Pedal Powered Electronics Charging System

/ Saturday, 19 March 2011 / Bike Related

As much as I’d like to get away from Technology, it still plays a very large role in my life, even while on the road. I use my Garmin GPS regularly to record my daily statistics and elevation charts not to mention getting me out of binds when I go off the beaten path. I carry an Apple iPhone with me, not so much to make calls over the cellular network, but to send text messages, check for available WI-FI networks, so that I can browse the web, check the weather, or use Skype. Not only that, I have an Mp3 Player with a set of portable speakers going almost all day long to assist from me going crazy listening to the music player that is running through my head without reprieve. When I stop riding for the day, I like to muck about on my laptop, read books on my Amazon Kindle device, and review footage that I’ve taken with a video camera throughout the day. That’s a lot of gear!

Electrical Charger mounted on bicycle


All of my devices have their own internal battery packs, good to last for extended amounts of time when out on the road, but this takes an excessive amount of time to recharge when they run low. If I had 1-2 hours a day to sit in a coffee shop this would be a non issue, however there are some days where I haven’t seen a single person, let alone a diner or any other public space with a spare power outlet. At night when entering in my daily journal, I would typically charge the components off of the USB ports of my laptop – resulting in less time to compute, and an even longer recharge process due to its much higher power demands.



Solar Panel Mounted to Handlebar Bag

I spent an awful lot of time researching an effective solution that would satisfy even 50% of my requirements, carefully balancing factors such as cost, weight, durability and ease of use. As with most things, you have to try a few options before you get it right. I invested a hefty chunk of change into portable USB batteries, using them when my devices components ran low, yet still faced the issue of finding a source to keep them topped up. Next, on the advice of a passing cycle tourist, I went down the path of Solar Panels, with newer generations able to charge even on cloudy days, but found them to be large, bulky, and a pain to strap onto the bicycle each time I needed access to my gear – not to mention the amount of power generated was barely enough to charge one of my components per day. Newer panels are on the market that are flexible and output a higher voltage, providing you have a source to store its sun-garnered energy and are willing to lug around heavy batteries.

It made sense that since I was on the saddle for 5-10 hours a day, why not deal with my power requirements by pedaling along? I recalled being a boy in the 80’s having a nifty light on the front of my bicycle, which turned on when I attached a (fairly loud mind you) small device known as a sidewall / bottle dynamo to the sidewall of a tire. It wasn’t extremely bright, but it worked in concept and I was pretty jazzed whenever I got to use it, having a similar love for gadgetry then as I do now. I commenced research and found that I was not alone with my quest to charge components, and that companies have stepped up to provide solutions for basic needs.

The bottle dynamos still exist, and output either 6 or 12 volts AC, enough to fire up a very bright headlight and tail light, but after further investigation, my components all took between 3.7 to 13 volts DC! (I won’t get into the explanation of what AC or DC current means, if you’d like – check out the Wikipedia articles). Nokia, a popular cellular phone maker from Finland came out with a bottle dynamo device that performed the AC-DC conversion to charge their phones, unfortunately Nokia uses proprietary 2mm connectors, and I haven’t owned a Nokia since 2003. Bottle Dynamos not only put out an annoying sound should one wish to ride in silence but also have a very high friction rate, equating to a loss of almost 7% in efficiency! I decided to look elsewhere.




Schmidt SON 28R Dyno Hub

Hub dynamos, which means all the electrical circuitry resides inside the bicycle wheels hub (typically the front) have been around since the 1930’s providing power for headlights and tail lights again, using AC voltage. Advancements have been made throughout the years to deal with their ‘drag’ and an attempt at reducing the weight of the unit, causing unnecessary slowdowns to the rider. Various Manufacturers such as Sturmey-Archer, Shimano, Pioneer, and Schmidt are known to produce reliable hub dynamos well suited for today’s cyclist, coming in a range of output voltages (6 or 12V AC), and the amount of spokes that need to be fitted when building a wheel. I decided this was going to be the solution for me, and commenced further research into reliability, weight, efficiency. I even found a company in Australia named Pedal-Power who is the first on the market to create a Dyno hub which primarily outputs 5 volts in DC! Bicycle Quarterly, a publication based out of Seattle, Washington, USA tested the efficiency of various manufacturers Dyno hubs in it’s June 2005 issue complimenting Chris Juden’s research on Efficiency and Electrical Output of Dyno Hubs. Finding reliability data was much more difficult especially for the extreme conditions faced when bicycle touring. I eventually settled on the Schmidt SON 28R Hub Dynamo, which has the longest warranty out of any of my other choices, with an operating time of 50,000km before servicing. While it only outputs 6V AC, I was still faced with the dilemma of voltage conversion.

