[MrBruce]

I've driven both my A's for over 34 years and never had a single problem with the 6 volt system. You can run your phone and GPS off the 6 volt system as they both only take 5 volts. If it doesn't spin the motor make sure that the battery cables are for the 6 volt system and that the starter isn't bad. Twelve volts are really hard on a 6 volt starter and you could be beside the road with a broken starter spring. Just my thoughts, but I've only been driving a Model A for 38 years.