Cycle dynamo / generator hubs?

[peterperkins]

Wanting to do some decent distance on my bike and to keep phone/mp3/gps/lights charged.

Any recommendations on low loss cycle wheel hub generators? I see lots of Shimano ones listed..

I could use a power pack thingy but that seems a bit overkill..

[frisbee]

Power packs are a few pounds though. Generator hubs are fairly pricey and you would need to get a wheel built up.

They apparently don't charge all devices either, so you end up charging a power pack and using that to charge the devices.

[JustinF]

Shimano hubs are reliable but heavy and not terribly efficient, running at about 60%
Shutter Precision (SP) are mid priced, lighter and 70%+ efficient, bearing however are not user serviceable, but unless you're talking 5000Km+ not likely to be an issue.
Son Delux are the Gucci option but the choice of most hyper distance riders, long lasting and user serviceable with good warranties.

I run a SP wired into a B+M front light and a Cycle to Charge USB converter, into which I have a cache battery, from which I power devices.
The hub generates 6v @ 0.5A at 20Km/h, so about equivalent to a slow USB1 socket.
(6v x 0.5A = 3W, take 70% efficiency into account and it's costing you about 4W to power it)

Having used it in the mountains, I'd rather just use powerbanks, as the climbing is too slow to generate significant charge and the descents are over too soon to get great benefit (also the circuitry caps power generation above 24 Km/h to prevent over voltage)

Just got back from a weeks touring and it was excellent, kept 2 GPS units topped up with enough spare capacity to top phones up for a bit of light use in the evenings.

[Celtic Dragon]

I've just put my Sp through its paces in Belgium, connected to a USB Werk. It happily charged everything I have apart from a powerbank. So Garmin, phone, iPod and rear Lyzene lights.

[JustinF]

frisbee said:

Power packs are a few pounds though. Generator hubs are fairly pricey and you would need to get a wheel built up.

They apparently don't charge all devices either, so you end up charging a power pack and using that to charge the devices.

Just to clarify, a well set up system uses a cache battery with a pass through ability, the power goes to the cache unless there is an item plugged into it's output, in which case the power goes straight to the output avoiding the 25-30% efficiency loss from going via the battery.

[SixPotBelly]

frisbee said:

Power packs are a few pounds though. Generator hubs are fairly pricey and you would need to get a wheel built up.

They apparently don't charge all devices either, so you end up charging a power pack and using that to charge the devices.

Power packs are cheaper, yes, but you need to charge them up when they run down. If you're only going for a day or maybe two, or credit-card touring and staying in hotels so you can fill them up again at night, then they make sense. But if you're bivvying on a multi-day trip then a dynamo makes sense. So I guess it depends on what the OP has in mind when he says "decent distance"..

[SixPotBelly]

JustinF said:

Just to clarify, a well set up system uses a cache battery with a pass through ability, the power goes to the cache unless there is an item plugged into it's output, in which case the power goes straight to the output avoiding the 25-30% efficiency loss from going via the battery.

Just to clarify the clarification, cache batteries and pass-thru batteries are different things. A proper cache battery, like the B&M, can charge a device whilst it is being charged. It still filters out the voltage drop outs when you slow or stop. Whereas a power bank with pass-through just passes through the supply voltage from the dynamo when connected inbetween the supply and the device. It doesn't perform any cache function and the output voltage still drops when you slow or stop.