2018 Prius Prime EV battery problem

Discussion in 'Prime Technical Discussion' started by Can Doan, Aug 15, 2021.

  1. Can Doan

    Can Doan Junior Member

    Joined:
    Oct 23, 2018
    13
    4
    0
    Location:
    Boston, MA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Hello all members,

    My name is Can Doan and I live in Boston, MA. I bought my car from Expressway Toyota in Dorchester, MA.

    I have been reading this forum since day 1 when I bought my car in October 2018.
    Everything was fine to excellent.
    This problem happened 3 weeks ago.
    Normally after a full charge, my car can read 30 miles EV driving and I could drive up to 29 or 30 miles out of the V battery before it change to gas engine, in the summer weather.
    So that day, after an overnight fully charge I saw only 24.4 miles EV driving, it was a chilly day and I thought because of weather, and I drove only 20 miles on EV battery.

    After of 10 days to determine because of weather or else and it was just like that, 24 miles something after full charge and 20 to 21 miles on EV driving, I brought my car to Expressway Toyota and I hope they could figure out the problems. But after 3 days keeping my car there, they could not see any problem. I mentioned that there was something wrong with the EV battery itself but they tried to blame on something else and asked me to take my car back. I have asked them to escalate this matter to higher level or to Head Quarter of Toyota but I don't think they did because I have heard anything else or from anyone at all.
    I have had my car back more than a week now and it stays the same problem.

    Here are my questions:

    1- Has anyone who owns Toyota Prius Prime got this problem yet? If yes, how could you handle it? Thanks.
    2- Anyone knows how to escalate this problem to someone or somewhere so who could help us out. Thanks.

    Can Doan
     
    #1 Can Doan, Aug 15, 2021
    Last edited: Aug 15, 2021
  2. Henrik Helmers

    Joined:
    Jan 3, 2020
    98
    142
    0
    Location:
    Norway
    Vehicle:
    2020 Prius PHV
    Model:
    N/A
    This is not necessarily a problem. The range indicator (Guess-o-meter) is extremely inaccurate, and should not be relied upon. Better for your sanity to change it to display the percent instead. I had similar experiences with my Leaf years ago. Hopefully, the estimates will improve in newer models.

    If you still believe something is wrong and wish to debug the battery, you can use a device to measure how much energy (kWh) is added to the battery when charging from 0 to 100%.
     
    mountaineer and jerrymildred like this.
  3. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

    Joined:
    Dec 4, 2014
    778
    513
    0
    Location:
    Outside Philly, PA
    Vehicle:
    2009 Prius
    Model:
    II
    I’ll let folks with a Prime chime in here, but temperature changes (which you described) will affect EV range as well as mpg. If you use the cabin heater, there’s a big draw on your battery, and the vehicle might be anticipating that in its calculations.

    Was your capacity back up there during the more recent summer months?
     
  4. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    10,231
    12,547
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    • Low temperatures will reduce range.
    • High temperatures will reduce range.
    • Low tire pressure will reduce range.
    • Wet roads will reduce range.
    • Hard stops will reduce range.
    • Dragging brakes will reduce range.
    • High speeds will reduce range.
    • Running the heat will reduce range.
    • Low AC temperature settings will reduce range.
    • Bad alignment will reduce range.
    • Dying 12V battery will reduce range.
    • Driving in PWR rather than ECO will reduce range.
    • Any combination of the above will reduce range even more.

    Did I miss anything?
     
  5. dig4dirt

    dig4dirt MoonGlow

    Joined:
    Apr 6, 2012
    1,118
    708
    0
    Location:
    Lancaster Co PA
    Vehicle:
    2014 Prius c
    Model:
    Two
    New tires will reduce range
    Hills will reduce range
    New driving routes will reduce range
    New drivers will reduce range
     
  6. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
    3,477
    1,539
    1
    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    New tires will reduce MPG if they have higher rolling resistance. They will appear to lower MPG due to a larger circumference than the worn previous tires (fewer revolutions/mile).

    JeffD
     
    Salamander_King likes this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,257
    43,192
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I wouldn’t describe it as chilly, but we did go from a mini heat wave around 90 to 59 one morning and high seventies.
    I don’t think that is your problem, my range didn’t change.
    Try an experiment. Charge up and go for a drive on local streets until you run out of ev.
    Then disconnect the 12v negative and do it again, see how they compare
     
    Salamander_King likes this.
  8. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    9,139
    7,284
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    The sudden change (usually a drop) in GOM displayed EV range is not uncommon. Upward change in GOM takes more effort (and some luck) so it is harder to increase the GOM indicated EV range following sudden drop. The causes of the drop in GOM indicated EV range are listed in @jerrymildred comment above.

