Confused about traction battery voltage.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ianmeister, Sep 7, 2019.

  1. Ianmeister

    Ianmeister Junior Member

    Joined:
    May 21, 2019
    48
    19
    0
    Location:
    Fremont
    Vehicle:
    2006 Prius
    Model:
    ----USA----
    Hey all.
    So I set up Torque pro so I can monitor my individual battery voltages. All 14 read 15.6 plus or minus .02. I’ve looked at some other voltage displays on other cars and seen anywhere from 16.3 - 17.5. Anyone know what’s going on? Bring me in he know folks. (2006 220k miles battery age unknown, average mile as over several tanks 44.3 mph)
     
  2. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    9,205
    12,421
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    It’s just the voltage at the condition the pack is in. So if you were at a lower %charge on the pack, the lower the voltage would be;).

    If they are that close, that’s a good sign:).

    But performing a load test is a better way to know(y).
     
    Skibob likes this.
  3. Ianmeister

    Ianmeister Junior Member

    Joined:
    May 21, 2019
    48
    19
    0
    Location:
    Fremont
    Vehicle:
    2006 Prius
    Model:
    ----USA----
    I see
    I’ll try checking the numbers at different soc. Yes they were all very nearly identical. Thanks!
     
    Raytheeagle likes this.
  4. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    2,392
    2,850
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Eagle hit it pretty good.

    15.6 is a fairly normal voltage for a block that has not been exposed to a charge condition recently or even overnight. Remember, that's still 7.8 volts per module. The ones you see >16 have most likely recently been exposed to a charge current, or currently being charged. for instance, if you roll under battery power for the last quarter or half mile when getting home, you'll see lower voltages. I don't think you have anything to worry about.
     
    Ianmeister and Raytheeagle like this.
  5. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    9,205
    12,421
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Sometimes the eagle does land:p.
     
  6. Ianmeister

    Ianmeister Junior Member

    Joined:
    May 21, 2019
    48
    19
    0
    Location:
    Fremont
    Vehicle:
    2006 Prius
    Model:
    ----USA----
    Ok. Cool. One thing I’ve noticed is that if I sit at a stoplight on a crazy hot day with the AC blasting the SOC drops to one purple forcing the engine to kick in after about 3 minutes. Is that normal?
     
  7. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    9,205
    12,421
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    The battery is weak and is close to failing. A quick cycling from full to empty is one of the first signs;).

    The load test with diagnostic readers will show you how bad it is, but it ain’t that great:cool:.

    I’d plan for either a replacement in the future, or reconditioning it if you like to DIY:).

    Good luck and keep us posted (y).
     
    Skibob likes this.
  8. Ianmeister

    Ianmeister Junior Member

    Joined:
    May 21, 2019
    48
    19
    0
    Location:
    Fremont
    Vehicle:
    2006 Prius
    Model:
    ----USA----
    Hmm. Sad face
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    2,392
    2,850
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    This is one of the great times for using the Hybrid Assistant/Hybrid Reporter apps with a bluetooth obd adapter. There's a HV battery test you can perform using the AC system. It will log and graph all 14 block voltages. It makes it very easy to see if all blocks are fairly well balanced or if there's weak blocks. A well balance battery will show all 14 graph lines in a tight group, very close to one another. Any weak module/block will fall out of that range much more quickly. It will be obvious.

    Just Another HV Battery Thread and Experiments | PriusChat

    Look at post 5...that graph is similar to what you may see. You can see one block that falls off a cliff about 5 minutes into the test.
     
    Ianmeister, Skibob and Raytheeagle like this.
Loading...