With the radio fully charged, and my iPhone 16 Pro Max at 32% battery I plugged it in and and let it start charging.

Immediately upon plugging the phone in, the radio battery indicator dropped to 1 of 3 bars and the phone started charging.

The phone made it to 33% charge and then stopped charging. I removed the voltmeter to see if that was affecting it but nothing change.

I hand cranked the radio for several min to see if that would help and did not see any notable change. The radio would play fine, it just didn't have what it needed to charge the smart phone.

A this point, I would not recommend relying on this radio to charge your smart phone. There are much more effective ways to charge your smart phone when the power is out. I would recommend a power bank for the job.