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What's better for EV Batt when using car only few times a week?

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by stevepea, Apr 21, 2017.

  1. stevepea

    stevepea Senior Member

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    What's the right thing to do in this situation, to try to keep the battery from degrading as much as possible over the years?

    The car will sit in the garage for maybe 3 days at a time without use at all (maybe the car is used twice a week, sometimes 3). But when it is used, the distance driven is enough to deplete the EV completely. And to make it worse, I don't usually have a lot of notice before I'm needed to leave (where I could just charge it the night before I need to leave).

    This also just isn't an occasional thing, but pretty much the norm.

    So... how much would it hurt the battery over the long run by constantly having it sit unused -- but fully charged -- for maybe 2-3 days before using it?

    Logically one would charge the car when one gets home, so it'll be charged for the next time it's needed. But if that next time it's needed isn't for another 2-3 days or so (sometimes it can be 1, sometimes it can be 5, and I don't know until early that morning when there's not enough time to charge it), what's the best thing to do (other than guess?)

    I guess what I'm asking is, how much would it hurt the battery to constantly (through the years) charge the battery when I get home, but have it sit there fully charged for 2 or 3 days each time? I'm not talking 2 weeks, but the car does not get used on a daily basis at all, and when needed it's usually without enough warning beforehand to charge.

    Hmm..
     
  2. Lee Jay

    Lee Jay Senior Member

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    Degradation will depend strongly on battery temperature.

    My opinion is that I'd charge up to about 90% of available range, and leave it there.
     
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  3. dalcon95

    dalcon95 Senior Member

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    I have read that it is best the store the battery with a full charge versus it being depleted.

    #1 in Easley,SC
     
  4. HPrimeAdvanced

    HPrimeAdvanced Senior Member

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    If I were in your situation, and it was my car, I would just go ahead and charge it and not sweat the details. These batteries are very very robust and I don't think they have any problem in the long haul. You're not talking about months and months, just a few days.

    Posted via the PriusChat mobile app.
     
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  5. joachimz

    joachimz Senior Member

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    I agree with @HPrimeAdvanced, also keep in mind that you don't fully charge the battery to beging with, just to somewhere in the low 80% range. The manual states that for "long term" non-use the battery should not be fully charged, i interpret "long term" as in the months range, but for a few days, wouldn't care ...
     
  6. Lee Jay

    Lee Jay Senior Member

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    I think you guys are missing that he would be doing this all the time. So, it may just be a few days at a time, but it will be most of its lifetime.
     
  7. Breatheintheair

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    Somewhere I read that leaving the battery discharged and charging only when ready to use was best for lifetime. Setting the charge schedule to complete charge as close to departure time would give longest life.

    I read it somewhere on this site.
     
  8. HPrimeAdvanced

    HPrimeAdvanced Senior Member

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    Again, he's talking a couple days and I'm presuming keeping the car an average of 5-6 years; he lives in California, so I'm presuming relatively minor weather extremes. The fact that Toyota neither charges nor discharges the car fully, again makes me comfortable (if it were my car) in pursuing this approach. If he plans on keeping the car 15 or 20 years,
    then maybe he could speak to Toyota Corporate Tech Support regarding this question.

    Posted via the PriusChat mobile app.
     
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  9. bisco

    bisco cookie crumbler

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    i would leave it discharged, get an L2 charger, so you can put as much charge in as possible when you get notification you have to leave. other than that, i wouldn't sweat it, it will be fine.
     
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  10. dalcon95

    dalcon95 Senior Member

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    Going by other batteries like for my lawnmower and such, they recommend storing the batteries in full charge state over the winter season to keep the battery life longer. I am assuming the Prime battery would be treated the same way. I know the Prius liftback I have had in the past seems to strive to keep the battery at the top of its charge status in its programmed operation.

    #1 in Easley,SC
     
  11. bisco

    bisco cookie crumbler

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    i believe the manual states to leave the battery discharged into hv mode when storing. not sure how long they mean though, typical legal ambiguity.
     
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  12. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    Lead-acid batteries, like traditional 12V car batteries, like to be stored with a full charge. Li-Ion batteries (like in the Prime) don't.
     
  13. giora

    giora Senior Member

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    Why going by the lawnmower supplier recommendation when you have the Toyota one in the manual?
    Your statement about the liftback striving to keep its battery 'at the top of its charge status' is incorrect either, it is striving to keep it at about 50-60% SOC.
    As for the O/P dilemma, I agree with both bisco and Lee Jay, both methods are reasonable for the situation described. I would use bisco's method in the hot summer months and Lee Jay's the rest of the year.
     
    #13 giora, Apr 21, 2017
    Last edited: Apr 21, 2017
  14. dalcon95

    dalcon95 Senior Member

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    The manual doesn't state whether to keep the battery discharged or fully charged. It does mention not to leave it plugged in when it isn't in use. So being it doesn't recommend either way by Toyota, I used the logic of another lithium ion battery in the purpose of storage. Why wouldn't it work for another lithium ion battery? As far as the hybrid state for charge by my personal experience during hybrid operation on my previous Prius, the battery showed charged up to the last 2 bars 95% of the time I drove my car. Whatever that percentage is, that's what it keep the charge at.
    Screenshot_20170421-194451.jpg

    #1 in Easley,SC
     
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  15. giora

    giora Senior Member

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    Yes it does:
    ●Leave a low level of charge in the hybrid battery (traction battery) when leaving the vehicle undriven for a long period of time. After confirming that EV mode has switched to HV mode, turn the power switch off.
    (page 133 of the on-line manual).
    Yes, but this '6 out of 8 bars' is not 'top of its charge status' it is 50-60% SOC.
     
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  16. Lee Jay

    Lee Jay Senior Member

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    Check the last two bullets.

    upload_2017-4-21_18-18-45.png
     
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