Join Date: Mar 2007
Location: New England
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Battery Question Number 92,457
My batteries are nearing their end. I want to replace them and I am frugal. I don't do extended cruising, mostly day sails with a couple of overnights each year. I am never really more than a few hours from land and don't run a lot of electronics.
Typically I run a GPS, wind indicator and depth meter when sailing. I do have auto pilot, a VHS, and Radar, but seldom turn them on.
My current batteries are Nautilus (Deep Cycle) that are 4 and 5 years old. The 5 year old battery has about 1 h of time for a simple car stereo. Even with repeated chargeing, it often won't start my motor. The other battery seems to be okay and has sufficient power to start my motor (Yanmar Diesel 3GM30) and run the electronic gizmos for a couple of hours.
I looked at a variety of batteries based on advice here on Sailnet. Since I am frugal, I thought a Seavolt Deep Cycle Group 27 with the following specs.
Group 27, 80 Ah, 745 MCA, 150 Res. Min.,
Or a Sears Diehard Marine:
Cold Cranking Amps (CCA at 0 deg.F): 575
Reserve Capacity (RC): 180 min.
Amp Hours at 20 Hour Rate: 105
The Diehard is $20 less than the Seavolt. ($119 vs $99)
I looked for other batteries in Walmart, NAPA, Pep Boys, etc., but could not find any that were suitable.
The Diehard has fewer CCA than the current batteries and the Seavolt, but a longer Reserve Capacity and more amp hours. The number of CCA needed to start the Yanmar is about 90 or so, so 575 is still 5X that number.