This is one of the very few marine batteries I have replaced due to being chronically over charged. The owner of a center console placed an unregulated 15W solar panel on his T-Top and fed it directly to his East Penn/West Marine starting battery. About 9 weeks later the battery shorted internally due to crumbling plates and refused to start the vessel.


Look at the bottom of the battery case and notice how close the positive & negative plates are to the plastic. When the plates started crumbling, due to chronic over charging, brittle flaking lead fell to the bottom and created an internal short. The end cell, closest to you, was the shorted one.


On the left you can also see how brittle the lead grid/plates had become.