The battery for the FJ80 is capable of several hundred full power flashes from a single charge. There are however a few things that can influence the total number of flashes.
To achieve a maximum number you should:
- Set the screen to level "1" (2 is the default) in the settings menu
- Use the FJ80 in speed light mode.
- Minimize use of the zoom feature
- Do not overheat the unit
- Power off the flash when not in use for an extended time.
- Do not use the Modeling lamp for an extended time.
- Use the FJ80 within normal sync speeds. HSS requires multiple rapid flashes at higher power levels and adds heat, both deplete battery life at a faster pace.
- Use Manual power settings. TTL adds a pre-flash which has a minimal effect on battery life.
For larger shoots, always have spare batteries on hand https://www.fjwestcott.com/fj80-lithium-polymer-battery