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Mobile Energy Supply

The list of electrical equipment on a bicycle trip is longer from time to time. In former days there was only a flashlight, today digital camera, headlamp, tent lamp, cell phone, MP3 player, GPS device and tablet PC are with us. And these devices have to be supplied with electricity far away from any power outlets. But how?

Hub Dynamo

Meanwhile sprout different charging systems from the ground, which are supplied from the hub dynamo of electrical power. It all started with the so-called Forum loader, a DIY project. This was followed by the Zzing from Berlin, also with the batteries (AA) can be loaded. The upper end of the price scale mark the moment the E-Werk and from Busch and Muller The Plug of Tout Terrain.

Magazine Fahrradzukunft (DE) keeps us ready with a good market overview of chargers with and without backup battery:

Busch und Müller E-Werk / USB-Werk

Our first try with getting Electricity from our hub dynamo was with an E-Werk, it {--has the best efficiency of all chargers and--} can score with adjustable voltage and amperage – whether one really needs this feature is another question. In 2011 whithin a very short time period there broke down both of our E-Werks. Busch und Müller changed the main board in one of them. Because of unreliability we sorted them out together with the belonging buffering accus.

ToutTerrain The Plug

The Plug disappears correctly in the steerer. However, it provides only 15 km/h of energy. In Tout Terrain represents one's position: "Either a full five volts or nothing, as some consumers with a fluctuating voltage caused problems." With children you drive rarely more than 15 km/h, therefore The plug is not suitable for us because it would hardly deliver electricity. Meanwhile they have a new version (The Plug II) which delivers electricity while driving slower. We could not test this til now.


Heiko's new Norwid traveling bike, that was ordered in 2014, has got a forumslader with integrated buffering accus in early 2015. We think it gets about double electricity from the hub dynamo. This is because of our now velocity and the four stage converter. The forumslader desappears completely in the head tube. In combination with the inside dynamo cable there is a very clean optic. The only visible thing is the USB-Cable leaving the ahead cap.


While cyclists can rely on the power of their hub dynamos, this source of energy is not available with walkers. But there are now very robust solar cells.

SolarCards from Sistech

We recommend warmly the Solarcard (voltage: 5 V) of Sistech from Switzerland to you. Do not be put off by the somewhat lurid text on the homepage, the modules are fine. Waterproof welded, tropicalised, flexible, light and durable – no kidding.

SolarCard (2.5 W) of SISTECH during direct loading an iPod. Due to the slightly varying voltage but should always buffer battery are interconnected.

SolarCard (2.5 W) of SISTECH during direct loading an iPod. Due to the slightly varying voltage but should always buffer battery are interconnected.

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We use the smaller version with 2.5 W. She is now no longer available. There are "only" solar Cards with 5 W, either as SolarCard ATON in DIN A4 format and as SolarCard HORUS in the format of two vertically superposed A5 sheets: solar Cards from Sistech.

We need the hub dynamo for powering the GPS device, that is why the new SolarCard ATON stucks on the back to charge the smartphone or a buffering battery.

We need the hub dynamo for powering the GPS device, that is why the new SolarCard ATON stucks on the back to charge the smartphone or a buffering battery.

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In 2012 Sistech sponsered a SolarCard ATON. In contrast to the smaller SolarCard having a Nokia connector, the larger one has a MicroUSB connector. The direct charging of Heikos Samsung Galaxy Y Pro works fine. Within two hours it is charged in the sunshine. Even on a cloudy day the charger works, it just lasts longer.
We cannot charge Claudia's Samsung Galaxy Ace 2. Even in intensive sunshine the capacaty increases only some percent per hour. With an puffer battery it works fine of course. {--We are searching for the problem, but --}we think it is the telephone that cannot use the offered electricity in an efficiant way.

The SolarCard ATON is listed with a nominal output of 5 W (equal 1 A). In bright sunshine with optimal orientation in our lines of latitude we metered 0.7 A at 5 V, that means 3.5 W. Since 2014 Sistech offers a bigger SolarCard with nominal output of 10 W. We think that this cell can produce 1.4 A respectively 7 W.

The advantage of the SolarCards is, that they produce electricity even when the sky is cloudy. Our 5-W-SolarCard delivers nearly 0.2 A when exposed to indirect solar radiation, this means nearly 1 W.

Anker PowerPort Solar

The SolarCard delivers summa sumarum not enough energy for our use. That is why we ordered an Anker PowerPort Solar 21 W. The result is very disappointing.

