Marine Dual Battery Selector Switch 1-2-BOTH, 175 A / 300 A, 134×134 mm

This marine rotary battery selector switch allows you to easily control the power from two separate batteries on board. It enables you to switch between Battery 1 and Battery 2, run them in parallel (“Both”) when you need maximum power (for example, engine starting or emergency), or completely shut off the power (“Off”) for safety. This makes it extremely useful for yachts and powerboats with dual battery banks, as well as RVs or solar setups using two batteries.

Key features:

• Dual Battery Management: The clearly labeled positions “1”, “2”, “Both” and “Off” give you full flexibility. For instance, you might use Battery 1 for engine starting, Battery 2 for running accessories while at anchor, and the “Both” position in an emergency when you need extra cranking power or want to charge both batteries simultaneously from the alternator.

• High Current Capacity: Rated at 175 A continuous, this switch can handle the steady electrical loads of your vessel (lighting, navigation systems, refrigerators, etc.). The 300 A peak capacity means it can safely withstand the high current surge of engine start or other short-term heavy loads without overheating or damage.

• Make-Before-Break Design: The switch is engineered so that when turning the knob through to the “Both” setting, one battery connection is not disconnected until the other is engaged. This prevents any loss of power to sensitive equipment (navigation electronics, radios, fishfinders) during switching. It also eliminates sudden voltage spikes that could potentially harm your electronics.

• Rugged and Durable: The housing, measuring 140×140 mm, is made of impact-resistant, UV-stabilized plastic. That means this battery switch can be mounted in exposed locations on your console or engine compartment without worry of corrosion or cracking. The large rotary knob is ergonomic and easy to turn, even with wet hands or gloves on.

• Installation and Use: The switch can be mounted on a flat surface (dashboard or bulkhead) or semi-flush, depending on your preference. All necessary mounting screws are included. The back of the unit features heavy-duty copper studs for Battery 1, Battery 2, and a common output to your loads. Wiring is straightforward – simply connect your battery cables to the labeled studs and secure them with the provided nuts (using appropriately sized lugs and cables for the current). Ensure all connections are tight to minimize contact resistance. For added safety, you may pair this switch with proper fuses or circuit breakers on each battery lead as required by marine standards.

With this dual battery master switch, you gain superior control over your vessel’s power distribution. You can easily isolate the electrical system when leaving the boat unattended (preventing battery drain and reducing fire risk), and you can manage backup power sources with a twist of the knob. This device is also a critical safety component – in an emergency it allows you to combine batteries for engine starting, and in everyday use it helps extend your batteries’ life by letting you utilize them efficiently. Rely on this rugged selector switch to provide dependable power management on board in every scenario.