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Battery Capacity Loss

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Norman Jensen, Nov 30, 2012.

  1. Norman Jensen

    Norman Jensen Junior Member

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    Can anyone tell me what is "reasonable" for the loss of capacity of the Prius Plug in battery? Ours started out with a max at 11.7 miles when fully charged. After 6,000 miles and 7 months it is down to 10.0 miles. This seems like an excessive loss to me. I have read the tips for maintaining capacity and we don't do all the them. e.g. we charge out battery asap so it will be ready for the next trip. Our schedule is not fixed enough to determine when the car will be needed next.
     
  2. Adam Leibovitch

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    10 miles is not really your battery's capacity, it is a computer estimate of how many miles the battery will get you. It guesses based on your driving patterns. A few tips are to check your tire pressure on a regular basis; brake early; and don't accelerate then slam on the brakes like a teenager.
     
  3. priuskitty

    priuskitty PIP FAN

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    actually it's an average of driving patterns, the more times you drive on EV the more average it plays in the calculations (like baseball ERA)
     
  4. Adam Leibovitch

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    yea, it will estimate based on your average driving patters, so it can take a long time to get it back up. If you make any changes like adding tire pressure, or a more flat route, check your actual range with the trip computer.

    Is your estimate accurate with the 10 miles?
     
  5. bisco

    bisco cookie crumbler

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    where are you located? it's probably temp related.
     
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  6. LenP

    LenP Member

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    What your seeing is a calculated guess the PIPs computer makes.
    It does this buy noting how we, accelerate, what terrain were driving on, speed etc. This isn’t a true estimate of how much charge, or the condition of the PIPs battery. I started out with 13 miles estimate and after 10 months I’m now showing 9.8, but depending on how and where I drive I still get 12 miles and over EV driving range. The computer doesn't show Battery State of charge or battery capacity. It just shows a guess based on your average driving.
     
  7. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    A reasonable "loss" is a couple of percent per year. As everyone else has stated you aren't seeing a number that tells you the number of kilowatt-hours your fully charged battery has, you are seeing how far "you" drive on a fully charged battery averaged over many trips. Colder weather, use of the heater, seat heaters, more use of headlights, etc all will lower the number of miles a given number of kw-hrs gives you.

    To demonstrate this you should drive a particuler route (such as a daily commute) and see how far get get on a full charge before you kick in to HV mode. Compare this on a regular basis (under the same conditions) and you should see no substantial change over time. Of course, "under the same conditions" will be difficult to replicate, so if you are really interested (like me) I have recorded my min and max for a number of different trips for later comparison.

    For example, in the summer I could go from Work-gym-home-work (14.0 miles) on a full charge and have 0.5 to 1 mile left. Although twice the ICE started with 0.1 or 0.2 miles to go (different traffic?). Now that it is colder, lights on for half the trip, etc I always run out of EV with 0.2 - 0.5 miles to go. (So I now charge for a few minutes at home). My "indicated" miles for a full charge has dropped from around 14.7-14.9 to about 13.8 - 14.1.

    Most people will have a lower indicated miles range than me since my route is mostly a very gentle 30-40 mph trip.

    Mike
     
  8. lensovet

    lensovet former BP Brigade 207

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    In addition to the answers above, note that this is covered in our FAQ, which is linked in my signature :)
     
  9. Norman Jensen

    Norman Jensen Junior Member

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    That estimate has gone down smoothly over the age of the car and we are not driving any differently than we did 7 months ago. I keep my tires at a pound over recommended and we don't accelerate or slam on the brakes. The computer estimate may be effected by the type of driving one does, but that would not explain a smooth decline. ?????
     
  10. priuskitty

    priuskitty PIP FAN

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    b/c of your AVERAGE driving habits. the faster you go the lower your average. driving at 62 MPH will give you 6.2 miles EV
     
  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The car started by estimating some average that Toyota programmed in, each drive it is learning more of YOUR average and throwing out more of Toyota's guess. That will be a smooth curve, it's direction is up to your driving style.
     
  12. Norman Jensen

    Norman Jensen Junior Member

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    San Rafeal, CA which is a quite moderate climate. I haven't seen freezing here in 10 years and this summer we only use AC for two days.
     
  13. bisco

    bisco cookie crumbler

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    the smooth decline is a reflection of your actual ev distance travelled. it comes programmed from the factory at a certain number and the tracks your past performance and updates that number. has your actual distance in ev gone down? do you ever drive all ev until the battery is drained and the ice comes on?
     
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  14. bisco

    bisco cookie crumbler

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    battery capacity drops when temps drop below 70 degrees in my experience. i'm down 20%.
     
  15. Norman Jensen

    Norman Jensen Junior Member

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    I wish there were some way to acutally check the miles, but things like weather , traffic, are never the same on the same route. I wonder if there is some way to actually measure the KW storage at full charge.
     
  16. lensovet

    lensovet former BP Brigade 207

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    Sure, install a kill-a-watt or similar device and measure how much energy gets pulled from the wall. Note that the charger is not 100% efficient, there's about 10-15% loss, so amount of actual energy in the battery will be less.
     
  17. bisco

    bisco cookie crumbler

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    i can only tell you that most of us have seen some loss with the cooler temps and are all hoping it will come back in the late spring/early summer.
     
  18. ukr2

    ukr2 Senior Member

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    Norm,

    My PIP started at 13 EV miles last March, drop to 10 until June, then increased to 12 thru the Summer and now is 10.7 with the colder weather. However, my actual EV miles is near the same. Shorter if I turn on the heater. Longer if I'm easy on the accelerator and coast as much as possible.

    Just Enjoy the Drive.
     
  19. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    I think this is a key point. If you do the exact same thing, your actual miles should be about the same. However, when the weather is colder you aren't doing the exact same thing. AND, for example, if you just turn on the heat (assuming the ICE already ran and provided some residual heat) the number of miles displayed will be lower, even if you just turn on the heat for a short time.

    Mike
     
  20. Adam Leibovitch

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    You can get the % of charge if you have a scangauge, but not kwh.