A couple of years ago, my brand new
B2630 had a leaky battery. At 50 hours, the radiator and all the hydraulic cooling lines had all the paint eaten away. Battery tray severely corroded. I disassembled the whole mess, cleaned, repainted and replaced the battery with an Optima sealed battery. Two years later, no problems. Couldn't be happier. I don't know if these little tractors overcharge the batteries or if it's just the bouncing around, but the problem is fairly common. John Deere sells a battery box to contain their leaks - terrible 'fix' in my opinion.
You can find other sealed batteries besides the Optimas as well. My Optima was purchased on Amazon.com for $141.00. You can ship these batteries as they are sealed.