    Similarly, a sudden drop in the ACTUAL EV range can also happen for various reasons listed in @jerrymildred comment above. I also add bad tires or new tires, increased cargo, or people riding on Jerry's list. But when this sudden drop in the ACTUAL EV range happens in absence of any common causes listed and persists even after eliminating all the factors that usually cause the reduction of the EV range, then there may be some other issues. I have read a few reports of others experiencing such a drop in the ACTUAL EV range, but most without very clear documentation of the problem, so it is hard to say what the cause is. Unfortunately, a dealer is even less helpful, and escalating such an issue with Toyota HQ is most likely to end up wasting your time.

    The most obvious cause would be a degradation of the traction battery but without a clear MIL code, the warranty will not cover it. Even though the traction battery is covered by 10yr/150K miles in your case, the Toyota warranty clearly states that reduction of lithium-ion battery capacity is NOT covered under warranty (emphasis not mine but by TOYOTA). You have a lost case even if you can show that the reduction in EV range is due to capacity reduction of the traction battery.

    upload_2021-8-17_9-47-42.png
     
    #8 Salamander_King, Aug 17, 2021
    Last edited: Aug 17, 2021
    jerrymildred likes this.
  9. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    9,139
    7,284
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    In my case,
    My wife reduces the range.:p
     
    JoeBlack and dig4dirt like this.
  10. Can Doan

    Can Doan Junior Member

    Joined:
    Oct 23, 2018
    13
    4
    0
    Location:
    Boston, MA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Thank you all for helpful tips and knowledge.
    The mile indication after full charge and the real mile driving after full charge is going down gradually.
    Usually after full charge it read about 30 miles in the summer and 26 in the winter. The problem started about 4 weeks ago. I started seeing the mile after full charge is sliding down from 29.5 and yesterday was 23.8 and the real mile driving from 26 and yesterday was only 20.
    From my house to work is 27 miles and usually when I got to work the EV battery was still have couple miles left.
    My car doesn't have anything changed.

    Should I escalate this matter to Toyota? And how to do it?

    Thanks again,

    Can Doan
     
    bisco likes this.
  11. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,257
    43,192
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    you can call toyota customer service (number in your manual) and file a complaint, but they are going to tell you it is not covered by warranty.
    still worth a try, that might have a dealer run a few checks if you're lucky.

    thy can test all the battery cells under load, check the hybrid system and charger. brakes, etc., but if they don't find anything, they'll probably tell you that you have to pay a diagnostic fee.
     
  12. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    9,139
    7,284
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Have you checked your daily eco log to see how your miles/kWh has changed? If it started 4 weeks ago, there should be close to all the daily logs still left how the daily miles/kWh and distance you drove over last month. Then You still have 24 month period of monthly logs to compare. If your recent drives are showing lower miles/kWh than used to be, then that is consistent with the shorter EV range. But it does not point to anything that is wrong with your car. It just eliminates one possibility of the traction battery somehow has lost capacity suddenly. Also, if you are using OEM L1 EVSE, you can try Kill-a-watt meter to check what amount kWh of electricity is going into the battery for a full charge session. It is one time $30 investment for the meter, but it is well worth it. The only thing is that you have no record of what the charge session kWh use to be, so this can't be a direct comparison. But if your traction battery is somehow taking less than 5.7kWh for a full charge, then you know something is wrong... either traction battery itself or charger or control unit.

    If it turns out the problem is an efficiency issue, rather than a capacity issue, then you can try increasing the efficiency. But most likely the dealer nor Toyota will do anything to fix the problem unless you can pinpoint a faulty mechanical issue that is causing low efficiency.

    This is not the answer you want to hear, but contacting Toyota HQ is not likely to solve the problem. It will likely just increase your frustration. If the dealer documented that there was nothing wrong with your car, there is very little chance Toyota HQ will do anything about it. And even if it was found to be the traction battery capacity loss, again Toyota clearly states that it is NOT covered by the warranty.

    If you still wish to escalate it to Toyota HQ, you can find the contact information easily on your Toyota App or on your warranty booklet or Toyota website.
     
    #12 Salamander_King, Aug 17, 2021
    Last edited: Aug 17, 2021
    Can Doan, jerrymildred and dig4dirt like this.
  13. dbstoo

    dbstoo Active Member

    Joined:
    Oct 7, 2012
    694
    361
    0
    Location:
    Near Silicon Valley
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    There are lots of threads that explain that the range displayed on the dash or HUD is just a guess as to how many miles you be able to drive based on the recent history (last 4 or 5 days) and the settings such as AC, defrost, etc.

