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12V battery charging is forbidden for the user/owner

spezwend

Active Member
Jun 23, 2023
68
35
Did you know, that user manual forbids car owner to charge vehicle 12V battery? This was new to me and what direction we are going. When my car battery voltage low or battery is flat I need to tow the car to dealer and use tow trucks for that... what?

Page 336 in owners manual:
1688293890064.png


This "special" technology is EFB battery, the charging program is the same as AGM battery which is used for many years. I've have had CTEK smart charger for many years and charged premium car brand batteries with no problem. Old Mercedes AGM battery lasted 11 years, newer Mercedes battery lasted 3 years. Now Cupra battery is almost flat in less than a week after the delivery?? CTEK lists EFB chargers as special new chargers and filters out AGM chargers from the EFB list. So buy a new charger. :D

And we were told to be enviroment friendly, are they?

Have you hard wired smart charger plug to your car? I have already had almost flat battery with many fault codes: https://www.seatcupra.net/forums/threads/formentor-system-errors.464758/post-5036407
 

andylong

Active Member
Jan 21, 2021
494
1
134
Charge it with a suitable charger but disconnect the cabling to the battery.
I rather think there's a, largely correct, assumption that the customer will screw up the electrics in some way in thier ignorance.
 

andylong

Active Member
Jan 21, 2021
494
1
134
Agm has different charging requirements to efb.
But it's unlikely you would notice any issues short term unless you are always charging it.
 

TheSwede

Active Member
Oct 20, 2018
356
197
Sweden
I always charge the Cupra 2018 with a Ctek mxs5 (5a). I don't dissconect the cables. Works fine.
My Cupra and our Skoda 2018 need some charging during the dark part of the year, not used so much. Both have EFB battery.
 

andylong

Active Member
Jan 21, 2021
494
1
134
Ctek are sophisticated chargers, humans make mistakes and sophisticated chargers have settings because the charger doesn't know what type of lead acid battery is installed. Choose the desulphation mode and bad things can happen.
Whilst one customer might understand this others may not. People have a long history of not RTFM.
The electronics in cars can be very sensitive to battery voltage, unlike in the old days, it's a matter for you if wish to trust the charger not to fail in such a way that damage occurs.
Not everyone wants to pay so much for a charger and manufacturers like to avoid issues if they can.
 

TheSwede

Active Member
Oct 20, 2018
356
197
Sweden
@andylong -Yes I understand what you mean. There are risks if you do it with wrong mode active.

If you disconnect the battery without a backup (parallel connected) battery you get error codes which some are not possible to get rid of without resetting them with tools like OBDeleven / VCDS.
Some settings need to be reseted as date/clock values.
No big deal but as I have written it should not cause you any problem if you do it the right way according to Ctek instruction. Then I mean ordinary charge NOT the RECOND mode!

I have never used RECOND mode so I can’t say anything about what happens then.
If I will do it in the future I will remove the battery from the engine bay, a couple of meters from the car ;).



RECOND mode in yellow circle:
 

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andylong

Active Member
Jan 21, 2021
494
1
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Quite so, on the other hand car charging systems are so much better than they were and flat batteries are rare now.
Even at idle my seat provides 14.6v after starting.
I have one of these for all my charging needs.

Haisito 80W 6A Lipo Battery Balance Charger Discharger for LiPo/Li-ion/LiFe (1-6S), NiMH/NiCd (1-15S), Rc Hobby Battery Balance Charger LED W/AC Power Adapter https://www.amazon.co.uk/dp/B07SS4VWSS?ref_=cm_sw_r_apann_dp_EQJ0281TKZ9FR7HA740S
 
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Wyld Stallyn

Be Excellent To Each Other and... Party On Dudes!
Mar 10, 2022
405
248
If they let me work on Nimrod, Eurofighter, Cobra and Apache Helicopters, Joint Strike Fighters and more worrying for the general populous, let me design bits of A380.

I think I can cope with charging a battery - what could possibly go wrong..? 🙈🤣

Q/.What are the strange terminals attatched to the battery leads for..?

A/.Voltage Monitoring 👍😁
 

TheSwede

Active Member
Oct 20, 2018
356
197
Sweden
@TheSwede Ctek lists MXS5 as not compatible with EFB battery:

Lead acid/WET, MXS5 See explaination in tabpage "Technical Data" the field "Battery types". It includes Battery types "12 V:; WET; MF; Ca/Ca; AGM; GEL".

EFB batteries are an enhanced version of standard wet-flooded technology therefore it will work also on an EFB battery (it is a lead acid battery).

I have used it for EFB batteries on Golf 7R 2014, Golf 7 TSI 1,4 2014, Golf / Alltrack Cupra Fabia 2018 and so on.
 
Last edited:

andylong

Active Member
Jan 21, 2021
494
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134
The difference between the lead acid batteries is not chemistry but construction.
AGM holds the electrolyte in an absorbent mat between the plates which uses less acid, is sealed but you must be cautious charging as only a limited amount of gas can be recombined in the case and heat (environmental) can be a problem.
EFB is a cheaper way of getting a battery that can be used harshly, but making thicker plates that last longer, but otherwise it's like a FLA battery.
Charge it like an FLA.
AGM batteries have a higher end of charge voltage than FLA.
 

TheSwede

Active Member
Oct 20, 2018
356
197
Sweden
@spezwend
The main reason for me to buy MXS5 (have two of them) is that I also charge a Ducati bike and old conventional car batteries. All these the MXS5 could handle including EFB and AGM battery. EFB is charged in normal mode.

If you just want it for EFB and AGM batteries then you can buy the Ctek CT5 Start/stop. Not so many modes as the MXS5.
....and of cause you can buy other brands too ;). I can't help with that.
 

spezwend

Active Member
Jun 23, 2023
68
35
@TheSwede I have worked professionally as a car diagnostic/electrician at the dealer for many years, but not with VW Group cars. So no problem with choosing the charger, but thanks anyway. :) We had 25A Ctek chargers then and at home I have had MXS 7.0 for 10 years.

This charging info just blew my mind, for example, Mercedes/BMW allow it's customers to charge their vehicles but VW does not, so VW Group think their customers are stupid? :D
 

andylong

Active Member
Jan 21, 2021
494
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Perhaps Mercedes and BMW think it unlikely Thier customers would dirty Thier hands lifting a bonnet.
VW group owners feel compelled to fiddle.
 
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andylong

Active Member
Jan 21, 2021
494
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134
I was 12 when I blew up my first battery...nicd transmitter pack as I recall