We have just designed the brand new D26-LED 3.7V Special that is specially designed for the 1 cell 3.7V rechargeable application.
This new module is very efficent and has a very constant output because it is specifically targeted for the said application. The maxmium output for this module is at 1200mA which even exceeds our already bright D26-LED 3.7V-13V module and it is much more efficent then the D26-LED when using the 1 cell 3.7V application. We even use the selected tint LEDs on everyone of them, so you wouldn't have to go through the "Tint Lottery".