  • In direct sunlight we metered 1.8 A, that means 9 W, which is very far away from the given 21 W.
  • The new devices do not only get electricity, they contact the power supply (in this case the photovoltaic module) before charging via the USB-Bus, and they agree over the amperage. Every cloud nullifies this result of the negotiations, the charging stopps. If the cloud moves away the PowerPort does not return to normal charging without restart (folding completely). This is not acceptable.

GoalZero Nomad

In 2018 we want to try a photovoltaic module from GoalZero. We keep you up to date.

Operating the GPS device directly

Our Garmin can be powered directly via the built in USB connector. Belonging to the brightness of the display it needs 0.1 to 0.2 A. When the energy supply ends (you are traveling less than 7 km/h or stop cycling, and you can be ensured, while traveling with children you stop very often!) the Garmin gives a status message, that the energy supply ends, and it asks what to do. If you do nothing, the garmin exits 30 s later. It only stays alive if you press the corresponding button. That is a very stupid solution and is not configurable.
Bicycle travelers normaly have longer times while driving, then this behaviour is not a disadvantage. But the hub dynomo offers more than 0.2 A, so the rest will not be used if riding without buffering battery. So if you want to charge a cell phone in the tent at the evening you need a buffering battery.

Buffering batteries

The electrical devices are operated on a cycling trip to the limits of their range of application in terms of vibration, humidity and temperature fluctuations. Not just once a device has given up because of the fluctuating voltage. E.g. an iPod mini, and it could only be reactivated back at home. Only our Garmin Oregon, which is designed for this hard operations, never bricks.

Therefore we recommend phones, MP3 players, chargers, etc. not to charge directly through the hub dynamo via an unbuffered rectifier. A buffer battery is in our opinion essential. This has the pleasant side effect that you charge the buffering battery while driving and in the evenings in the tent you can comfortably take care for the loading of small electric consumers. The other thing is that you, while driving, don't have to check permanently, whether the connected device is already loaded and you have to plug it in next one so that no energy is wasted.

That is the theory. In praxis it looks like, that the industry has big problems to build a long lasting robust buffering battery.

Busch und Müller buffering battery for E-Werk

Busch and Muller offers a waterproof taped up battery since 2010. The supply list of the E-Werk also includes a miini-USB connector, that can be used for supplying the GPS with power. Our experience: from an average speed of 10 km/h, the electric power is just enough.

Mini USB connector for direct connection of the GPS device to the power supply.

Mini USB connector for direct connection of the GPS device to the power supply.

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The buffering battery cannot be used for charging your cell phone in the evening in the tent because it is hardly mounted at your bike, and there is no display of how much energy is in.
Another disadvantage is that the USB connector, which runs with the E-Werk/USB-Werk, rusts. A gilded variant would be nice here. You must also not touch the plug, which sits a little bit loose in the socket, or the GPS unit has no power and halts immediately. The workaround includes a little knife as tool. Therefore, even during direct operation, always leave in batteries for such cases. Perhaps it would be better to offer an angled mini-USB connector, which would not be so far from the unit: a tip for Busch und Müller. In addition, the Garmin devices have difficulty detecting the external power supply when the USB connector is full of water. In case of rain, for example.

We don't use the buffering battery from Busch und Müller any more since 2013, because two of them bricks within two years in use.

Busch und Müller headlamp Luxos U

Since 2012 Busch and Muller offers a new headlamp (LUXOS U) with integrated Li-Ion battery and USB socket on the light switch, which is mounted on the handlebars. In our first Luxos the battery was defect from the factory on. The replacement unit was defect within two weeks after a big rain, the bike lied on the side in the grass. But in the two weeks we found out that the battery in the Luxos headlight is much too small. In addition, the rectifier does not provide enough energy to charge GPS or cell phone. Nice idea, but unfortunately not suitable for cyclists. On demand, Busch and Muller confirmed to us this issue, and recommended the E-Werk, that we had in use until we switched to an inside head tube Forumslader in 2015.

