Dynamo Hubs

Models

There are other manufacturers, variations and rebranding of SP hubs. For 15mmx110mm consider a 100mm hub with a conversion kit. ¹ is a German regulation which stipulates the amount of output power at 15kph with a 26" wheel. Using the dynamo in a smaller wheel increases wattage but also drag while the opposite is true for a larger wheel. 2.4W hubs are not recommended for USB charging when riding at slower speeds.

USB Chargers

Igaro

D2

The Igaro D2 is designed to be small, performant and informative. Due to it's lack of storage it's best suited to more stable speeds of the sort found on longer sections of road, which avoids stop/start situations. Most USB devices will charge well from the Igaro D2 and auto-reconnect technology alleviates issues from the variable speed of the bicycle. Some USB devices may charge sub-optimally and riders may choose to put the power into a USB power-bank instead. Most users place the Igaro D2 in a small top-tube bag although the under-stem mount we offer is also a popular option.

S1

The Igaro S1 inherits the Igaro D2's qualities but adds huge super-capacitors making it the better option for variable riding conditions of the sort found on 'bikepacking' trips. All USB devices charge optimally from the Igaro S1 and a USB power-bank need only be considered for capturing excess power over longer-duration riding. The Igaro S1's design places indication lights in the riders field of view and offers inherent USB protection from rain.

Attributes

We have done our best to ensure data is valid and up-to-date. Please contact us if this is not the case.

¹ current is the maximum supported (manufacturer specification) but is limited by dynamo hub characteristics and may burst only while internal storage charge (if any) is available. ² Excludes USB port which will suffer electrical corrosion. ³ PCB protected from vibration by silicone or epoxy fill. ⁴ prevents rapid power cycling at low speeds which can software lock or damage some devices. ⁵ Excludes cabling and optional accessories. ⁶ Color rating reflects component selection and packing effort. Value excludes any mounts/brackets. ⁷ U.K price inc. VAT, exc. postage - priced @ 27/Dec/22

Performance

We can't directly compare devices with internal storage (like our Igaro S1) to those that don't (like our Igaro D2) due to storage skewing the output. Instead we use our automated test-rig to run separate tests.

These values assume a perfect USB device (a resistor!) is consuming power. For real USB devices there's potential factors to consider - see our compatibility page for further information.

Kph values are based on a 700c wheel.

With Storage

With storage depleted we record the True Power from the dynamo hub. This is a measure of how much power the device is consuming, however by itself it's meaningless as the device could be transferring power into storage using an inefficient implementation. We can't say whether a higher or lower power is better unless we know what happens with it.

These values are recorded with the storage level at half of the maximum capacity and no load applied to the USB output.

With three manufacturer supplied efficiency values; one to calculate power being transferred into storage, one to model storage loss, and one for conversion of the storage into USB voltage, we can make the above data meaningful. These values will vary based on input voltage and output current and are averaged across them. They are based on the storage level being at half of the maximum capacity.

These values may vary considerably when storage level changes. For example the Igaro S1 Pro has an output efficiency of 99%+ when its super-capacitors are 95%+ charged.

Power is converted into current by dividing by 5 (volts).

Finally we calculate an average of the speed/current ratios and estimate the speed at which USB current requirements could be met. Because these values are predicted we wont merge them into the table for devices without storage.

Without Storage

For these devices we use a test-rig program which automatically determines the lowest speed at which USB specification current levels can be met. This program requires no human intervention and guarantees repeated accuracy.

Please be wary of comparing these values to those provided by other websites, which are often using inaccurate test equipment or bending the truth to promote sales.

All values are with the minimum USB voltage specification of 4.4v being met. If the device falls below this voltage the test will automatically end. ¹ Failed due to erratic behaviour (evidence on YouTube channel).