The fastest way to ruin a battery is to let it sit and do nothing.
If you let a lead acid battery sit for long without trickle charging, or charging, it can become sulfated between the plates which short circuits 1 or more cells.
So to answer your question:
Batteries can destroy themselves in short order if you do not trickle charge them occasionally.
BTW. You should be using a 12 Volt 7.5 Amp Battery at minimum.
Read this link and you will be an expert.
http://www.batterystuff.com/tutorial_battery.html