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Parallel battery question

Discussion in 'Gen 2 Prius Technical Discussion' started by Jaron Lindow, Jul 4, 2018.

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  1. Jaron Lindow

    Jaron Lindow Junior Member

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    Has anyone tried running parallel battery modules? Not parallel packs, but individual modules twinned with other modules.

    Assuming the supplemental modules can be cooled, compressed, secured, and each supplemental module is wired directly to just one original module, it seems like this would increase capacity and reduce resistance.

    This must be a bad idea or I think I'd have found an example of it being done. What am I missing?
     

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    #1 Jaron Lindow, Jul 4, 2018
  2. jerrymildred

    jerrymildred Senior Member

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    I haven't heard of anyone doing that. It sounds theoretically possible, but would be a huge job, plus expense, that would never pay for itself.
     
    #2 jerrymildred, Jul 4, 2018
  3. Jaron Lindow

    Jaron Lindow Junior Member

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    If someone had an extra battery pack lying around, it would mainly just be a matter of wiring. What's the main downside? Would the weaker module of the pair kill the good module? Or explode?
     
    #3 Jaron Lindow, Jul 4, 2018
  4. bisco

    bisco cookie crumbler

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    wouldn't you need to rework the control software? that is the hard part. if it was easy, it would have been done, unless you've stumbled onto an easter egg.
     
    #4 bisco, Jul 4, 2018
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  5. Raytheeagle

    Raytheeagle Senior Member

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    You got some of those lying around still from Easter :p?
     
    #5 Raytheeagle, Jul 4, 2018
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  6. fuzzy1

    fuzzy1 Senior Member

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    Electrically, it would be no different than simply paralleling two whole packs. But mechanically, it would be more difficult.
     
    #6 fuzzy1, Jul 4, 2018
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  7. bisco

    bisco cookie crumbler

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    #7 bisco, Jul 4, 2018
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  8. Jaron Lindow

    Jaron Lindow Junior Member

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    batt.png
     
    #8 Jaron Lindow, Jul 4, 2018
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  9. bisco

    bisco cookie crumbler

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    eureka! that's it!(y)
     
    #9 bisco, Jul 4, 2018
  10. Jaron Lindow

    Jaron Lindow Junior Member

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    The voltage sensors would need to be split between the two packs as well.

    batt2.png
     
    #10 Jaron Lindow, Jul 4, 2018
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  11. MickyMatter

    MickyMatter Active Member

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    I was wrong, deleted.
     
    #11 MickyMatter, Jul 4, 2018
  12. bisco

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    :ROFLMAO:
     
    #12 bisco, Jul 4, 2018
  13. jerrymildred

    jerrymildred Senior Member

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    You'd give up storage and add weight. And your gas mileage would maybe go up by 1 or 2 mpg at most assuming you would operate it like a normal hybrid.

    Well, I did think of one sort-of positive. With more cells, the cells would cycle less and should last longer.

    But it would be interesting as an experiment.
     
    #13 jerrymildred, Jul 4, 2018
  14. Dxta

    Dxta Senior Member

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    I think that can be achieved. But my concerns would be that the arranged packs would occupy more space. And what exactly are you trying to achieve?
    I do know laptops, and some stuffs, have got parallel/series arrangement in their circuitries.
     
    #14 Dxta, Jul 4, 2018
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  15. Jaron Lindow

    Jaron Lindow Junior Member

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    It's wasted space presently. Just an empty plastic bin sitting above the spare tire. And the curb weight increase would only be 3%.

    The objective would be to get a setup with better charge/discharge/capacity (i.e. performs more like new) using old modules, which would be significantly cheaper than a brand new battery pack.
     
    #15 Jaron Lindow, Jul 4, 2018
  16. Raytheeagle

    Raytheeagle Senior Member

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    Using old modules runs the risk of failing modules and then rebuilding again and again and again.

    You would also have 2x the problem as normal owners would have;).

    Good luck with your project(y).
     
    #16 Raytheeagle, Jul 4, 2018
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  17. padroo

    padroo Senior Member

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    I would think software issues too.

    Without the ability to charge the larger pack probably not much gain.

    Has anyone ever added charging capabilities to the existing battery pack?
     
    #17 padroo, Jul 4, 2018
  18. Dxta

    Dxta Senior Member

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    ...and if you want a success to em, I think you got to add a separate BMS to the pack, to care for the added one.
     
    #18 Dxta, Jul 4, 2018
  19. bisco

    bisco cookie crumbler

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    no one has ever added a plug to the stock pack, it wouldn't be worth the cost or effort.

    people have added batteries and a plug though, back in the day before the plug in came out. and they were geniuses.

    now, it's just pointless.
     
    #19 bisco, Jul 4, 2018
  20. edthefox5

    edthefox5 Senior Member

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    Toyota already thought of that. Then realized how much power it would take to charge double battery load and how much weight it would add.
    G2 degined mgs would not able to charge that load without killing car power and that forced them to the drawing board and out came the g3 mgs.
     
    #20 edthefox5, Jul 4, 2018
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