e-Hybrid and 12v battery question

[oldgitdave]

My car is a 204 e-Hybrid V2 and I'm interested to know how the 12v battery interacts with the EV battery. 90% of my driving is in milk float mode, so on a couple of occasions I've had a warning in the Connect app that the 12v battery is getting low. A message something like; "you can only send 3 more commands to the vehicle as the 12v battery is getting low".
In this colder weather I'm using the app to heat the windows and to activate the a/c prior to going on my journey (it beats having to scrape the ice off the windows!). This is with the car connected to the wallbox and the EV battery charging or fully charged.
Now I'd have thought the charging system would be used to charge the 12v battery as well. Or is the 12v battery only charged whilst driving either in electric mode or when the ICE is running?

 

[dashnine]

This is only guess work, but I don't think the external charger would be used to charge the 12V battery too - but I would have though the hybrid battery would charge the 12V battery (permanently or as required - maybe this function has failed?).

But as you only use the petrol engine for 10% of the time and you're suffering 12V battery issues, I think you might be right in that the 12V battery is only charged with the engine is running. Perhaps the proof is to check for an alternator (and belt) on the engine?

 

[dashnine]

This is only guess work, but I don't think the external charger would be used to charge the 12V battery too - but I would have though the hybrid battery would charge the 12V battery (permanently or as required - maybe this function has failed?).

But as you only use the petrol engine for 10% of the time and you're suffering 12V battery issues, I think you might be right in that the 12V battery is only charged with the engine is running. Perhaps the proof is to check for an alternator (and belt) on the engine?

Almost answering my own questions, it doesn't appear to have an alternator. Photos of various bits of a hybrid engine for sale on the Bay show no auxiliary belt and no alternator. The AC compressor is in the 'usual' place aligned as if there were a belt, but with a 48V motor bolted onto the front. Obviously having a 48V motor driving a 12V alternator would be a bit silly!

 

[oldgitdave]

This is only guess work, but I don't think the external charger would be used to charge the 12V battery too - but I would have though the hybrid battery would charge the 12V battery (permanently or as required - maybe this function has failed?).

But as you only use the petrol engine for 10% of the time and you're suffering 12V battery issues, I think you might be right in that the 12V battery is only charged with the engine is running. Perhaps the proof is to check for an alternator (and belt) on the engine?

Almost answering my own questions, it doesn't appear to have an alternator. Photos of various bits of a hybrid engine for sale on the Bay show no auxiliary belt and no alternator. The AC compressor is in the 'usual' place aligned as if there were a belt, but with a 48V motor bolted onto the front. Obviously having a 48V motor driving a 12V alternator would be a bit silly!

Thanks, what you're saying makes sense. I didn't expect the wall charger to charge the 12V battery directly but thought it might through the 48V system as you said, but maybe it only does it only when driving? That would explain why I got the message probably. As there's no alternator then the 12V battery must charge through the 48V system but you'd think it would get a top up whilst plugged in tbh.

I don't think I have a problem with anything really, the car had been stood for a few days and it was -5°C outside at the time. I shall see how it goes.

Still interested if someone knows exactly how the system works. Curious more than anything.

 

[RUM4MO]

I have no experience of EVs, but, I have read that Skoda EV owners are having this issue as well and there is some chatter that S/W updates will/have been rolled out to sort this out, if so then this is a massive oversight by VW Group EV design teams, and that includes making sure that the 12V service battery gets charged up when using a wall charger - to me, as someone that worked in engineering, if no 12V service battery charging is being planned for when the EV is being wall charged, then someone has made a massive error in judgement.

Edit:- obviously the 12V service battery should be getting charged or re-charged while the EV is being used as "no/low charge" in the 12V service battery means that EV is OOU.
I think that some people that run VW Group EVs, when they know that their EV is not going to be used for a few days/weeks, are connecting a CTEK smart charger to that 12V service battery. Maybe more relevant where the car does not have access to a wall box, well once the S/W has been updated.

 

[oldgitdave]

I have no experience of EVs, but, I have read that Skoda EV owners are having this issue as well and there is some chatter that S/W updates will/have been rolled out to sort this out, if so then this is a massive oversight by VW Group EV design teams, and that includes making sure that the 12V service battery gets charged up when using a wall charger - to me, as someone that worked in engineering, if no 12V service battery charging is being planned for when the EV is being wall charged, then someone has made a massive error in judgement.

Edit:- obviously the 12V service battery should be getting charged or re-charged while the EV is being used as "no/low charge" in the 12V service battery means that EV is OOU.
I think that some people that run VW Group EVs, when they know that their EV is not going to be used for a few days/weeks, are connecting a CTEK smart charger to that 12V service battery. Maybe more relevant where the car does not have access to a wall box, well once the S/W has been updated.

