When I got my car I found a little cable with a plug at the end with three LED’s, red, amber and green, I found out this was for plugging a Ctek charger into and is permanently connected to the battery (with fuse) The lights flash to indicate the condition of the battery but in practice it tends to go red if the car isn’t used for a couple of day but there is plenty juice in the battery even if left for a month or so.
It’s a Ctek part so probably still available and makes it very easy to plug in the charger when I want.
