Electrical system: Main battery switch for two battery banks with emergency start function

Blue Sea Systems is launching the e-Series Dual Circuit Plus, a battery master switch for boats with two battery banks. The battery master switch switches both banks on simultaneously or combines them for emergency starts. The make-before-break contact design prevents power interruptions.

Unlike simple battery isolating switches, the 5511e model works according to the make-before-break principle: the new contact is closed before the old one is opened. This prevents voltage dips and protects sensitive electronics when switching between positions. The spark-proof design also qualifies the battery main switch for installation on petrol-powered boats.

Two-in-one battery master switch

The Dual Circuit Plus offers three switching positions: With "Off", both circuits are separated. If you turn to "On", both circuits are closed, but remain isolated from each other as if two individual switches had been operated. In the "Combine" position, both banks are connected in parallel - for example, to start an engine with an empty starter battery using the consumer bank. The housing design enables surface and rear panel mounting. At 22 millimetres in length, the tin-plated copper connection bolts are sufficiently dimensioned to connect several ring cable lugs.

Load capacity also for larger boat engines

Blue Sea specifies a continuous load capacity of 350 amps per circuit for the main battery switch. When starting, 700 amps may even flow for 30 seconds. During the switching process, however, the current should not exceed 25 amps.

For owners who are also looking for an automatic charging relay, Blue Sea offers a starter kit: it combines the 5511e battery main switch with the BS7610 charging current distributor and costs around 231 euros. The relay separates the starter and supply battery during discharge and automatically connects them when charging via the alternator or shore power charger.

• Model: Blue Sea e-Series Dual Circuit Plus (5511e)
• Type: Battery main switch, 3-position with combination function
• Continuous load capacity: 350 A per circuit
• Starting power: 700 A (30 sec)
• Maximum voltage: 32 V DC
• Switching capacity: 25 A
• Connections: M10 tinned copper studs, 22 mm long
• Cable cross-section: up to 120 mm²
• Mounting: surface or rear panel mounting
• Spark-proof: Yes (suitable for petrol engines)
• Price: 77 euros (single), 231 euros (starter kit with BS7610 charging relay)
• Source of supply: Lindemann KG

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