V40 Battery Charge
 

I am sure that I have read in the manual that you cannot use a smart charger on these cars, is this true?

My car has the stop-start function, which means that it has an additional battery in the front.

Does anyone know why I cannot use a smart charger ?

You can, but you should connect the negative lead of the charger to a convenient earth point on the chassis, not to the battery negative terminal.

If you connect the charger to the negative battery terminal, it bypasses the battery monitoring sensor and the system will disable stop-start until it has recalculated the battery condition. Connecting to the chassis allows the battery monitor to sense the charge being applied to the battery and stay synchronised.

There is a convenient bolt in a bracket on the left suspension strut turret on my car, just to the nearside of the battery.

^^^^^^^^ that - what he said.