I have some bar end lights like these but the batteries only seem to last about 10 hours (a weeks worth of riding) and it is getting expensive at $8 a time (4 batteries) to replace them. The above website seems to claim 100 hours battery life - in your dreams I say. I only use them on flashing mode not steady. I think the complete units with batteries already installed only cost about $10 from PBK on sale. Any ideas for longer battery life?