'Interesting' Observations On Traction Battery Recharging And Other Things

Discussion in 'Gen 5 Prius Main Forum' started by VelvetFoot, Nov 28, 2025 at 8:10 AM.

  1. VelvetFoot

    VelvetFoot Active Member

    Joined:
    Sep 17, 2025
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    Location:
    New York State
    Vehicle:
    2026 Prius
    Model:
    LE
    My LE is still new, so I'm still learning.

    I've started driving around with OBD Fusion displaying Engine RPM, Engine Coolant Temp, Oil Temperature, and Battery Pack State Of Charge % on CarPlay.

    I noticed that the SOC increases when driving along with the ICE on and going uphill, ie, not regenerative.

    Also, unrelated, I got the SOC down to the thirties (%). How low will it go?

    Is keeping the heat turned off until the engine warms up to X degrees advisable or does the system take care of that-my HVAC is set to 'ECO'?

    On a side note, to look at other real time info, it'd be nice to get some custom PIDs for the OBD Fusion, or Car Scanner apps, which I've. found are the only CarPlay compatible apps available-again, as far as I've found.
     
    #1 VelvetFoot, Nov 28, 2025 at 8:10 AM
    Last edited: Nov 28, 2025 at 8:24 AM
  2. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
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    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    A portion of engine torque (about 1/5) is always going to the generator in a power split hybrid like the Prius. If the traction motor doesn't use all the electricity generated, the excess goes to the battery. I think this how most of the energy in the battery is generated; not from regenerating braking.

    With the Li-ion pack, around 20% capacity is put aside as a buffer. You might see it get down to 10% if you push it in EV mode. Otherwise, the system will mostly keep it closer to the middle of the range.

    In general, today's auto HVAC systems keep the fan speed low until the engine warms up. In the Subaru, the minimum point it starts heating the cabin can mean the coolant temp drops on freezing days. So I leave it turned off until the temp gauge gets closer to the middle. Advisable for you will come down to your preferences. Letting the HVAC just do its thing won't cause any harm though.
     
    #2 Trollbait, Nov 28, 2025 at 10:01 AM
    Xse and VelvetFoot like this.
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