I got sick of thinking about batteries so just kept buying chargers.
I've got a ctek (racecar), a "noco" thing from supercheap (tow car with 2 batteries), and an old "SupaCharge" branded lead acid thing (farm ute/mower) and will need 1 more when the Silvia gets a battery again (if the 86 stays).
I always make sure the charger itself is in free space/away from car etc, just to be sure.