At the heart of all well-conceived marine electrical power systems is a good selection of switches, wire conductors and connectors, and wire distribution points and other accessories.
STYLES
Battery switches come in several different styles:
1-2-BOTH-OFF switches are the most common switches used when there are two "house" banks present.
- Electrical loads and charging sources are usually wired to the common terminal on this type of battery switch
- The house banks are wired so the operator can choose which bank is supplying electrical load or receiving charging current: bank 1, bank 2, or both banks temporarily acting like one large bank.
- The alternator charging current can also be wired directly to the house banks through isolating diodes. In this case the battery switch is used only for selecting which bank supplies the loads.
- The OFF position disconnects all batteries from the loads and charging sources.
- Some 1-2-BOTH-OFF battery switches have an Alternator Field Disconnect (AFD) feature that helps prevent alternator damage if the switch is operated while the engine is running.
ON-OFF heavy-duty battery switches serve as main disconnects when there is one main house bank.
- All loads and charging sources feed directly into that bank. This is a much less complicated setup, since the operator doesn't have to keep track of which battery was last used or for what purpose (supplying loads or being charged).
- If additional banks are used for specific heavy-duty loads such as large inverters or windlasses, they are typically charged through a battery combiner or link device, which joins all banks temporarily under the influence of a charge.
- If one or more batteries are used strictly for engine or generator starting, a better alternative to a combiner is an "echo-charge" device from Heart Interface that simply trickles the right amount of charge current from house bank to starter bank(s) as needed.
- ON-OFF battery switches can also be used to disconnect or isolate starting batteries and a variety of heavy DC loads on board, including windlasses, power winches, engine starter motors, inverters, and battery chargers.
- Some ON-OFF switches come with a removable key to avoid inadvertently disconnecting the circuit.
|
TIPS
Switches should be able to handle the maximum amount of current in a circuit.
For house battery banks and starting bank applications, look for a switch with a 300-amp rating.
Light-duty switches can be used for disconnecting appliance loads.
Heavy-duty DC circuit breakers are an alternative to using battery switches as disconnects, since they offer circuit disconnect and over-current protection in a single device.
Heavy-duty circuit breakers with a 3,000 amp Interrupt Rating (AIC) are not appropriate for systems with total connected battery CCA (cold cranking amps) over 1,100.
INSTALLATION
Fundamentals of DC electrical systems and a complete electrical toolbox are required for battery switch installations.
Toolbox
- Tin-plated wire
- Heavy-duty terminal connectors or pre-made battery cables for each battery bank
- Drill and bits
- Screwdriver
- Bolts, nuts, and washers
- Soldering iron or compact butane torch if required for connectors
- Multi-meter
- Wire ties or clips
View products
Linear Mode
