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Can the traction battery be charged while parked?

Discussion in 'Prius v Main Forum' started by Offline, Apr 18, 2020.

  1. Offline

    Offline Active Member

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    Our 2012 Prius v has been sitting unused for the past six weeks during our "corona virus staycation". The traction battery charge level was high when it was parked based on the meter in the instrument cluster but it is now down to only two bars.

    Starting the car and let it "idle" doesn't work since the ICE stops running almost immediately with the car then going into EV mode. Pressing the Power button doesn't cause the ICE to start and the car remains in EV mode. I haven't tried running the A/C and as many electrical features as possible to try to force the ICE to run but that seems a little silly and likely won't be productive.

    I can force the ICE to continuously run by putting the car into a diagnostic mode using a procedure involving pedal presses, gear shift lever changes, etc. but when that is done, the energy monitor display shows the traction battery charging only for the first three minutes or so.

    Does anyone know how to continuously charge the traction battery while the ICE is running or any method while the car is sitting still? I've searched Prius Chat and with Google with no success.

    Thanks.
     
  2. ChapmanF

    ChapmanF Senior Member

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    The engine doesn't shut off unless the car considers the traction battery charge to be adequate. So if your engine is shutting off, it thinks the charge is ok. It doesn't need to be 60 or 80 percent all the time. You can force charge it higher (just shift to D and apply the brake and go pedal together), but except for some special purposes or testing, there's no reason to think that's particularly good for the battery.
     
  3. GTW

    GTW Junior Member

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    Edit. Someone else beat me to the answer
     
  4. bisco

    bisco cookie crumbler

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  5. rjparker

    rjparker Tu Humilde Sirviente

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    The reality is the hybrid battery is still about 60-70% charged even when the battery meter shows low. As stated above you can "power brake" it to charge fully but its not essential and you risk flying into the garage wall. The Dr Prius app has you do exactly the same forced charging before it evaluates the hv battery while driving.

    If it were me, I would put a good trickle charger (eg "Battery Tender Jr") on the 12v battery or the under hood charge point to ensure the 12v battery does not die, which is more likely. Second, I would get it out at least every two weeks and drive it around the neighborhood for ten minutes to ensure everything is warmed up, lubricated and the tires don't flat spot.

     
    #5 rjparker, Apr 18, 2020
    Last edited: Apr 18, 2020
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  6. Offline

    Offline Active Member

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    Thanks. I know I can use the "D, brake and gas pedal" trick to force the ICE to run and charge the traction battery but I'm looking for something either my wife or I could do without having to be inside the Prius and without risking crashing into a garage wall.

    My understanding is that it can require a Toyota dealership's intervention to get the ICE started if the traction battery becomes fully depleted and that a battery tender on the Prius 12V battery won't charge the traction battery and won't provide enough power to start the ICE. Please correct me if I'm wrong about that.

    It's funny I never thought about this issue. If it wasn't for the corona virus situation, we would be away "fly/drive" traveling for several months at a time for the first time since we retired. The non-hybrid vehicles would have been fine on their battery tenders but I never considered the Prius.
     
  7. Offline

    Offline Active Member

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    Dang! So the traction battery meter is useless?
     
  8. bisco

    bisco cookie crumbler

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    it is also fine. i leave mine every winter for over two months since 2004
     
  9. sam spade 2

    sam spade 2 Senior Member

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    His percentage is a bit high but yes, mostly.

    You are worrying WAY too much here.
    The traction battery does not lose it's charge anywhere NEAR to what the 12 V wet cell battery does.

    Just drive it once every couple of weeks.....and keep the 12 V up.
    If the traction battery fails while just sitting, it wasn't very healthy to start with.

    Not only is it not easy to externally charge the traction battery, it is not really a good idea either.
     
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  10. Offline

    Offline Active Member

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    OK, thanks all. I was just surprised that the traction battery went from full (8 bars) to only 2 bars in just 6 weeks. I had wondered if the EVAP system self check was running it down but I don't know if the EVAP check happens based on miles driven or time. When our Prius was used mostly daily it seemed like I heard the EVAP check run every evening but I haven't spent much time in our garage the past 6 weeks and noticed.