The Dahon Biologic ReeCharge, Pedal-Power V4I, DynaLader Eco, Tout Terrains ‘The Plug’, Kuhn’s KECHARGER, and the ZZing all are products which have been on the market to handle the voltage conversion process, using basically the same techniques, however some models include a battery to store the power. These devices are rated to output a maximum of 5 volts DC with at 500mA (If you have two devices that both operate at 5 volts, the it may require a higher amperage to power and charge – These devices seem to be designed to charge one single device at a time. Typical USB devices draw 500mA and in some cases electronics such as the Apple iPad require chargers of up to 2.1A!). A reader of my website Christian Benke, who right now is cycling from Europe to Asia alerted me to an online community who make DIY chargers that are suitable for charging USB components with some models even outputting 12V (the same voltage your car lighter outputs). I hadn’t worked with electronics other than the odd soldering fix-it job in almost 20 years, but was prepared to give it a whirl, that is until I found the Busch and Mueller E-WERK.




B&M E-Werk Contents

B&M E-WERK and its included components

Well known for their lights for cyclists,B&M goes above and beyond what other manufacturers are offering – It has the capability of allowing you to dial in the voltage that you need (too high of voltage is a quick way to see smoke come out of your components) from 3.6 volts all the way to 13.6 volts and a selectable amperage output from 100mA all the way up to 1.5 amps (enough to power 3 USB components at once!). It’s waterproof, sealed in a plastic casing, and all interconnection cables to and from the device offer o-ring seals to protect from moisture. It’s very small and lightweight can be mounted on the bicycle with rubber bands, or zip straps, or simply carried around in a bag. B&M states it can accept a wide variety of voltage of both AC and DC up to 50 volts, so it is compatible with not only bicycle Dynamos, but Electric bikes, and automobile systems. B&M provides a series of cables to connect directly to your Hub Dynamo, an extension cable, various USB connectors, and 2 spare cables with no ends, to be used for what you wish.

With this device, I set out putting together a component list to adequately charge the majority of my components while riding. Since the B&M came with single USB connectors, I devised a plan to use a USB Hub, that I found on a popular Chinese wholesale site, Deal Extreme. The hub is fairly unique, as it offers the ability to split one USB connection into four, but offers switches to independently control each of the ports. I’d yet to see one in Canada, so patiently waited 1 month for it to arrive, spending my spare time devising other aspects of the system.


USB Hub w/ Independent Switches

USB Hub with Independent Switches

The next piece to the puzzle was the fact that some of my devices had a tendency to reset, power off, or freak out with audible and visual alerts when they lost power. If I was to stop to grab to adjust something, snap a photo, or wait for a traffic light to turn green, I’d have to fiddle and fudge around with the devices to get them in operation again. I noticed that some of the other manufacturers offered batteries to combat this solution and set out to find a battery that would suit my needs. Most backup power packs only supply 5VDC at 500mA, putting the whole idea right back at square one. Thankfully due to the increased power consumption of Tablet devices such as the Apple IPAD and Motorola Xoom require, manufacturers now offer devices that output higher current, such as the Hypermac Mini, and the Tekkeon 1860A. Both have different storage capacities but share another required feature – Passive Charging. This feature allows the user to charge the connected components & the battery simultaneously, switching between the two when either is fully charged. If you were to use a battery without this feature it would add more to your time at the end of the day charging the electronic components internal systems, and it would be quite difficult to know when the battery itself was charged, potentially wasting efficiency.


