Turbo is not a specific number of lumens; it is direct drive. Brightness is determined by where the LED’s forward voltage curve meets the battery’s discharge curve. And, at only 2.9V, it won’t be very bright no matter what kind of battery is used. That is an empty battery pushing less voltage than the emitter wants.
According to Texas_Ace’s testing, it would max out at less than 230 lumens per emitter at 2.9V, even if the battery was capable of pushing a thousand Amps.