accessory power

Hi there, My 12 volt accessory battery in my Sera EV is dying mainly due to high draw from vacuum brake pump. The battery is standard 12 volt lead acid car battery about 45ah. It is dying due to high draw and is charged by the alternator which works only when EV is driving. This has lasted well...

Hey guys, I'm in the middle of my 48V Lithium electric motorcycle build and I'm pretty sure that road rules in Australia require a separate battery for the 12V system so you can still run hazard lights etc if the main pack quits. I'm wondering whether you guys think I will need a DC-DC converter...