E Werk, Revolution or Reactor

[Dave855]

Interesting points. Am I right in thinking that there is a difference in opinion here with regards to charging a cache battery from the E Werk?

Samuel, you mention "You can’t simply increase the voltage to charge a lithium-ion battery quicker."

Interestedcp you mention that with an E Werk "the faster you go, the faster it can charge a large battery pack"

Or are we talking certain camera batteries as opposed to cache batteries such as the Portapow 10200mAh battery Steve uses? Could Steve charge his battery more effectively with the E Werk rather than the Revolution?

[Bigdummysteve]

My experience with this particular battery was that it would accept a very slow charge from a panel even in low light, obvious it would charge quicker from a hub dyno at speed or in bright sunlight from a panel. Looking at the output of the werk it does produce output at very low speed and would seem to be able to provide some charge most of the time.
While I'm no expert I would think low output might not be acceptable to say an iPhone but might be able to provide some useful charge to a suitable battery. I think they missed I trick with the USB werk by not making the battery bigger.

[Dave855]

I've been trying to clarify the issue of pedalling speed in relation to charging speed. If you look at the speed required to produce a charge equivalent to that achieved with a USB wall socket, it appears the results are as follows;

the Plug III -12kmph
Sinewave Revolution- 14.4 kmph
Sinewave Reactor - 14.4kmph
B&M E Werk - 15kmph
B&M Werk - some sources claim 15kmph while others state 17kmph (such as http://www.bike24.com/p238306.html)

Is it as cut and dry as that?

[Samuel D]

I don’t think there’s a “difference in opinion” between interestedcp and me about charging rates with the E-Werk. It is certainly true that it will charge a battery pack faster if riding faster, but it doesn’t do that by increasing the voltage. Rather, it increases the current flow.

There is more information about the effects of voltage on lithium-ion batteries here. You can see the voltage selector on the E-Werk will not be useful for charging such batteries.

I would ignore small differences in charge rates and especially claims by third-party reviewers who may or may not know what they’re doing and will anyway all have different dynamo hubs and speed-measuring devices.

[edocaster]

Whatever works and continues to work for your setup is basically the most important consideration. Getting into the nitty gritty of the electrical performance can be misleading. For example, lots of people seem happy with the Plug III, but you can see a comment I left here: http://thorncyclesforum.co.uk/index.php ... 1#msg73381 - if the Youtube video is accurate, the Plug III doesn't look very efficient at all. Effective, but not efficient. But if it works, then no-one minds.

I certainly think it's worth buying a 'USB doctor' type device which will show you how well a device is charging, current-wise. As you can sometimes be surprised and find out that, in certain circumstances devices aren't actually charging at all.

[Dave855]

Agreed-there are limited options on the market and as long as the device you choose does what you require then that is all that really matters. For me, the choice is between the E Werk and any of the alternatives. The E Werk is unique in what it can do whereas the alternatives will all do much the same. The question of whether the features of the E Werk are worth having over a standard USB charging device is what stands out as unanswered to me. I'll have to do some research into amps and volts and see if I can get my head around it.....I just want to make best use of the power generated by the hub. It's pointless having power going to waste if, say, the E Werk could utilise more of it than the other options

[ConRAD]

... the question of whether the features of the E Werk are worth having over a standard USB charging device is what stands out as unanswered to me ...

… unanswered to me either !!

Indeed:

- 4.9V and 5.6V seem to be respectively a bit too low or too high for a correct USB voltage output
- 5.6V seems to be good only for 4 X NiMH batteries or for their proprietary cache battery
- 4.2V and 8.2V seem to have been engineered for charging single or double Li-ion cells that, in turn, are not suitable at all to be charged via two poles only (plus-minus) requiring for safety reasons, most of the times, an additional third/fourth pole for temperature sensing
- it has no buffer battery incorporated thus obligatorily requiring a separated “cache-battery” without which at low speeds your gps or whatsoever connected devices might have unpredictable problems
- solderings on the inside pcb seem to be too weak considered the continuous stress of the soldered wires
- it doesn’t seem to be truly waterproof/weatherproof, internal condensation might be a problem, external connectors are nevertheless definitely of an excellent quality
- on the other hand, however, I must recognize that electronics are pretty well engineered, reliable and rugged constructed