[Ukflyer]

Sat in car park waiting recovery. Phone hyundai and they said they wanted the date my car was serviced as this validates the 12month recovery. Explained I was in a, car park in the cold and dark, who on earth carries there service documents with them? They said I could pay for the AA!!! What's the point in paying for the AA when I have recovery as part of my service with hyundai but can't remember the exact date it was serviced. Managed to eventually find the date I purchased the car and it was serviced then. I noticed that the AA are struggling to get to me because although I reported a flat 12v battery, and the initial response by text advised it was a flat battery, it suddenly changed on an update to OUT OF FUEL and apologies as they are struggling to get someone out. There's no contact number for the AA to call them, just a 'no reply' text to say they'll call me with an update when they can.

 

[Sandy]

Sat in car park waiting recovery. Phone hyundai and they said they wanted the date my car was serviced as this validates the 12month recovery. Explained I was in a, car park in the cold and dark, who on earth carries there service documents with them? They said I could pay for the AA!!! What's the point in paying for the AA when I have recovery as part of my service with hyundai but can't remember the exact date it was serviced. Managed to eventually find the date I purchased the car and it was serviced then. I noticed that the AA are struggling to get to me because although I reported a flat 12v battery, and the initial response by text advised it was a flat battery, it suddenly changed on an update to OUT OF FUEL and apologies as they are struggling to get someone out. There's no contact number for the AA to call them, just a 'no reply' text to say they'll call me with an update when they can.

Sounds like Hyundais customer service is going from strength to strength.... if the race is to be the worst.

Hopefully the AA will get you going/ Makes me wonder what caused the 12v to go flat?

 

[Harry6]

Sorry to hear about your situation but I thought all service information was stored digitally nowadays so surely from the registration they can tell when it was last serviced and if the AA was still valid. I hope they get to you soon

 

[cah197]

Sounds like Hyundais customer service is going from strength to strength.... if the race is to be the worst.

Hopefully the AA will get you going/ Makes me wonder what caused the 12v to go flat?

Did he dare to not quite shut the boot properly?

 

[Hitstirrer]

Usually just needs a normal jump start from another 12v DC battery to start the car and then the DC to DC converter will charge the car's aux battery and it will run normally. Then either a slow charge at home or if the battery is really dead a 12v battery transplant.

Such incidents are not at all rare though. Check the forum search feature for numerous threads on this topic. Some years ago I began to top the 12v battery up once a month when doing the normal tyre kicking and screen water bottle filling routine.

 

[cah197]

Sorry to hear about your situation but I thought all service information was stored digitally nowadays so surely from the registration they can tell when it was last serviced and if the AA was still valid. I hope they get to you soon

You’d think.

Sounds like they were trying to wheedle out of it.

Certain manufacturers don’t care about when it was serviced. But the idea that the 12 volt battery needs changing after 18 months is laughable.

Here’s hoping the Ioniq 5 is better designed!

 

[Sandy]

Did he dare to not quite shut the boot properly?

Perhaps? Yup MG can suffer from this, but the car also beeps if the boot isn't shut properly if you lock the car.

 

[Ukflyer]

Update. Waited and waited for the AA. All the 'live' updates said that they were trying to get assistance to me and would ring with an update. After waiting 3 hours I had to call my Mrs who had just finished her 12hr shift. She managed to find the jump leads and rescued me. I have a battery monitor on the 12v battery and it shows that the voltage just suddenly 'fell off a cliffe' and the car trying to charge it until it seems to have given up. Got home OK and plugged it into my granny charger and it's charging merrily. I'll see how it is at 0430am in the morning when I get up for work. Its been a long day folks.

 

[Tandy0]

Some years ago I began to top the 12v battery up once a month when doing the normal tyre kicking and screen water bottle filling routine.

Always amazes me that folk here ignore this simple remedy, and let their batteries go down until the point they break down. Then rather than buy a £25 charger, they expect the car's built in one to restore it.

 

[Middlewife]

Glad you got home. I had to threaten hyundai with legal action to get a clutch replaced under warranty in a new car. Would NEVER buy from them again. As others have said 12v battery failure seems surprisingly common. I must buy some jump leads
Sleep well.

 

[Sandy]

Always amazes me that folk here ignore this simple remedy, and let their batteries go down until the point they break down. Then rather than buy a £25 charger, they expect the car's built in one to restore it.

...Because the internal DC-DC is supposed to do that. If you use a car frequently you shouldn't need heath robinson "fixes" to keep the car reliable. I agree if you use the car infrequently then topping up the 12v from an external source makes sense. But if you use the car semi-daily then no you shouldn't have to top up the 12v unless the DC-DC has a fault.

 

[Tandy0]

...Because the internal DC-DC is supposed to do that.

Which it already failed to do.

 

[Hitstirrer]

Always amazes me that folk here ignore this simple remedy, and let their batteries go down until the point they break down. Then rather than buy a £25 charger, they expect the car's built in one to restore it.

This has been an issue in loads of EV's for the seven years I've had one. There must be a dozen past threads in here of people pulling their hair out trying to track the cause down. But the only one that has really been tracked down recently is the Kona rear door failing to properly latch and keeping the car's systems alive when parked, with this result. Dozens of suggestions made for other incidents without verification.

At least some of these events can be avoided by always maintaining the 12v at a high charge using a good quality smart charger which analyses the condition and then runs a phased charge programme to keep it in good shape. People who do that regularly seem to now be immune to these 12v problems. That is unless they don't fully shut the rear door of a Kona. Allegedly.

