In October of 2002, I bought the Light and Motion ARC light. It's an HID light. I wrote a review then:
http://www.bikeforums.net/showthread...&highlight=HID
Last October, October 2004, I posted a two-year review of the light:
http://www.bikeforums.net/showthread.php?t=68678
There have since been some further developments in my light's career, so I thought I'd post them.
The battery finally crapped out last week. It was the battery that came with the light. I'd estimate the battery went through n>300 charge cycles, with anywhere between three-hundred something and five hundred hours of use. L&M claim that the battery is good for 500 charge cycles, but mine certainly didn't get that far.
I had noticed a drop off in the run times this winter. I would get no more than about 1:30 from the battery when it was fully charged. That's about half of its expected performance. I might have thought it was the cold weather that was sapping the battery, but I'd been through two winters with the battery previously and never saw the cold hamper the battery's performance nearly this much. Finally, the battery just gave out. It wouldn't start the lamp, and the charger didn't indicate any connection when it was plugged in to the battery. (I opened the battery pack, and the connections inside were still intact.)
I should add that I cared for the battery pretty well throughout its life. Only once did I leave it on the charger too long. L&M's charger does have an automatic shutoff, but even with that feature it's not recommended that the battery remain connected for more than fourteen hours straight. Only once did I run afoul of this recommendation. I just forgot and left the battery on for about a day. It wasn't long after that that I noticed the performance degredation, so perhaps I accelerated the battery's decline.
Batteries give out, though. Two and-a-half years of regular use is about what I had hoped for from the battery when I bought the light, and that's what I got. In any event, the battery is well out of warranty.
I just went ahead and ordered another Ni-MH battery from L&M. The one I had was a water bottle cage model. Those are no more, and now the only batteries L&M sells are smaller, top-tube mounted versions. That's just fine with me. It's nice to have the water bottle cages back. The new battery holder and strap are well designed, by the standards of these things. The replacement was about $100, plus shipping.
Another option was to buy a longer burning lithium battery. The thing is impressive-- it's supposed to give *six hours* of burn time, according to L&M. That lithium battery was more expensive than than the Ni-MH battery, of course, but on top of that I would have had to buy a new charger, too. The total for both things-- even given L&M's ongoing discount for battery and charger upgrades-- would have been well over $200. That wasn't worth doing for a lamp that's probably somewhere near halfway through its working life. I don't need more than three hours of light for my night riding, anyway.
While I was waiting for the new battery, I didn't have an HID light. That was for about three days, but those were three demoralizing days. I hate my pathetic, flickering, halogen backup lighting.
I ride at night on completely dark rural roads. There is a fair amount of crap that finds its way onto those roads. It was frustrating not to have the road bathed in the brilliant blue-white light.
Even worse, I had forgotten how much contempt a cyclist with halogen lights inspires around here. Oncoming motorists would see the light, but they would not turn down their high beams. Just some guy on a bike, after all. They always turn down their high beams when I've got the HID light on. There are various interpretations of this difference in behavior, none of them flattering to the drivers, but rather than delve into them, I'll just focus on the fact that I've got a working HID light back and these problems are not mine anymore.
I'm still happy with the light. HID makes night riding into an entirely new activity. If I can get another two and-a-half years out of this new battery and the original lamp, I would consider the purchase of this light an excellent value. As it is, I think it's worth it for HID lighting for anyone who rides a lot at night.