I had posted this elsewhere and it applies here. we were discussing whether to use a second battery a backup or as an auxillary. I'm not getting into that discussion now, but I directly compared a Odyssey and Optima. Personally, I run a Odyssey 1200 as my main and the same as a backup with a
HellRoaring isolator
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Taking a closer look, let's compare the Optima Yellow top 34/78 with the Odyssey 1500 34/78
The Odyssey is not rated as a "deep discharge" yet has a longer reserve and more cold cranking amps than the Optima.
The Odyssey has 62 amp hours vs. 55ah, 135 minutes of reserve vs. 120 minutes and has 880 cold cranking amps (0 degrees F) vs. 750CCA. The Odyssey is ever so slightly smaller (not really, but .3 inches in width) but weighs 6 more lbs. Other than cost, which I think the Optima has an edge, I don't see any reason to go with the Yellow Top over the 1500 34/78. No need for a "deep discharge" battery when you can have both longer discharges and more CCA with the Odyssey.
Also, the Odyssey has a 6-8 year service life and shows some other stats on amount of discharges and battery life. The Optima doesn't have that info on their site.