Axiom Power Bag

Axiom Power Bag II - Sharpied

Next, was the storage of the charging system. I considered using the E-WERK as a portable device, not permanently affixed to the bicycle, but thought about the ramifications of repeat insertion and removal of the waterproof cabling. I opted to mount it on the bicycle’s fork keeping the connections permanently attached to the hub, allowing only a commonly available USB port to wear out. I then set out to find a suitable bag – something that was easily attached and removed, well-built and large enough to store the gear yet compact enough to not get in the way. I tried two bicycle stem bags, one from Topeak, finally returning it and upgrading to the Axiom Power Bag II, which offered more space, and separate compartments for isolation. The first thing I did with the Axiom bag was pulled out the trusty Sharpie black marker and spent a few minutes colouring in the annoying white embroidery. I’m not at all into being a riding billboard for manufacturers, and find it annoying that they continue to plaster their branding all over components, no matter how small or big.


I then took a knife and cut holes in the top pocket to allow a USB plug to fit through it, but not wide enough so that the MP3 Player would slip through. I also cut slits in the backside of each  of the main compartments, enough to fit 4 USB cables and enough room to get the connector in and out should I ever have to replace it. Since it is a nylon material I used clear nail polish to seal the edges to avoid fraying.

Axiom Power Bag - Knife ActionMake cuts on each side of the bagMake sure they are through both sides and create slackLine up Cables Flat

After the holes were cut I carefully placed the cables through the holes and gave them enough slack so that when they rested on the top tube of my bicycle they didn’t cause any more bulk than necessary. I lined them up beside each other and then covered it with duct tape. I didn’t have any black tape lying around, so again, it got the sharpie treatment. 2 minutes of my life that I’ll never get back. Finally, I mounted the components inside the bag and performed test fitting to see if my idea actually worked – it did! I can fit the battery and USB hub on one side, the Mp3 Player on the top pocket, and the other side is reserved for cable storage, the phone, and if I need to take the bag off the bike, I can store the GPS and my speakers as well.

Right Compartment - Hub and BatteryIMG_0492Line up Cables FlatA little bit of duct tape wil keep the cables in placeDidn't have black tape, but had a Sharpie!Tape the inside to make sure the cables are secure

One of the benefits about this bag is that I can take it off the bicycle in a short amount of time if it rains, protecting the electronic components from shorting out. It fits nicely in my handlebar bag, and can also be stored flat in a pannier to save space. Since these devices sometimes still need to be connected to a computer to do synchronizing of libraries, reloading of content I can simply unplug the USB cable from the battery inside the bag and plug it into a computer. This will keep things a bit more organized over the long run as well.


IMG_0501Full Bag with side doors Open


This sorts out the portable devices that I carry with me, if I ever decide to upgrade, or face a catastrophic failure of one of the components or devices they are easily replaceable, and swapping out the cables should be a non issue. There is still one more component that needs to be addressed which is the laptop…


I use an Acer 1830T laptop which is netbook sized (11.6″) but has a great amount of horsepower behind it and is chock full of RAM. I need a fast computer as most can’t keep up to my usage patterns and this suited me almost exactly at a reasonable price and very light weight (It’s barely 3 pounds) with a serious amount of battery life. The power consumption requirements are very low on this unit, so I began to research if I could perform charging with the spare voltage the B&M E-WERK provided. An hour of searching on the internet as to what sort of jack is required and what voltage I would need at a minimum to charge the unit was all it took, and I managed to find an off-brand charger designed to charge laptops in automobiles for the whopping price of.99 cents (free shipping too!) from China. I’ll write a post in the future about all the great goodies that one can find with a bit of searching from all of these discount warehouses – it’s a goldmine!

.99cent Laptop 12V Car Charger for my laptop getting a bit of a treatment to be able to charge off my bicycle.99cent Laptop 12V Car Charger for my laptop getting a bit of a treatment to be able to charge off my bicycle.99cent Laptop 12V Car Charger for my laptop getting a bit of a treatment to be able to charge off my bicycle.99cent Laptop 12V Car Charger for my laptop getting a bit of a treatment to be able to charge off my bicycle

When it arrived it didn’t take long for me to cut it open with a knife and solder on one of the spare cables that came with the B&M E-WERK, To avoid any stress to the cable from it dangling while riding I applied a generous amount of marine ‘goop’ I found in someones closet. What I need to do when I want to charge the laptop is make sure my other electronics components are charged, and disconnect the charging system, moving it over to the newly modified adapter, and adjust the B&M E-WERK to output 12 volts. It’s a simple modification that can either be done with a small hex tool, or the included plastic key that fits into the E-WERK’s backside.

