Originally Posted by
polyphrast
Well on this weight discussion a crucial point is overlooked: any normal bike has a front hub. And those range between 170 and 250 grams (100 mm axle for quick release), depending on the amount of money spent.
Weights for the most important dyno hubs (all as 100mm axle versions):
SON 490 g
Shimanos LX equivalents at 550 g, the xt version is at 480g
SP Dynamos (8 Series) 400 g
SONdelux: 390 g
SP 9 series: 310 g
The latter two i wouldn't use if one wants to generate a lot of power, as they have less magnets so they generate at lower speeds less power. For any modern LED light still totally sufficient.
So the
weight penalty for a (normal) hub dyno is
between 150 g to 380 g, depending on the type of hub used before and on the hub dyno.....For the weight weenies there is still the velogical generator at 75 g additional weight. No solar panel/battery combo can top this
My standard hub is the DT Swiss 240s. In a centerlock disc version, that’s 126g.
And to be clear, we’re not just talking weight - it’s going to be really a watts/kg number. The dynamos are both heavier and put out considerably lower power without even taking into account the increased power requirements at the crank. There is also the convenience factor - I don’t have to pedal every day for 6 hours or more to get my daily power consumption replaced.
On the weight piece, we’re talking about a difference of about 100g give or take (Close to a wash for all intents and purposes). But for that 100g we get more power generation and that power doesn’t depend on having have the bike in motion.
Originally Posted by
noglider
Wow, those slimq chargers are really something. With so much power going through so little mass, I wonder what the fire risk is.
Yep. That makes for a very hard combination to beat if you’re anywhere near the grid. They don’t get all that warm.
Originally Posted by
Ogsarg
GaN (Gallium Nitride) is so much more efficient than Silicon so generates far less heat and therefore can be packaged much tighter. Assuming the design is proper, I would not be concerned.
yep. This is the enabling tech for small high power chargers.