Based on the protocol trace taken with software from Granite River Labs, at first glance the iVoler charger supports 15 watts (5 volts @ 3 amps), 27 watts (9 volts @ 3 amps), and 45 watts (15 volts @ 3 amps) power profiles. However, when you look deeper, the iVoler charger is issuing source capabilities that advertise different PDO's- one source capability advertises 3 PDO's (5, 9, 12 V) while another source capability advertises 4 PDO's (5, 9, 12, 20 V). Issuing source capabilities that advertise different PDO's violates USB Power Delivery Compliance.
In this previous review, we learned that the LG G5 can support 15 watts (5 volts @ 3 amps) or 18 watts (9 volts @ 2 amps) power charging profiles so ideally the LG G5 would charge from the iVoler charger at 18 watts (9 volts @ 2 amps).
From the protocol trace below, the LG G5 does request 9 volts @ 2 amps.
The LG G5 also does advertise it can support an Alternate mode adapter.
However, we observe that the iVoler charger is sending a HardReset message since the LG G5 does not send the REQUEST message for the Source Capabilities message sent by the iVoler charger. For some reason, the iVoler charger is sending the Source Capabilities message again even after a successful PD contract is closed, and there is therefore a continual series of hard resets ...
... with current staying at 0 amps ...
... which you can also see over long time periods.
The result is that the LG G5 doesn't charge at all from the iVoler 75W USB Type C Charger with Power Delivery and the 'Battery & power savings screen' on the G5 shows the battery discharging as if it wasn't connected to the charger at all.
Perhaps this is due to LG G5 unable to handle multiple PDO's but more investigation and analysis is needed to see what's going wrong.