Test runs have so far been successful, and it remains to see how this will work out in the long-term, but I will be sure to keep reporting on any changes in architecture, additions, or meltdowns. It was a costly project to put together, but when one does the math of how much it costs to sit in a coffee shop on a regular basis, let alone the time it takes having to sit and guard electronics components either in a public space/cooped up in a tent waiting for things to charge, it becomes a non-issue and the return on investment is seen very shortly. If I was doing short trips on the weekend, or the odd week long tour a year, I would likely accept the fact that things are going to run out of battery power eventually, but since this is my home on wheels, some adjustments had to be made and priorities set.

If you have any questions or want more information, speak up in the comments!



  1. Jose Santos
    June 1st, 2011

    I heard about your adventure from my co-worker Serra Boten; I think what you’re doing is amazing. Good luck and let me know if you make it all the way down to Miami, I’d like to take you out for lunch or dinner – take care!

    • June 6th, 2011

      Cool! I don’t think I’m going to head through Florida anymore – I have to head over to Austin Tx for the 4th of July, but glad you came along and checked the site out!

  2. Douglas
    July 31st, 2011

    Dave, from Threewheeljourney is follow you, so I checked you out myself. Very good. What a adventure. I’m going to plan a trip in 2012. I just need to find a why to finace some of the trip. I going to start a blogg myself soon. Anyways, I will be following you…Safe travels to you!!..:)

  3. piano
    October 21st, 2011


    How has your system held up? I am embarking on a solo cross-Africa trip in a couple months and will be mimicking your setup, with the addition of some extra battery cells as backup/off-bike power. How durable has your system been? Are there any changes you would make? Would you rely on it for several months in undeveloped countries when you know there is no possibility of acquiring repair parts or replacing components or devices?

    Thank you.

    • October 25th, 2011

      Hello! After almost 10,000km of riding it has held up wonderfully with no issues as of yet. I’ve had power every day for all of my components, and while I worry at some point in time I will have the cables start fraying I can always order more from B&M, so far they are doing wonderfully. I’ve even pressurewashed the unit and it still works fine.

      I too am traveling through Africa at the moment, I would like to hear more about your travels. dave at tiredofit dot ca

  4. Jacob
    March 25th, 2012

    Hi Dave,

    I love your site! It looks great and has some great info. Actually, it’s one of the best designed bike tourist’s sites I’ve seen and I’ve gleaned some good design ideas from you. We have a very similar touring style (I’ve got a Thorn Raven Tour, Schmidt dynohub, and B&W E-Werk) and I thought I’d recommend a few things that might supplement your sweet system. First is the Goal Zero Guide 10 battery charger. I can charge AA and AAA with it and it has a reverse flow feature to charge other items from AAs (like my speaker or mp3 player) in case I run out while in camp. I like depending on AAs for a back-up rather than Lithium, even though they’re not quite as weight efficient. The second thing is the Sawyer Complete Water Filtration System. It’s lighter than the Miniworks and because it uses two bags and gravity to filter you don’t need to carry a Dromedary either (it comes in either 4L or 8L total capacity). I haven’t used it much but I already like it better than my old Miniworks and it is far more weight efficient. Finally, a question: I thought the Schmidt had an internal voltage limiter. I tried to jerry-rigged my own adapter with a car adapter to charge my SLR battery but it requires 12v. My E-Werk can handle that but it still doesn’t work. I thought the hub limited output. Did you find a way around that or I am I mistaken about its output voltage? Thanks.

    Cheers and happy travels,


  5. Dave Williams
    July 23rd, 2012


    Love your site. You’re helping me enormously! Just a quick question about the DynoHub and E-Work. I’m thinking about buying a power gorilla battery and just charging that all day. Then i’ll just plug my devices into that to charge. The people at power gorilla however have told me that the Schmidt Dyno Hub won’t charge it as it needs 15 volts to charge. Does this sound right to you? Any advice on using a cache style battery with the Schimidt would be fantastic.



    • July 23rd, 2012

      That Power Gorilla looks pretty bad ass. Surprised that it doesn’t take a 13v as I am able to charge my laptop at 13v even though it really wants 19 some odd.
      I’m using a Tekkeon MP1860 (dual 5V 2.1A output) and it seems to do everything I need but the laptop – I _rarelY_ run out of power on my laptop even though I bang away for 6 hours on it before going down. The Tekkeon is light and I’m not too upset if it breaks, although I’m sure I would be when it happens here in Africa.
      What you _could_ do, is there is a comment here showing the DIY power generator kit (Christian Benke wrote the comment) – You could order some LiON batteries from and make your own cache battery – but would want to make sure it is regulated, and safe from moisture.

