Projecta 8A 12V 6-Stage Smart Battery Charger SMC800 $49 + Delivery ($0 C&C/ in-Store/ OnePass) @ Bunnings

Seems way too cheap, not sure what normal price is but $49 for an 8amp charger is pretty good!

Suits 12V Automotive, Marine and Deep Cycle batteries
LCD Display indicates charge status, current voltage and charge type
Safe and simple, comes with spark-free and polarity protected alligator clip harness, safe to use while the battery is still in the vehicle
Interchangeable fused wiring harness included for permanent installation
IP65 Weather Proof