I'm sure the 12V battery is getting charged whilst in EV mode and in ICE mode as I've not had to charge it independently. I've had no messages in the last couple of days so all good. It does seem, from what you've said, that the 12V battery doesn't get a sniff of energy whilst the EV battery is being charged by the wall box, how did VAG miss that! I have a CTEK from when I used to SORN my Z4 Roadster through the winter months but it shouldn't be needed on a modern car even if left for a few weeks tbh.
I wonder why they bother with a 12V battery on a hybrid in any case. Surely just reserve some EV battery for the 12V requirements and drop the voltage down for the systems that need 12V rather than have an independent lead acid battery. Do full EV's still have a 12V battery?

 

[RUM4MO]

One good reason would be for safety reasons, ie the high voltage traction battery pack can be isolated when the car is not "powered up" for moving.

Edit:- the 12V service battery seems to be a weak link in all EV vehicles.

 

[elzo]

I'm sure the 12V battery is getting charged whilst in EV mode and in ICE mode as I've not had to charge it independently.

The 12v battery ONLY charges when the fuel engine is running! I have verified this from a few dealers. Therefore, it is important to use a fuel engine in a hybrid car, at least once a week!

 

[oldgitdave]

The 12v battery ONLY charges when the fuel engine is running! I have verified this from a few dealers. Therefore, it is important to use a fuel engine in a hybrid car, at least once a week!

So it would seem! My car has regularly activated the ICE whilst driving in EV mode and I never new why but I guess this is the way it keeps the 12v battery charged. Ridiculous situation when you have 13kW of battery power just sitting there!

 

[CupForm]

...simply because they're too cheap to install a voltage inverter to charge the 12V battery from the HV one. That's absolutely ridiculous!
They're not rediscovering the wheel, those are technical solutions already employed by other brands (other than VAG I mean).

 

[oldgitdave]

Agreed! Ever since I've had mine I've always thought I wouldn't dare own it after the 3 year warranty expires. I might be getting rid sooner the way things are going.

 

[elzo]

...simply because they're too cheap to install a voltage inverter to charge the 12V battery from the HV one. That's absolutely ridiculous!
They're not rediscovering the wheel, those are technical solutions already employed by other brands (other than VAG I mean).

I asked the dealer. they can supply charger for 12v battery. But I will have to connect an additional wire to the socket and it will cost 700€ with installation.

 

[oldgitdave]

I asked the dealer. they can supply charger for 12v battery. But I will have to connect an additional wire to the socket and it will cost 700€ with installation.

Well that's just stupid, it's more than an EV charging station!

I have a Ctek battery conditioner/trickle charger and a 800A car jump starter (the latter is in the boot of the car)! Together they cost less than 200€.
Of course I can't use either at the moment because I can't open anything bar the drivers door.

Car Dead!

Not driven my 204 V2 Hybrid for 9 days and its been sat on the drive. Connected to it via the Connect app and set a departure time for tomorrow at 11am, something I do regularly. It took a couple of goes to get it to register but that's nothing unusual. Went out to the car to connect the charger...

www.seatcupra.net

 

[elzo]

Well that's just stupid, it's more than an EV charging station!

I have a Ctek battery conditioner/trickle charger and a 800A car jump starter (the latter is in the boot of the car)! Together they cost less than 200€.
Of course I can't use either at the moment because I can't open anything bar the drivers door.

Car Dead!

Not driven my 204 V2 Hybrid for 9 days and its been sat on the drive. Connected to it via the Connect app and set a departure time for tomorrow at 11am, something I do regularly. It took a couple of goes to get it to register but that's nothing unusual. Went out to the car to connect the charger...

www.seatcupra.net

The trunk can be accessed by folding the rear seat. Also there should be a lever for mechanically opening the trunk from the inside. I read about it in the instructions.

 

[oldgitdave]

The 12v battery ONLY charges when the fuel engine is running! I have verified this from a few dealers. Therefore, it is important to use a fuel engine in a hybrid car, at least once a week!

I've done some checks this morning and 100% can say that the EV system does indeed charge the 12v battery when in electric mode only. I checked the voltage at the battery and in the engine bay. First pic is with the car off, second pic with the car started but the ICE not running.

 

[elzo]

I've done some checks this morning and 100% can say that the EV system does indeed charge the 12v battery when in electric mode only. I checked the voltage at the battery and in the engine bay. First pic is with the car off, second pic with the car started but the ICE not running.
View attachment 38130 View attachment 38131

This is interesting.
If the 12v battery actually charges even when I'm driving an electric motor - then that changes things for the better!
Why doesn't the dealer know about this?!
Is there any way to confirm this? It would be nice to get a more official answer from a Cupra.

 

[CupForm]

I found this on the Skoda Forum - but it's all the same hybrid system... The screenshots from ERWIN are actually for Seat SSP174 Concepts of Electromobility (so even better!!!). Have a look at those diagrams - it would seem that the 12V battery would be charged only when driving on ICE (when the Electric Motor runs as a generator), or when slow/medium charging the HV battery. I would ignore the Fast-charging part since our cars don't have this option:

https://www.briskoda.net/forums/top...ft-to-e-drive/?do=findComment&comment=5684673

And last, but not least: check with your dealer for SW updates concerning the 12V charging management. Apparently the Octavia had such an update sometime during 2022; AFAIK most of the SW is shared between all VAG members. It was also the case with the crappy infotainment system - they fixed it almost simultaneously for VW Golf, Skoda Octavia, Seat Leon and Cupra Formentor...