      I want to see what you come up with!

  6. Brendon Cary
    August 25th, 2012

    Hi Dave,

    Thanks for the blogs. Just found you while i was doing my research into this same dilemma of charging gear on the road. Just a few questions you might be able to help me clarify.

    We will be running a Mac book air on our trip. Would you know if your idea of modifying a car charger would work using a Mac specific one I have found and directly attaching it to the e-werk? or could I use a usb/female cigaret lighter connection directly from a Tekkeon cache battery and then plug the original Mac car charger into this set up?

    2- do you run the usb hub you have set up off the tekkeon cache battery and then plug your tech items into the usb hub?

    I think your have helped me with sorting through a number of questions about recharging options while bike touring which is making it much easier as we move towards our start date to get our set up as close to perfect as possible. Thanks for the time you have put into passing this info on. Much appreciated.


    • August 28th, 2012

      Hi Brendon! Glad you are following along and that I could help with the elusive charging issue.

      Certainly you wouldn’t be able to use the Tekkeon Cache to charge the Mac as it only outputs 5V, and a typical Car Charger requires 12v. In Fact most laptops want even higher voltage (from 15-19V) and the up the voltage a bit at the sacrifice of less amperage from what I understand. However – I found that most laptops will charge at a lower voltage as long as they are _OFF_ Meaning no Suspend, no Hibernate, fully off. You may want to try it out, and go to Ebay and hack apart a car charger for this test, let us know if it works!

      2 – Yes, when I used the hub that is exactly how I did it. I eventually trashed the hub and just run off the dual output ports of the Tekkeon as that seems to fit my needs at present. The Tekkeon is now discontinued, I am going to look for a new battery in a few months for my next maildrop – I will share it here in this post. There are some ridiculous 10,000 mAH batteries I have seen whizzing past on tech sites but haven’t paid too much attention to.

      • Brendon Cary
        August 28th, 2012

        Thanks Dave,

        Have been doing some more looking and what you have said is kind of what I have come to realise. I have however found a solution to the Mac charging issues (e.g the magsafe system for the MacBooks). The hyper juice cache battery has voltage control as well as a system to splice into a Macbook charging system and looks like it will be able to achieve what I want to do as well as having the usb charging capabilities. It unfortunately is a pricey unit at $170.00 plus $50.00 for the extra kit for the macbook.

        Still trying to work out what Tech kit I really need out there, but we are planning a North and South America mission over 12 to 18 months, and are thinking the advantage of a laptop computer over a tablet is a must.

        Will keep up with what you are up to and any advances you come up with in regards to you charging system.

        Cheers for taking the time to reply, travel safe out there.


  7. Nigel Healy
    November 14th, 2012

    Hi I have a SON 28 hub on a Brompton folding bike, which is my preferred touring bike, moved to it from a Dawes Super Galaxy for compactness inside tent and to take indoors. I was looking at using the hub for charging gadgets, such as the Reecharge for $30. I see the mention of e-werk and charging laptop, well I did my own crude calculations and it seems close to not even worth bothering for a laptop, but it DOES seem worthwhile for lower power gadgets like a small tablet, cellphone, etc. I’d be interested on feedback if my maths is remotely correct? My travel laptop is a 10″ netbook, it needs 19V half-regulated DC in to charge a 11V 5200mah 56Wh battery, on that battery I get between 6 and 9 hours use depending on what I’m doing. The SON hub is about 3W-3.5W so not taking efficiency into account means (56/3) 19 hours charging for 9 hours us, so a little over 2 hours pedaling for 1 hours use. However, I see you’re daisy-chainring a few inverters in the sequence and each will provide some power loss. So hub-6V is itself efficient, it goes into basically an inverter (say e-werk) with about 80% efficiency to make the 12V and the cigarette lighter converter to make the 19V then is also say 80% efficiency, those stack up to be around 60%-70% efficiency, so my calc is nearer (53/3/0.6) 29 hours riding per 9 hours battery use, or 3 hours pedalling for every hour of laptop use. If the e-werks were to make the 19V for the laptop then one set of inverter and more efficient, did you set e-werk to laptop voltage or use the inverter in the cigarette lighter to have two inverters? The calc is a lot better with a USB 5V charging scenario, as that’s a small voltage reduction (no inverter required) it will be nearer 85%-90% efficient so a tablet with a 4500mah battery could be charged (excluding the trickle charge issue) in around 7 hours of riding, and a tablet gives say 8-9 hours of use, so you’re getting slightly better than 1 hours of tablet use per 1 hour of pedaling. You really REALLY need to justify a laptop for this type of usage scenario. Have you done some pedaling with the SON – e-werks-cigarettelighter-laptop and see what % battery charge you got for a given amount of riding?

