Definition
A battery connected in parallel with the aircraft's electrical bus and generator (or alternator) so that under normal operating conditions the generator carries the entire electrical load and supplies a small, continuous charging current to the battery. The battery does not normally power the loads; it stays fully charged and is held ready to take over only if the generator fails.
Plain English
A battery wired into the system so that the generator does all the work during flight, while the battery just sits there topped up and ready as a backup.
Context Anchor
Seen in aircraft electrical system discussions, especially where the battery and generator or alternator are described as working together.
Derivation
The term comes from electrical engineering, where 'floating' a battery means letting it sit at a steady voltage on the line — essentially 'floating' on the bus voltage rather than actively discharging or being heavily charged. The image is of the battery resting on the system rather than working it.
Why Pilots Care
Keeps the battery at full capacity for engine starts and emergency power while avoiding overcharge damage.
Intuition Check
“Floated” does not mean the battery is loose, suspended, or physically floating. Here it means the battery is connected and kept ready while another source normally carries the electrical load.
Example Sentence 1
Because the battery is floated across the bus, the generator handles all loads in flight while the battery stays topped up.
Example Sentence 2
With the battery floated, the ammeter shows little or no current flow under normal conditions.