A trickle charger is a device that is used to slowly charge batteries over a prolonged period of time. Some synonyms for trickle charger include battery maintainer, float charger, slow charger, and low current charger. These devices are useful for keeping batteries fully charged and ready for use, particularly for long-term storage. Trickle chargers are commonly used to maintain the charge of cars, boats, motorcycles, and other vehicles and equipment that may be in storage for extended periods of time. With an array of options available, choosing the best synonym for trickle charger will depend on the specific use case and the capacity of the battery being charged.