 

[Jeremy Harris]

Not sure why this should be such a problem for some EVs, maybe the manufacturers of a few models just haven't sorted the design of the 12 V system properly, or maybe they underrate the 12 V charging system. I had a look at the way Tesla charge the 12 V system and was astonished to find that the 12 V battery charging system is massively over-rated, something like 200 A peak IIRC. Perhaps Tesla did this so that the 12 V could be topped up quickly in the event of it being drained whilst the car's parked. I know that my Model 3 used to turn itself on for around ten minutes most nights when parked, and every time it did this it topped up the 12 V battery. Perhaps that was, in part, a way to ensure that the battery stayed OK.

 

[Sandy]

Which it already failed to do.

Getting the underlying fault fixed is always preferential than stroking a car along with temporary fixes though. Yes one time you'll break down, then take it to dealer and they replace expensive parts. Or you spend all your time wondering if that one time will you break down because you forgot to charge the 12v.

 

[Hitstirrer]

But if you use the car semi-daily then no you shouldn't have to top up the 12v unless the DC-DC has a fault.

We all know that. And it's perfectly true. Preventative maintenance of the 12v battery should not be necessary. So your choice is this. Do you accept the negligible bother and clip a smart charger on once a month when you check the tyre conditions and fill the screen bottle? Or do you ignore the 12v battery for 18 months feeling lucky, and assume that you will never get locked out of the car one dark wet night in a remote carpark. I chose to use a smarty regularly following a lockout six years ago. And have not had another similar problem.

We know it shouldn't be necessary but life is too short to stress over never knowing when it will happen a second time. Many use belt n braces and also carry around a battery booster in the glovebox in case they accidentally leave the interior light on one day. Others prefer to hang around for hours in cold conditions waiting for the RAC. Each to their own as they say.

 

[Tandy0]

We used to have this problem when motor caravanning. If we took too much out of the 2nd battery, the alternator could not recharge it. Yes, the voltage would come up, and the alternator stopped charging. But that evening the lights would get dim after a couple of hours. The only option was to find somewhere to charge the battery from the mains, slowly.

I suspect the dc/dc converter tries to mimic the action of the alternator, and so cannot restore the 12v once it's below maybe 50%.

 

[Hitstirrer]

Getting the underlying fault fixed is always preferential than stroking a car along with temporary fixes though.

Nice idea. Except in my experience, and that of dozens of forum members, the dealers are both incapable of tracing the cause, and more usually, unwilling to spend time trying to discover why the 12v went flat. They invariably just swap the 12v battery for a new one - usually under warranty - and the cause is ignored.

I am aware of one car in here having two 12v batteries swapped in one year for the same reason - with the dealer shrugging and blaming a bad batch of batteries. That guy then ran a preventative charging regime as suggested.

It used to be a really annoying aspect of being an early adopter and hopefully now solved by OEM's. Recently almost all of the reported incidents turn out to be either an accidental drain from something left on, or something diagnosed such as water ingress in a door that shorts out a contact and empties the 12v battery.

Even in those cases perhaps having a well maintained and fully charged 12v battery can avoid being stranded rather than a weak battery with a low charge unable to cope with a slow drain. I prefer to keep the battery in good condition just in case. Others can make their own decision.

 

[Sandy]

We all know that. And it's perfectly true. Preventative maintenance of the 12v battery should not be necessary. So your choice is this. Do you accept the negligible bother and clip a smart charger on once a month when you check the tyre conditions and fill the screen bottle? Or do you ignore the 12v battery for 18 months feeling lucky, and assume that you will never get locked out of the car one dark wet night in a remote carpark. I chose to use a smarty regularly following a lockout six years ago. And have not had another similar problem.

We know it shouldn't be necessary but life is too short to stress over never knowing when it will happen a second time. Many use belt n braces and also carry around a battery booster in the glovebox in case they accidentally leave the interior light on one day. Others prefer to hang around for hours in cold conditions waiting for the RAC. Each to their own as they say.

I did 57k in my Zoe, never charged the 12v once, even ran it with the same 12v from day one until I sold it 6 years later. The best preventative maintenance is to use your car. Most of those I've seen that have had issues with their 12v are also low mileage users, they probably had similar problems when they had an ICE.

I do charge my clasic minis battery once a year, but even then I can usually start it with no issue. But then I do isolate the battery when not in use.

 

[Hitstirrer]

I did 57k in my Zoe, never charged the 12v once, even ran it with the same 12v from day one until I sold it 6 years later. The best preventative maintenance is to use your car.

I don't remember any Zoe being reported as having this 12v problem as it happens. Perhaps Renault managed to solve the issue in the first place. But I agree that people who ran an EV at least an hour every day seemed to escape this glitch. The algorithms coped with a decent period daily to operate the DC to DC converter and keep the 12v fully charged.

But as many early EV's had a low range they tended to be used as short commute and shopping tools. Often never going further than 10 miles from home. The systems didn't like that and over a week or so any abnormal extra drain could flatten the battery and cause a myriad of bizarre electrical events to bemuse owners and dealers. That is when a helping hand of a regular extra charge helped.

These days, with longer ranges, EVs tend to be used for longer distances and operate for up to an hour regularly so that the systems can keep the 12v full. And recently all reports of flat 12v batteries tend to be a sudden 'off a cliff ' event which suggest an accidental drain over a few hours rather than an endemic system fault over a long period. It will be interesting to eventually learn what caused this thread's situation.