My three-bank marine battery charger was 20 years old, so I replaced it with a state-of-the-art Guest ChargePro 30A three-bank onboard model that pumps out 10 amps per -12-volt DC circuit. It is suitable for batteries wired in series or parallel, which mine are. The five-stage digital charging technology senses battery levels and applies charging as needed. It’s fully automatic, conserves energy, and is safe for long-term storage. LED graphics keep me posted on status. The extruded aluminum housing maintains an IP67 waterproof rating. The 30A was easy to install, with all 6-foot, 12-volt leads fitted with inline fuses and terminals. Lead extensions are available for extra length. The 120-volt AC cord is also 6 feet long. One caveat: This and the 40A model (both 9 inches tall by 4.1 inches deep by 8.7 inches wide) must be mounted vertically. Six other models in the series mount horizontally. $338.99; atlanticmarinedepot.com
