It's just bugging me in the back of my mind.... Weren't the electric motors in our PiP's made to go in a much lighter duty application (regular hybrid use)? I'm just wondering if over time they will wear or break down faster since they might not be able to handle daily heavy full EV use. Thoughts?
I'd direct this question to the people responsible for the existence of the PIP. No, not Toyota. I mean the folks who made their own Plug-In Priuses, using add-on battery packs. That began about a decade ago, so they should have real world info on motor wear. My guess is that because Toyota used to routinely over-engineer components for longevity, and because the Prius predates the 2006 takeover of the company by Junior, the motors were probably (even the latest generation) designed to handle much more power than the battery pack could provide at the time...
This thought crossed my mind as well. The arguments I gave myself (for peace of mind) were: I do not think PIP MG1 is working harder or more frequent than the regular Prius. Max power draw from battery is 27 kW for regular Prius and about 35-38 kW for PIP, both are considerably below the 60 kW rating of the MG2, so it is working under-loaded. Electric motors are working for years with no issue even when fully loaded.
It's electric motors, and those are known to be able to resist any amount of abuse. An uncle of mine was in charge of a city trolleybus fleet many years ago, they all had more than 600,000 miles on the clock and were still going strong, and that was 1950s technology. He often told me he was dreaming of the day when the technology could be applied to cars. Well, he's long dead now, but his dream has come true ! So, just use it, abuse it and don't worry about a thing.
You ask a good question because part of an electric motor design can be based on duty cycle, the ON time versus the OFF time. Motors designed for other than continuous duty can have less iron and copper since they are dependent on the OFF time for cooling. The regular Prius MG2 normally only sees high currents for brief periods when stopping and starting or for limited EV use. With the PiP the EV can be for a much longer period of time. You would need to know Toyota's design criteria for these motors. Without this criteria, you can monitor MG1 and MG2 temperature. I know from the 2010 Repair Manual the upper temperature range of the motors are quite high. I would think monitoring these motor temperatures should help answer this question for you.
Of course only time will tell but the motors in a Prius are operating all the time when the gas engine is running as well and, as someone noted, are operating well under the design peak capacity in EV mode due to limitations in the power output of the plugin's battery pack. I'm sure Toyota considered all of this carefully. I wouldn't worry about it any more than any other major powertrain component. Do you worry about the water pump as you are driving down the freeway?
For a temperature reference I went back and checked the 2010 Repair Manual. MG1 Temp High - 334F (168C) MG2 Temp High - 324F (162C)
Supposedly, the Gen III was designed from the beginning with plug-in use in mind. Technology File | TOYOTA MOTOR CORPORATION GLOBAL WEBSITE
Yes, and once again, that's because of the people who ignored Toyota's naysaying and adapted their Priuses to become plug-ins.