Fresh back from a ride - this (out-of-focus) photo shows the lamp mounted on the bar with the 8 AA cell holder, under the stem, in a neoprene mobile phone case that I got from Tesco (about £4). The case has just enough stretch to fit around the 8 cell holder and also has enough length to take a 10 cell holder with no problem. I added my emergency backup PP3 into the bottom and wired the two batteries through a locking DPDT toggle switch so I can select which battery to run from. A SPDT toggle acts as a power switch.
I can run the light for over 4 hours and then instantly switch over to the reserve for at least another hour of full intensity light - even without having to stop. I've got at least 6 hours of useable light!
I tried riding flat-out to see if there was enough light to reach into the gloom; I got tired before finding anything lurking in the shadows. On downhill, super-fast stuff it might not be enough though.
The light body never got more than slightly warm.
I've made a small light controller, bar mounted, providing a remote button, mode selection and indication and a battery level bargraph with two stage warnings. See a description of the functions here.
My latest constant current driver and controller. More details to follow (it’s nearly 2 a.m. and I’ve got work in the morning!).
