What indicates that maintenance-free batteries require a condition check?

Maintenance-free batteries are designed to operate without regular electrolyte checks or top-ups, as they are sealed and may not have accessible fluid levels. However, they can still experience issues that require attention.

When it comes to condition checks for these batteries, a built-in hydrometer alert plays a crucial role. A built-in hydrometer is a device that can provide an indication of the battery's state of charge by measuring the specific gravity of the electrolyte. An alert from this hydrometer can signal if the battery is discharging and may indicate that a condition check is needed. This proactive measure helps maintain the performance and longevity of the battery, preventing potential failures during operation.

Other indicators such as low electrolyte levels, high voltage readings, or corroded terminals do not directly relate to maintenance-free batteries in the same way. Low electrolyte levels would typically indicate a standard battery needing maintenance, high voltage readings may not relate to battery condition directly, and while corroded terminals can affect functionality, they do not serve as an indicator specifically for condition checks of maintenance-free batteries.