A place for more technical discussions. Please make sure you post in the correct section on the site, this way it keeps the site tidy AND ensures you get a more relevant answer.
Any ignition live will do that job, the colour is black with white trace: there is one feeding the coils, and it also feeds the alternator.
These are fused with a 15A fuse.
Will just parallel the batteries all the time the ignition is on.
If it suddenly breaks, go back to the last thing that you did before it broke and start looking there