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Do you wait till your battery drains down or top it off at 1/2 full or more ?

Discussion in 'Prime Plug-in Charging' started by GKL, Jun 14, 2020.

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  1. GKL

    GKL Active Member

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    I'm retired so I don't have a set work/driving schedule and how much the battery gets used can vary from week to week.

    I would prefer to not let the battery drain all the way down before recharging in case I have a day I wish it was fully charged.

    Does it really make a big difference if you top off the battery ?

    If not, is it okay to top it off at any level, if it is still 3/4 full, 1/2 full, does it matter ?
     
    #1 GKL, Jun 14, 2020
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  2. Raytheeagle

    Raytheeagle Senior Member

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    No issues in any of the scenarios above;).

    Advice is to not leave the battery full for a long period of time:whistle:.

    In the owners manual, a long period of time is not defined:cool:.

    So I'd say a week or less is what I use as a gauge for that, given stay at home orders (y).
     
    #2 Raytheeagle, Jun 14, 2020
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  3. Salamander_King

    Salamander_King Senior Member

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    Although I have no data or proof, from what I have read here, keeping the traction battery fully charged is more detrimental than keeping it empty. I don't think it matters too much how often you top off the battery as long as you don't let the car sit for a long time fully charged. If you don't plan to use the car following day, it may be better to let it sit half empty for the longevity of the traction battery.
     
    #3 Salamander_King, Jun 14, 2020
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  4. GKL

    GKL Active Member

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    Thanks for posting, yes, it would be nice if Toyota specified what they consider a long period of time :rolleyes:

    …...a long period of time to them could be a month or more, or maybe a week or more :unsure:

    Thanks, I wonder if it's significantly detrimental or not, if it caused you to only lose one mile of range every 5 years no big deal.

    The thing is some days I might decide to do some running that wasn't planned the day before and I'd irk me to have to use gas when I could have otherwise stayed in EV mode if it was charged up.
     
    #4 GKL, Jun 14, 2020
  5. Raytheeagle

    Raytheeagle Senior Member

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    Meh, I leave our 2019 for a day or so fully charged and don't think twice about it ;).

    I do not consider a day or two a long period of time :).

    But maybe Toyota does:whistle:.

    If they'd only define their terms better:rolleyes:.

    But Id say your fine for a short period of time fully charged(y).
     
    #5 Raytheeagle, Jun 14, 2020
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  6. GKL

    GKL Active Member

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    Yeah, to me it'd be frustrating to leave it on a low charge (1/4 or less ?) not always knowing till that day if I might do running that day and either have to use gas or wait 4-5 hours to charge before doing some running :rolleyes:

    If leaving it fully charged for a "long" period (whatever that is) is not preferred, then I wonder if leaving it 1/2 charged okay or 3/4 charged okay for a 3-4 days ?
     
    #6 GKL, Jun 15, 2020
  7. Raytheeagle

    Raytheeagle Senior Member

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    It all falls into the short period of time to me;).

    A long period of time would be a month or so. In the wife's RX450h manual, it says if you leave it for more than a month, to take the car for a ride or start it :).

    While different battery technology, I'm using that as the definition of a long period of time(y).
     
    #7 Raytheeagle, Jun 15, 2020
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  8. GKL

    GKL Active Member

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    Thanks for sharing that, that sounds hopeful !

    Now if that hopefully does also apply to the Prime - to simply start it or take a ride if it's been fully charged a month, then that would be great. (not that I'd normally go a month without driving)

    I'm not familiar with the RX450h, but with Toyota having a great reputation I'd hope their battery would be at least as durable.

    I'm the tech person in my family but there is a lot to understand about the Prime, I have to understand it well enough to be able to share it with my wife :D
     
    #8 GKL, Jun 15, 2020
    Last edited: Jun 15, 2020
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  9. Tideland Prius

    Tideland Prius Moderator of the North
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    It depends how much charge I need for later in the day. Or I try to plan such that I can charge up before I go even if I left a low charge overnight (I have 240V so I usually don’t need more than 2 hours to charge since I’m rarely completely empty from the day before).

    The first hour gets you 60%. The second hour gets you to 100%. That last 10 mins appears to be conditioning or balancing.
     
    #9 Tideland Prius, Jun 15, 2020
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  10. GKL

    GKL Active Member

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    Thanks, we use the 120 volt charger so completely empty it will say 5 hours 50 minutes to charge.

    We thought about doing the 240 volt hook up (and still might later) but since we usually rarely drive over 25 miles a day it was not a big deal. The other thing is I think I remember reading a post (not sure how accurate) that doing the fast 240 volt charging is harder on the battery.

    I'll have to see how much the 120 volt charges for lesser times, like 1 hour, 2 hours, ect. so if I need some extra miles and don't have time to wait for a full charge I'll have an idea what a shorter charge time might do.
     
