Bisun - making a range of LED lighting systems for cavers.
Complete twin-beam caving lights and drop-in upgrades.
Bright spot beams for Duos. Dive and Photo lighting.

Flexitwin V5 miscellaneous stuff


The normal operation of the Flexitwin achieves power control by PWM control (rapidly turning the LEDs on and off), This may cause triggering of photographic slave units.
If light is desired for use in the vicinity of photographic slaves, the backup low power flood beam the Flexitwin produces after having the power switch down for more than 2 seconds does not flicker, and should be slave-safe.

Redundant electronics

As is typical of Bisun lights, wherever it is practical there is redundancy in the electronics, for maximum peace of mind.
In the case of the Flexitwin, this takes the form of the flood LED being powered at a pilot level by additional circuitry whenever the control switch is down.
This is why the flood LED increases in power a little whenever the switch is blipped downwards to change power levels. It is also why there is a 'pre-off' pilot setting when the switch is left down for more than 2s - at that point, the main circuitry is already off, and the flood LED is being powered solely by the extra electronics.


Configuration of the Flexitwin into various modes and power ranges is simple, though it requires access to the Flexitiwn unit by opening the headset. In reality it is unlikely that most people will reconfigure the unit at all, and those who might do will likely only do so once or twice. Making reconfiguration an open-headset operation does means that the unit can't be accidentally reconfigured by someone just playing with it.

Thermal Limiting

The Flexitwin has thermal limiting to keep the unit at a sensible temperature even if operated at full power in warm conditions, or if insulated inside a bag, etc. This limiting is subtle in nature, gently reducing the power from the chosen level if the temperature approaches the limit, and gently increasing it again if conditions change and the unit cools down.
Even if the thermal limiting does engage, it is unlikely to be noticed by the user.