The SON 28
The SON 28 is designed to deliver high performance even at low speeds, such as 15 km/h. This allows it to generate enough power to operate the bicycle lighting or to charge external devices like a phone or navigation system while riding. The SON 28 meets the legally required voltage output for all wheel sizes up to 28/29 inches.
The SONdelux
On the other hand, the SONdelux is specifically designed for LED headlights, like the SON Edelux II. The voltage curve of the SONdelux increases a bit more slowly, meaning it requires a slightly higher speed of around 20 km/h to generate the same voltage and performance as the SON 28 does at 15 km/h.
Modern LEDs are capable of producing a significant amount of light even with low electrical power. While the SONdelux may have lower light output at speeds below 20 km/h, it still provides sufficient brightness of over 60 lux at 15 km/h to ensure visibility during the ride. Above 20 km/h, the difference in brightness between the two models is practically negligible.
Further Differences
The SONdelux utilizes a reduced magnetic system, allowing for a weight reduction of up to 50 grams depending on the hub model. It is optimized for low rolling resistance and lightweight without compromising the strength of the housing. This reduces the average power demand by approximately 15%. When used as a hub dynamo, the additional power requirement with the lights off is negligible and barely noticeable. Therefore, the SONdelux rotates faster than the SON 28 to achieve the same output, making it more suitable for rides at higher speeds (< 20 km/h) or bicycles with smaller wheel diameter.
When the bicycle light is switched on, the power demand significantly increases as up to 4 watts are supplied to the lighting system. In this scenario, the SONdelux can showcase its technical advantages. The power loss caused by the SON hub dynamo is so minimal that turning on the lights has hardly any noticeable impact. Compared to a conventional front hub without a dynamo, the power loss with the SONdelux at a speed of 25 km/h is less than 1%, and for the SON 28 it is around 1.2%. Therefore, it requires only a minor increase in effort. While it is possible to turn off the light in broad daylight, it is recommended to always ride with lights on in cloudy weather and in urban traffic to enhance visibility to other road users.
