Why a Start Stop Battery in my MY 12 T5

[Izabarack]

I notice my ex-ambo T5 has a Start Stop battery fitted as a start battery, in the engine bay. Varta brand, 70 AH. Advertising on the battery label says good for installations with lots of accessories. No auto stop/start in this vehicle like son's Golf so I'm thinking the battery was an ambo upgrade because they normally run lots of "stuff". Bloke doing my roadworthy to change rego confirmed VWs do not like anything other than VW approved batteries (Owner's manual has a warning against replacing battery with standard stuff).

There is a second battery installed under the passenger seat. I have not worked out all the wiring yet but a solenoid controlled by a switch on the dash parallels this second battery (AGM) with the start battery.

Any experience with VW battery requirements out there who might comment? I already have a LiFePo battery it install as a third, to run a fridge, and will be tapping a charge output from the current second battery to the Lithium battery.

Iza

[Syncrotek]

What year is the ex ambo ?, a Varta battery might be the original. 70 Ah imo is a bit small for having a bit of reserve,
does it have a CCA rating on it ? It might be a good idea to have a decent automatic aux. battery charging unit fitted
rather than a switch on the dash - there is heaps of info on that you can Google -

[Sunny43.5]

I have replaced several batteries in both of our T5's and even went as far to go as high in amperage output as I could as we run big stereos and not had a single issue with electrics as a result . I think you will find most car makers put some sort of warning about "non genuine "batteries etc . I suppose they are trying to cover their arses in case something goes wrong . I mean to say 12 volts is 12 volts its just how long its on tap when you turn the key .

[DonJuan]

If the CCA rating suits the application then the battery will do the job. The second battery will be linked to the first so it also gets charged by the alternator. This AGM is probably kept charged if they needed to use high power equipment when they're not near s power point.

[DonJuan]

Much like 4x4 and motor home camping...