Solar backpack (Solar charger)

Al Johnson openmoko at mazikeen.demon.co.uk
Tue Jun 2 16:15:36 CEST 2009


You might like to check this comparison of dynamo efficiency [1]. The Shimano 
has as much drag with the lights off as on! It's missing the B&M [2] models 
though, which is a pity as they do a 12V 6W bottle model with a claimed 
efficiency of 70%, beating even the Schmidt. The LightSPIN had a similar 
verified efficiency so it's possible, but they're out of production now, and 
were quirky to get DC out of.

[1] http://myra-simon.com/bike/dynotest.html
[2] http://www.bumm.de/

On Saturday 23 May 2009, David Reyes Samblas Martinez wrote:
> in australia there is a company  called www.pedalpower.com that has
> the full solution, I trying to reach them but with any luck I will try
> again tomorrow morning. but in  parelell I trying to make my own
> solution, just a aux batery able to recharge while charging providing
> 500mA will do the trick, just precharge that battery and it will at
> least be mantained by the dynamo. I still searching for one that
> fits. For the dynamo hubs , my local bike workshop is searching for an
> affordable one(shimano, afiline..), but the main problem is that all
> dynamo hubs requires to unmount and remount the hole wheel, and this
> is  an added cost in the total  amount. so he is also searching for
> wheels with the dynamo hub already mounted. once I got information I
> will post.
>
> 2009/5/23 Michal Brzozowski <rusolis at poczta.fm>:
> > Ok, I wasn't specific enough. What I'm looking for is exactly that thing
> > in the middle :-) that will output the 500mA or 1A through a USB.
> >
> > Is a bike dynamo powerful enough to provide the 500mA or 1A to charge the
> > Freerunner?
> >
> > 2009/5/23 David Reyes Samblas Martinez <david at tuxbrain.com>
> >
> >> look at http://www.sheldonbrown.com/harris/lighting/shimano.html
> >>
> >> but remember you will have to have a good voltage regulator or better
> >> a battery charger able to charge itself and the neo at time, in the
> >> middle, to avoid the current variance of the dinamo
> >>
> >> 2009/5/23 Michal Brzozowski <rusolis at poczta.fm>:
> >> > 2009/5/21 Al Johnson <openmoko at mazikeen.demon.co.uk>
> >> >
> >> >> If you want something effective for emergencies or extended periods
> >> >> away
> >> >> from
> >> >> power a mechanical device is probably more effective. For cycling a
> >> >> good
> >> >> dynamo will provide more, and more reliable, power than any
> >> >> bike-mounted
> >> >> solar
> >> >> panel. Other than that there are some good quality hand cranked
> >> >> generators
> >> >> available, along with a lot of bad ones. There are even a few devices
> >> >> that
> >> >> will take energy from irregular movement, a bit like a self-winding
> >> >> watch.
> >> >
> >> > I'm looking for a bicycle or hand driven dynamo for use with
> >> > Freerunner. Do
> >> > you have any links where to find such devices?





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