    I have no idea as to the health of the traction battery. It seems to charge up pretty fast from regenerative braking. The odometer is at only 45K miles after eight years from new and the car hasn't sat unused for more than a week at a time. The test on whether or not the Prius would have started would have been after the multi-month long trip outside the U.S. we were planning for later this year but now that's off due to the pandemic.

    If we do ever get to take extended duration trips, it looks like we're going to have to have someone occasionally drive the Prius or the 2021 RAV4 Prime my wife was planning to replace it with. I say "was planning" since the 5th generation RAV4 seems to be getting a lot of complaints on other forums. I had assumed that the RAV4 Prime could be left plugged in for extended periods to keep it's traction battery charged but it doesn't seem to work that way for the Prius Prime.
     
  11. bisco

    bisco cookie crumbler

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    when you leave phev batteries in storage (lithium) you leave them in a lower state of charge vs nimh. you don't want any wall charge left in it.

    no need to have someone drive the rav4 prime occasionally.

    our son has a new rav4h and loves it. haven't heard one complaint except he sometimes has to pump gas slowly. averaging 40 mpg.
     
  12. ChapmanF

    ChapmanF Senior Member

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    I wouldn't say the bargraph on the dash is useless. It just shows a certain range of actual battery state of charge.

    If you have an OBD-II gizmo to read the actual state of charge as a percentage from the car's computers, you will see that the car tries to pretty much always keep the battery spot on 60%. If it's below that, the car will look for opportunities to charge it, if it's above that, the car will look for opportunities to use it. The car will pretty much never, ever allow the battery above 80% (except during some very specialized battery maintenance cycles the Gen 1 would run from time to time; I don't know if the later generations do). It also rarely allows below 40%, unless the engine is being hard to start.

    The bargraph on the dash just basically covers that 40% to 80% range that the car actually uses, which is what is best for the battery's longevity.

    The car adjusts the target point sometimes. If I am car camping, the car will eventually figure out I'm not going anywhere, and shut the engine off earlier, around 50% charge rather than the usual 60%. Once I pull out on the road, it will bump the target back to 60% again.

    Best thing for it is just drive around the neighborhood every week or two. Avoid tire flat spots, scrub some rust off the brakes, wait for the engine to stop before you power down, that way you know the traction battery is adequately charged.

    The 'needing a dealer recharge to start' usually comes up if you have done work on the engine and missed some detail and it won't start; if you keep trying to without fixing the problem, eventually the charge gets down to some level (below 20% maybe) and the car says "I'm not going to do that anymore." Then it's a headache. I don't know what the exact cutoff level is, because I've never reached that point. I know it's under 20%, because I have reached that point. :whistle:
     
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  13. jzchen

    jzchen Newbie!

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    Driving around with a steady foot on the gas pedal usually gets it charged up to 6 or 7 out of 8 bars pretty quickly. To avoid all this complication I'd just do that once every two weeks or so.

    moto g(7) power ?
     
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  14. rjparker

    rjparker Tu Humilde Sirviente

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    The rest of the car has more problems sitting than the nickel-metal hydride traction battery. It is much closer to a lithium battery in its ability to retain charge over many months, probably years. People buy them out of junk yards where they sat for many months or years and they work. Everyone's paradigm was created with Nicad and lead acid batteries that do self discharge fast and fail sooner.

    Toyota is only showing the serviceable percentage on the meter, meaning the charge levels where the nihm battery can add power to the drivetrain. When you experience a large discharge on the nihm battery the gas engine is the only power. When that happens the car can barely drive and especially has a hard time accelerating. How do you get to that state? Once in my gen2 I ran out of gas three miles from a station at 65 mph. The nihm battery made it all the way to the station, far exceeding the car's normal one mile ev capability. It was really depleted when I put gas in the car and yes, I was concerned about the thing cranking. It started no problem but ran like poo for about ten miles while the engine was pushing the car and charging the nihm.

