External USB connection - wireless charging

Some Stromer models (e.g. ST2 / ST3 / ST5) have a micro USB 2.0 output in the daytime running light. This is connected to the Omni-C using a cable. Some ST1 / ST1x models have a daytime running light but no USB connection.

Stromer advertises the connection of external USB devices such as smartphones, which can be charged on it. The output power is limited to 2.5 watts. This means that charging the smartphone takes forever, but may be sufficient for the dashcam or the trip computer.

The Stromer ST7 now has a USB-C port on the underside of the top tube, but unfortunately only uses the USB 2.0 standard, i.e. 5V and 0.5 A. 'Stupid' devices are supplied with up to 1 A. (Source)

If you unplug the existing cable on the Omni and install a corresponding socket in the stem in DIY style, you can also route the USB connection to the outside.
> See also 'Omni - Removal - Removal Tool (SUI NutTool)'

Here, for example, you can see a wireless charger on an ST5.

Possible voltage sources

1. If 5 V at the USB connection is not sufficient, you can use a step-up DC-DC converter. Note that a maximum of 2.5 / 5 W is still only available. (Source)
   
2. Another pick-up source would be a Y-junction on the Omni JST connection of the daytime running light. This provides 12 V, e.g. for additional indicators. The Stromer dealers Riesewijk and Vietz apparently tap into this voltage source for their blinker conversions. > See Turn signal.
   
3. By means of a step-down DC-DC converter (1 | 2 e.g. from Amazon), a very simple solution can also be realized. The input voltage is taken directly via a Y-branch at the bottom of the battery output in the bottom bracket shell. To avoid interference in the electrical system, it may be necessary to suppress interference from In/Out with a Sheath wave filter necessary.
   
4. Here a somewhat older manual from 'Deszynski' on how he realized a USB connection on his Stromer.
   
5. The website gpsradler.de also describes how to retrofit a USB port on an e-bike, but not specific to Stromer. As a source of ideas, it is worth a visit.