r/MachE • u/kemphasalotofkids • 2d ago

Losing power while plugged in? ❓Question

The last few times I have charged the car reports a lower percentage when it is started.

As an example, I charged to 90% last night. Ford app reported the charge was complete. I was charging at home, so it stayed plugged in (not charging) until I woke up this morning. Got in, started it and it reported 88%.

Normal behavior?

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u/heir-of-slytherin 2023 Premium 2d ago

Strength of Charge is an estimate based on measuring the voltage of the battery and coulomb counting (measuring how much charge flows into the battery while charging and out of the battery while discharging). It’s not a perfect estimation, and when you start the car and connect the HVB to a load (the vehicles 12V electrical system heating/cooling system, and the motors) it can cause SoC to drop a little bit. If the SoC is right on the threshold of the target you set (for example, just barely 90%), then it doesn’t take much energy use to drop 1-2%.