Thorn Cycles Forum

Technical => Lighting and Electronics => Topic started by: Matt2matt2002 on March 26, 2013, 05:43:14 PM

Title: bike chain charger
Post by: Matt2matt2002 on March 26, 2013, 05:43:14 PM

Anyone any info on this charger?
Looks a bit iffy to me.
http://www.ebay.co.uk/itm/Bicycle-Chain-Charger-to-USB-Dynamo-1000mAh-/261187652783?pt=UK_Spots_Leisure_Cycling_Tools_RepairKits&hash=item3ccfff4caf

Title: Re: bike chain charger
Post by: Danneaux on March 26, 2013, 06:19:22 PM

Hi Matt!

I have seen this -- in person! While I think the basic idea is clever, it sort of misses the mark. Compared to a hub dynamo which is capable fof generating power all the time the the bike is moving, this one only works when one is pedaling. It bypasses the "free-ride" aspect of power generation while coasting.

The example I saw was noisy and clattered horribly when pedaled. It might work better on a single-speed, Fixed, or IGH hub, but it didn't accommodate the changing chainline of a derailleur bike very well.

Best,

Dan. (...who thinks there's no such thing as a free ride...but sometimes a free ride can mean free 'lectricity)

Title: Re: bike chain charger
Post by: rualexander on March 26, 2013, 06:37:27 PM

This is a charging method I wondered about a couple of years ago,.
It maybe makes sense for loaded touring where although you won't be generating any power while freewheeling, you might get better power generation going up long climbs for example.
Reasonably steady cadence will mean the chain speed through the generator remains high even though groundspeed is slow.
And we all know that we spend more time grinding our way uphill than we do whizzing downhill!

Title: Re: bike chain charger
Post by: Danneaux on March 26, 2013, 06:43:49 PM

Good points all, Rual.

I'd like to know more about the handlebar-mounted cache battery in the upper-right photo of the listing picture.

I would feel better if they didn't show the power specs based on speeds in kilograms/hour.

Best,

Dan.