  8. Nigel Healy
    November 14th, 2012

    ….. “….and adjust the B&M E-WERK to output 12 volts…” “….Acer 1830T …” … is 19VDC. So my comment and question are valid for your laptop. The e-werk “Adjustable from 2.8 V to 13,3 V – in steps of 0.7 V” so I can see you *HAVE* to go via 12V adaptor, that confirms you are stacking two inverters, to step-up 6V to 12V and 12V to 19V, so conversely the amps is stepping down. I’d expect probably 85%-90% efficiency so to make 19V you’re losing between 19%-28% of the hub’s power as heat in the e-werk and the cigarette-lighter-converter. The SON’s hub would step down from 500mA to 210mA out of the e-werks 12V (is that true?) and then 110ma into the laptop (is that true?). To put in perspective your laptop’s PSU is chucking out 2.1A, so you’re feeding at 5% of mains power.

  9. Rob
    May 10th, 2013

    I thought it would be helpful for you or anyone visiting to know about 18650 batteries. Being in I.T., I’m sure you’ve had to replace dead laptop batteries from time to time. Even non-techie people do it. Then, most figure the battery is dead and just recycle it. But, actually, it is still quite useful.

    If you crack open the laptop battery pack (kind of hard to do, but shouldn’t take more than 10-15 minutes), you’ll see it comprises of several small batteries (google it for images). They are usually referred to as “cells”, as in a “6-cell laptop battery”. They look like AA batteries, but slightly larger. They are a standard, called “18650” (because they’re 18mm x 65mm).

    The main benefits of these batteries are:
    1) They’re made of Lithium (#3 on the periodic table), so they are awfully lightweight.
    2) They hold a much more power than Alkaline (3000-4000 mAh… each)
    3) Accessories for them seem to be cheap/reasonable:
    3a) Here is a charger for 37 cents ($0.37 USD):
    3b) Here’s a 1200 lumen flashlight for $12USD:
    3c) Simple charger and USB battery pack:
    4) The batteries themselves can be acquired for free!

    But wait, free batteries? I mean, sure, you can get dead laptop batteries for free, but what good are those?

    Turns out: when a laptop battery pack dies, it’s usually just one of the cells that goes bad. I could go into how the charging circuit load balancer powers all cells equally until one cell dies, then its resistance drops and takes over yadda yadda, doesn’t matter. Just take each cell and try to charge them in the battery charger you purchased until you find one that won’t charge. Recycle that one and use the rest.

    I found a single battery will power my flashlight (SSC P7 900 lumen) for 24 hours straight. I have a 4-pack as my main bicycle electrical system (BES) which is connected to, among other things, my headlamp, taillights, and and extra USB ports for friends’ phones. I have found that it will top off my cell phone dozens of times, or fully charge it 4 or 5 times. For long trips with limited AC power access, I just bring an extra handful of batteries.

    Hope someone finds this helpful.

  10. dragonfly
    November 23rd, 2013

    Hi Dave,

    I have been cycling in Vietnam for a year (just finish my trip from Hanoi to Saigon). I like to share with you the various set up I have been experimenting to meet my electrical need while on the road. But my electrical need is not quite the same as yours in that I own a Sony Vaio laptop (Z-Series) among other things like cell phone, GPS and camera. Also my method is more DIY than yours.

    Here is the things I have tried.
    My laptop battery has a charge content of 8Ah and takes max charging voltage of 12V at max current of 2A. There are three methods that I have tried successfully.

