Amp setting is set by the onboard charger to be the lower of the two: 1. Its own current rating. 2. The maximum current allowed by the EVSE as reported to the charger during the "shake hands". This is part of the J1772 communication and safety protocol and to my opinion it is obeyed in any car using this charging protocol including the Volt. So, not familiar with the Volt but I doubt its system breaks this safety feature by defaulting to certain current irrelevant to what the EVSE is transmitting to it in the communication line. So, if you want a limited low current to be used, you have to program it (or select it) in the EVSE (those that have this feature). With the PiP, OEM supplied EVSE does not have this feature, it is rated 15A (I think) without the possibility of setting lower current, and this (15A) is what this EVSE is reporting to the charger, and the current used in this case is always the charger rated current (~13A L1 and ~10A L2) because it is lower than 15A.
12 amps max in the US by law on any 15 amp electrical circuit. 80% max rule. Some level 2 EVSE's have internal switches for selecting among the common circuit amperage's used here in the US. Optional amperage settings are less than EVSE max rating and require an electrician to change according the their manufacturer. The cars onboard charger will only draw current up to the lessor of the EVSE limit or the chargers maximum design value irregardless of how much above this value the EVSE says is available. And possible/likely less like the Volts 8-9amps. Over lap with Giora, typing and transmitting in Morse code.
