Theft alarm = low 12v battery!

[simcity]

Yep, but crazy to use a unique battery which costs that much.

Pound for pound (literally) it was cheaper than the Lithium battery in my ‘blade. That was ridiculously priced too.

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[simcity]

No, nothing after market. No dash cam. Also had the big update (that was supposed to be a remedy) last year.

I reported it to my OPC and they had 'no concerns about my battery'. They thought it was due to:

a) the car's low mileage
b) it being 'fairly normal to lose charge' over 2 weeks
c) keyless entry (which I don't have) discharging the battery
d) the need to use a trickle charger

I'm waiting for a further response from them as this isn't good enough. I'm not going to grovel around the fuse box with a spare battery to get the frunk open to reboot the 12v... Or hang about for Porsche Assist.

I believe it's software related. The HV battery should always ensure the 12v is charged (as long as there's more than say, 10% charge left) becuase it is so central to the operation of the car.

That’s a classic fob off job. Get the useless twats to load test the 12v battery. They can do it. Just required willpower

Jesus I left Audi because they were utterly useless - please tell me Porsche are better at customer care. Don’t shatter my boyhood dream

 

[Scandinavian]

It is a right muddle with incomplete / conflicting advice in various Porsche documents.

My logic is that the HV masters the 12v and so when needed tops up the 12v automatically at a certain threshold. HV maintains this when left connected to an EVSE and so a trickle to the HV to keep say at 85% and should the 12v drop then the HV tops it off without the car being powered on by the owner.

Fortunately I never leave my car at an airport nor have a boat and therefore hopefully never have this level of stress to contend with.

Clarification is needed from Porsche and documentation amended as appropriate. Dealerships need to up their game in terms of education as there is a wave coming in the shape of a Macan EV where Joe Public likely won't be on this forum and left high and dry with a product they're I'll equipment to run and maintain.

Suspect this isn't unique to Porsche.

It certainly is confusing and we should ask Porsche for an explanation.

Even if the 12 volt battery should need topping up more that the 8 times as stated in Audi material, that would only be 8X40 AhX 12 volt about 4kWh plus some losses in conversion from 800 volt to 14 volts etc.

And many of the new EV’s have had trouble with the 12 volt. Tesla had it in the beginning, Polestar have had it etc. So there is some learning out there that should be helpful.

I just wish Porsche would take this a bit more serious, but I did not get that feeling from my Service guy? He had a few Taycan in the workshop that had the same issue and that after only 10 days??

 

[simcity]

And many of the new EV’s have had trouble with the 12 volt. Tesla had it in the beginning, Polestar have had it etc. So there is some learning out there that should be helpful.

Don’t know about the others, but Tesla kept using good old fashioned lead-acid 12v batteries up until fairly recently (ok about 2020 or so) and as far as I know never had such a ‘limited’ recharge profile. As long as the HV had enough juice (plugged in to EVSE) they’d top the 12v forever if necessary.

The 12v in mine lasted near enough 5 years. So not that bad and it was £145 to get a new one.

 

[tchavei]

Even if the 12 volt battery should need topping up more that the 8 times as stated in Audi material, that would only be 8X40 AhX 12 volt about 4kWh plus some losses in conversion from 800 volt to 14 volts etc.

It's worse than that. According to the audi manual, the first time the charging kicks in is when the 12V has 8Ah left (20% charge). Then it will charge it until it reaches 50% or 30 min whatever comes first (we have no specs on the charging circuit so it's possible it doesn't even charge to 20Ah). The remaining 7 cycles will kick in much sooner than the first if the draw remains the same.

So in theory, in a perfect scenario where we start with a full 12V battery and the car is always able to charge it back to 50%, we get:

32A + 7 X 12A = 116A

Meaning the car is allowed to draw 116A total from the 12V before it's dead.

I can see Porsche engineers thinking 116A is going to be enough but apparently it either isn't or there is something else triggering these 'offline' situations. I can't believe the car is drawing 116A in a week

Edit: actually it's quite feasible. A constant 700mAh current will drain 117A in exactly 7 days... At 500mah it won't even last 10 days.

 

[ciaranob]

Don’t know about the others, but Tesla kept using good old fashioned lead-acid 12v batteries up until fairly recently (ok about 2020 or so) and as far as I know never had such a ‘limited’ recharge profile. As long as the HV had enough juice (plugged in to EVSE) they’d top the 12v forever if necessary.

The 12v in mine lasted near enough 5 years. So not that bad and it was £145 to get a new one.

My 2014 M4 Convertible car came with a very expensive Lithium ion battery - had the car for 8 years (sold last year for 60% of original cost!) and never had a single issue with the battery - my Li-ion specific CTEK trickle charger was literally used twice and more to see how it worked than anything else and is completely compatible with the Taycan battery and thankfully never had to use it for the Porsche either.

 

[Speuk]

Is there any benefit in trickle charging the 12v battery before a stay at an airport or similar.... to ensure it is at 100% before the car gets parked up for a few weeks? Just thinking that for people who only do short runs in their cars they could have a partly depleted battery at start of a holiday period.

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