Technical article from Blue Sea Systems
October 8, 2007
Using a remote battery switch instead of a mechanical battery switch can result in increased safety and convenience, and significant reduction in cost, weight, and voltage drop. A remote battery switch is installed as close as possible to battery banks, and is operated by a low-current control switch in a convenient location.
Advantages of installing a remote battery switch close to battery source:
- Increased safety-Battery switch activation at a safe distance away from a likely source of fire, high current wires routed distances through bulkheads, etc. is reduced.
- Reduced cost-Save the expense of large diameter wire runs over long distances. In addition, when wire length is reduced, wire gauge also can be reduced. For example, a two engine, two battery bank configuration has four 20 foot runs of 4/0 wire (2 for each isolated circuit). Two remote battery switches are installed reducing the four runs to 5 feet each. When the short-run wire is chosen for the same voltage drop as the original long-run wire, the wire can be reduced to 2 gauge. The cost of the long run 4/0 wire is: 80 ft x $20.29 = $1623.20; the cost of the 2 gauge wire is: 20 ft x $5.99 = $119.80; resulting in a cost savings at retail prices of $1503.40.
- Reduced weight-Save the weight of large diameter wire runs over long distance, for example, 4/0 wire weighs approximately 0.9lbs/foot
- Lower voltage drop-When high current is not being carried over long distances, there is considerably less voltage drop in the system.
- Added convenience-Switch battery banks from a more convenient location. When a battery switch is placed near the engine and battery, it may be in the engine compartment accessible through a hatch. It is more convenient and intuitive to place a control switch near other electrical controls or the companionway.
When choosing a high-current remote battery switch, look for these features:
- Continuous and intermittent current rating suitable for the application
- Ability to switch under high current load
- Manual ON/OFF-added level of safety by allowing control with or without power
- Safety lockout capability for servicing downstream circuits
- Local and remote indication of contact position (per ABYC - UL 1107)
- Water ingress protection-enables operation in harsh environments
- Ignition protection-enables operation in a gasoline engine room
- Only draws current when changing the state of the switch; no current is used to hold the contacts in place
- G-force resistance-withstands high-shock loading so contacts maintain position in the roughest seas
Original article from Blue Sea Systems