Optima Batteries - $224.99

Optima batteries provide more usable power, unequalled vibration resistance, and the cranking power needed to start all of today's largest boat engines. Advanced Spiralcell technology, made up of high purity lead plates wound with an electrolyte-absorbing glass mat, provides extremely high power and very low internal resistance. Compared to conventional batteries, they have up to two times the life and 15 times more vibration resistance. A low self-discharge rate means that when stored with a full charge, they can sit for a year and still start your boat. They also have a higher reserve capacity over time, are nonspillable, maintenance-free and can be charged in as little as one hour. All come with a 24-month warranty. D34M fits in a Group 24 battery box and D31M fits in a Group 27 battery box. - $224.99