The TomTom has here many POWER! Even with ongoing navigation and enabled Bluetooth, it loads the phone to quickly and permanently. In this case, the charger hardly heated. And it can then load a second device via the second USB port, but then only with the USB 500 mA typical.
Incidentally, the USB ports are swapped with my device. It took a while until I realized that: The fast loading goes with me only through the lower bushing; the top, with "quick-charge" called, invites slowly with 500mA. Maybe this helps one or the other, which therefore keeps his unit defective.
A note yet: Even with this device, it may happen that the Smartphone times "Slow Charging 'message displays. This happens especially when the phone is exposed to strong sunlight and therefore too hot. This is then not at TomTom, but at the charging electronics in the smartphone that wants to conserve battery power. It can help to mount the mobile phone from the vents and thus let cool by air conditioning.