Battery Relocation

Discussion in 'E9 General Discussion' started by e30strube, Jul 29, 2014.

  1. e30strube

    e30strube Member

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    I am interested in relocating the battery to the trunk, while using an E30 style "power block" in the engine bay. For those that have done this, where did you run the ground? Did you connect to something in the trunk or run another wire back to the engine bay? Would 2ga be sufficient for the power and ground?
     
  2. Mike Goble

    Mike Goble Active Member

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    I used a stock E30 battery cable and ground my battery to the rear frame using a regular battery ground cable from a Chevrolet. I have three grounds coming off the engine block to the frame.
     
  3. Ohmess

    Ohmess I wanna DRIVE! Site Donor

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    There is no need to run the ground back up to the front of the car.
     
  4. Peter Coomaraswamy

    Peter Coomaraswamy Well-Known Member Site Donor $

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    What's the best wire to use? Stuff from Home Depot won't work :-(
     
  5. Mike Goble

    Mike Goble Active Member

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    You can buy battery cable kits from Summit, you can use welding cable, or you can go to Pick-n-Pull and get one from a BMW.
     
  6. Jellobmw

    Jellobmw Member

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    I used welding wire, not sure of the gage but it was bigger than the std ground cable, when I ran the + from the trunk to the engine bay.
     
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  7. decoupe

    decoupe New Member

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    I used 4ga welding cable from the battery (under the rear seat in this case) through disconnect switch to a power distribution block in the driver footwell and then 8ga to the alternator and starter. Removing the switch "key" is my low tech immobilizer.

    Grounds from the battery to chassis (used rear seatbelt anchor - seats deleted) and engine to three locations using the 4ga.

    Doug
     
  8. Ohmess

    Ohmess I wanna DRIVE! Site Donor

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  9. daicos35

    daicos35 Member

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    put an odyssey pc680 under your back seat,,,, smaller and more powerful than a regular battery,,,
     
  10. Peter Coomaraswamy

    Peter Coomaraswamy Well-Known Member Site Donor $

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    Dai, I looked and found a plethora of options for odyssey pc680. Which one is best?

    Thanks,

    Peter
     
  11. decoupe

    decoupe New Member

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  12. daddywad

    daddywad Active Member

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    Battery relocated in trunk

    Battery relocated in trunk, (Odyssey 40)
     

    Attached Files:

  13. Nicad

    Nicad Well-Known Member

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    I think if I did this, I would hollow out a period correct battery in the stock position and use it for storage of relays, electronics,etc. Maybe a good place to hide electronic ignition. My battery tray is pretty ugly, so something that looks have decent would have to take it's place. Have you gone back to a back seat now Doug? That installation under the seats looks great.
     
  14. decoupe

    decoupe New Member

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    Still have all the parts but no intention of undeleting the deleted rear seats. Vague notions of using the rear seats as furniture in my studio - BMW meets Ames chair. Just about as bizarre as your hollowed out battery battery. Do it.
     
  15. daicos35

    daicos35 Member

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    pc 680 -mjt (the one with the metal case), fits neatly under a rear seat... i removed the battery tray all together....
     
  16. bfeng

    bfeng Well-Known Member Site Donor

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    BMW furniture

    We have a guy here at work that built a desk using body panels from a 2002.
    The desk has a glass top that is 2" above a 2002 trunk lid. The trimmed trunk lid covers the top of the actual desk 'case'. IIRC, he used part of the 2002 nose to clad the front of the desk (the privacy panel). I could see cutting an old door pair and using them to clad the desk sides or as doors for a cabinet. Us E9'ers would put fender side grills on the sides of the desk. Where would you put your spare C-pillar badges? I'd be tempted to mount the grills and a functional set of headlamps on the privacy panel.

    Anyway, I thought it looked really great and was a nice way to customize a bland office. Now I know what I'm going to do with my left over 2002 body panels, grills and roundels.
     
  17. Stevehose

    Stevehose Well-Known Member Site Donor $

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    Out of curiosity, what makes Odyssey batteries better than others? It weighs more than an Optima and apparently lesser stats and more expensive:

    Odyssey:
    Specifications Pulse (5-second) Hot Cranking Amps (PHCA) 1200
    Cold Cranking Amps (CCA) 540
    20Hr Nominal Capacity (Ah) 42
    Reserve Capacity Minutes 78
    Dimensions L x W x H (in) 7.87x6.66x6.80
    Weight (lbs) 38.2

    Optima:
    Cold Cranking Amps: 720
    Cranking Amps: 910
    Nominal Voltage: 12 volts Open Circuit Voltage (fully charged): 12.8 volts
    Internal Resistance (fully charged): 0.0030 ohms
    Capacity: 44 Ah (C/20)
    Reserve Capacity: BCI: 100 minutes (25 amp discharge, 80°F (26.7°C), to 10.5 volts cut-off)
    Weight: 31.7 lb
     
  18. teahead

    teahead aka "Rob" Site Donor

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    Didn't put dual batteries under the rear seats? Anyone have that thread?
     
  19. jmackro

    jmackro Well-Known Member

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    Steve:

    The Odyssey PC680 in my Alfa doesn't match the specifications that you posted at all:

    Weight: The Odyssey model PC680 weighs 15.4 pounds; not the 38.2 that you show. This compares with your figure of 31.7 pounds for the Optima.

    Size: The Odyssey PC680 is much smaller than a 12V Optima. Your specs show dimensions of 7.87x6.66x6.80, or about 360 cu in, but the Odyssey PC680 only measures 7.15 x 3.00 x 6.65 or about 142 cu in. An Optima red top measures 10.06 x 6.94 x 7.88 or about 545 cu in.

    Price: An Odyssey PC680 costs $129 on Amazon, while they charge $225 for an Optima 8002-002 34 Red Top.

    I'll give you that an Optima has more cranking amps than the Odyssey.
     
    Last edited: Jan 12, 2019
  20. teahead

    teahead aka "Rob" Site Donor

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    Odyssey PC680:

    Pulse (5-second) Hot Cranking Amps (PHCA) 520
    Cold Cranking Amps (CCA) 170
    20Hr Nominal Capacity (Ah) 16
    Reserve Capacity Minutes 24
    Dimensions L x W x H (in) 7.15 x 3.00 x 6.65
    Metric Dimensions L x W x H (mm) 181.5 x 76.3 x 167.8
    Weight (lbs) 15.4
    Weight (kg) 7

    https://shop.odysseybattery.com/p/pc680


    Seems small enough to run two in parallel under the rear seat.
     

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