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Retrofit Prius for Secondary Battery?

Discussion in 'Gen 2 Prius Technical Discussion' started by Houston Hybrids, Apr 9, 2014.

  1. Houston Hybrids

    Houston Hybrids Junior Member

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    I am trying to retrofit my Prius to allow a secondary battery to be tested while another battery is actually installed in place. I don't neeeeed to do this, but we are so sick of taking batteries in and out of the car for testing purposes. My biceps are getting out of control, lol. Has anyone ever seen this done? I have an idea of what I need to do, but I don't want to reinvent the wheel if it isn't necessary!

    Thanks,
    Jessica
     
  2. JC91006

    JC91006 Senior Member

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    What idea did you have in mind? I don't see any way to get around lifting batteries in and out, even as a secondary battery.
     
  3. bisco

    bisco cookie crumbler

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    you just want some extended cables and switches so you can throw it in the trunk and switch from one to the other?
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Jessica, can you give me some hint of which battery you are referencing? (Almost certainly NOT the Fob battery, but might be either the AGM 12 volt battery or the High Voltage battery

    Battery Box & Relocation Kit
    Battery Selector Switch
    would work for 12 volts
     
  5. Houston Hybrids

    Houston Hybrids Junior Member

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    I know I will still have to do the lifting unfortunately, but I won't have to take out the back seats and trunk... I would like to be able to just set the battery in the trunk and hook it up without having to uninstall the other battery. The design I am thinking of would have two A/C disconnect switches, allowing me to turn one unit off and the other on....

    Dealing with one 100lb beast is easier on me than two ;)

    Jessica

    Bisco- Pretty much what I am looking for! Also, I am worried about the battery sliding around during testing or God forbid I get rear-ended. Not sure if I should have a way to secure it with tie-downs or something? Maybe bolt a 2x12 board into the trunk and mount some 10mm's from underneath so I can secure it in place using the battery case's existing hardware.

    IDK, just thinking out loud...

    Jess
     
  6. JC91006

    JC91006 Senior Member

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    How does Toyota test their batteries?
     
  7. Houston Hybrids

    Houston Hybrids Junior Member

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    I have no idea how they test their batteries during the manufacturing process, but when a failing battery is taken to a dealership, they just use a code reader I believe.


    Jessica
     
  8. JC91006

    JC91006 Senior Member

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    I was thinking Toyota must have a way to test these batteries without having them in the car. Will make life much easier.
     
  9. Houston Hybrids

    Houston Hybrids Junior Member

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    Ohhhhhh, I will have to look into that! Never even occurred to me to test it without driving on it... Good thinking :)

    Jessica
     
  10. JC91006

    JC91006 Senior Member

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    Maybe you can start another thread and other battery experts will ring in with some ideas.
     
  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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  12. nh7o

    nh7o Off grid since 1980

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    My guess is that Panasonic tests each module as they come off the line, using much the same methods as the rebalancing setups described on PC. Toyota probably only does some basic tests at assembly, but only to verify that the modules are OK.

    If you want to test a whole battery pack at typical current levels, you would need a suitable dump load capable of something like 10kW (although not continuous), and a charging supply of similar levels. Then you would need data acquisition on all the modules to calculate the internal resistance and module variations. That would be a long project to build all that.

    Since all those functions are built into the battery ECU, it ought to be possible using something like one of the single board computers out there, which have CAN-BUS built in, to talk directly to the battery ECU, as happens with Techstream. Again, some real R and D there, but maybe it has been done already.

    I would think that if the module level testing has been done thoroughly, it will be redundant to then test the whole battery again. What does need checking is all the voltage monitoring leads, and the ECU, but I would think that could be done in the client vehicle at install time.

    Just my 2 cents...
     
  13. ericbecky

    ericbecky Hybrid Battery Hero

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    Jessica,
    There are ways to test it when not in the car.
    Depends on how detailed you want to go.

    We should hang out some time and talk shop. :)
     
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  14. Houston Hybrids

    Houston Hybrids Junior Member

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    I am extremely pernickety when it comes to "my precious's" so... detailed it is!

    Gollum

    Jessica
     
  15. MTL_hihy

    MTL_hihy Active Member

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    The Toyota techs will use Techstream to view the individual banks (2 modules per bank). If any of the banks show as weak (may only have one cell on one module bad), they will recommend replacement. New battery packs will be placed on a grid charger at the dealer before being installed in the vehicle.

    I'm sure you can develop a way to test these on the fly with a little ingenuity.
     
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  16. Mr.Electric

    Mr.Electric Member

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    I think that you could extend cables and sit a second battery on top of the first. Unlike some computers gen 2 Prius battery computers do not need to be reflashed to match the car software version. This means you could put the second battery on top and use the lower battery computer or if the second batt comes with a computer use the upper battery computers. Seems like the hardest part will be extending all the wires.
     
  17. Houston Hybrids

    Houston Hybrids Junior Member

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    Thank you so much! I was wondering if this was possible, but scrapped the idea because it sounded too good to be true. I am trying to post a picture of the design I have so far, but keep getting an error message... I will try again soon.

    Jessica
     
  18. KhaPhoRa

    KhaPhoRa Member

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    While the battery ECU may not care what car it is in it wouldn't be able to read the voltages, resistance, temperature of the second battery above it unless you also transferred over all the leads, and if it can't get SOC the car would never know it needed to be charged and would likely run it down to zero rather quickly, possibly killing it... plus the fact that any problems with the pack being tested wouldn't be reported as all measurements would come from the good "idle" pack. Now the second part is true of course about using the replacement packs ECU. If you could lengthen all the harnesses you could disconnect from one and connect to the other fairly easy, just monitor the air temp inside. Depending on how many wires are involved a nasa style control board with an array of single pole double throw switches might work, and would look really cool! :) Houston prepare for battery disconnect. Roger we are go with battery disconnect.


    the Seahawks training facility ?
     
  19. Houston Hybrids

    Houston Hybrids Junior Member

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    I wonder why my picture won't load?!?!? Ive tried reducing the size, but still getting an error. The picture would be good for sharing with other's....if it works lol.
     
  20. bisco

    bisco cookie crumbler

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    there is a current issue with uploads on the site, might be awhile...