Hybrid Battery Drains Upon Startup

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by mdmllins21, Jun 9, 2020.

Tags:
  1. mdmllins21

    mdmllins21 New Member

    Joined:
    Jun 9, 2020
    2
    2
    0
    Location:
    United States
    Vehicle:
    2016 Prius
    Model:
    Two
    Background: 2016 Prius two with 40,000 miles recently purchased a couple months ago.

    The potential issue I am seeing is when I start up the car after sitting at least 3 to 4 hours the battery will drain to 2 bars quickly (within a couple of minutes). It charges back up normally (not too fast) after driving for 5 to 10 minutes. I then don't really see any rapid fluctuation after that. I've owned the Gen 3 prius for 5 years and never saw this happen. I am wondering if this behavior is typically seen in a Gen 4. If not, any suggestions on what it might could be. Thanks!

    This may or may not be relevant. After the first week of purchasing the 12V battery went out (sat in the driveway for 4 to 5 days) and was replaced (reimbursed by dealer thankfully).
     
    #1 mdmllins21, Jun 9, 2020
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,155
    50,598
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    welcome!
    seems normal to me. is this during warm up? the software protects the engine by using battery if available.

    from how many bars is it dropping to two?

    is the a/c on?
     
    #2 bisco, Jun 9, 2020
    amos likes this.
  3. krmcg

    krmcg Lowered Blizzard Pearl Beauty

    Joined:
    May 15, 2008
    2,592
    2,390
    0
    Location:
    Whittier, CA
    Vehicle:
    2016 Prius
    Model:
    Four
    Have you calculated the MPGs? Low mileage value would be a sign of a problem more than the battery bars...
     
    #3 krmcg, Jun 9, 2020
    amos likes this.
  4. FuelMiser

    FuelMiser Senior Member

    Joined:
    Jun 29, 2008
    1,329
    914
    0
    Location:
    Monument, CO
    Vehicle:
    2016 Prius
    Model:
    Touring
    I believe there were two styles of traction battery in the 2016 depending on model: a NiMH and Li-Ion. Mine, the Three Touring, has the Li-Ion battery, and with just over 30,000 miles now, the battery level is rock steady. No rapid depletion at all. We had a Gen 2 with NiMH battery, and it began rapid depletion after several years and over 100,000 miles. This was a sign the battery was losing capacity and maybe balance of the cells. There are cell balancing equipment and procedures for NiMH batteries that you might want to investigate, if it turns out you have that style battery.
     
    #4 FuelMiser, Jun 10, 2020
    amos likes this.
  5. mdmllins21

    mdmllins21 New Member

    Joined:
    Jun 9, 2020
    2
    2
    0
    Location:
    United States
    Vehicle:
    2016 Prius
    Model:
    Two
    I appreciate the responses! Yes this is during the car first starts up. The car usually drops from about 6 bars. The car A/C is usually turned on when it the car started up.

    The MPGs are where they should be (between 55-60MPG)
     
    #5 mdmllins21, Jun 10, 2020
    bisco and krmcg like this.
  6. kithmo

    kithmo Couch Potato

    Joined:
    Apr 25, 2010
    2,404
    2,774
    47
    Location:
    South Yorkshire, UK
    Vehicle:
    2016 Prius
    I wouldn't rely on the accuracy of the HV battery gauge.
     
    #6 kithmo, Jun 10, 2020
    fotomoto and krmcg like this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,155
    50,598
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    sounds like all is well
     
    #7 bisco, Jun 11, 2020
    krmcg likes this.
  8. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    5,623
    3,800
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    It did. TONS of threads on this over the years. I can also vouch that other hybrids do this too including plug-ins.
     
    #8 fotomoto, Jun 11, 2020
  9. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,517
    14,132
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    This sounds totally normal. As previously mentioned, the car is borrowing from the battery and babying the ICE when you start it up. Add to that the A/C load on a hot cabin and you'll suck lots of juice from the battery which the ICE pays back after it hits a more normal operating temperature. You'll see evidence on the instantaneous MPG display. When it starts out, it'll be ridiculously high. Then it'll be crazy low while it puts electrons back in the battery. Then it'll level off.
     
    #9 jerrymildred, Jun 11, 2020
    Last edited: Jun 11, 2020
    robsnyder20, amos, Princer and 2 others like this.
  10. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    5,623
    3,800
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    Now combine this with regular daily short drives and it equates to A) very low mpg (for a hybrid) and B) hard on a small battery. Once I learned this, swapping to plug-ins was the solution for me.
     
    #10 fotomoto, Jun 11, 2020
    jerrymildred likes this.
(You must log in or sign up to post here.)