Is anyone using the Andrew supervolt coils as mentioned in the Minton mods? I am in the UK but I can see them available in the USA. I do find my standard ones behave poorly using electric start unless the battery is fully charged. The kicker is fine which I prefer anyway but a bit extra would be good. Any comments?
If you want your bike to start perfectly, with the electric starter, every time, every day without fail, buy an Accel #140403S ignition coil. I've been using that coil for 8 years now, and my engine has always started immediately using the electric starter. Not even one fail to start in 8 years, so that's why I can recommend that coil.
I use the stock size 14 amp/hour, lead/acid battery, and find it has lots of power to crank the engine.
Yes, the battery needs to be fully charged. You indicate that your battery is not being fully charged, so I recommend that you install a voltmeter on your bike. The voltmeter will allow you to monitor the charging system while you drive. You need to see 14 volts or greater while you drive down the road. If you don't get 14 volts, then your battery is never going to reach full charge.
Tons of info on this site, as to how to troubleshoot the charging system.
If you are using smaller than 14 amp/hr battery, then all bets are off.
Make sure your large cables from the battery positive and negative terminals are clean with no corrsion. Same for where the negative cable contacts the frame.
Changing over to LED taillight(s), will also aid the charging system to reach 14+ volts.