How to troubleshoot battery not holding charge?

Steps to diagnose batteries that won’t hold charge

When batteries lose capacity, the cause may be age, improper charging, or temperature stress. Identifying the root cause helps decide whether repair or replacement is needed.

Diagnostic checklist:

• Measure resting battery voltage and compare to rated values
• Check for bulging, leaks, or signs of physical damage
• Review charging profile from the controller to ensure proper voltage and settings
• Consider battery age and cycle count versus expected lifespan

If batteries are old or have been deeply cycled frequently, replacement is often the only option. For lithium batteries, ensure the battery management system is functioning. For lead-acid types, sulfation may reduce capacity and in some cases can be partially recovered with controlled conditioning, but this requires care.