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  • TwoWheelsCarryTheSoul

PedalCell Rim Dynamo (w/field edit)

Updated: Dec 6, 2021

In search of absolute powah!


In my review of the PedalCell rim dynamo, I not only evaluate the product itself but also provide you with important background information into MY selection – it’s important to note that in no way shape or form am I saying this is the best product out there. However, it’s important to know some background as it may apply to your needs. EDIT: A field review has been posted at the end of is post, after using on my recent trip on the Pacific Coast Highway.



While preparing for an extended cross-country bike trip, I came to the realization that I needed a consistent and reliable source of power. I did not want to add stress of constantly seeking outlets to recharge batteries along my route, refusing to relinquish valuable daylight time when I could otherwise be riding. I also use the same bike more regularly for commuting – 20–30 miles each way, satisfied with rechargeable lights for that purpose, so my desire for power is something that I would utilize only for longer trips, to recharge battery packs, not for powering a light system or anything else.

Exploring the Options

The most common solution that touring cyclist can turn to is the traditional hub dynamo, and there is no doubt the role that they have played. There are many to choose from, and as much data and research as you want to find. The more I read, however, I kept having two nagging thoughts. Speed and cost.

First, a concern over the necessity to maintain a minimum level of speed. While there is some variance in the power output/operational speed of various hubs, a common factor is limited/consistent power output at slower speeds. Not as much a factor of properties inherent to hub dynamos, but more out of "traditional" intended purpose. Hub dynamos are centered around powering lights designed around the German StVZO standards. If one wants to use this standard to charge a battery pack via USB, it's sort of like fitting a square peg into a round hole - you're wanting to do something a system was not originally designed to do. This could be especially problematic for devices requiring a consistent threshold to trigger charging status, and if spending a day climbing at lower speeds.

The second factor was cost. In particular, while pre-fabricated wheels are available, given my circumstances I would want to build a wheel. Let the domino's begin to fall... This would include not only be the cost of the hub (~$300, depending on source), spokes/nipples (~$40), rim ($70 cost for my selected choice), but I would also want to transition to a tubeless setup. Of course, because I would not want to have two different types of wheels to contend with (tube/tubeless), the cost would also include rebuilding a rear wheel to make it tubeless as well (another $70 for rim, I'd use my existing hub, ~$40 spokes) and cost to set up tubeless (rim tape, valves, sealant... oh, and new tires...). Gulp. Ok, a hub dynamo will cost me over $600 - and crap! I've not got anything to bridge the power to make it useable - cables, and a USB hub. Check.... book... Cha-ching. (for the record, I would do the labor myself - and working in a LBS, I not only have great support and expertise to guide me, I can get a break on some of the material pricing... For the average consumer, we're looking at $1000+ total). For this trip, it was obvious that a hub-dynamo option would be a major part of my budget.

Were there other options?

Some people have referred to solar power - but quickly I found two factors that would not work for me. The clearest being the reliance on sunshine. I could go as slow as I wanted, but what would I do on cloudy days? A second factor was that I could find no panels available specifically made for bicycle touring. Every application was a fabrication, or simply strapped to the top of a rack/gear. For me, I can see this being one more element of gadget-fidgetry that I would not want to deal with. A solar panel works best when sitting still - like recharging RV batteries all day - but not convinced this was an option for me.

A rim dynamo?

I know, I know… I had one of those bottle-generators for a light too… but these are different. Solid mounting, and rotating on the rim braking surface. Efficiency is the name of the game here - and it's super quiet. It seemed to address one of my major concerns – providing consistent power at lower speeds. The “standard” appeared to be produced by a German company, Velological. Another, newer, PedalCell was also in the market. Plus - they are reporting 2x less drag/watt compared to Velological, with higher power output (independent data here). It should be noted that I made several attempts to contact the folks at Velological for product and purchasing information. Call me old-fashioned, but a shy away from products that seem to be only available on eBay, and limited product support available. After several attempts, I still have yet to receive any response.

Enter PedalCell

At first...

I had been contacted early by Adam Hokin, co-founder of PedalCell, in response to a couple of posts that I had made in a couple social groups on Facebook. He directed me further to their webpage, where I was easily able to find the answers to nearly every question that I had about their product. Adam was very receptive to additional questions, even scheduling a phone conversation with me that lasted almost an hour and a half! (edit: since, we've chatted even an hour more!)

Basic v. Package - What’s Included?

