On 6/7/06, Gerhard Fiedler wrote: > Jinx wrote: > > http://home.clear.net.nz/pages/joecolquitt/luxeon_lamp.gif > > Is there a purpose in the fuse F2 being between one cell and the other > three? It looks purposeful, but I can't really see one. > > Gerhard Thermal fuses in rechargable battery packs are wired this way. Rechargable battery packs (that I've seen for nimh and nicd) don't typically have current fuses, since you may need to pull several amps from a pack. Li-Ion packs usually have several forms of protection since overcurrent conditions can result in a volatile situation immediately. NiCad and NiMH are much more tolerant to over current conditions. Still, the thermal fuse acts as a slow current fuse since drawing too much current (or charging too much) for too long will overheat the pack and open the fuse. By placing it between two batteries in the schematic it is explicit that it be placed in the pack rather than relegated to a seperate board where it would be ineffective. The fuse is marked as a current fuse though, so I too am curious about the designer's intent. Either they knew a fuse of some sort went inbetween the cells, and picked a current fuse suitable for their project, or they aren't specifying that the fuse is also a thermal fuse. If it only reacts to current, then it doesn't need to be inbetween the cells. -Adam -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist