I had the same in Golf 3 with the radio Pioneer 180ub. After changing the car to Golf 5 with the same charger and original Grundig RCD300 radio - no noise.
I can recommend you a better charger, but I don't want to do advertising. There will be less noise or not at all. The charger looks like the picture below. It can be bought, for example, at Orlen stations or at popular GSM wholesalers (partner, trade class). Alternatively, ask at some gsm service to order one. They will shout PLN 20-30. But if you have a bazaar radio, don't count on miracles.
With my Xiaomi redmi note 3 phone, the original Samsung charger in Golf 3 noisy almost all stations. Charged real 0.5A so that the battery disappeared during navigation. There was much less noise after buying this charger. The charging current is between 1 and 1.9 A depending on the cable. 1 A - original Sony / HTC 0.7M cables. 1.9 A - original Xiaomi / Samsung cable. Subject to! There are a lot of fake Samsung cables. For example, on my 4 Samsung cables, three charge with an intensity of 0.5 A or less, and the fourth, original from Samsung s5 charges as much as the factory gives.
After changing the car to Golf 5 - no noise on both cars. And after changing the radio to 2 din (Chinese on Android 7.0) you can hear a slight noise on this recommended charger. As for samsung - I do not know, it has long been in the basket.
I solved the problem by loading the phone from a 2 din radio that has 2 USB ports. After starting the car, the radio turns on giving a voltage of 5 V on usb. This voltage supplies:
- 3g router connected (internet to Yanosik and hotspot in the car)
- MIO video recorder connected
- And the ability to connect the phone on the cable pulled out under the handle on the glass.
Aesthetically made using a larger capacitor = no noise.
If you have a bad radio then the noise from the alternator will be heard.
Summarizing:
1. Connect the radio to the battery.
2. The quality of the radio itself.
3. Incorrect installation of the radio antenna.
4. Connection lighter - battery.
5. USB charger filters.
6. USB cable, micro usb connector wear - impact on charging intensity