BLUE SEA SYSTEMS ALTERNATOR MODE switch

The Blue Sea Systems Alternator Mode switch is a battery management device designed for marine electrical systems. Its main function is to allow switching between different battery banks while protecting the alternator from potential damage, particularly when disconnecting batteries with the engine running.

The alternator field disconnect (AFD) function is a key feature of this switch. It prevents damage to the alternator diodes that could occur if the battery switch is turned to OFF while the engine is running. This ensures the longevity and reliability of your alternator.

The "Make-Before-Break" contact design allows switching between battery banks without interrupting the electrical supply. This ensures continuous power for the boat's essential systems, preventing untimely power cuts when changing battery sources.

This switch is designed to operate with marine electrical systems up to a maximum voltage of 32V DC. It is therefore compatible with most 12V and 24V installations.

Blue Sea Systems' Alternator Mode switch is made from non-corrosive marine-grade metals and molded in durable reinforced polycarbonate. This composition ensures excellent resistance to harsh marine environments. The connection studs are made of tinned copper for optimal conductivity and corrosion resistance.

Yes, this switch is ignition-protected. This feature is critical for safety on board, especially in engine compartments where flammable vapors may be present.

The Alternator Mode 7775B-BSS switch has a continuous rated current of 300 amperes (A). This means it can handle a 300A current continuously without overheating or damage.

The 7775B-BSS switch has a nominal intermittent current rating of 500 amperes (A) for 5 minutes. This capacity allows handling temporary current peaks, such as during engine start-up.

The cranking rating of this switch is 900 amperes (A) for 30 seconds. This specification is critical to ensure the switch can handle the high currents required for engine starting.

It is important to use a battery switch with AFD function to protect your alternator. Without this function, if you cut the power to the batteries while the engine is running, the alternator may suffer a destructive overvoltage to its internal diodes. The AFD prevents this risk by disconnecting the alternator field before the batteries are cut.

The switch must be mounted on a flat and solid surface using the appropriate fasteners. It is recommended to position it in a location that is easily accessible to the operator but protected from direct water spray where possible, even though it is designed for the marine environment.

The connection bolts for the 7775B-BSS switch are size 3/8"-16 (M10). It is important to use cable lugs sized for this diameter to ensure a solid and secure electrical connection.

For a typical setup, the 7775B-BSS switch is wired between the batteries and the boat's main electrical system, as well as to the alternator via the AFD function. The studs are usually marked for connections to the batteries (1 and 2), to the load (COMMON), and to the alternator field. Refer to the wiring diagram provided with the product for detailed instructions.

While installation can be performed by an experienced user, it is strongly recommended to hire a marine electrician. Incorrect installation may result in safety hazards, equipment damage, or inefficient operation of the electrical system.

This switch is compatible with most marine electrical systems operating at 12V, 24V, or up to 32V DC. It is ideal for boats equipped with one or two battery banks and an alternator requiring protection against unintended disconnections.

Yes, the alternator field disconnection function is designed to protect the alternator regardless of its power output, as long as it operates within the 32V DC voltage range. The switch manages the field cutoff, which is a universal protection measure for alternators.

Yes, the 7775B-BSS model, being a 4-position selector (OFF, 1, 2, BOTH), is specifically designed to manage and isolate two separate battery banks, or combine them if needed. This provides high flexibility for onboard power management.