If a charger malfunctions, internal pressure can build up, causing the battery to swell and eventually crack the outer shell.

Cracks in these specialized AGM (Absorbed Glass Mat) batteries usually stem from one of three causes:

A cracked battery should never be ignored. Even if the device still powers on, the following risks are present:

Despite being designed for rugged environments, severe impacts or unsecured mounting can cause the polypropylene (PP) case to split.

In cold climates, a discharged battery’s electrolyte can freeze, expanding and cracking the case from the inside. Immediate Safety Risks

Damaged Lithium Ion Batteries: Storing & Shipping - Expert Advice