Totally dead

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Re: Totally dead

Post by OllyExeterID3 » Fri Apr 23, 2021 8:06 am

Folkramfer wrote:
Fri Apr 23, 2021 7:31 am
I'm a bit bemused as to why you need a lead acid battery. Its adding all that extra weight and taking up space. If vw felt the need for extra electric capacity why did they not put in a slightly higher rated main battery. I'm sure any need for reserve power, segregation of supply and voltage differences could have been handled electronically. Oops! VW aren't too good at electronics these days.
Agree with this - I wonder if there is a practical reason why a lead acid battery is needed. Any engineers/electricians who can shed light on this? Not sure it is to do with battery chemistry/design that means that auxiliaries are better run from lead acid or not.

Either way, we got through out 2.1 update the other day so fingers crossed this will never be a problem for us. But, as we rarely use the car daily, I think I am going to be always a little worried!

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Re: Totally dead

Post by G43FAN » Fri Apr 23, 2021 8:17 am

All BEVs have a 12volt battery even the gods that are Tesla are only just looking at moving to Lithium based batteries to replace the Lead Acid.. It's not a VW thing.

1. To ensure that in the event of a main battery failure there is still braking and hazard functionality.
2. To trigger the main battery back to life otherwise it would have to be on all the time
3. To avoid a vampire drain from electrical systems killing the main battery completely
and others..
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Re: Totally dead

Post by HeidiFlowerpt Driver » Fri Apr 23, 2021 8:57 am

Also I believe the electronics are run from the 12V battery rather than the HV array.
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Re: Totally dead

Post by thefordprefect » Fri Apr 23, 2021 3:30 pm

the vehicle battery is around 400 volts fully charged. they would need a medium power convertor to reduce this voltage down to the 12 volts/3volts/5volts to run the electronics and lights. This may introduce failures as 400volts is/was a tricky voltage for most commercial electronics. And perhaps more relevant would be safety of breaking steering etc if the 400v battery is depleted. there is also power loss in the convertor and possibly having to route high voltage dc lines round the vehicle..
I understand the need for the battery. I do not understand why they cannot maintain the battery and why they cannot switch everything off when the vehicle is off. When I was working on power assisted steering electronics there were very tough specifications on the off (quiescent) current (less than 1/1000 of Amp (1mA) I think!). The power assistance requirement was around 50Amps so that would be a heavy load for a convertor!

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Re: Totally dead

Post by Folkramfer » Fri Apr 23, 2021 4:23 pm

I reckon the systems are just not developed enough to rely on single power source. I'm sure that we'll see the demise of an auxiliary battery in the not too distant future.

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Re: Totally dead

Post by Sindidziwa » Mon Apr 26, 2021 10:23 am

scott28tt wrote:
Mon Apr 12, 2021 2:19 pm
Once it's on 2.0 or later the car monitors the 12V and tops it up from the "drive" batteries if needed, in theory you shouldn't get a repeat.
Unfortunately, my 12V problems have only arisen _after_ being upgraded to 2.1 (0792) - secondtimme showing 'drive to charge' message despite driving 80+ miles yesterday...

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Re: Totally dead

Post by Sheila » Tue May 11, 2021 10:44 pm

After 7 months of having the ID.3 1st Plus with sw 2.1 (0792), it would seem that I am now having issues with the battery. I don't know for sure because I did not get any warnings and had even driven it with no issues over the 2 days prior, but when I unlocked the door and sat in it Tuesday morning, I could not shift it to D/B or R (I did double tap on the brakes as usual to start it, but nothing happened this time). In the end, we got the road assist truck to come by and tow it to the VW workshop that is luckily just a 5 min walk from where I live. Before towing it away, the road assist mechanic tried to disconnect the 12V battery and reconnect it again. This created all imaginable error codes to show up, and though it went back to normal in the end, the car stubbornly still remained in (P)ark.

Due to Ascension Day this week, VW said they can get back to me only on Monday, so yeah...let's see what they say. My car has been to the workshop around 7-8 times already, mainly because they still can't seem to get the keyless access feature to work (the only keyless thing I can do is to lock the door by touching the handle). So hopefully they will be able to fix these two issues when they return the car back. Good thing my car is leased, so if all kinds of issues continue to persist, I can stop the leasing contract after September. It is otherwise a fantastic car to drive in, so I don't hope it comes to that.

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Re: Totally dead

Post by G4XUR » Wed May 12, 2021 10:16 pm

Having suffered the same issues I am concluding the battery (12v) has become knackered with abnormal discharges below the battery manufacturers stated limits on numerous times, which after after the 2.1 update; is capacity degraded even though 2.1ensures the 12v battery gets a little charge when the HV battery is being charged. I measured it across the battery terminals as over 16v which suggests the battery impedance is far higher than a normal battery specification (knackered 12v battery). I got mine swapped out for a new one a month ago and all is now well. Well, I used the ID3 at the weekend and next time will be tomorrow!! hope all is ok! VW have lost their reliability reputation with this one and the ID4. Such a shame for VW as was.

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Re: Totally dead

Post by Matthewwoolf » Sun May 23, 2021 8:10 pm

To add my experience here today I had the 2nd occurrence of a dead 12v battery and the AA had to recover the car.

I’m gutted and really upset about this issue and going to be engaging a lawyer to try and understand how to resolve this issue. Ideally I want a return snd refund. Unless there is a proper fix to constantly think your car will not start makes it unfit for purpose.
ID3 Life Pro - 2021

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Re: Totally dead

Post by Matthewwoolf » Tue May 25, 2021 4:21 pm

As an update to my post I have now had VW confirm there is a part that needs replacing ( I believe this to be a transformer between the 12v battery and the car). It was due to arrive today however VW UK put a stop to the delivery stating that the part is faulty and its going through a re-design or re-programming (they were not clear). Either way I wont get another update until later in the week but clearly there is an issue here!
ID3 Life Pro - 2021

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