Lead Acid Aircraft Battery Maintenance & Charging

March 2021

All aircraft batteries, regardless of whether they're a ni-cad, lead acid or lithium, will require maintenance at some point and time. That maintenance may come in the form of an Open Circuit voltage (OCV) check, periodic check, capacity test or various other inspection criteria. It is important to perform these maintenance checks at the required intervals and as instructed in the prescribed maintenance instructions.

Sulfating in lead acid batteries is a condition in which hardened sulfate builds up on the plates of the battery. The condition is usually caused by leaving a battery in a discharged state for a period of time or improper charging procedures that do not charge the battery to a 100% state.

When charging a battery, you first need to know the type of battery and the type of charging required. Some batteries require a constant voltage while others require a constant current. If you employ the wrong type of charge to a battery it can damage the battery or even worse, it could cause damage to the aircraft and/or bodily harm.

Some sulfated batteries can be reclaimed while others will need to be replaced. A quick check of the open current voltage following a charge can determine, to a certain extent, the level of hardened sulfate in the battery. For example, after a charge, a 12-volt aircraft battery OCV would read above 12.7 volts. If it reads 12.5 one could assume that the battery has minor sulfating, but if it reads 12 volts then sulfate has definitely become a factor in performance and battery life.

Ensure you are using the proper charging technique. Follow required inspection intervals and try to never leave a battery in a discharged state for any period of time. A battery left in a discharged state, or if it is deeply discharged, should be subjected to a capacity test. Most battery manufacturers will not grant warranty for batteries that have been sulfated, so following these procedures will increase battery life and keep the battery within warranty consideration.

All of our MRO locations in Battle Creek, MI; Lincoln, NE; and Provo, UT; as well as many of our Satellites locations have battery testing capabilities.

Call a Duncan Aviation Component Customer Account Rep at 800.228.4277 or your local Satellite location to schedule battery service.