Topic 14 - Power supply
Fish finders and other electronics need electricity to function. On boats electricity is supplied from the batteries installed in the battery compartment. Excluding special super compact fish finders, most fish finders use DC 12-24 volt power supply. As long as the voltage is between 12 and 24 volt, the fish finder unit will function properly. For exact details please look up the respective product information sheet regarding your fish finder. Smaller boats will usually come installed with one DC 12 volt battery, for boats with two DC batteries in a serial connection 24 volt can be used.
The battery is connected to the main switchboard, and the power cable from the fish finder is connected to the same switchboard. A common practice is to install manual switches on the power cable in order to turn on or off the power to the fish finder unit quickly. It is important to remember to first turn off the fish finder unit before cutting the power, in order to avoid malfunctions. For vessels utilizing 24 volt batteries, the fish finder should always be attached to the switchboard first.
The capacity of a battery is predetermined (capacity being how much charge it can deliver at a specific voltage). Larger batteries offer longer operational time versus smaller batteries that can only keep the fish finder active for a limited amount of time.
In order to know the capacity of the battery simply look at the packaging for “AH”, meaning “Ampere Hour”.
When connecting your fish finder to power, it is important to use separate batteries for the engine generator and the fish finder if possible. The reason for this is that there can be a lot of engine noise interfering with the signal to the fish finder. In order to avoid unnecessary noise and interference, it is advisable to install the power cable and transducer cable to the fish finder separately.