I haven't used two batteries in over 40 years. Properly grounded system, good 12 volt battery, and 5 or so years ago I added an alternator and will never run a car without one again.I put a slow charger on my car at home every 3-4 weeks just to top it off.

1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time