HI everyone, here is some hardware info on modding the Kemo M172n USB dynamo charger, its largish but quite a cheap USB charger made in germany, that I have modded to 930mA output...attached are some pics of how its done...

Basically I removed the switch at top, or if your careful, you can, once switch is loose up top, clip the 3 switch terminals, and re-use that switch...however, you need to bridge the contacts left on the main board, (left by switch) so the its allways in USB mode...so bridge center contact to right contact of switch (at board level)....now its always in USB mode, we simply are adding a 'booster cap',(50v 100uf bipolar) IN SERIES with the input...as per circuit diagram...the main switch now offers the boost cap, or bypass the boost cap to offer 500mA or 930mA @5v USB output,. from any Shimano, SON or SP hub. Questions are fine...

if you want a OFF, in the mix just use a SPDT switch w center OFF...

Kemo M172n USB dynamo charger modding-kemo-booster.jpgKemo M172n USB dynamo charger modding-2014-02-13-11.52.55-1-.jpg