 30 amp breakers. I have also seen a circuit with #8 wire with a 40amp breaker that someone added for a 30amp EV charger. So even when you use a dedicated 240 circuit you should make sure it can handle the amperage selected in the charger.

Sponsored

 

[daveo4EV]

for apartment complexes I think Tesla is on the right track with their Gen 3 Wall charger - these chargers can "network" up to 16 chargers via point-to-point wifi - and they can all be configured to "share" a single high amperage 240 volt circuit - you tell the chargers that maximum number of amp available, and the chargers all co-operate with each other to not exceed 80% of the breaker size - while providing as much power to each of the EV's charging as possible - the chargers are in an ideal position to know how much each vehicle is currently demanding and can adjust and ramp the charging load up or down based on real time charging demands of the current EV's engaged in a charging session…couple this with some integration with power management and knowledge if there is currently excess solar power or you're on battery power and you can dynamically adjust loads and EV charging to optimize for a variety of micro & macro power management goals.

it's really really clever and I look forward to future software exploiting these sorts of capabilities.

 

[daveo4EV]

two 100 amp dedicated shared circuits in a parking complex - with 8 chargers each on the 100 amp circuit - sharing 100 amps - would cover charging 16 EV's at once with dynamic charging load management making sure each EV is currently charging at fast as possible - but not overloading the "core" circuit - and as EV's finish charging excess capacity can be directed to the remaining EV's to accelerate the end of their charging sessions…

I love me some dynamic load EV charging setup - and I love my 4 charger 100 amp setup and really like being able to charge 2 or 3 EV's at once and have the chargers optimize the amps dynamically during the charging session.

the Gen3 chargers while they can share 100 amp circuits (or potentially larger) each charger itself is only capable of 48 amps maximum - this means you can setup a 100 amp subpanel, but the wire run to each EV charger need only be a wire gauge suitable for 48 amps - since no one charger will ever deliver more than 48 amps (12 kW) - this saves on high end wire costs to wire each charger (smaller conduit, and less stiff wire)

so you run one big pull of 2-0 wire for a 200 amp subpanel - and then install two 100 amp breakers - but off of each 100 amp breaker you only need to run 6 gauge 3 conductor wire to each charger - you then configure each "bank" of 8 chargers to tell them they can split 100 amps each - and the charger software will co-operate among each of the 8 chargers to manage the 80 amp "budget" of available power - never overloading the main 200 amp feed, but charging up to 16 EV's at once each receiving 10 amps (or 2.4 kW) when all 16 vehicles are charging, or 40 amps each if only 4 EV's are charging - or 48 amps each if only one or two EV's are charging...

this sort of setup would work really really well for an apartment complex.

 

[struther]

two 100 amp dedicated shared circuits in a parking complex - with 8 chargers each on the 100 amp circuit - sharing 100 amps - would cover charging 16 EV's at once with dynamic charging load management making sure each EV is currently charging at fast as possible - but not overloading the "core" circuit - and as EV's finish charging excess capacity can be directed to the remaining EV's to accelerate the end of their charging sessions…

I love me some dynamic load EV charging setup - and I love my 4 charger 100 amp setup and really like being able to charge 2 or 3 EV's at once and have the chargers optimize the amps dynamically during the charging session.

the Gen3 chargers while they can share 100 amp circuits (or potentially larger) each charger itself is only capable of 48 amps maximum - this means you can setup a 100 amp subpanel, but the wire run to each EV charger need only be a wire gauge suitable for 48 amps - since no one charger will ever deliver more than 48 amps (12 kW) - this saves on high end wire costs to wire each charger (smaller conduit, and less stiff wire)

so you run one big pull of 2-0 wire for a 200 amp subpanel - and then install two 100 amp breakers - but off of each 100 amp breaker you only need to run 6 gauge 3 conductor wire to each charger - you then configure each "bank" of 8 chargers to tell them they can split 100 amps each - and the charger software will co-operate among each of the 8 chargers to manage the 80 amp "budget" of available power - never overloading the main 200 amp feed, but charging up to 16 EV's at once each receiving 10 amps (or 2.4 kW) when all 16 vehicles are charging, or 40 amps each if only 4 EV's are charging - or 48 amps each if only one or two EV's are charging...

this sort of setup would work really really well for an apartment complex.

