My Bike and Lighting System

I don't care for riding around in the dark, and I don't care for things that don't work right. So my bike choice for around-town riding is a Schwinn Homegrown limited edition. I think it's from around 2002 or somewhere around there. All Shimano XTR parts, and I keep it that way - it weighs in at an astounding 9.5 kilograms (21 pounds), and it's a pleasure to ride. It's not that much heavier than a 10-speed (but much more rugged to withstand winter-climate roads), and lighter than most any other mountain bike I've tried.

As for my lighting system, I could have DIY'ed the whole thing but I didn't. I bought a set of lights from Mountain Equipment Co-op, but I don't recall the brand. It used a 12V lead-acid gel cell in a water bottle, and three MR11-20W-10degree spotlamps in rather nice enclosures. But the lead-acid battery died, and I don't like those very much. What do I use instead? a LiteStorm LiPo model aircraft battery, 5000mA*h, 4S or 14.8V. A problem with this type of battery is that it starts at about 18V and slowly drops down to about 12V. The MR11's don't last that long at 18V. My solution is a small power supply made with an LM5115A buck regulator control IC. I just used their evaluation board and changed out a few parts on it - I had the board and had no use to evaluate it for anything I do at work right now, though we use the LM5574 with its built-in power switch. Anyways, I set up this board for a 11.5 volt output, which should keep the lights from burning out. I also changed one of the 20 watt spots to a 35 watt spot as a 'high beam'. The eval board does not have enough heatsink or MOSFET to run the high-beam all of the time, so when I get a chance to do some PC boards, I'll do a version of the board with a bigger MOSFET, as well as reverse polarity detection, and low-voltage warning for the LiPo battery. I use a HyperIon 610i battery charger for all of my small battery charging needs - my LiPo's, gel-cells, and even the 24V lead battery pack for my garden tiller. It's a great charger!

Christmas wish list? Zanier heated gloves and shoes with lithium battery packs.

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