Sistech PowerTanks

Until 2015 we used two PowerTanks from Sistech, because they can be charged and discharged at the same time. This is the precondition for powering your GPS while driving and storing the surplus energy in the battery for charging your cell phone or digital camera in the evening. The smaller PowerTank has a loose contact for some months. And the big PowerTank bricks at Whitsun while driving. This one has been defect two times before, each when the temperature was under -5 °C, but its temperature range is written down til -20 °C. Each time it was possible to enable the integrated LED (it lasts weeks til the battery is empty), and after total discharge the device started and could be used again.
Since Whitsun the device is dead. A click on the push button reacts the system with a short blink of the display.
[Update]In the meanwhile the accu is working again. But we protect it from deep temperatures, and we don't take it on cycle tour again: carrying unuseable 255 g is without sense.[/Update]

Xtorm Power Banks

Xtorm sends us two wonderful 15 Ah Powerbanks for testing. The devices have a built in USB plug for connecting with the USB female connector of the E-Werk. The device also has a Micro USB connector, there you can plug in the SolarCard. The great thing is, that the PowerBank can be charged on both inputs simultaneously, there is nothing comparable on the market. We metered 4 W over the Plug and 3 W over the Micro USB Connector at the same time. That is ideal for bicyclist.
In addition you can charge three(!) devices at the same time with together 3 A, e.g. a tablet (2 A), a cell phone (0.7 A) and an iPod nano (0.1 A).

Unfortunately the PowerBank can either be charged or discharged. Therefore you cannot use it as buffering battery.

One of the two power banks was defect after unpacking, the other was stolen ...

Xtrom PowerBank Free is charging a Lenovo Yoga Tablet (8")

Xtrom PowerBank Free is charging a Lenovo Yoga Tablet (8")

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Anker Astro E7

Running out of energy is not fun, so we bought an Astro E7 in 2017. The advantage: there is always enough energy. The disadvantages: 490 g and no charge-through.

What next?

{--Seen from the hardware we don't have any solution for a GPS buffering battery. The Xtorm PowerBanks seem to be very robust. We will see, maybe Xtorm will update their platines so that charging and discharging at the same time woult be possible.--}
A soluten for every problem. We fixed this by integrating a Forumslader to Heikos head tube.


Pixo C-USB

After a long search and some bad buys we have found a charger that can be connected to USB (5 V), and that can only NiMH batteries of size AA (AA) and micro load (AAA) as well Li-Ion batteries with 3.6 V and 7.2 V. This is the Pixo C-USB Universal Charger, the one-for-all machine, if want her so. It works very well, and is barely noticeable warm, which indicates a very high efficiency.

The Pixo Charger when loading a Li-Ion batteries (digital camera) with 7.2 V. In the background lies the daytime charged Power Tank from Sistech. Note: Pixo does not longer exist.

The Pixo Charger when loading a Li-Ion batteries (digital camera) with 7.2 V. In the background lies the daytime charged Power Tank from Sistech. Note: Pixo does not longer exist.

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Single drop of bitterness: There can be only two AA or Micro-charging the batteries at once, although the housing definitely still has room for two more charging bays.

The C-USB was stolen in 2016, it is no longer produced.

Ansmann PhotoCam Vario

Again, we had to search a long time to get a replacement for the Pixo C-USB. At least we found the Ansmann PhotoCam Vario, that is able to charge NiMH-Accus and 3,7 V and 7,4 V LiIon-Accus and is driven by 5 V. Unfortunately one can only charge exactly two NiMH-Accus whith no single battery monitoring. So it is not possible to charge the three accus of a Petzl Head Lamp if you are on tour.

Choosing the right equipment

An example of a device that we can not charge the way, is Claudia's cell phone Sony Ericson W508. Absolutely do not want it to be loaded via a USB cable, but instead always expected at the other end connected computer. Function even when the charging device, this would still not suitable, because the manufacturer has developed a plug over which the data is transmitted, a headset or speaker can be connected or indeed a charger. It can, however, connect only a part, so shop and simultaneously listening to music through external speakers would funktioneren not so.

When choosing the accessories that is the "chargeability way" plays a big role. Either it can upload directly via USB or it can be run on regular batteries which can be recharged on the road easily. If the device has a Li-ion battery, can go out to you, offering also to yet, this external charge on the Pixo.

More energy

On his North Cape Tour 1993 Heiko has driven an average of 21 km/h with a regular travel time of about five hours per day. In that case you don't need to think about flagging batteries. Each evening there will be available about 20 Wh. No problem to run a tablet PC for updating your own blog.

In the wheel of our Bob trailer we mounted a 28" SON hub dynamo, because of the small 16" rim as a specion version with only 28 spoke holes. We can charge a second Li-Ion-battery with a second E-Werk. The smaller wheel rotates 50 % faster, therefore it provides more power. At a speed of 10 km/h the battery is already loaded with a power of 2 watts, and at 20 km/h there is already a power of 4.5 watts. After three hours cycling we can "burn" 6 Wh in the evening.


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