So do I understand correctly that with an 18650 at the highest brightness mode (965 lumens), after 200 seconds the light automatically shuts down to 965 x 75% = 724 lumens and that's all you get?
You have to turn it off then on to reset the timer, which may be a pain every 200 seconds.
No that is incorrect.
You only need to the press the button to reset the 200 second timer.
The light will continue to stay in Turbo without turning off.
You do not have to turn it off and then on.
However, you can disable the step-down from 25% to 10%.
"Enabled by default, this feature reduces output by 25% or 10% when disabled after 200 seconds at turbo mode."
Also:
"Low dropout voltage, enable circuit to current regulate even with a single 18650 for most of the runtime at turbo output."
http://www.eagletac.com/html/tx25c2/specs.html
I was thinking of getting this for a bike light but that's a real bummer. If you go for a half-hour bike ride, the light is really only good for 724 lumens. So IO guess there no way to may it stay on 965 lumens continuously?
The TX25C2 is a very compact thrower.
It is small enough to fit in you pocket.
It is not intended to stay in Turbo for an extended period of time.
But without the extra mass to wick away the heat from the LED,
it cannot stay very bright without getting the LED too hot.
If you want a light to stay at 1000 lumens for 30 minutes,
the light will need to be much bigger mass in order to handle all the extra heat.
It will also need to have several 18650 batteries to maintain that much brightness.
This would be a fairly large bike light.
The Nitecore Tiny Monster series comes to mind.
The very idea of Turbo is a brief temporary extra burst of brightness.
Turbo is not meant to run continuously.
Hi mode is meant to be run continuously.
So you are look for a light that can do 1000 lumens for 30 minutes on Hi mode.
See the dotted purple line of the TX25C2 Turbo 'No Step".
It only stays at 965 lumens for a few minutes.
The battery cannot maintain that much brightness for very long.
It will continue to dim as the battery is drained.
Most 1x18650 lights have this same type of diminishing runtime curve at Turbo.