Instructables
Picture of Kemo M172n USB charger hacking
kemomod.jpg
kemo booster.jpg
Hey got 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...

So when testing it was sometimes hard to find a 'load' to charge that pulls over 900mA....if you plug in your half charge iphone for testing it won't pull 900mA, so some may think the mod don't work...don't' get caught by this...use your meter to test your load pulls at least 1A...then you will have a correct test to see if you can get 930mA....as allways guys, its power, so stay away if you don't know what your doing...

green thing is a switch unit for LIGHTS or CHARGER, and connects to the Dynamo hub

enjoy
craftclarity5 months ago
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