[McGillicuddy]

All batteries are not the same! Even within Johnson controls who makes a huge number of brands at numerous price points, the quality ranges from top of the class to depths of Bowery gutters in bad times.

I also have group 27 Deka AGM, deep cycle for house and starting for starting. Bought them from a battery shop for nearly half of the West Marine price.

Thus far I've had better luck with AGM than gel, but I think the manufacture quality may have more to do w/that than the type.

If you have a newer motor you may have to go up to a Group 31 to get desired cranking amps (e.g., I think Optimaxes require at least 1000 cca).

I think a key to longevity of any battery is that it be used or charged regularly. Even Concorde and Rolls batteries will fail if they just sit...