Blue Sea 24V 500A ML Heavy Duty Charging Relay

The Blue Sea Systems 7623 ML-Series Automatic Charging Relay handles two 24V banks at 500A continuous, with magnetic latching and a manual override.

Start Isolation is the function worth understanding, and it protects the equipment most likely to be damaged. During engine cranking the system voltage dips hard. Start Isolation temporarily separates the house bank so sensitive electronics never see that dip, which is what saves chartplotters and audio gear over years of starts.

Engine Isolation covers a different case, separating two engine circuits when both are running so neither alternator fights the other. Both functions are beyond what a basic charging relay does, and on a twin-engine boat with electronics the difference is real.

Five hundred amps continuous supports very high alternator output, above what standard automatic charging relays handle. The magnetic-latching design draws very little current in either steady state, a manual switch allows local operation without control power with a locked-off position for service, and LED outputs give remote status. Explore more battery charging accessories.

• Start Isolation protects electronics from cranking dips
• That dip is what kills chartplotters over time
• Engine Isolation separates two running alternators
• 500A continuous, above a standard ACR