Because of my needs, I went ahead and ordered their ultimate package ($349 at time of writing) which meant that for only an extra $50 over the base unit price of $299, an extra supply of O-rings, added cable connectors, a set of security mounting screws, and a handlebar mounted phone holder was included. Considering the price for needing to order additional O-rings necessary for my trip, and the added cable extensions would be nice to have, it is like getting the security bolts and phone holder as a bonus. The kit comes complete in a single well package box, each component securely held in a formed cut-out (TIP: do not throw this box away! Since the kit can be mounted and removed very easily, it makes a great place to keep it stored when not in use!)

In a Word: Adaptability

PedalCell has several YouTube videos that show a variety of mounting applications – each one was just as easy to explore as noted in the video, and in short order I had the unit mounted on the left fork, facing rearward (image at top of page is my application). It’s important to note here the first main difference to note between PedalCell and its competitor, Velological. PedalCell can be mounted in several locations, including either side of the fork, and seat/chain stays as tubing and clearance allow. Two sizes of bushings allow a tight fit to a multitude of applications (PedalCell notes that they are not to be used on carbon rims nor inverted suspension forks). With Velological, you have to specifically order the side/application that you want, being stuck with one purchase choice once made.

It is also important to note that the PedalCell package – even in the basic kit – is all-inclusive and ready to install and use out of the box. The PedalCell unit comes with a securely mounted cable connecting the generator to their Smart Power Hub, which provides two USB-C outputs. The Smart Power Hub can be mounted with an included rubber strap to stem, handlebar, or frame as applicable to your unique situation - noting that the strap can also be removed completely if you plan to stow in a bar bag, etc.

Electronic Quirkyness

If you use electronics, you know that manufacturers like to use proprietary methods to keep their use tied to a product name (cough, cough... Apple... cough, cough). My first test run, while installed perfectly, registered no activity. When I bridged the supplied USB-C-to-USB plug to the charging cable provided by the battery pack I was charging, problem solved. Be prepared to play around with cable configurations if you have this problem. The "White Paper" also gives product-specific tips on how to best use with PedalCell.

At the Core - The Smart Power Hub

The Smart Power Hub provides two USB-C outputs - a prioritized port with a stable 600mA at 5V (or 3 Watts) and a high-power port with a maximum output of 2.4A at 5V (or 12 Watts). As the unit is capacitor driven, the prioritized port provides "first-on/last-off" power for approximately 30 seconds while the bike is stopped, for example at a traffic light, not interrupting charging/output. The second port provides power output proportional to the speed that you are going. You can refer to the power charts here. It should also be noted that both outputs are operational – you can be charging two devices at once. The cable that is included in the basic unit is a short adapter that connects the USB-C output to provide a traditional USB plug. Additional cables included in the package include USB to USB-B & C as well as Lightning (Apple). All of these additional cables are approximately 4 inches in length, keeping excess slack at a minimum (though I redirect you again to the comment above about cable quirkiness).

How it Works


I found my most practical mounting application was the traditional location on the left fork leg. It mounted quickly, as described. No surprises. It is important to take the time to mount accurately, taking into account the rotating arm of the generator unit - allowing it to position so that the generator wheel is aligned exactly perpendicular to roll straight on the rim. I was much better off mounting the Smart Power Hub to my stem, and keeping my battery pack in a top-tube frame bag while charging. As already noted, I found that using specific power cords designed for my devices gave me more cable slack between the Smart Power Hub unit and my device.

The PedalCell generator cantilevers, so that if charging is not needed, it can be disengaged. For those that are concerned about drag, this is a huge benefit over hub dynos. Just as with any dynamo - rim or hub - there is drag in operation. I have ridden hub dynamos, and did not feel any noticeable difference in using the PedalCell - though I will admit, there was some satisfaction on steep, slow climbs knowing I can disengage and have *no* drag.

I have used the unit several times, both on my extended commute as well as one overnight touring trip, simulating a daily regimen of use and recharge. The battery pack I use is a 10,000mAh, and I was able to charge at a rate of approximately ¼ of the battery capacity per hour on a consistent basis (total charge from empty in about 4 hours). I found that if the days’ ride includes pauses, stops and starts, and inconsistent speeds (ie, riding through a town or commuting) you will best be served by the stable output. If you know you will be riding a consistent, steady pace for extended periods, then the variable rate output will serve well (I should note here another element of electronic quirkiness - some devices can take a fluctuating charge, others need to register a consistent charge before allowing recharge - read The White Paper for more details. Again, both can be used simultaneously to charge two devices.

