Battery failure is the single most frequent service call for generator malfunction. Eighty percent of all battery failure is related to sulfation build-up, which is the accumulation of lead sulfates on the plates of lead-acid batteries. Build-up may occur when the sulfur molecules in the electrolyte (battery acid) become so severely discharged that they begin to coat the battery's lead plates. When enough plate area has sulfated, the battery cannot provide enough current and will most likely need replacement.
Common causes for sulfation build-up:
- Battery failure is usually the result of low electrolyte levels - battery plates exposed to air will immediately sulfate.
- Batteries that are always on a charge use water. Today's newer maintenance-free batteries allow water to condensate and refill their cells. As soon as the plates are exposed, the battery is useless.
- Battery cells are shorted when sedimentary trays fill up with lead debris. This can be avoided if batteries are replaced every three years.
- Frequently, battery failure is due to the charger breaker being open or tripped; most often this is the result of human error rather than actual charger failure. It usually occurs after service, or some type of maintenance, in which the charger has been turned off and is not turned back on again when the service is completed. The unit's various alarms should catch this error before an attempt is even made to start the generator, but it's important to always double check a generator system after any service or maintenance to make sure that everything is in proper functioning order.
Battery maintenance is an important issue that could be as simple as cleaning and tightening cable connections on a regular basis. Although battery charger failures are difficult to prevent and cannot be accurately predicted, monitoring the charge rates from month to month will establish a trend that can help map the potential for failure. A properly functioning battery charger will have a constant charge rate for any given system. An increase of amperage may show signs of malfunction of either the battery or charger. Any sudden change in the charge rate for no apparent reason is cause to investigate the charging system.