    #10 GKL, Jun 15, 2020
  11. Hicksite

    Hicksite Member

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    But “fully charged” (100% on the display) is really only 80% charged, right?
     
    #11 Hicksite, Jun 15, 2020
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  12. Tideland Prius

    Tideland Prius Moderator of the North
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    The average speed is 4mph (7km/h). I’ve found that about 3 hours nets you about 50-60% (which is about 20-22 miles in the summer for me) but yeah it’ll behoove you to check so that you know how long you need to wait for get the distance you need. I live in the city so my daily mileage is usually 12-25 miles a day.

    83% but yes you’re right.
     
    #12 Tideland Prius, Jun 15, 2020
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  13. Salamander_King

    Salamander_King Senior Member

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    Correct. Still Toyota recommends to minimize the period the battery is fully charge (= ~80% real SoC).

    Observing the following can help suppress battery capacity decline.
    ●Avoid parking the vehicle in areas with a high temperature under direct sunlight when the hybrid battery (traction battery) is fully charged.
    ●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.
    ●Use the charging timer function as much as possible in order to fully charge the hybrid battery (traction battery) immediately before starting off. (P. 157)​
     
    #13 Salamander_King, Jun 15, 2020
    Last edited: Jun 15, 2020
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  14. GKL

    GKL Active Member

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    I'll have to watch the rate of charge next time I charge it to get an idea how much is added from start to hour 1, then hour 1 to hour 2, ect.

    We have a 10x20 canopy ordered to park the Prime under. (good for protection from both the sun and bird droppings :LOL:)

    The thing is Toyota does not say what they consider a "long" period of time, if you read the post from Raytheeage he gives a reason to think a "long" time would be a month.

    Since I'm retired and don't have a regular set work/driving routine the charging timer function doesn't work for us since the use of the car can vary from week to week and many times we might not know until the day we drive it how much we might drive it that day.
     
    #14 GKL, Jun 15, 2020
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  15. Salamander_King

    Salamander_King Senior Member

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    I don't think Toyota or anyone else really knows the exact time period of fully charged traction battery and its correlation to the battery degradation. I think, in general it is bad to store a fully charged traction battery for a month or longer, but is that mean a day is perfectly OK? What if someone store the car 24 hours with a fully charged traction every other day? For example, if you drive only three days a week on M, W, F, and other 4 days car sits fully charged. Is it perfectly OK? Probably not. The general idea is that you want to minimize the time the car sit with a full traction charge as much as you can reasonably manage. So, it it is not how long in a consecutive days or weeks, but how many hours in total the car sit with a fully charged traction battery. But, even with the greatest care, I am sure there is going to be many other variables that is going to affect the longevity of the traction battery. So, maybe the best advise would be not to worry too much but just charge and drive whenever you can.
     
    #15 Salamander_King, Jun 15, 2020
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  16. alinica2001

    alinica2001 Member

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    Hello,

    Did you tried to charge using 8Amp option and 240V ? Charging time ( mine says 4 hours and 40 min from empty to fully charged but it only takes around 3 hours and 30 min to charge) is not right in this scenario. Therefore if I'm using this setup and set "departure at" option, then usually my charging is finished more than one hour before departure time set.
     
    #16 alinica2001, Jun 15, 2020
  17. GKL

    GKL Active Member

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    Thanks for the various thoughts, I guess it isn't as much of an exact science as we wish it was :LOL:

    If instead of leaving it fully charged I left it about 3/4 charged, do you think that would make a good difference ? …...or even 1/2 charged, though I'd prefer more than half, at least 2/3 charged.
     
    #17 GKL, Jun 15, 2020
  18. Salamander_King

    Salamander_King Senior Member

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    My guess is as good as yours. I would think since the 100% charged is really ~80%. And Toyota is recommending to store the car at 0% charged (which is ~14% SoC) if leaving the vehicle undriven for a long period of time, the logic tells me that the lower the better. However, more knowledgable people on this forum actually differ in opinion on this and recommends to keep 30-40% SoC in the traction battery for a long inactivity period. I am keeping my car at around 30-40% SoC now that I only drive once a week or less.
     
    #18 Salamander_King, Jun 15, 2020
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  19. GKL

    GKL Active Member

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    You driving once a week or less you should be able to tell over time if even 40% has any real effect on the battery.

    I'll see what level others keep theirs at, 40% would equal roughly 10 miles of EV driving, that might be acceptable most days of local errand running, though I'd prefer about 60% if it didn't make a big difference.
     
    #19 GKL, Jun 15, 2020
  20. bisco

    bisco cookie crumbler

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    i leave my pip around half charged until i know i'm going somewhere that needs more. 50,000 ev miles on her.
    the prime battery is improved, i'm sure.
     
    #20 bisco, Jun 15, 2020
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