So, my 2017 O3 1.4 TSI still has the original Banner EFB battery. 120k km so far, mostly long ad rare drives (could be almost 2-3 weeks of car just sitting).

S/S does not work unless in summer and after a very long holiday drive, but otherwise car starts with no issues and no warning about low voltage. Tries measuring the voltage after almost 2 weeks and it read 12.3V (I know therte are other important metrics involved, don't have a smart battery tester).

So, as winter is approaching, instead of buying a jump-starter like 70Mai Midrive and then having also to replace the battery, I'd go directly for the battery change.

And, if you agree with me 🙂, should I stay on EFB or go with an AGM battery? (one local shop told me to stay on EFB if I don't drive the car more frequent, but I'm not sure this is true).

And, second question, Banner or Exide?

Thanks!

If it's an EFB I would replace it with an EFB no need for the extra expense of an AGM. What you could do if you have low usage case is get a larger capacity for the storage element.

https://www.tayna.co.uk/

There are cheaper but this is 65ah not 60ah and longer warranty than

Edited 18 November, 202518 Nov by Stonekeeper

Hello, not sure if it's a good assumption that your Banner-branded battery is original - I'd agree it to be more likely if it had been a Moll EFB.

There will possibly be a date code stamped on the top of the negative terminal, which can confirm age.

AGM performance is superior to EFB and is possibly worth the extra cost - but it is even more important that new type is adapted (coded) into the vehicles BCM if changing type (any replacement battery should be adapted anyway)

1 hour ago, Warrior193 said:

Hello, not sure if it's a good assumption that your Banner-branded battery is original - I'd agree it to be more likely if it had been a Moll EFB.

I’m the first owner of the car and bought it from the Skoda dealer.

Never changed it.

Of course I’ll go and make the proper coding, but I was wondering if AGM is worth the money and to figure out why one of the shops mentioned that for non-frequent use EFB is better.

Also, I guess either Exide or Banner would be ok - found some 70Ah - 760A as I recall so a tad more than my current one

I guess it depends on the price difference between the two types, the AGM is reputed to have considerable performance and life advantages over the EFB.

If anything, the AGM should be more suited to relatively infrequent use.

@Warrior193 : if I take into account that my original Banner has lasted me since 2017 and I guess is still going quite ok, I tend to say EFB is pretty solid.

My main concern is that, with the upcoming winter and as I don’t usually use the car, I’d get into trouble when wanting to drive one morning… this is why I would consider replacing the battery now, when I’m not under pressure.

And to maybe avoid having low voltage errors.

And, what are the minimum values for battery health, SOH, voltage etc. when one should consider replacing an old battery. For example, it the shop says battery is stil around (let’s say) 65%, should I change it?

If that notional 65% battery health condition was with the battery charge state at normal level by the vehicle alternator, I personally would keep the battery in service.

You would almost certainly see an improved health percentage if the battery was to be charged fully - as would probably be the case after a decent run.

I would get one of these doubles as a powerbank to charge your phone etc.

Ready for when the battery starts to fail and the cheapest place i can find it

https://www.diagnosticconnections.co.uk/topdon-v1500

3 hours ago, SwatKat said:

@Warrior193 : if I take into account that my original Banner has lasted me since 2017 and I guess is still going quite ok, I tend to say EFB is pretty solid.

My main concern is that, with the upcoming winter and as I don’t usually use the car, I’d get into trouble when wanting to drive one morning… this is why I would consider replacing the battery now, when I’m not under pressure.

And to maybe avoid having low voltage errors.

And, what are the minimum values for battery health, SOH, voltage etc. when one should consider replacing an old battery. For example, it the shop says battery is stil around (let’s say) 65%, should I change it?

My nearly 7 year old original (Polo) 59AH EFB battery on a VCDS scan last month shows a battery at rest voltage of 12.4V which is nominally 70% SOC, it shows a usable battery charge of 23AH which might indicate that the 100% SOC or maybe state of health? is now, 23/0.7, 32.9AH or the battery capacity is now, 32.9/59, only 55.8% of its original 59AH capacity. The stop/start (used selectively) has never failed to operate even down to 65/68% SOC and the BMS does return the battery to its normal indicated max of 85% SOC but it can take days, you can see that even with a alternator charging voltage of 14.6V that the charging current is still only 3A and goes as low as 1.5/2A when the charging voltage falls to 13.3/13.6V while driving normally, it never maintains a high charging voltage continuously up to 85% SOC.

IDE01829 Generator exciter current 2.125 A

IDE01834 Battery voltage 14.598 V

IDE01836 Battery current 3.024 A

IDE01837 Temperature of battery sensor 26 °C

IDE01839 Battery charge level 70 %

IDE01841 Battery internal resistance 7.8 mOhm

IDE01842 Usable battery charge 23 Ah

IDE01843 Battery voltage at rest 12.4 V

Edited 19 November, 202519 Nov by Johngerard