DC-DC-Converters

Here is a comparison of some DC-DC-Converters for USB-supply.

All electric bikes have a battery and everyone uses smartphones. So you need converter. So I can advice you, which kind of converter you can take to charge a mobil phone.

This converter hasn’t any inteligence inside. It offers just 5.1 Volts. Meanwhile, since this year (2022) this kind of converter ( here GYVRM K480508 ) is avaiable with USB plug.
Example of charging of a mobil phone with a DC-DC-Converter. This converter recognices, if the consumer load wants more current and rises the voltage, if necessary.
Don’t tacke car converters. This 12 volts car converter can’t supply any phone, because the voltage isn’t stable.
This abnormal use of a converter is only possible for low-costs-AC-DC-converters, but it works. If you buy a normal cheap converter, it may work with a voltage over 45 Volt DC, as you see here on the foto. If you buy a very, very cheap one, it may work even with a lower input voltage (over 25 Volt DC). But the output is often low. For example 4.6 Volts (instead of normaly 5.2 Volts) at a small current of 0,6 Ampere.

To charge a smartphone (or other small devices) via Mini-USB-cable or USC-C cable, you usually need a voltage between 5.1 and 5.2 Volts an an current between 0.7 and 1.5 Ampere. All batterys like slow charging. Avoid quick charging processes.

This is only the begining of my consulting. More later.