1.2 PureTech 82 Stop/Start - which battery?

Hi

I bought Citroen c3 in 2019 and this year it started to have problems with the battery, i does not turn off when standing still (start-stop) for couple of months.... Anyway, i took a look at the battery and discovered that it is not an AGM battery but a EFB battery.
My question is, can I change that battery with an AGM battery that is better ?
I looked at the Diagbox and in the options of the battery i cannot find AGM replacement, only lead acid, GEL and EFBC. Maybe the alternator cannnot charge AGM battery ?

I’m unfamiliar with the workings of the Citroen so can only compare it to my Volvo with stop/start. The Volvo employs two batteries, the main battery that is used for starting the car and a secondary that keeps everything running whilst the car is in (Stop) mode at the traffic lights etc. The main batteries are so power sensitive that if the car isn’t used for a fortnight you need to charge the battery( Volvo even tell you to charge your battery regularly to keep it topped up). So if Citroen don’t use a support battery, you are draining your main battery every time you stop, with heater, lights, radio, etc etc.
I now use a smart charger at least once a month for 48 hours to keep the battery at peak power, Stop/start hasn’t let me down once since. A good charger is far less cost that a new battery,

Thanks for response.
I tried that, i must say that i drive car every day... The moment i get it out of the car and put it on charger it almost instantly says that the battery is fully charged. Charger wont charge it...
After a night (fully charged battery - 12 hours later) i connected the car to Diagbox and the diagnostics say that it is only 69% charged. It is loosing power over the night.

What gets to my mind is this value "Voltage estimated on starting - 7.86V". Isn't that too low ?

Gonzales wrote: ↑Sat Feb 19, 2022 5:34 pm What gets to my mind is this value "Voltage estimated on starting - 7.86V". Isn't that too low ?

I would use a multimeter or voltmeter to check the actual value and not what the computer reports.

On my early car the voltage reported by Lexia from the BSI is not accurate.

You were right. Those numbers does not mean anything... I bought a new battery Exide EFB 60Ah 640A, replaced the old Varta and after that it was pretty much same values, the start stop system now works. But BSI still thinks that it is Varta inside the car.

Before - with Varta After - with Exide