My advice would be never start off with a discharged battery, I now have a Grosset electric start so always keep my battery topped up, once the starter has been used the ammeter shows a heavy charge for a second or two to replace what has been used by the starter and then settles very quickly to a central balance, that is using a Walkernator with a Nippon Denso, fantastic bit of kit, never let me down, fit and forget, carry a spare belt but never had to use it, never had a problem with the primary drive chain or sprockets, doesn't look standard, who cares!