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Gen3 HV batteries for Gen2?

Discussion in 'Gen 3 Prius Accessories and Modifications' started by JC91006, Feb 22, 2014.

  1. JC91006

    JC91006 Senior Member

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    I'm beginning to see a few Gen3 batteries selling on the used market. Apparently from wrecked Gen3 cars. My question is how difficult is it to use these Gen3 cells to put into a Gen2 car? These Gen3 battery packs are selling for a fraction of Gen2 packs.
     
  2. Prius_Cub

    Prius_Cub Member

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    I'm sure somebody has rebuilt a second gen pack with third gen modules by now. I'd imagine it's like swapping second gen modules into a first gen pack. Might be a tighter squeeze but it will work. My plan is to locate a low mileage salvaged third gen pack when my HV battery fails and swap all of the modules out.

    HTC Evo 3D
     
  3. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Considering the higher number of gen3 battery failures I'd question why you'd want to use them in a gen2.
     
  4. Prius_Cub

    Prius_Cub Member

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    Hi GrumppyCabbie,

    I mostly hang out or peruse the Gen II section here. Haven't browsed over to the Gen III section much. Do we know if it's related to the design/manufacture of the modules themselves? My reasoning in Gen II vs. Gen III modules in a second gen pack would be that Gen III modules are obviously newer and there's more of a chance to find a low mileage pack from a wrecked vehicle.

    In the meantime, my HV pack is still going strong and I don't have any reason to replace/repair it yet. If there is proof there is a problem with the actual Gen III modules themselves then I won't be taking that route when the time comes.

    HTC Evo 3D
     
  5. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Outside my knowledge. Not sure if it's the modules themselves or that they are worked harder and get hotter causing premature failure.
     
  6. Prius_Cub

    Prius_Cub Member

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    I'm going to have to pay more attention to HV battery failures in the Gen IIIs. Thanks for the heads up!

    HTC Evo 3D
     
  7. jdenenberg

    jdenenberg EE Professor

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    The Gen3 modules have a lower series resistance and therefore are rated to handle 30% higher max current. The Gen3 ECU is programmed to push the HV battery harder which may contribute to the reported failures in heavy (taxi) applications. I tend to prefer Gen3 modules over Gen2 modules for a Gen2 HV battery rebuild, but then again, my rebuilt battery (a ReInVolt) with Gen2 modules is still working well after 60k miles and 2.5 years.

    JeffD
     
  8. JC91006

    JC91006 Senior Member

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    There seems to be more inventory on the gen3 battery packs in the used market. Those can be had for $400 per pack, vs Gen2 packs sell for about double the price. Also the gen3 cells seem to be much fresher than the gen2 cell packs.
     
  9. Robert Holt

    Robert Holt Senior Member

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    Would you just happen to know if the cell module assemblies can be switched between Gen 2 and Gen 3 batteries?(I.e. Same shape, connections, etc.?)
    Or if they differ in internal resistance would that be a very bad idea?
     
  10. jdenenberg

    jdenenberg EE Professor

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    I would not mix Gen2 and Gen3 modules in a Gen2 battery, but the lower series resistance is a good thing - less heat generated. As far as I know, the Gen3 modules should mechanically fit in a Gen2 battery housing.

    JeffD
     
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  11. JC91006

    JC91006 Senior Member

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    Crazy question but why can't you just bolt on a gen3 battery to use in gen2?

    SM-N900P ?
     
  12. JC91006

    JC91006 Senior Member

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    In theory, if I wanted newer cells, I can buy a gen3 battery from a wreck and move the cells over to a gen2 housing and it'll work? No other balancing required?

    SM-N900P ?
     
  13. jdenenberg

    jdenenberg EE Professor

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    The two batteries are built with different HW/SW interfaces to the rest of the Prius so I believe that this will not work.
    You can do that and it should work as long as the salvaged Gen3 battery was in good shape. I would go through the balance/test procedure for my own Prius to insure a better chance of the repair lasting longer.

    JeffD
     
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  14. JC91006

    JC91006 Senior Member

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    This is very valuable information. I know my batteries will eventually need replacement and I don't feel replacing with remanufacturer gen2 cells would be a lasting repair.

    If I can switch over cells from a wrecked late model Gen3 (should be a working unit), then I don't have to buy extra equipment (chargers) to make the battery cell swap. This is something many DIYers can probably do.
     
  15. JC91006

    JC91006 Senior Member

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    I understand the Gen2 battery packs have 28 modules, are there the same amounts in Gen3?
     
  16. SageBrush

    SageBrush Senior Member

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    I was told the same by Carolyn of Luscious Garage.

    Lightly used Gen3 packs are so cheap right now I have thought more than fleetingly about swapping out the pack in my '04 Prius as a preventive maintenance, even though it runs just fine.
     
  17. JC91006

    JC91006 Senior Member

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    There are 2 units that are sold locally from wrecks for only $395....no core exchange. I think I would just want to do the preventive swap just for fun.
     
  18. jdenenberg

    jdenenberg EE Professor

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    28 as well, the Prius "C" has fewer.

    JeffD
     
  19. JC91006

    JC91006 Senior Member

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    Get a bunch of local guys together and 1 professor and do a bunch at once :)
     
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  20. Robert Holt

    Robert Holt Senior Member

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    Sounds like fun!

    Maybe we East Coastians can do that also!

    Any way to safely keep charge levels up if I purchase a pack now for use in a year or two? For lead acid I would use a trickle or float charger , but this is a different chemistry and way more volts.