12v battery problems - again

[Raphie]

This is getting silly people! We shouldn't have to do this. The 12v battery and charging software is not fit for purpose if we have to go to these lengths to trickle charge it!

Spend £100k and see the car dead every 2 weeks if you don't use it? I don't think so

I agree, but what can you do?

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[tchavei]

This is getting silly people! We shouldn't have to do this. The 12v battery and charging software is not fit for purpose if we have to go to these lengths to trickle charge it!

Spend £100k and see the car dead every 2 weeks if you don't use it? I don't think so

In my future use case, I'd call it mea culpa since my draw should be higher than average. Just getting ready for the unavoidable "dead" car after 7 days when going on holidays (unless I cut holidays down to 5 days max... Not happening).

 

[simcity]

This is getting silly people! We shouldn't have to do this. The 12v battery and charging software is not fit for purpose if we have to go to these lengths to trickle charge it!

Spend £100k and see the car dead every 2 weeks if you don't use it? I don't think so

I completely agree - at 2 weeks unacceptable!

Like I said earlier if your car is dead in 2 weeks then you definitely have an underlying issue with either the battery or the car’s electrical systems that needs correction.

…if the car is sitting for 8+ weeks…then that’s more a debatable point. That is long term storage in my opinion - and trickle charging isn’t off the table, and probably a good idea.

 

[Scandinavian]

So I tried using the NOCO Genius 5 and a small battery booster. Documenting this in case anyone else tries.

The small battery booster will activate the car ( can hear the relays click ) and the car wakes up but after a few seconds the booster will go into overload protection. I am guessing that this is because the 12V Taycan battery can deliver more current than the small booster. It stays awake for some seconds, enough that I can switch over to the NOCO Genius 5 and put it into force mode.

However the car then turns off. The NOCO Genius will only do force mode for 5 minutes before going back to regular charging which isn't enough to keep the battery "on" to actually charge.

---

So I am now thinking to buy a bigger booster so at it can keep the car awake for sometime, at least enough to be able to have some options on how to charge the 12V battery.

The NOCO Genius 5 is probably better as a trickle charger for Lithium-Ion batteries, but has worked really well for other battery types in the past.

That does not sound good?
When I boosted my 12 volt battery after getting the frunk open, I also turned on the car with the on button. Then the car stayed on and started charging the 12 volt battery, and all has beeen fine since then.

Did you turn on your car after the booster did its duty? I guess not and then your trickle charger did not seem to have enough power to deliver to the battery so the relay opened again? Guessing from what you stated.

I have checked my battery for a couple of days now after having it charged with the trickle charger for some 30 hours and all seems fine. After 3 days standing it still showed 13.35 volts, which should indicate about 95% level?

 

[simcity]

After 3 days standing it still showed 13.35 volts, which should indicate about 95% level?

 

[dtich]

I completely agree - at 2 weeks unacceptable!

Like I said earlier if your car is dead in 2 weeks then you definitely have an underlying issue with either the battery or the car’s electrical systems that needs correction.

…if the car is sitting for 8+ weeks…then that’s more a debatable point. That is long term storage in my opinion - and trickle charging isn’t off the table, and probably a good idea.

i understand your point, but i feel you're being far too 'understanding' on this issue -- which is an epic fail of code writing. there is no reason on earth that a 30 or 40Ah 12v battery that is connected to a ~90kWh battery that is in turn connected to mains should EVER deplete. barring battery failure (manu defect) or similar... what is the excuse here?

and as far as not being on mains, it should last for months. i mean MONTHS. weeks shouldn't even enter into the conversation. this is plain and simple a fail on Ps part in the code writing. to even discuss having to put a tender on these 12v's is... ludicrous. in my mind. honestly. yes, we have to play the cards as dealt, obviously, but no one should consider this a solution. this is a lame-ass workaround for a lame-ass code block. and it should be rectified, should HAVE been rectified by now really (no puns intended there).

i mean, why on earth limit the 12v dc-dc charging to 8 cycles between key offs???? just keep maintaining the 12v until the HV battery is too low, which should be MONTHS and MONTHS when it's not on mains (which it always should be if left for more than a few days if circumstances allow; airports etc, are the odd cases where it cannot.... and still this shouldn't be an issue...).

