One of our readers, KTronik left a comment on the Shimano Dynamo Hub report we posted.
FYI…
I have found a way to get up to 12.8w from the shimano / SON dynamo hub, using a series cap before the t
normally the hub, wants to give 500ma @ all speed by changing the voltage…by holding the voltage low (series cap), the current rises
using a 100uf Bi-polar cap in series before the bridge ref I get:
7km/hr=8.47v @ 50ma
15km/hr=9.44v @ 250ma
23km/hr=10.24 @ 610mq
27.5km/hr=10.62 @ 910ma
37km/hr=10.14 @ 630ma
using a 200uf bi-polar cap in series before the bridge ref I get: (same speeds as above)
100ma, 480ma, 18km/hr peak @ 660ma, then 600ma @ 24km/hr, I use this curve for off road racing & the 100uf curve for on road commute…
I bigger the cap the more boost down low amp; the less peak power…
You can mix 2 different curves together, or even mix in a voltage doubler for up to 75ma @ 4km/hr, 100ma @ 5km/hr & 200ma @ 7km/hr…
So a lot can be done just by using a series cap before the bridge ref…
The dynamo hub could be used for powering equipment in the day…maybe use a LM7805 to give USB power…GPS, MP3, phone charging, etc.
You also could use the circuit to charge battery’s amp; run your stuff off that, that way when you stopped your GPS wouldn’t turn off… & yes you would have a little switch box on your bar to select the different riding curves / low speed boost or battery charging…
all this can work… amp; its all very easy to do…
I been testing this circuit with both Shimano amp; SON hubs, for about 2 years… not one problem…now that the new breed of LEDs are out, it makes sense to dynamo it up!! my dynamo light is now as bright as a HID (on paper)
BTW the cree LED is a better bet rather than the SSC p4… it has less colour shift when over driven & less colour shift over time…the seoul is also a more floody type of beam…
I use the SSC P4 of off-road racing using the 200uf curve (peak 660ma)& the cree on-road with the 100uf curve (peak 910ma)…
I have full data for DIYers if needed… just drop me a EMAIL…
best
Ktronik
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