What's the best substitute to the adapter (charger head)?

Every computer with a running USB port can charge your iPhone.

This operation could be a little bit slower than charging your device via wall charger, and you need to keep your computer turned on...

Have you checked if you can find a wall charger, being sure that it's MFi certified? (MFi = Made for iPhone, iPod, iPpad).

Regards

Giulio

Any major, trustworthy brand of USB power supply should be fine. Belkin is certainly popular and easy to find - I have a Belkin 1amp USB power supply I’ve used with numerous iPhones back to my iPhone 4 with no issues.

I have also used vendor giveaway 1amp USB adapters at meetings in a pinch without issue. As long it outputs USB standard 5v and at least 1A the power adapter should be fine.

Whatever you use, make sure to use an Apple or MFI certified USB-to-lightening cable.