Today’s electronics have a bunch of horsepower and with that comes significantly increased power usage. While most depthfinders are efficient, additional bells and whistles such as “smart boxes” can put even the best batteries to the test. Add a Hydrowave, a plug-in to charge your phone, a hydraulic jackplate and some windy conditions and you can sap a starting battery in no time at all.
Many of the best anglers are now running two 12-volt, dual-purpose starting and deep cycle batteries in parallel; meaning positive-to-positive and negative-to-negative. This maintains a 12-volt system but increases longevity. Heavy-duty jumpers of 6 or 8-gauge are best for this application.
Some anglers in small boats are actually using 12-volt tractor or utility batteries with at least 300 cold cranking amps (CCA), also wired parallel. The more CCA the better.
These batteries take much less room in smaller boats than typical group 24 or 27 series batteries but give the battery used for cranking the big engine and electronics more sustainable power for a longer period of time. It is recommended matching the types of batteries like lead/acid or AGM for this use. Also, use heavy-gauge connections on the battery instead of clips like those found on motorcycle or utility vehicles.
Smaller tractor-style batteries won’t increase the weight much on smaller boats. Although onboard chargers to the starting battery will charge the extra battery, it may be more efficient to charge the extra battery independently.