This:
20-30 Watts over time is a significant drag.
I have a USB port on the battery for my bike, the battery being quite big enough for the necessary assistance (rather than using it as an electric motorcycle) for a day’s ride with plenty left over for charging devices, but I’ve never used it. I just believe in redundant security in depth. Instead I prefer to carry a rechargeable power bank of the right size for whatever I will do on the day. Usually it is plugged into my phone and on from home, because on shorter rides I like my phone fully charged; the phone is in constant use monitoring my heart rate, which is limited by order of my cardiologist, and my heart rate on any hill determines when the motor is cut in and then cut out again. The small power bank is big enough to recharge my iPhone SE (chosen for its sturdy aluminium shell) from dead to full three times, with some left over, and the bigger power bank can keep up reports (audio as well as visual) from the phone for eight hours. Either fits with the iPhone in a transparent weatherproof bag on the handlebar that was bought from my supermarket, Lidl, in one of their biannual bicycle weeks, and has lasted many years.
I did have a charger of my own construction to replenish devices from the SON hub dynamo but soon decided it was more of a danger to my health by blowing up the iPhone, which is sensitive to the regulation of the current fed to it, than a help, and repurposed the cheap parts from Aliexpress. I built it on a strip of ali angle which also offered mounting holes, and shrink wrapped the whole thing in piece of cable tidy I begged from an electrical contractor.
The Pedal Cell seems to me an accident waiting to happen when inevitably it slips into the spokes. That, as has been observed already, is not sound engineering, especially on a bicycle where fallback systems in depth have to be very carefully considered for whatever additional pedal power they will consume.
If that isn’t enough to condemn the Pedal Cell for me, the thing will demand replacement of the O-rings used for driving it (in the 21st century — pull the other one!) and on a tyre-driven generator just any O-rings won’t do. I live in an agricultural centre with lots of hardware and machine shops, and have experience of spending a whole morning going from place to place to find an even approximately right O-ring. I’ve spent time and money, and a lot of the patient help from friends here and on other cycling conferences, rebuilding my bike as a low-tending-to-zero maintenance bicycle, so fragile O-rings are a personal no-no as well as unacceptable engineering.
But there’s more: I’m not the first in this thread to observe that a gennie on the tyre depends for its efficiency on a clean contact between the tyre and the generator’s drive wheelie, and all the more so when the drive wheelie is not toothed metal but an O-ring. More maintenance, probably daily in foul-condition riding. I confidently forecast that those of us who fitted a Hebie Chainglider won’t consider the Pedal Cell long before we turn it down. It seems to me the Pedal Cell is an implement for clean tarmac and fair weather, which cyclists on tour cannot guarantee.
And still more: Has Apple certified the output as copacetic for iPhones? Just asking, rhetorically: If Apple did, you can bet the makers of the Pedal Cell would shout it from the rooftops.
Lastly, the thing costs a niche-market, big margin price. I’m nobody’s unpaid beta-tester. For such a high-rent tyre gennie, there is the known, proven top B&M tyre generator, which should be considered first (and probably last — it’s a very long time since I rode a bike without a hub dynamo), and other stalwarts of European four-seasons cycling also offer quality rim generators without the Pedal Cell’s engineering solecisms. Frankly, that so few cyclists today choose a tyre dynamo, when for the same money they can have a hub dynamo, is already an overwhelming argument.
If the Pedal Cell won’t do for a credit card, short range, only in civilisation, rider like me, I think it needs stronger arguments in its favour than we’ve heard yet.
***
The Pedal Cell, like other bicycle charging schemes, is a bodge made necessary by those German legislators in the pockets of VW-Audi and Daimler-Benz who made the law that a bicycle’s power plant should deliver 3W at 15kph, which then became the universal de facto standard for bicycle lighting. Try this thought experiment of an alternative reality:
Suppose bicycle hubs were freed from ignorant, motorist-biased legislators. By now we would have hub dynamos, perhaps even tyre generators, that could produce 50W for the same drag as we now gain a miserable 3W. And manufacturers would already have developed much more robust regulation circuits so as not to blow out the car-strength lamps that this different direction of bicycle lighting plus the invention of the LED would have made possible. And it would all be pretty cheap because car parts could be used.
Pedal Cell’s makers would then have directed their energies into devising a splitter board with regulation and protection to suit all kinds of implements on the bike to use the extra potential not required for the lamps.
There’d be hardly any extra weight…
Ain’t gonna happen, of course.
