I don't have much experience with gel batteries. I wonder if they can better tollerate the bouncing and vibration that Bobcat's dish out compared to lead plate batteries. As far as your problem of you machine sitting for a long period of time, I don't see how there would be a big difference in the batteries. If you typical lead plate battery discharged over this long sitting period, it's seems a gel battery would as well. Maybe you have a current draw of milliamps from the ECU that discharges the battery. Try installing a battery disconnect switch near the battery so you can just disconnect it when not in use. I've also seen 12V solar chargers you can put on your machine that keeps the battery charged up. Just some options.