    1) I installed four Tung-Lin bicycle dynamos on my bike. Connected them in parallel to up the Amp.
    The Tung-Lin generator is the only bike generator I have found that have the right voltage and Amp for this
    purpose. It is rated at 12V and 0.5 Amp, so in theory, with four in parallel you get 12V and 2 Amp.
    However in practice, you get about 12V and 1 Amp pedaling at about 15km/hr. This is because it is hard
    to pedal fast enough to generate 24Watts of power. With this method I can fully charge my laptop battery
    in 7 to 8 hours of biking.

    Here is the link to the Tung-Lin dynamo at Amazon:

    2) This method is a solar method. Here I used the Brunton 26 Watt Foldable Solar Array. I also used a
    stand-alone laptop battery charger. Also I wanted to charge my battery while cycling so I constructed a
    “Top” for my bike out of stainless steel tubes but you may or may not need this. The “top” can be disassembled into 16 stainless steel rods and put away along with the Foldable solar array when not used. This method can also charge my battery in about 7 to 8 hours

    The advantage with this method is you don’t need to deal with the drag from the dynamo, but the solar array
    is not small (50 cm by 100 cm). It is the only solar array that can charge a full size laptop.
    Here is the link to the Brunton Array:

    3) This idea is just like number 1) but use one dynamo instead. But you have to build this dynamo.
    I used the “Hacker A50-16L Brushless Outrunner RC Motor”. This is a motor used by toy hobbyist to make
    toy vehicles. This method is very complicated and you may not want to do this. But basically I had to
    use a gear couple to the motor to step up the rotation of the bike wheel. Then I have to build my own
    friction wheel with the right diameter to output 2A at 10km/hr biking speed. Also I fabricated a water tight
    aluminum housing for the motor and two aluminum supports to support the whole contraption at the front
    wheel. I used two springs placed inside the two supports to make the friction wheel pressed to the front
    wheel. This took a long time to build and in the end it worked very well. With this method, I can charge
    my battery in about 4 hours. This is the same rate that it would take if I plug the stand alone charger
    into the wall outlet. However the down side is it is very heavy to pedal so I can only go at about 7km/hr.
    For this reason, I later adjusted the diameter of the friction wheel so that I can bike at 10km/hr. This
    made the pedaling not as heavy but it reduced the output power and take longer to charge my battery.
    So in the end the charging rate is the same as that of method 1). Thus the lesson is: The charging rate
    depend more on the individual pedaling ability than the dynamo. In other word, how much power can your
    body generate? and how long can you maintain it will determine how fast you can charge your battery.
    Here is the link to the Hacker motor:

    In summery I found method 1) and 2) very effective. I used both. When it is sunny, I used solar and at
    night or in the cloudy rainy weather, the four dynamo are very effective.

    Check out a picture of my bike with the solar array

    Also you might find this thing useful. It allow you to see exactly how much current and charge enter your
    battery in real time while you charge.

  11. March 6th, 2014

    Thx for fast tweet response. Using 11,000 mah battery for iPhone w/gps & map app with screen full bright. Good for 2-3 days but uses 110v to recharge. Usually carry Mophie Juice Pack as backup. My power needs are typically iphone use for 3 day rides to record data with BikemateGPS app and motel to recharge each day. Might try camping with elec hookup. Experiment in progress!

    Testing the water for touring. 245K solo ride 3 days last year. About 6.5 hrs for 100 miles 1st & last day. Really excited about trying touring camping this year with Eureka Solitaire tent. My 1st lightweight randonneuring/cycling tent!
    Decided to try a cheapy speaker system with an old iPod shuffle 1st Gen. Satisfied. Speaker uses just 1 AA battery so carrying spare batteries is not an issue & haven’t used speakers for any rides before as I usually use Bluetooth & don’t listen much to
    music on rides. Prefer the solitude.
    Was considering a Son hub for my Trek Navigator. My power needs are less because of daily charging.
    One issue I haven’t cracked yet is where to carry a sleeping bag. Rear rack panniers w/ top bag I need access to. Low rider rack on front w/ handlebar bag & speaker. Can you suggest a way to carry a large sleeping bag?

  12. July 26th, 2015

    Nice article but what I would like to know how is what amperage to set on any given device that needs to be charged.The volts is clearly listed but not the amps if only the makers of the E-Werk gave this out when you purchased their device or maybe they either expect purchasers to be electronic engineers or people that learn by trial and error.


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