On the Road and Final comments

On the ride, PedalCell hardly makes any noise at all… while if you listen carefully, you can hear the whir of the generator, it is scarcely enough to offset the sound of your tires biting the riding surface or the wind in your face. While I did not fully test in adverse weather, I did have a chance to spend a day in the rain. The generator spun flawlessly in the wetness, due to the rubber o-ring and spring tension. While I do not intend to operate the unit in mud and grime (using primarily for road touring), it's clear that the PedalCell can go where ever you're willing to go (Check out PedalCell on the Arizona Trail!). Having power to recharge batteries or devices while you ride is a nice luxury. I knew I did not want to have my riding schedule tethered to outlets, and with that also wanting something that works within the widest range of speeds. PedalCell fits that bill nicely.

Questions? Customer Service?

In short, there are few companies that stand behind their product the way PedalCell does. In preparing for this write-up, I regularly returned to their web page ( and not only readily found the information I was looking for, but also found the website continually being updated and refreshed with *new* information, how-to's, and reviews (wave!). Even those who want to "geek out" with all the engineering behind the scenes can access the "White Paper" (If you don't know about the "White Paper" by this point... ;-) .

Notwithstanding, this is truly a piece of equipment, and not only needs to be set up correctly, but given the nature of technology there are many quirks that you may encounter. Be patient, and work through them - a step at a time - and you will be rewarded with a power source that brings to mind such words as "reliable", 'adaptable", "affordable", and "accessible". In one sense, they are bringing a new standard and need to stand up in these areas in order to stand out amongst the competition and old stereotypes. If you are looking for something else, and thinking outside the traditional box, then PedalCell may just be for you. It is for me.

Field Update - Pacific Coast Highway - Sept/Oct 2021 With confidence of testing in a variety positions, I set off on September 11 from Seattle. Armed with PedalCell, a 10,000mAh back-up battery, a cell phone, headlamp, a headlight, and 2 tail lights. I also had an iPad, but found I never used it - so for all intents and purposes, it played no role except this disclosure. I found quickly that a routine allowed me to top off my items (in order - phone, lights, headlamp) for 2-3 nights with my 10,000mAh battery. The first rotation also showed me that on that 4th day ("Great, I've fully drained my battery, no I can find out how quickly PedalCell will work in the field") showed me a better adage - which applies to water as well as your battery - "Top off whenever you can". That fourth day found us riding some hilly coastal roads, and thus a shorter day than our average. That day, I *was* able to load the backup battery with enough to top off the phone and a tail light - but it also told me that if my battery needs a charge, charge it for the ready - but I *can* go 2-3 nights of recharging with my back-up alone. For the rest of the 41 days, I had zero issues with electricity. Of course, when we stopped at a hotel (only 2 on the trip - one as a rest-day, the other on the very last night before driving home), or campground (where outlets available) - outlets were taken full advantage of.

I did mount the PedalCell unit on the left chainstay, as I found mounting on the fork did interfere with my wireless computer. No issue there, except, ironically, on my very last day. I was riding along, thinking "I could just take the PedalCell off, as I won't be using it again..." - and while pulling into the next stop, I somehow managed - for the first time in over 1600 miles - to clip the edge of the unit, bending the engagement tab :-( (It should be noted that while this could be bent back, I was quickly and graciously provided with a replacement arm, as well as the extra-think bumper for use with mounting on the chainstay - noting that this new bumper now moves the unit just a bit more to avoid such contact with the pin. Great follow-up customer service, as well as a problem-solving solution!). Because of the PedalCell positioning, I was able to keep the Smart Power Hub in my top-tube frame bag, a pouch where I kept all of my electronics together. There were times where I noticed that the plug had disconnected from the Smart Power Hub - solved by rigging a rubber band wrapped around the cable end, and wrapping around the Smart Power Hub. If you mount the Smart Power Hub to the stem, you may not have the issue of the cable disconnecting - I am assuming my experience was caused by being in a bag with other items that contributed to dislodging the cable from the unit.

In the end - I am completely satisfied with the PedalCell to meet *my* needs - taking home the following key bulleted points:

  • Consistent, reliable power source that can charge a 10,000mAh battery pack in ~4 hours of pedal time.

  • Consistent charge provided as low as 6 mph.

  • Can *easily* disengage for *zero* drag on climbs.

  • Use days of flat or moderate terrain to top off, even if it's just 10%

  • Cables, cables, cables... make sure they work with your units (not all will 'activate' - kinda like how Apple can detect non-Apple cables, and not allow functionality). That's an issue of industry compatability, not PedalCell

If your journeys are hotel-to-hotel, or short enough to just rely on a backup battery or two, then you don't need PedalCell (or a hub dynamo for that matter). If you are going to be on longer trips, where outlets may be an issue, and you just want efficient, reliable power, then PedallCell is not just a viable contender to the hub dynamo - it raises the bar and sets a new standard.

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