October 20, 2004 Digger posted: If you want a high CCA battery that will fit under the seat, get one for a mazda miata or a dry cell battery for an airplane, like a Cessna.
That same day, the late Tom Kelley wrote: Get some measurements and look for a small auto battery. More power, much cheaper, longer warrantry, and lastly,,,much less in price. I have Two Gravely riders with automotive batteries. One from 1997 and one 1998 and act like new. I can run for hours with the charging system not working as well. with manual PTO and with lights on..
Another post that day from pullingtractor: Go to Wal-Mart & buy one of their 350 or 375 cold cranking amp garden tractor batteries. They seem to hold up very well in a garden tractor.
So, after buying $45 garden tractor batteries at the auto parts that had a three month warranty, in May of 2014 I bought a Miata battery plus the post conversion to flat cables. As the voltage regulator does not work, every two-three months my wife puts it on the charger. The only maintenance it gets is cleaning terminals and the top of the battery. A BIG thank you to Digger for the suggestion;-)