LectricGT
Active Member
- Joined
- Jun 24, 2022
- Threads
- 3
- Messages
- 25
- Reaction score
- 39
- Location
- Wisconsin
- Vehicles
- 2021 MachE GT
- Occupation
- Electrical Engineer
Yes, I understand all that.
My question is: Does anything else cause heat, or a bug that caused something to draw/discharge power when it shouldn't have been, to the contractors which could cause them to have been at a higher starting temperature, therefore making repeated WOT events and/or DCFC charging put the contactors in the "danger zone" temp wise? Whereas if this "something" wasn't drawing/discharging power, the starting temp would have been lower thus the max temp created from WOT events and DCFC charging would be lower, too.
This contactor (electromechanical switch) connects and disconnects the HV battery from the car. Anything that charges or discharges the HV battery will contribute in some way to heat developing in the contactor. The A/C compressor and cabin heat technically would contribute, but their contribution is dwarfed by the drivetrain, and these loads appear to be already taken into consideration with the drivetrain power limiting algorithm, anyway.
The other side of the equation is how well the contactor can sink and dissipate the heat that is created. Warmer ambient temperatures, warmer battery all work against this dissipation to some extent. Overheating would seem to be more probable on a really hot day than a cold one.
Another thought that came to mind was how the initial temperature of a calculation was seeded, whether by something such as a battery temperature sensor or making an assumption (e.g. always starting with 30Ā°C), and does this calculation stop once the car is turned off. If it does, then conceivably the contactor temperature could be pushed into the danger zone by turning the car on and off frequency (think very short trips) and doing those regular hard pulls. But this case seems rather remote since it would involve a rather specific and unusual operating behavior.
Sponsored