Definition
A battery charger that delivers a low, steady current — just enough to keep a fully charged battery topped up by replacing the small amount of charge lost to natural self-discharge, without overcharging or overheating the battery.
Plain English
A charger that feeds a battery a small, slow current to keep it full when the aircraft isn't being flown, rather than recharging a flat battery quickly.
Context Anchor
Seen in aircraft storage, hangar maintenance, and battery-care instructions when an airplane will sit unused for a period of time.
Derivation
From 'trickle,' meaning a slow, thin flow of liquid. The charger delivers electricity in the same way — a thin, steady flow rather than a strong rush.
Why Pilots Care
Maintains battery health during storage, prevents sulfation, and ensures reliable engine starts after long periods on the ground.
Intuition Check
Do not read “trickle charger” as just any battery charger. It means a low-rate charger for maintaining charge over time, not a fast way to recover a dead battery.
Example Sentence 1
Before leaving the aircraft hangared for the winter, the owner connected a trickle charger to keep the battery from going flat.
Example Sentence 2
A trickle charger kept the battery voltage steady while the airplane sat unused in the hangar for two weeks.