The SON 28 dynamo hub delivers its nominal power of 3W from 15km/h, while the SON Delux reaches this power from 20km/h. The SON 28 dynamo hub is therefore recommended for applications requiring maximum power at low speeds, making it the model of choice if you want to recharge devices while driving.
The SON Delux dynamo hub is optimized to be as light as possible (by optimizing the winding and not by compromising the strength of the body) and to offer the least resistance to rolling. It therefore needs to turn faster to achieve the same power and will therefore be suitable for cycling at a higher pace or for bikes with smaller diameter wheels.
Compared to a classic front hub, the loss of efficiency at 25 km/h is less than 1% for the SON Delux and about 1.2% for the SON 28
In addition to powering lighting, it is possible to recharge devices with a dynamo hub. Recharging devices requires the installation of the charger of your choice, which will rectify and transform the alternating current delivered by the dynamo to send it to your device.
The proper recharging of devices depends greatly on the charger chosen, but especially on their energy consumption and your pace. To guarantee the safety of your devices, choose a charger capable of managing the variations of the current delivered by the dynamo or the use of a buffer battery.
Indeed, at high speed (downhill for example), the dynamo hub delivers much more than its nominal power of 3W and it is therefore necessary to protect the devices during the recharge. For the most efficient charging possible, the SON 28 model is recommended.
To install the charger of your choice on your bike, you will need to install a bypass box. The bypass box is available as a spare part, but it is also possible to buy the SON Edelux II headlight with this box pre-installed.