Minelab Li-Ion Battery GPX 4800 , 5000 and earlier 4000 and 4500 models GPX4800 GPX5000 GPX4000 GPX4500 3011-0227 Old Batteries can have High Self-discharge, Shorted Cell Life, & Loss of Electrolytes Old batteries run the risk of leaking, over-heating, catching on fire, and possible explosion. A new battery means more stable power  More power will help your GPX run smother and better with stoner hits, and less false positives. A new battery will last longer, allowing you to go further. Are you sick of quitting to soon because your battery won't last the day? 100%  Money Back  Guarantee