Revolution FAQ

What devices can I charge with the Revolution?

The Revolution output is a standard USB charger (5V), and can provide up to 1 Amp. If your device can charge from a standard USB connector, it should be able to charge from the Revolution. This includes iPhones®, smartphones, GPS devices, USB battery packs, headlights, rechargeable speakers, etc...

How fast do I have to ride to charge my phone?

With a hub generator, charging starts at only 3.5 MPH (5.5 km/h), although this can depend on your device's ability to trickle charge. At only 9 MPH (14.4 km/h), charging is as fast as a wall-powered charger.

    Will I damage the Revolution when I ride too fast?

    No, you will not. Many dynamo-powered electronics suffer from this problem. Even products that claim to be “protected” will actually draw extra power and heat up when you go faster than about 20 mph (35 km/h). The Revolution has a novel, integrated protection circuit that will not draw extra power or heat up at any speed.

      Is the Revolution weather resistant?

      Yes. The Revolution can be left on your bike in the rain. Click here to see the Revolution working under water!

        How can the Revolution be so waterproof with an open USB connector?

        First, the electronics are fully encapsulated in epoxy.  This means that water can not touch any of the components, even if it gets past the connector.
        Second, the USB connector itself features gold plated contacts that will not rust or corrode.

          Can the Revolution stand up to shocks, vibrations, and off-road riding?

          Yes. The electronics are fully encapsulated in epoxy. In addition to providing complete protection from the elements, this makes the Revolution extremely resistant to bumps and vibrations.

            Why does it take 15 seconds for charging to begin?

            Some devices, such as the iPhone®, require a minimum amount of power to charge correctly. If charging begins before input power is sufficient, the device may refuse to charge. The 15 second delay gives you time to reach a minimum speed. This allows you to charge an iPhone® or other devices that would not otherwise charge correctly.

              How do I mount the Revolution to my bike?

              The Revolution can be mounted anywhere on the bike with the included zip-tie. If you plan to often install and remove the Revolution, we recommend using a reusable zip-tie. Alternatively, the Revolution is small enough that it can easily be placed in a pannier or handlebar bag.

                Does the Revolution have a built-in battery?

                No - and this is a good thing. Most chargers that include a "cache battery" do so because they are not efficient enough to directly charge a phone - they must slowly charge a battery, then charge the phone from the battery. This adds further inefficiency to the system, as well as a delay while the internal battery is charged. The Revolution is able to directly charge your phone, making the cache battery unnecessary.

                  Some chargers have a larger built-in battery, meant to store a large amount of energy. There are several reasons we don't like this system:

                      1. Product lifetime. Batteries wear out. Even the highest quality lithium ion battery is rated for about 3 years from manufacturing, independent of how much you use it. There's nothing in the Revolution that wears out. When you build up a touring bike you select parts based on reliability and durability first, and everything else second. We want the Revolution to be the same way.
                      2. Efficiency. The extra steps to charge the battery, then use the battery to power the output is a significant hit on efficiency. Most users directly charge their phone, and the extra conversion steps mean wasted energy.
                      3. Flexibility. A product with an internal battery is stuck with that one battery, which may be too small for some users and too large for others. There are many USB battery packs available in all sorts of shapes and sizes and capacities. The freedom to use a battery that fits your bike and your tour is lost when an internal battery is used. This also allows the Revolution to be as small as possible.

                      Will the Revolution work with my dynamo?

                      Yes. The Revolution can be used with any hub, bottle or spoke dynamos. Any standard 6V/3W dynamo will generate enough power for the Revolution to charge your device. We have also had good results with 6V/2.4W dynamos.  The less-common 12V/6W dynamo can be used as well.

                        How do I connect the Revolution to my Dynamo?

                        This varies by dynamo type and manufacturer. The exposed ends of the wire can be used to connect to any dynamo. Consult your dynamo’s instruction manual.

                          Can I connect the Revolution to the taillight output of my headlight?

                          This is not recommended.  The main reason is that, since the taillight is turned on and off with the headlight, the Revolution will only be powered when the headlight is on.  In most cases you want to use the Revolution when the headlight is off, and vise-versa, and this is not possible when using the taillight output.

                            Can I use the Revolution and my lights at the same time? 

                            Yes. Simply connect the wires to the dynamo along with the headlight cable (in parallel). The dynamo power will be shared by the Revolution and the headlight, so we advise unplugging your phone/gps/device being charged to ensure that your headlights are at full brightness. You do not need to disconnect the Revolution - it draws practically zero power when not charging a device.

                              Can I use the Revolution with an e-Bike battery?

                              Yes.  The Revolution works with e-Bike batteries up to 36V.  The Revolution has no polarity to worry about when connecting to a battery.  Note that many e-Bike systems have a 12V accessory output and this can be used to power the Revolution.

                                Can I use the Revolution with a regular battery? 

                                Yes. The Revolution works with any DC input voltage above 6V, up to 52V. This means the Revolution can be used as an emergency charger with a 9V battery, car battery, 4 AA or AAA batteries, etc.

                                  Can I use the Revolution with a solar panel?

                                  Yes. A solar panel generates DC voltage so the Revolution will work with a solar panel the same way it works with a battery.

                                    Will the Revolution damage my device?

                                    No. The output is fixed at 5V, so unlike chargers with an “adjustable” output, you can not accidentally damage your device with incorrect settings. The high speed overload protection circuitry will protect the Revolution and your device from the high voltage generated when you go fast.

                                      How much power does the Revolution draw when it is not in use? 

                                      By itself, the Revolution draws only 0.025W at 35 km/h. The current draw is only 1.6mA.

                                        Do you have any recommended USB battery packs?

                                        Most USB battery packs are very flexible and do a great job charging from the Revolution, even at low speed.  If you simply want to charge a battery while riding and use it later to charge your devices, almost any battery pack can be used.
                                          If you want to use your battery like a buffer, and connect from Revolution to battery and battery to USB device, you need a battery that supports 'pass through charging'.  This feature is not always clearly advertised and is implemented differently by different brands. 

                                            How can I test that my Revolution is working? 

                                            Wiring and connection issues are the most common causes of problems. Because the Revolution can be powered by a DC source it can be tested independently of the wiring and the rest of the system:
                                                1. Get a 9V battery (fresh, if possible)
                                                2. Disconnect the Revolution wires from the dynamo or any other devices.
                                                3. Plug a USB device into the Revolution USB connector.
                                                4. Touch the Revolution wires to the battery terminals (polarity does not matter).
                                                5. After the usual 15 second delay the USB device should start charging.
                                                If this test works, the Revolution itself is OK and any problems lay elsewhere, most likely the wiring, connections, or dynamo.

                                                  What if I have a question that isn't answered here?

                                                  Please email us at