    It is NOT a problem. It's just the way it works. If there was a problem the dealer would have found something. Do NOT unplug the 12Volt battery, since all that does is make the car forget your driving habits and lose other settings.

    When you drive, the car keeps track (visible in the "diary") of how you drive and adjusts the range estimates based on that. If it's hot or cold you will use the climate control and that will suck up some of the battery power. If you sit at a lot of stop signs/lights with the AC running it will eventually impact your expected range. If you sat in line at the local starbucks drive through in 106 degree heat several times a day that will lower the range today AND it will lower the forecasted range tomorrow. The lowest "range" I got on my PRIME was during the summer when my wife "went shopping" with me but actually stayed in the car the whole time with the AC running.

    If you want to see the impact of the climate control, just check the expected range, then turn off the climate control and look at the range again. You will see a jump.

    Just in case i was not clear... IT IS NOT A PROBLEM. The expected range display is just badly described.
     
    Can Doan likes this.
  14. EdPalmer42

    EdPalmer42 Member

    Joined:
    Dec 3, 2019
    69
    38
    0
    Location:
    Canada
    Vehicle:
    2020 Prius Prime
    Model:
    Base
    If you have or can borrow an OBDII - Bluetooth adapter you could run the Dr. Prius app to see if one or more of the battery cells are failing. When the SOC is very low, look for a large voltage difference between the highest and lowest cell. Take screen captures, note the date, and watch the low cells to see if they're falling further.

    This still won't get you a new battery unless yours absolutely fails but it will improve your credibility with the dealer. He probably has this data from when he had the car for three days, but he doesn't have multiple readings over a period of days or weeks. And it never hurts to have your own copy of the data to challenge him if he says there's nothing wrong.

    I've attached a screencap from my car. As you can see, the voltage difference is only 0.01V, but that's at a 21% SOC. You want to do it at a very low SOC to accentuate the voltage difference. No, it isn't charging at 3269 Amps! That appears to be a calibration error in the program that, AFAIK, hasn't been fixed yet.

    Screenshot_20201112-145850[1].png
     
    Can Doan likes this.
  15. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    10,231
    12,547
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    This is VERY good advice.

    BTW, I mentioned AC load affecting range. Today I drove to a place about 1-3/4 miles away. The car had been parked outside with about 25% left in the battery. Temperature was over 90ºF. Even though my speed topped out at a brief 45 mph, I only got a little over 3 m/kWh. 35% of the battery use over that 3-1/2 mile round trip went for air conditioning.
     
    Can Doan likes this.
  16. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,257
    43,192
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    a real drop from 30 to 20 miles is a major change. i have never seen mine drop by a third in 9 years, not even through the four seasons
     
    Can Doan likes this.
  17. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    9,139
    7,284
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    If the EV range decreased 33% without any changes in the driving condition, I would worry too, especially if it happened suddenly. But, it does not take much to have totally different driving conditions from one day to the next even on the same route. My PP dropped roughly 50% of EV range from the peak during summertime (~36miles) to the lowest in the middle of the winter (~18miles) for exactly the same commuting route. In my case, a 50% drop is almost totally an efficiency loss. And I learned to accept the fact the car loses that much of EV range in the middle of winter.

    That's why it is important to distinguish difference between the EV range loss due to the capacity loss and due to efficiency loss. Now, if this happened in the middle of summer as OP has described, I would be worried too.
     
    Can Doan likes this.
  18. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,257
    43,192
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    that's amazing. i wonder if the chemistry producing so many ev miles (i've never seen 18) is also less efficient in winter. i currently go from about 14 peak to 11 minimum.

    as you know, we don't get anything like summer to winter weather swings in a couple of weeks.
    even 95f to 60f doesn't affect my real ev miles much.
     
  19. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    9,139
    7,284
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    It must be because the same amount of kWh went into the battery summer or winter. And after getting only 18 miles in winter, as soon as the weather got better, it recovered back to 36miles. So it was not due to capacity loss. A large part of efficiency loss occurs due to heating. But other factors such as snow tires and snow/ice-covered roads also affect winter EV driving efficiency negatively. But, yeah, this did not happen in 4 weeks period in the summertime.
     
    bisco likes this.
  20. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,257
    43,192
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    yes, heat is probably a big drain, even with the heat pump. snow will definitely reduce my miles further.

    i wish the o/p would attempt to fill in more details.
     
    dig4dirt likes this.
Loading...