I've been doing a lot of research and work toward developing a solid way of keeping plugged-in while away from home, and have now acquired a pretty substantial quantity of electricity-producing devices, and I'd like to see what the differences are between each device.
Until now, I've been relying upon an AXA HR Traction coupled with a Lightcharge for producing DC power (via USB) while touring, but wanting to do a little more touring, I've begun the process of upgrading to instead use a Shimano Alfine Dynamo Hub (DH-S501) coupled with a B&M E-WERK.
For producing AC current:
For converting the AC current into DC:
- Measured various devices connected to both the B&M E-WERK and the
Lightcharge using the AXA HR Traction as a power source.
- As expected, the Lightcharge is current limited at 250mA.
- Unfortunately, I wasn't able to get more than 180mA out of the E-WERK, and I'm not precisely sure why.
- In an attempt at isolating what might be causing the E-WERK to produce
less current than I had expected -- I had thought maybe it might be
able to produce a full amp if I pedaled hard enough -- I recruited TJ
to use his Oscilliscope to make a few observations regarding both the
AC power source and each of the DC power converter outputs.
- The Dynamo itself produces a square-like wave, and as I pedal faster, the frequency increases.
- The Ligtcharge produces 5v almost instantaneously when I begin pedaling, and the current dissipates immediately.
- The E-WERK produces 5v almost instantaneously, too, when I begin pedaling, but the current takes quite a while to dissipate.
- In an attempt at getting an idea of how much current I will be able to expect to draw from the E-WERK, TJ has suggested that we eliminate the dynamo from consideration, and instead utilize his function generator to produce a predictable power source.
- He has also suggested that we may be able to calculate the maximum theoretical amperage by attaching a "load box" to the dynamo.