    The point is there is built in extra capacity even when a forced discharge happens OR when you really do have a failing traction battery. The failing battery scenario is when you stop at a light and it goes down while you are waiting. Then you might have engine only for a quarter of a mile in terms of power to the wheels. This happened on my 2012 v but the car started everytime for 25k more miles. Plenty of remaining capacity to start even when it was worn out.

    The most important thing is the 12v battery. It won't start if its depleted and its old fashioned lead acid. You lose the 12v and you lose engine tuning as well. Plus the lubrication and flat spotting issues for long storage (month or more). Of course, for the 12v issue (which can happen if the hatch is not closed 100%) you can just keep a small lithium jump starter accessible to the back seat . The hatch won't open with a dead 12v battery and you have to know how to use the key fob's hidden key to get into the car (which many don't know).

    Drive it around the block for ten minutes under the current circumstances every couple of weeks and it will be fine with no further considerations. A battery tender and or a lithium jump starter (stores for a year or more) is a good preventive measure.
     
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  15. sam spade 2

    sam spade 2 Senior Member

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    And it will actually accomplish...........nothing useful.
     
  16. fuzzy1

    fuzzy1 Senior Member

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    I had understood the EVAP check system to run just once, 5 hours after shutdown, no repeat. It should also run from 12V, not from the traction battery.
    A healthy traction battery should be good for many months, though my longest has been 44 days. I don't remember snowbirds having trouble with traction battery storage, just with 12V.

    How many times have you turned the car on to check the traction battery level? Could the depletion be caused more by the on-time of these checks than from actual self-discharge?
     
  17. Offline

    Offline Active Member

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    I may put the Prius 12V on a battery tender and not worry about it starting. It wouldn't be the first time we've had a vehicle dragged out of our garage and flatbed-ed to a repair facility.

    We've left non-hybrid vehicles parked for a month at a time with no problems ... started right up, no tire flat spotting. If we ever do get to take our long retirement trips, our vehicles will stay in the garage and we'll use a shuttle service to/from the airport. A shuttle is cheaper and more convenient than long-term parking and we don't have to worry about parking lot damage, hail damage, and starting.

    Regarding the generation 5 RAV4 Hybrid, other than the fuel tank issues that limit range, others I've been reading about and I remember right now involve directional stability at highway speeds, marginal headroom for tall drivers and noise levels at highway speeds. I assume the RAV4 Prime will essentially be the same in these respects. I didn't try the driver seat when my wife took a gen 5 RAV4 Hybrid for a test drive late last year. I sat in the back seat while a car salesman occupied the front passenger seat. The test drive was short and my wife seemed happy with it. She was ready to buy a RAV4 Hybrid but decided to wait when the RAV4 Prime was announced.

    All that's on hold anyway. Based on the mortality rate for people in our age group, we're not leaving the house until the tail of the corona virus infection rate curve gets down to near zero or until there's a vaccine. Infections aren't forecasted to peak here until several weeks from now which means that the tail of the curve could be several months away. The overall death rate here is running about 5% if age isn't considered and the hospitalization rate is running at 26% for confirmed infections. What I find particularly alarming is that the death rate for those that have had to be intubated has been running at 80%.
     
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  18. Offline

    Offline Active Member

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    We might be away on the first planned trip for about 3 months ... i.e. 90 days.

    I double pressed the Start button at about 3 weeks and then at 6 weeks (yesterday) to check the traction battery charge level. Each check took just a few seconds. After the 2nd check yesterday, I put the Prius into diagnostic mode like I said previously so that the ICE would run continuously but the Energy Monitor screen showed the traction battery charging for only the first thee minutes or so and the charge level didn't change.

    I'm really not all that concerned about this. Just thought I would ask on this forum. If for any reason it doesn't start, it will be trucked to the Toyota dealership which is barely 2 miles away.
     
  19. bisco

    bisco cookie crumbler

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    i'm wondering about florida next january, never mind 3 months from now
     
  20. Offline

    Offline Active Member

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    Florida will likely be warmer in January than most of the U.S. mainland like it usually is.