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Traction Battery Display Question

Discussion in 'Prius c Main Forum' started by ilsfbs3, Dec 3, 2019.

  1. ilsfbs3

    ilsfbs3 New Member

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    Hello, I just purchased a used 2013 Prius C (Three) from a dealership. I'm brand new to hybrid cars and the Prius in general.

    I have a question that might be relatively simple but I'm having issues finding answers online in other threads.

    When I look at the display of the engine or power source there is a little battery pack display. It is about half filled up with 3 or 4 little blue segments inside.

    I believe that is the traction battery and I'm wondering if that gets charged on its own through regular use of the car or if thats the indicator on when you need to replace your battery. Let me know if I'm understanding anything wrong or if you're able to clarify what that battery marker indicates!

    Thank you!
     
    bisco likes this.
  2. Ronald Doles

    Ronald Doles Active Member

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    You would have to acquire some software for your phone or laptop to check the state of the traction battery.

    That indicator you mentioned is a state of charge (SOC) indicator. One bar on that indicator is 40% charged and 8 bars is 80% charged. As you drive the car, the number of bars will fluctuate.

    Light acceleration will draw power from the traction battery to drive an electric motor which moves the vehicle. Heavy acceleration will start the internal combustion engine (ICE) which will assist the electric motor in moving the vehicle. Braking will switch off the ICE and the electric motor becomes a generator (regenerative braking) to capture energy while slowing the car. It will use that braking energy to charge the traction battery.
     
  3. jerrymildred

    jerrymildred Senior Member

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    Wow. I just looked at the manual for the Prius c and it doesn't explain anything about the battery indicator as far as I could tell other than one little diagram that shows full, mid, low or something like that.

    The quick answer is that it is just a state of charge indicator like a fuel gauge. It has nothing to do with wear and tear or with replacing anything. The dealer should have explained this along with lots of other things, but most of them work very hard to remain ignorant of anything having to do with the Prius.

    The longer answer is that if it shows all bars filled, that's still not 100% SOC and no bars is not 0% because the car won't let it go that high or low. It reserves charge at the top and bottom that you can't see or use in order to protect the battery. Most of the time, it should stay in the middle or a little above the middle. Big down hill slopes or repeated braking might fill the indicator. It should be very rare for it to get all the way "full" or "empty."
     
  4. bisco

    bisco cookie crumbler

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    congrats and welcome!
    it is simply showing you the relative state of charge. it charges and discharges on its own when the car is made 'ready'.
    it doesnt really mean much, but can be useful as an indicator of a battery nearing the end of its useful life if you see repetitive swings between one bar and 8 bars.

    your battery has an 8/100 warranty

    all the best!(y)
     
  5. jerrymildred

    jerrymildred Senior Member

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    In California it's a 10/150 warranty. ;)

    OOPS!! I looked it up and the c doesn't have the CARB warranty. :oops:
     
    #5 jerrymildred, Dec 5, 2019
    Last edited: Dec 5, 2019
  6. bisco

    bisco cookie crumbler

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    on the c?
     
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  7. jerrymildred

    jerrymildred Senior Member

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    Nice catch, Bisco. I didn't know that about the c. I looked it up from Toyota's online manuals and you're absolutely right.
     
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  8. bisco

    bisco cookie crumbler

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    i was surprised when i learned that, from ray i think. the nuances of warranties are frustrating
     
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  9. Raytheeagle

    Raytheeagle Senior Member

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    The RX450H battery is also 8/100:cool:.

    But just because the batteries warranty is shorter, doesn’t mean it’s less reliable ;).

    Just how the car is classified. Since they use the same technology, why wouldn’t it last equivalently :whistle:?

    That’s what I’m operating on anyway:).

    We just did our SoCal trip in the RX450h this time and the battery did very well. Even in LA traffic the battery seemed brand new but is 2.5 years old and 31k miles seasoned(y).
     
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  10. vvillovv

    vvillovv Senior Member

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    Just one thing to add
    All of what Ronald mentioned above is right, but regenerative braking is not always easy to understand, especially when moving into a hybrid from and ICE car.

    Regeneration is handled by the computers in the car, much like the SOC state of charge of the Prius C "traction pack" battery.

