I can highly recommend a 13 plate heavy duty 6v battery from Lincon Batteries in Leigh on Sea. Good price, excellent mail order service, plenty of power. I try to keep it on a conditioner, but often forget as the car gets lots of use. I have just fitted the third in our car, the previous two having lasted 5 years each. Eventually they get sluggish on frosty mornings. W

The Halfords 12v one in my A7 is now still functioning as normal after 13 years. I charge it with the Lidl intelligent charger. The 12v system in the car has a Seven Workshop solid state regulator. The battery has got to pack up soon surely.
Dave.

Location: Sheffield