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What is the voltage of traction battery?

Discussion in 'Prime Technical Discussion' started by Salamander_King, Oct 2, 2020.

  1. Salamander_King

    Salamander_King Senior Member

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    This might have been discussed somewhere, but I can't find it. What is the voltage of the traction battery when it is in Ready mode? Is it always near-constant or does it fluctuate as the car is driven and EV range diminishes?
     
  2. EdPalmer42

    EdPalmer42 Member

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    The traction battery is about 350 volts. You can find an exact voltage if you look around, but the voltage will vary with state of charge and age. The voltage will drop as the battery discharges and also as the battery gets old. Hybrid Assistant can show you the current voltage.
     
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  3. Salamander_King

    Salamander_King Senior Member

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    Thank you for the answer. I knew I could find an answer here. I have a few more questions if can provide another answer. What is the voltage of the traction batteries for the Gen4? Are Lithium-ion and NiMH types both have the same voltage out? How about older Gen2 and Gen3 traction battery voltages compared to Gen4 and PRIME? Finally, any specs on other Toyotas namely HiHy and Rav4 (both Hybrid and Prime) and other models of hybrids and BEVs? Are they all similar voltage, or are the specific to a vehicle model or make?
     
  4. jerrymildred

    jerrymildred Senior Member

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    Per the 2018 Prius brochure, the nominal battery voltage for the Li-ion is 207.2V. The NiMH is 201.6V which is the same as the Gen 2 & 3.
    2018 Prime brochure says that it's 351.5V.

    Those are the brochures that I have downloaded. I didn't take the time to check the others in your list.

    Edit to add that the 2013 PiP brochure doesn't give the battery voltage, just that it's Li-ion.
     
    #4 jerrymildred, Oct 3, 2020
    Last edited: Oct 3, 2020
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  5. fuzzy1

    fuzzy1 Senior Member

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    Nominally 355.2V for the RAV4 Prime which has 96 cells, vs 95 cells for the Prius Prime.
     
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  6. Salamander_King

    Salamander_King Senior Member

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    Thanks for the info. So, both Prius Prime and Rav4 Prime traction batteries do output substantially higher voltage than regular Prius. But the actual voltage is not something that is fixed.

    The reason I wanted to find out about Prius Prime traction battery voltage was that I was told by the inventor of the PlugOut inverter (formerly known as Converdant vehicle inverter) that PP is able to output more power because of the higher voltage of the traction battery. I was at a demonstration/testing of the new version of the 5kw inverter hooked up to a PP. The inverter was able to sustain the 5.02kw of load at 240v for the duration of the testing which was ~20 min long. For that duration, the engine did not start. I was told that a practical limit of the output for the regular Prius Gen2-4 is about 3.7kw.


    upload_2020-10-3_17-54-7.png
     
  7. fuzzy1

    fuzzy1 Senior Member

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    The PP battery should have a higher current capacity too. Output power is the product of those two figures, P = V * I.
     
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  8. Salamander_King

    Salamander_King Senior Member

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    So, if the inverter output is 5020w @240v, then I(out)=5020/240=20.91Amp? But for the input end of the inverter, what is the current? All I know is 351.5v. Or the 5020w is the same on the input side and output side of the inverter? If so, I(in)=5020/351.5=14.28Amp?
     
  9. fuzzy1

    fuzzy1 Senior Member

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    Battery current would be that 14.28 amps if the inverter was 100% efficient, which none are. If 95% efficient, the battery current would be 15.0 amps, rising a bit as the battery voltage slows falls.
     
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  10. Salamander_King

    Salamander_King Senior Member

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    OK, but that means if I assume Gen2,3,4 has a max power of 3.7kw output then the invert(out) I=3700/240=15.41amp. And Gen2,3,4 battery has rated 201.6v NiMH battery, the inverter(in) I=3700/201.6=18.35amp, which is higher than PP's value. This suggests that with an even bigger inverter (remember that one used for this demonstration was 5kw inverter), PP might be able to output higher than 5kw with higher than 18.35amp.
     
  11. Sunshine88

    Sunshine88 New Member

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    Did you buy one? Would love to see the insides.

    You could put a big inverter on any battery but doesn’t mean you should. Tests are done at different charge/discharge rates to determine what’s best for performance vs cell life/health.
     
  12. Salamander_King

    Salamander_King Senior Member

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    NO. Too expensive and not big enough for my need to run the whole house. There was a thread by another PC user who recently purchased a 3kW inverter.

    PlugOut Power Inverter | PriusChat
     
  13. AzusaPrius

    AzusaPrius Senior Member

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  14. PiPLosAngeles

    PiPLosAngeles Senior Member

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    3 or 5 kW is great for the first ~6 kWh, but what happens after that? Does the unit prevent over-discharge of the traction battery? What's the maximum power available once the car switches to HV mode and has to periodically start the ICE to charge the HV portion of the battery?

    What's the advantage over a natural gas standby generator that is significantly less expensive?
    Home Generator Cost - Generac Power Systems
     
  15. jerrymildred

    jerrymildred Senior Member

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    The car prevents over discharge of the traction battery by starting up the ICE. One should ONLY use these in ready mode.
     
  16. ChapmanF

    ChapmanF Senior Member

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    Randy, who runs PlugOut Power, seems to have empirically studied how much you can count on from the hybrid system in each vehicle model. We know the system will start the engine to replace charge whenever it has to, and of course the engine and inverter routinely traffic in multiple tens of kilowatts just driving the car down the road. Of course for those larger driving demands the engine RPM rises.

    While the car does run the engine as needed to keep the battery charged, I've never seen it go to a higher-than-idle engine RPM to do it. It seems to generally use whatever charging power is available with the engine doing 1000 or 1200 RPM. (It is definitely not really "idling" then, it is throttled up and working harder, and you can hear the exhaust note deepen when charging is happening.) There might not be any programming built into the car to increase the engine power further than that, to handle mystery loads on the HV system that weren't planned for. Also, if it did, we don't know that the cooling system would keep up, with the car not moving.

    So those seem to be the considerations behind the practical power limits that Randy publishes for each model vehicle.
     
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  17. PiPLosAngeles

    PiPLosAngeles Senior Member

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    That's my worry. If you're drawing 5000W from the traction battery in ready mode, will the ICE be able to supply that kind of current (350+A at 12V)? If not, will the unit stop so the traction battery isn't over-discharged?
     
  18. jerrymildred

    jerrymildred Senior Member

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    In charge mode, it pumps almost 5,000 watt/hours into the battery in less than a half hour while charging from depleted to an indicate 80%. So, if the battery could hold it, the ICE could pump roughly 10 kWH into the battery in one hour and that works out very easily to roughly 10,000 watts. So, 5,000 watts should be pretty easy for the Prime. But I don't know for sure if the regular Prius can charge that fast. There are some differences, as I recall, in the MGs.
     
  19. PiPLosAngeles

    PiPLosAngeles Senior Member

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    Will the Prime enter charge mode on its own just being in ready mode?
     
  20. Salamander_King

    Salamander_King Senior Member

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    Even with a 5kw inverter, I was warned not to exceed the safe level of 3.5kw load at any given point in order to prevent disastrous overload consequences on the traction battery. 3.5kw is just not a big enough number for a whole-house hook-up.

    The benefit is much quieter and very efficient operation than any portable or standby generators. Also less maintenance specific to a generator. But I don't think Generac stand-by system is cheaper than this inverter set up. There is no stand-by system of 3-5kw, AFAIK.
     
    #20 Salamander_King, Mar 28, 2021
    Last edited: Mar 28, 2021
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