    With regenerative breaking, the electric motor will regenerate "traction pack" SOC state of charge, All the time you are braking,

    but the " Prii"

    also has regular disc breaks, and they are used as well, by the computers to determine when and how the regular disc breaks are used.

    It's a computer control thing,
    Like Ronald say above,
    The computers use regeneration while you are driving regularly too,
    which is one of the reasons why Hybrid cars slow down different than normal ICE car slow down.
     
    #10 vvillovv, Dec 6, 2019
    Last edited: Dec 6, 2019
  11. Ronald Doles

    Ronald Doles Active Member

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    I agree with what you say Vvillovv.

    The Prius is a front wheel drive car so regenerative braking can only be applied to the front wheels. The rear brakes on the Prius are mechanical (friction) and can only assist the front.

    Up to 75% of a cars braking force comes from the front brakes which is why vehicle front rotors are always larger than the rear rotors. It is the job of the braking computer to maintain the balance of front-to-rear braking force (proportional braking).The harder you brake, the more the front of the car dips down and the rear of the car raises. That means more braking force needs to be transferred from the rear brakes to the front brakes or else the rear brakes would lock up.

    The braking computer also has to account for how much regenerative braking is being applied to the front wheels and release an equal amount of mechanical braking from the front brakes to maintain the front-rear brake balance.

    Next there is the regeneration current limit. Increasing the pressure on the brake pedal increases this regeneration current up to and beyond the 110 amp limit. Braking harder than the 110 amp limit just adds more mechanical braking into the mix and that energy is lost as heat in the rotors. Since batteries don't charge instantaneously, gradual braking keeps the regeneration below the 110 amp limit and the longer charge time allows the traction battery to recover the maximum amount of electrical energy.

    Finally, the regenerative braking is switched off below 8 mph. Below 8 mph the Prius brakes are just like any other car.

    That has to be some pretty amazing software. Hats off to the engineers that developed it.
     
    dig4dirt likes this.
  12. dubit

    dubit Senior Member

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    Holy crap - You all are aware that your replying to yourselves I hope.

    The original poster hasn't been back. Probably won't, but you never know. If he/she did return, they'll probably be so confused they'll never return until panic sets in down the road when the car breaks. Gotta keep it simple. All this SOC / ICE / Regenerative braking and the technicalities behind it all will most likely completely overwhelm and thoroughly confuse a 1st time Prius owner.
     
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  13. Ronald Doles

    Ronald Doles Active Member

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    I have been a car enthusiast since I was a teenager. I read every hot rod magazine I could get my hands on. Rebuilt engines and transmissions and built racing engines for a few of my friends cars. I put a turbocharger and water injection on a "Sleeper" economy car that I owned that was fun to drive in the "stoplight gran prix". I do all my own work on our cars as well as any electrical, plumbing or mechanical work on our home. I am fairly new to Prius but I want to know every detail of how my cars and everything else works. I just took my wife to an Urgent Care and sat in our Odyssey reading the 300 page owners manual while she was waiting to be seen. I learned a few things. OK, so I am a geek.

    My wife on the other hand is not the least bit interested in anything mechanical. She is smarter and has way more people skills than me but her only mechanical curiosity is seeing how long she can drive the car with the "low gas" light on.

    I assume that we have some new Prius owners like myself, some like my wife and then there are many in between.
     
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  14. vvillovv

    vvillovv Senior Member

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    I have to admit, I wan't thinking much about the OP in my post above.
    I was trying to explain that most people don't understand what regenerative braking is or how it work due mostly to the way
    it's been explained to drivers since the beginning of hybrid regenerative braking systems

    I still see post here where drivers actually believe the regeneration is being done by the disc brakes somehow.
     
  15. Moving Right Along

    Moving Right Along Senior Member

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    Just in case the original poster does come back, an “8/100” warranty means the hybrid traction battery is warranted to be free of material defects for 8 years or 100,000 miles, whichever comes first.
     
  16. ilsfbs3

    ilsfbs3 New Member

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    Hi everyone, this is the OP - thank you so much for all of this information! I kind of figured it out on my own when that indicator went purple but then driving on the freeway brought it back up again! But all of this was really helpful and thank you for making clear what I should have known before I drove it!

    I bought the car used from a Honda dealership near me, so maybe Prii are not their forte.
     
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