Topeak's new 1W LED commuter light is powered by three AA batteries, which offer a decent run time at full power, and with the light set at half power the run time doubles.
The illumination at that level is easily enough for pretty much all urban riding. It doesn’t offer much peripheral lighting but was still powerful enough for completely unlit routes, though we wouldn’t really recommend it if you do much of this.
Ideally, we’d back the WhiteLite up with a small ﬂashing LED for the best of both worlds. An alternative version with a built-in rechargeable battery is available for a ﬁver more.