 

[oldgitdave]

Update:

I've been in touch with Cupra UK customer services and finally have definitive answers regarding charging of the 12v battery. Here are the official replies, the first regarding directly charging the 12v battery, the second regarding how the car charges the 12v battery. I have removed names and most of the irrelevant information.

Re: CUPRA FORMENTOR - Battery Issue with CUPRA FORMENTOR V2 Hybrid 204

Dear Dave

Thank you for contacting CUPRA UK regarding your vehicle's12v battery issues. It can be frustrating when such problems arise and I apologise for the delay in my response.

To address your question, yes, you can use a battery maintenance charger to trickle charge the 12v battery in your car. Connecting it to the terminals in the engine bay is a viable option. This can help ensure the 12v battery remains charged and operational, as it's crucial for various systems in your vehicle.

However, I recommend checking your vehicle's manual or reaching out to a CUPRA Retailer for specific guidance on where to connect the charger and any precautions you should take to avoid damaging the vehicle's electrical system. Different vehicle models may have variations in their recommended procedures.

I hope this information helps, and your vehicle remains trouble-free moving forward.

If you have any more questions or need further assistance, please feel free to ask.

Thank you for contacting CUPRA UK.

Kind regards
K
Customer Relations Advisor

A Lifestyle and Sports Car Brand with a Passion for Racing | CUPRA

High performance. Innovation. Craft. CUPRA is the new definition of racing. A brand made to be different. Discover our contemporary sports car brand today!

www.cupraofficial.co.uk

Dear Dave

I acknowledge your recent contact made with CUPRA Customer Care. I apologise for the delay in my response.

I completed my investigation with our Technical Support Team who advised the following, the 12 Volt battery is recharged by the electric drive motor via the voltage converter while the vehicle is moving, regardless of whether the combustion engine is being used or the vehicle is in electric mode.

When the hybrid battery unit is being recharged by an external charger, the voltage converter is in operation and the 12 Volt battery is therefore recharged.

I hope this information proves useful.

Thank you for contacting CUPRA UK.

Kind regards
K
Customer Relations Advisor

T: 0800 049 7106
E:[email protected]

CUPRA UK
Yeomans Drive
Blakelands
Milton Keynes
MK14 5AN
www.cupraofficial.co.uk

 

[EVangelist]

Update:

I've been in touch with Cupra UK customer services and finally have definitive answers regarding charging of the 12v battery. Here are the official replies, the first regarding directly charging the 12v battery, the second regarding how the car charges the 12v battery. I have removed names and most of the irrelevant information.

Re: CUPRA FORMENTOR - Battery Issue with CUPRA FORMENTOR V2 Hybrid 204

Dear Dave

Thank you for contacting CUPRA UK regarding your vehicle's12v battery issues. It can be frustrating when such problems arise and I apologise for the delay in my response.

To address your question, yes, you can use a battery maintenance charger to trickle charge the 12v battery in your car. Connecting it to the terminals in the engine bay is a viable option. This can help ensure the 12v battery remains charged and operational, as it's crucial for various systems in your vehicle.

However, I recommend checking your vehicle's manual or reaching out to a CUPRA Retailer for specific guidance on where to connect the charger and any precautions you should take to avoid damaging the vehicle's electrical system. Different vehicle models may have variations in their recommended procedures.

I hope this information helps, and your vehicle remains trouble-free moving forward.

If you have any more questions or need further assistance, please feel free to ask.

Thank you for contacting CUPRA UK.

Kind regards
K
Customer Relations Advisor

A Lifestyle and Sports Car Brand with a Passion for Racing | CUPRA

High performance. Innovation. Craft. CUPRA is the new definition of racing. A brand made to be different. Discover our contemporary sports car brand today!

www.cupraofficial.co.uk

Dear Dave

I acknowledge your recent contact made with CUPRA Customer Care. I apologise for the delay in my response.

I completed my investigation with our Technical Support Team who advised the following, the 12 Volt battery is recharged by the electric drive motor via the voltage converter while the vehicle is moving, regardless of whether the combustion engine is being used or the vehicle is in electric mode.

When the hybrid battery unit is being recharged by an external charger, the voltage converter is in operation and the 12 Volt battery is therefore recharged.

I hope this information proves useful.

Thank you for contacting CUPRA UK.

Kind regards
K
Customer Relations Advisor

T: 0800 049 7106
E:[email protected]

CUPRA UK
Yeomans Drive
Blakelands
Milton Keynes
MK14 5AN
www.cupraofficial.co.uk

Great to get clarity on that!

 

[elzo]

When the hybrid battery unit is being recharged by an external charger, the voltage converter is in operation and the 12 Volt battery is therefore recharged.

Am I correct in understanding that when I charge my hybrid battery from the outlet, my 12v battery is also charged along with it?

If this is indeed the case, then this changes things radically.

For what reason then was your battery dead one morning if the car was plugged in to charge the hybrid battery?