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2010 Prius Extra Battery?

Discussion in 'Gen 3 Prius Main Forum' started by froSTed, Dec 28, 2010.

  1. froSTed

    froSTed Junior Member

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    Hi everyone, I haven't posted in a while.
    I noticed the large space in the back of the my Prius in the trunk area above the spare tire, and it got me thinking..
    Would it be possible to add another battery, not to add plug-in capability but to extend the range of the current battery, the one that is recharged as you drive?
    What I want to do is have greater range on the battery, and that should improve mileage. Is this possible? Has it been done already?
     
  2. penquin230

    penquin230 "Golden Hawk"

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    Any "extra Battery" would have to be plugged in for charging. There are many kits for Gen 2 Prius out there. I believe Enginer has a Gen 3 kit, can increase mpg to 85 check out there web site http://www.enginer.us/
     
  3. froSTed

    froSTed Junior Member

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    I respectfully disagree.
    You do not have to plug in, you can reclaim more power, and charge the battery the same way the battery is already charged with fewer modifications. Think about it as a booster pack, feeds into the regular battery extending it.
     
  4. spiderman

    spiderman wretched

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    You would think you could place another pack in parallel with the existing. But I am sure that is way to simple to work.
     
  5. froSTed

    froSTed Junior Member

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    That's what I want!
    Simple!
     
  6. David Beale

    David Beale Senior Member

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    Toyota engineers have already told us it wouldn't improve mileage. They didn't do it for patent infringement reasons, but as the HSD has been designed for a 6.5 A-Hr battery it won't be able to use a larger one. You would have to re-write the firmware. Actually, I believe someone actually tried it with the GII and it didn't help.

    At any rate, nice idea (repeated by many), but I don't think it will improve mileage unless you can somehow completely re-write the firmware. Good luck with that!
     
  7. GrumpyCabbie

    GrumpyCabbie Senior Member

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    I could be wrong here, but I'm sure a PriusChat member from the Bristol area here in the UK did the above and the second battery exploded! They weren't sure if it was damaged before they installed it (it came from a wreck) or whether it was overloaded.

    A safer way is the enginer system.
     
  8. Flaninacupboard

    Flaninacupboard Senior Member

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    Yeah, google up aminorjourney for an exploding phev. it was a bms+ system which involves spoofing the SOC to get good performance from the mains charged packs.

    As D Beale says, an extra pack in parallel won't help, since the prius doesn't know it's there.
     
  9. macman408

    macman408 Electron Guidance Counselor

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    You'd only "reclaim more power" if you regularly fill the battery - not just 8 bars, which most people rarely see, but actually comPletely full, so the engine is spinning to burn extra energy. This really only happens if you go down a mountain, and the vast majority of people don't. Those that do usually don't go up and down several mountains - usually no more than one big up+down on each trip, so the gains to be had are minimal. Plugging in really is the only way to take advantage of a bigger battery.

    Please keep in mind that storing energy in (and using it from) the battery is actually a *bad* thing: It means you accelerated too much to begin with. All energy in the Prius must come from the gas engine at some point, and putting it only into your momentum is better than converting it back and forth from kinetic to chemical energy in the battery a few times. However, it's less bad than wasting the energy as heat in the brakes, which is what most cars do. If you drive as efficiently as possible, you'll use a very small range of the battery's capacity.
     
  10. hampdenwireless

    hampdenwireless Active Member

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    The current battery is able to absorb most but not all of the generated electricity. If you added an extra battery you might have some situations where more energy generated was captured and less was 'thrown out' but the extra weight of the battery would hurt your mpg and make up for any gains.

    Toyota engineers have the battery sized at the 'sweet spot'. Improvements in batteries could be made but not by adding more of the same battery that are not charged with outside power.

    Examples of possible improvements:
    - more capacity at the same weight
    - better battery chemistry with less charging resistance (charging loss)
    - same capacity at a lighter weight

    Most of these improvements would need different electronics and or software.
     
  11. Troyroy

    Troyroy Member

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    I'm no electrical engineer, it seems to me that the original battery that comes with the car needs to be beefed up some. Maybe...just maybe it can be replaced with a deep charge battery as is used in trolling motors. I know it would be of a different size...but if it better serves the owner so be it.
     
  12. pakitt

    pakitt Senior Member

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    A bigger battery needs to be re-charged by the engine for a longer time. So, unless the charging process (fuel consumed) + plus discharging (driving at 0L/100km) = lower fuel consumption to drive same length of flat road with engine running the whole time, an extra battery is useless.

    When driving normally the battery is never fully charged, unless driving downhill - it gets fully depleted only when I drive very slowly on flat roads or heavy stop&go traffic. I think the mpg that could be achieved with a bigger battery are limited from the charging/discharging process (limited from the technology of the battery itself) and the extra weight.

    I don't think therefore that you could get better mpg with a bigger battery of the same type, since the engine would have to run longer to charge it more thus consuming more fuel that would be then offset by the extra miles run electrically - yielding the same fuel consumption.
    Please note that Gen 2 and Gen 3 have the same battery capacity and type. Yet gen 3 has better fuel efficiency because of improvements elsewhere and not due to a bigger battery (here a table in Italian - I could not find the same table in English - check out the "batteria" section).

    Maybe, as mentioned, a battery with a more efficient conversion ratio, could be a bigger battery that can store more energy generated with the same amount of fuel being used.
     
  13. Penny's Dad

    Penny's Dad New Member

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    prove futile but I just hate that thread and its timing so much it brings back bad memories of when my Gen III was new and my early ownership experience was spoiled.