is there an adapter cable that i can plug into mains power to convert to 12v so i can connect to a car battery?

if so whats it called

if not what do i need as trying to figure out why my car wont run but the battery keeps dying

thanks in advance

 

A decent battery charger should have a 12v supply setting.

Ion't think I'd want to use just a lead or a transformer feeding power to the battery direct - if it explodes it will be messy.