How much "(milli)amp hours" capacity is needed to unlock rear trunk?

Discussion in 'Gen 3 Prius Technical Discussion' started by StephenFromCT, Nov 24, 2019.

  1. StephenFromCT

    StephenFromCT Junior Member

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    Hello,

    I am hoping to store my 4 gauge 16 feet jumper cables in the plastic storage tray located immediately above the spare wheel (2011 Gen 3 Prius).

    I understand that the rear trunk cannot be opened using the emergency key if the small 12 volt auxiliary battery is dead. I am hoping that fewer amps are needed to unlock the rear trunk vs the number of amps needed to start the computer (which then boots the large high voltage battery).

    Specifically, if I attach 12 volts (eg. a single 9 volt battery plus two 1.5 volt batteries in series = 12 volts) to the engine compartment fuse box jump starter connection (+ positive) and the engine block (- negative) using thin gauge cooper wire (eg. using 120 volt AC household "lamp" wire and tiny alligator clips), does this provide enough (milli)amps to unlock the rear trunk?

    If I can use this strategy then I will have more space in the main trunk, behind the rear seats, for other temporary loads (groceries, etc). Plus, if my 12 volt auxilary battery dies then this strategy can be used to remove the dead battery (eg. to attempt to recharge it) without the need to access the emergency trunk release latch. If my battery dies when I am at home my plan is to remove the battery and to recharge it indoors.

    Assuming I do not reverse polarity, I assume this would be a safe procedure (with minimal risk to the computer, etc).

    Thanks for your insights!

    Stephen
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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  3. bisco

    bisco cookie crumbler

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    i have read that 8 d cells would work, but i haven't tried it.

    you can also just climb in the back and open the hatch manually from inside
     
  4. Grit

    Grit Senior Member

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    Why do that? We like to keep things difficult here.
     
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  5. bisco

    bisco cookie crumbler

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    at my age, its difficult enough :cool:
     
  6. StephenFromCT

    StephenFromCT Junior Member

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    Hello all,

    @TMR-JWAP After I receive answers to questions which I sent to MightMaxBattery.com customer support I am planning to write up a description of my DIY "jump starter". What I am assembling is larger than a bread box, but it has more features. It was not part of my plan, but I think my "jump starter" can be rigged to make toast. Stay tuned!

    @bisco Yes, I learned to open the rear hatch using the emergency lever, after lowering the rear seats and crawling inside. Much easier to do when the trunk is empty. If access to the lever is blocked then the contents need to be removed via the rear side doors.

    Yes, eight D cells in series would provide the 12 volts. I read one reference which confirmed that when batteries are connected in series the volts add up, thank you high school physics class (so 8X1.5V=12V), but that the "amp hours" do not change.

    In March, 2013 David Beale described using an emergency light 12V gel cell battery to open the rear hatch or even to put the hybrid in "ready" mode. David, I assume you are describing the small battery "bricks" used as "backups"? What size battery (how many "amp hours") has worked well for you? I have seen some as small as 5-7 amp hours. These batteries are not very tall and would easily fit under the front seats of a Prius.

    Thanks again for your insights and suggestions.
     
    #6 StephenFromCT, Nov 25, 2019
    Last edited: Nov 25, 2019
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