I finally got around to improving my bike lighting solution.  I've been using a Nite Rider Trail Rat 1.0 (only the 2.0 is on their site) for several years.  The system had a 6V lead acid battery with a 10W halogen bulb and would no longer run for the duration of my commute one way (just over an hour each way).  That resulted in having to turn it off as much as possible to conserve power for when it was really needed for visibility or to be seen by traffic as well as lugging the recharger in my pocket or pack.   I have a light mounted on my helmet as well that I would rely on when in battery conservation mode but its function is more to help traffic see me than help me see where I'm going.

After an unexpected encounter with a fallen tree on a downhill, I decided it was time to upgrade my light.

I looked around at HID lights and other halogen systems.  The $200-$500 price range for the higher end solutions just didn't tip the value scale the right way for me.  Since the problem I was out to solve was battery life, I hunted around for something I could just use as a replacement for my lead acid battery.

I found a Li-Ion battery that has more capacity, is smaller and weighs about 1/5 as much as the lead acid battery for about $55 including the charger.  It came with a variety of adapters that let me plug it in directly to the existing light.  The first couple of times I used it I also carried the lead acid battery in my back pack as a spare.  I'm able to run the Li-Ion continously for each leg of my commute without having to recharge it.  The lead acid battery now has a comfy spot on a shelf in my garage.  Sort of funny that BatterySpace.com sometimes compares batteries for bike lights to the size of a pack of cigarettes as at the bottom of this page.

The Nite Rider Trail Rat has held up really well for me.  Next time I'll likely investigate using the housing and battery and see if I can replace the bulb with a HID bulb.  The HID bulbs alone are about $70 today and will undoubtebly drain the battery more quickly which will lead to the next round of upgrades.