That would have been a better solution for where I live. I had to install my own dedicated charger and a separate breaker with a separate meter. Cost a small fortune and I had to pay the condo legal fee for the agreement. Total was about $10K - I found that expensive even compared to other Porsche options!!

I like the idea of a shared network of chargers. Much more scalable. Others in my building likely won’t be able to get a charger until we upgrade the panel and lines into the building.

 

[chrisk]

Here is Porsche's official TSB for the 12V b drain issue.
Resharing from another thread.

https://www.taycanforum.com/forum/threads/taycan-12v-drain-issues-caught-in-the-act.3729/post-51293

Tldr; Multiple reasons why it can happen are identified, a fix is on the works, and there are some suggested actions to reduce the chance of happening.

 

[Chuck J]

I hear the new update that is being offered to 2020 Taycan owners fixes the 12v battery problem. Has anyone confirmed that?

Chuck J

 

[daveo4EV]

12V issue is discussed in service technician release notes - but they specifically call out "12v issues when charging with the PMCC" - my personal experience with this issue has been with non-Porsche EVSE's - I'm hoping they have addressed additional cases with this release as well. However it's unlikely we'll know for sure until we have "time" with the update - since the problem was rare and non-reproducible in the 1st the place - only time will tell if the 12V issues have been reduced or eradicated.

 

[RickDC]

How hard is to meter the 12V battery with the app? Or the car itself send a warning message. I don’t this is hard in today’s cars to keep updating the 12V battery health.

 

[Ron R]

for apartment complexes I think Tesla is on the right track with their Gen 3 Wall charger - these chargers can "network" up to 16 chargers via point-to-point wifi - and they can all be configured to "share" a single high amperage 240 volt circuit - you tell the chargers that maximum number of amp available, and the chargers all co-operate with each other to not exceed 80% of the breaker size - while providing as much power to each of the EV's charging as possible - the chargers are in an ideal position to know how much each vehicle is currently demanding and can adjust and ramp the charging load up or down based on real time charging demands of the current EV's engaged in a charging session…couple this with some integration with power management and knowledge if there is currently excess solar power or you're on battery power and you can dynamically adjust loads and EV charging to optimize for a variety of micro & macro power management goals.

it's really really clever and I look forward to future software exploiting these sorts of capabilities.

I agree that this is a great capability. It is something they offer in their older (Gen 2) Wall Charger, but unfortunately it's not currently supported in the Gen 3 units. Tesla has been talking about this capability since the charger came out, but they have yet to provide the firmware that supports it.

 

[Colin the Best]

Hi everybody
yesterday afternoon I decided to download an additional service on the car (active driving in the lane) and the process started regularly for the download ... this morning, arrived at the garage, I open the car and the door opening anomaly message appears, ... I manage to enter and the message appears that the 12v battery is low ... "approach the charging source" ... the machine started regularly and the new service was unloaded and works regularly, but I can't explain what happened and above all, what should I approach and to what? ......

 

[sveinaan]

How hard is to meter the 12V battery with the app? Or the car itself send a warning message. I don’t this is hard in today’s cars to keep updating the 12V battery health.

My cars is left unused for weeks from time to time. And had this from another that I sold. https://smartercharger.com/collections/accessories/products/ctek-ctx-battery-sense Looks like car is waking up like once a week to charge 12V battery.

 

[Scandinavian]

My cars is left unused for weeks from time to time. And had this from another that I sold. https://smartercharger.com/collections/accessories/products/ctek-ctx-battery-sense Looks like car is waking up like once a week to charge 12V battery.

That is an interesting one. What equipment is that you have installed to get this information? I have a CTEK Lithium charger but no measurement from that one?

 

[sveinaan]

I bought it localy. But the link to the device in my previos post still works.

 

[Scandinavian]

I bought it localy. But the link to the device in my previos post still works.

Thanks. Found it now but seems no longer available???

 

[ciaranob]

I bought it localy. But the link to the device in my previos post still works.

Neat piece of kit - thanks for posting - just ordered so apparently is still available (at least in US).

Sponsored