/rant

 

[tchavei]

i understand your point, but i feel you're being far too 'understanding' on this issue -- which is an epic fail of code writing. there is no reason on earth that a 30 or 40Ah 12v battery that is connected to a ~90kWh battery that is in turn connected to mains should EVER deplete. barring battery failure (manu defect) or similar... what is the excuse here?

and as far as not being on mains, it should last for months. i mean MONTHS. weeks shouldn't even enter into the conversation. this is plain and simple a fail on Ps part in the code writing. to even discuss having to put a tender on these 12v's is... ludicrous. in my mind. honestly. yes, we have to play the cards as dealt, obviously, but no one should consider this a solution. this is a lame-ass workaround for a lame-ass code block. and it should be rectified, should HAVE been rectified by now really (no puns intended there).

i mean, why on earth limit the 12v dc-dc charging to 8 cycles between key offs???? just keep maintaining the 12v until the HV battery is too low, which should be MONTHS and MONTHS when it's not on mains (which it always should be if left for more than a few days if circumstances allow; airports etc, are the odd cases where it cannot.... and still this shouldn't be an issue...).

/rant

I agree with you 20% only because I feel discharged and offline right now. I will agree 50% when I get my 30 min charge (fingers crossed it isn't the 9th charge) and maybe 100% when I go work tomorrow

???

 

[rb33gl]

there is no reason on earth that a 30 or 40Ah 12v battery that is connected to a ~90kWh battery that is in turn connected to mains should EVER deplete. barring battery failure (manu defect) or similar... what is the excuse here?


/rant

Totally agree. This has been my point all along. Work arounds are for 20+ year old cars.

Porsche need to resolve this with an OTA update, soon.

 

[timc3]

That does not sound good?
When I boosted my 12 volt battery after getting the frunk open, I also turned on the car with the on button. Then the car stayed on and started charging the 12 volt battery, and all has beeen fine since then.

Did you turn on your car after the booster did its duty? I guess not and then your trickle charger did not seem to have enough power to deliver to the battery so the relay opened again? Guessing from what you stated.

You are 100% correct - I didn't actually get in the car and turn it on. I am going to try that!

 

[timc3]

Well that did indeed work, turning the car on - the battery got charged more (I think up to the maximum the NOCO supports).

Now the only problem is that as the car started I now have 6 faults, from Steering to various safety systems. Not sure that I can clear them. Will take a picture of them if they show up the next time I go and check not he car.

 

[800v]

Nice table! Where did you get this from? Is this specific to the Taycan or for LiFePo4 In general?

 

[tchavei]

Nice table! Where did you get this from? Is this specific to the Taycan or for LiFePo4 In general?

If that table is accurate it means the car should trigger a charge whenever the battery hits 12.9V at rest (8A left)... 8 times before it gives up.

That also means that the voltage sensors in most dashcams (11.5V,12V,12.5V) are all useless. Battery will be long dead before it hits 12.5v

 

[800v]

That also means that the voltage sensors in most dashcams (11.5V,12V,12.5V) are all useless. Battery will be long dead before it hits 12.5v

12.5V cutoff would not be too bad right, that would leave the battery at 10%... good for a few days more, maybe a week? (I don't know the draw of the car by itself)

 

[tchavei]

12.5V cutoff would not be too bad right, that would leave the battery at 10%... good for a few days more, maybe a week? (I don't know the draw of the car by itself)

You might be right. If I get the car before June and will be able to fit the dashcam/noco sense, I'll make sure to leave it standing as much as possible when I go on vacations in the summer to record what actually happens. By my math, it should last 7 days before the car harakiris. If it lasts longer, I'll be happy.

No idea at what level the battery "goes offline" though. I'm sure it has deep discharge protections.

 

[800v]

I recently installed a bluetooth voltage meter and plan to measure this as well once I won't drive the car for awhile.. would be good to know how long it can last from 12.5v as the dropoff may be steep.

Ah, so silly the recharging is limited to 8 times Please Porsche, make it 50 times or more with an OTA !!

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