Solar Panel 12v/ 120 Watt

Hello James
The USB port should be putting out 5V to a USB cable and that should charge things OK, Some electrical devices seem to have an inbuilt system which tells it if it has genuine charging equipment. That may stop the iphone from charging 'cos it isn't an Apple supplying device. Rotten apples!

The phone should not go flat though unless the connected usb makes it go haywire.

The regulator press button is probably a switch for the load connections to be operated on or off and isn't part of the charging regime. Aldi panels and reg are similar.
Unless the regulator has a bit of weight to it, to indicate it has a switchmode DC/ DC converter system inside it, I would think it is definitely not an MPPT controller at all and simply a pulse width type regulator.

Do you have the panel and regulator connected to a battery before trying any function including USB charging???? Essential to have it connected to battery. If not on a 12v battery the regulator will not know what to do as it has no refence voltage to work with. That might affect the iphone usb charging side.

A panel tha size in full sun should be able to supply around 8 amps to a discharged Gel or AGM battery, and when charged the regulator should reduce the voltage to a floating charge level of around 13.4v although initially for a while charging solidly it should be above 14.5v

Once the battery has been fully charged by the system that 13,4v or maybe 13,2v is regarded as fully charged, as a result the amount of current input (average) will be very low.

PS, the two outermost connections in the usb port should only have 5v at those terminals. Can be tested with a multimeter set on 20v setting (excellent tool to have any time) to check that supply voltage presented to the usb cable. Care must be exercised if testing, so ONLY the contacts are being touched and nothing else shorted out.

Where is the USB port you mention.

At the very least, all charging of devices should be by way of a 12v battery. The USB port would be an option on the battery box, or other device connected to it.

The solar panel by way of a controller and preferably a charger, simply provides a means of maintaining a charge to the battery bank it is connected to.
You cannot connect a USB "box" directly to the solar panel and expect it to work.

I,ve had a couple of the cheap regulators. In the bin now and bought a decent Victron MPPT. Works great. The cheapies put out in excess of 16 volts and performance was weak to say the least.