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I have a 2019 eGolf with 8K miles & I love it. I and take care of it, properly keeping it to a charge between 20- 80% typically.
I came home after a few days on the road to find my eGolf dead, not a light on, both the 12 volt and the power battery drained to nothing. My wife used the car once while I was away, she left it in the driveway for two days without putting it on the charger since it still had 70 miles left of charge. So I had it towed to the dealer.
24 hours later the dealer says we don't know what is going on, the 12v wont take a charge. I ask if its a phantom drain and they say - likely. 48 hours later the dealer says its charged & fine now, take it home. When I asked for the diagnosis they said 'You need to leave it on a charger'. I became irate, I yelled stating 'your telling me that after two days off of a charger I should expect to find my car drained to zero?!!!! ' They said : 'you should always keep an electric car on a charger'. I was furious, that is nonsense and I told them so. The dealer also said that if we left the key fob inside it could drain to nothing. My wife swears the key was inside the whole time. The dealer stuck by the cause being 'not being left on a charger'.
Any help here please?
 

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With covid, my 2019 SE has gone weeks without being plugged in and it starts up just fine and has the same SoC as where I left it.
 

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Name and shame the dealer. At least on this forum. It's BS. The amount of power needed by a car when off is negligible. Even if you have an app that allows you to "talk" to the car remotely it shows the status of various things like battery level as it was the moment before the car was last turned off because the car "talks" to a server and your app then gets its data from the server. The alarm will use a bit but not enough to drain 70 miles of range so should last several weeks. Otherwise the dealer is saying you could drive to an airport, go on holiday and find you're screwed when you return. If that's VW design feature then no one would buy a VW
 

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Without a service manual to reference my theory is that something was left on (dome light?) that drained the 12 volt battery. With its voltage below the threshold (10 volts or so is typical), it won’t power up the computer which means the relays that connect the high voltage battery and the dc to dc converter can’t do their thing, making it appear that the high voltage battery is dead as well. The dealer’s claim of the key fob discharging the 12 volt sounds suspect to me, especially if it’s tiny battery didn’t drain, which it very well could if left in the car. Not sure why they had trouble charging the 12 volt battery. Anyone know if there is a reset procedure required when replacing the 12 volt? If so it would probably be necessary when recharging a drained one too.
I want a service manual so I can troubleshoot my car if it fails. If anyone knows of one please speak up.
 

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I read on another forum that if your fob is close enough to the car, it will be in constant communication with the car which then could cause battery drain for both the car and the fob.
 

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Discussion Starter #11
Without a service manual to reference my theory is that something was left on (dome light?) that drained the 12 volt battery. With its voltage below the threshold (10 volts or so is typical), it won’t power up the computer which means the relays that connect the high voltage battery and the dc to dc converter can’t do their thing, making it appear that the high voltage battery is dead as well. The dealer’s claim of the key fob discharging the 12 volt sounds suspect to me, especially if it’s tiny battery didn’t drain, which it very well could if left in the car. Not sure why they had trouble charging the 12 volt battery. Anyone know if there is a reset procedure required when replacing the 12 volt? If so it would probably be necessary when recharging a drained one too.
I want a service manual so I can troubleshoot my car if it fails. If anyone knows of one please speak up.
Good thoughts Eguy, maybe a dome light or something of the sort, I am actually hoping this is the case, but wondering why they could not charge 12V it after 24 hours? hmmm.
 

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Perhaps the flat 12v battery needs the negative terminal disconnecting for 10-15 mins before reconnecting and adding the 12v trickle charger, to do a hard reset of the cars systems?
James Watson , I know they removed the 12v battery after 24 hours without it taking a charge - so maybe that was the hard reset.
 

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It is my understanding that the 12 V battery will not charge if the car is off, so keeping your car plugged in (but not charging once high voltage battery hits 100% SoC) will not maintain a charge in the 12 V battery.
 

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I have heard that the 12v charges separately, but I don't know if they missed that. I should ask.
 

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Whilst my e-golf wasn't being used during lockdown, I checked the 12v battery every couple of weeks. It did drain a little bit, but I turned the car on for an hour or so to allow it to charge back up. I checked the system with a meter whilst the car was off and on, and I can verify that it only charged with the car 'on'.
 

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Whilst my e-golf wasn't being used during lockdown, I checked the 12v battery every couple of weeks. It did drain a little bit, but I turned the car on for an hour or so to allow it to charge back up. I checked the system with a meter whilst the car was off and on, and I can verify that it only charged with the car 'on'.
My guess is that the main batteries were not drained, just that the 12v battery controls all the electronics and that's why it read empty, the logic for the 12v to be completely flat its got to be faulty, or had a continuous drain of power.
Not sure what can be left on with the car turned off never tried. Having a list of what takes power from the 12 volt then establishing if any of those can remain on? . What can be accidently switched on from the app?
 

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Good thoughts Eguy, maybe a dome light or something of the sort, I am actually hoping this is the case, but wondering why they could not charge 12V it after 24 hours? hmmm.
I have a 2019 eGolf with 8K miles & I love it. I and take care of it, properly keeping it to a charge between 20- 80% typically.
I came home after a few days on the road to find my eGolf dead, not a light on, both the 12 volt and the power battery drained to nothing. My wife used the car once while I was away, she left it in the driveway for two days without putting it on the charger since it still had 70 miles left of charge. So I had it towed to the dealer.
24 hours later the dealer says we don't know what is going on, the 12v wont take a charge. I ask if its a phantom drain and they say - likely. 48 hours later the dealer says its charged & fine now, take it home. When I asked for the diagnosis they said 'You need to leave it on a charger'. I became irate, I yelled stating 'your telling me that after two days off of a charger I should expect to find my car drained to zero?!!!! ' They said : 'you should always keep an electric car on a charger'. I was furious, that is nonsense and I told them so. The dealer also said that if we left the key fob inside it could drain to nothing. My wife swears the key was inside the whole time. The dealer stuck by the cause being 'not being left on a charger'.
Any help here please?
My guess is that the main batteries were not drained, just that the 12v battery controls all the electronics and that's why it read empty ( as stated elsewhere), the logic for the 12v to be completely flat its got to be faulty, or had a continuous drain of power.
Not sure what can be left on with the car turned off never tried. Having a list of what takes power from the 12 volt then establishing if any of those can remain on? . What can be accidently switched on from the app?

I have read that if you leave the car in drive with ignition on it will flatten the 12v battery in double quick time.
If memory serves me correctly the hand book recommends turning the ignition off if your stuck in stationary traffic for a period of time.

Dealers giving you an accurate assessment of an EGolf, is considered an act of god in the insurance industry.
 

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It's high time EV manufacturers realised that letting the 12v go flat when there is a dirty great traction battery is totally incompetent. Even Nissan wake theirs up to check the 12v and charge it up every few days.
 

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I assume you've ruled out the obvious causes; door left ajar, interior/exterior lights off, dsshcam not shutting off, etc.?
 
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