I bought a NR Trinewt a year and a half ago for my 10 mile (each way) year 'round commute.
I went to plug the light in to the battery after it had sat for awhile, and it told me low battery. So the next week I brought home the charger from work and plugged it in. I go an error code that would not go away, and the battery wouldn't charge.
I took it to my LBS where I had bought it, and they sent it in to NR. NR looked at it, fixed it, and sent it back. $20 in shipping later, back in business. I'm not sure where this fell under their warranty, but they did not charge me anything.
A happy customer
P.S. I had ridden with my old light while it was in the shop. Was REALLY happy to get the better light back!