My Subaru Forester Low Impact Installation

Discussion in 'Mobile Radio Systems' started by KN3O, Feb 19, 2016.

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  1. AG6JU

    AG6JU Ham Member QRZ Page

    Most of Hot Melt Glue came loose within several months, so I re glued them using Marine Goop Glue, which is much stronger and lasting 3 years so far in very cold -20 degree Celsius and +45 degree Celsius weather.
    I have Tupperware in engine compartment , which I keep spare light bulbs. it has been there for last 3 years , but has not had any water leakage or melting problem.
    Subaru engine is Flat Boxer Engine , similar to air craft engine, most of engine are in bottom half of Hood and there are a lot of opening on top of engine between Hood.
    and Exhaust come out of Bottom of engine, so it may be different from other cars.
  2. AG6JU

    AG6JU Ham Member QRZ Page

    Question ?

    I looked at 2014 2.5i Forester Positive battery terminal.
    it seems like positive battery terminal is divided into 3 section.
    #1 Positive Battery Terminal itself
    #2 between 80A fuse and Current sensor.
    #3 after 80A fuse

    it seems like heavy wire to Starter Motor is connected directly to Battery , Not through current sensor.
    some unknown wire ( possibly alternator output ) is connect to between 80 A Fuse and Current Sensor.

    any suggestion on which part, should I connect to my HAM Radio DC power ?


    bottom side of Battery Positive Terminal
    KX4O likes this.
  3. KE4OZD

    KE4OZD Ham Member QRZ Page

    Don't want to step into a "conflict" here....but I will share some information I received today..
    While attending the Orlando Hamcation today Sat 9 Feb 2019, I had driven my brand new Subaru Forester 2018 and was looking for any other like mine and stumbled onto K3RRR who was experiencing dying battery problems after wiring in his rig. I'm trying to find the "Subaru" company answer to all this before or after the battery sensor I dropped by a huge dealership one block from the Hamcation and the service manager called all three of his electronic techs out to meet me and they all agreed that you should "NEVER" connect anything to the sensor module...In plain english connect ham radio power cables directly to the battery terminals NOT to the sensor input on the positive battery terminal or you could experience all sorts of poltergeist issues with your Subaru...I am not getting into ground issues....but I'm wiring mine tomorrow rain permitting and as far as I'm concerned the negative battery terminal is already connected to the frame/ I will connect the negative ham radio power cable directly to the negative battery terminal....
  4. WB2LBV

    WB2LBV Ham Member QRZ Page

    Please refer to my post here (#10 in the thread), do NOT connect anything directly to the negative battery terminal of your Subaru as that will effectively bypass the sensor and cause issues. Use a ground connection elsewhere and stay away from the sensor completely.
    I have a mobile radio installed under the front seat in mine and it is connected to a frame ground using a short cable to a terminal attached to one of the seat mounting bolts. This has been working well for quite some time and there have been no electrical problems from the installation.
  5. KE4OZD

    KE4OZD Ham Member QRZ Page

    I'm afraid I DO NOT UNDERSTAND how a direct line to the negative battery post has anything to do with the battery monitor sensor that resides between the alternator and the positive battery post...the whole purpose is to bypass the sensor completely...
    Are you stating that the battery cable on the negative battery post is not connected to frame ground but rather goes through another battery monitor module ??

    I will chase this for myself....tnx
  6. WB2LBV

    WB2LBV Ham Member QRZ Page

    Looking at this it appears there may be two possible configurations for the battery sensor-
    It would help if you took a clear pic of your battery with the connected terminals and wiring and posted it here. As you can see from the pic I posted of my '15 Subaru it definitely has a sensor on the negative terminal. Perhaps yours is different.
  7. K0BG

    K0BG Ham Member QRZ Page

    You DO NOT want to bypass the battery monitoring system, on any vehicle! You do that by connection to the positive battery connection, and the the same chassis ground the battery uses, or at least very close to it.

    See my wiring article:
  8. KE4OZD

    KE4OZD Ham Member QRZ Page

    I see the logic on the negative battery connection thanks to Alan's article....rather than just blindly following someone else's methods....I will have to physically find that ELD then connect appropriately...and connect to the battery side of that 80 amp fuse at positive.

    Tnx again Alan...well done...
  9. KE4OZD

    KE4OZD Ham Member QRZ Page

    OK installed...
    Dropped by my dealership and head tech went out to my car and explained exactly where to connect what to avoid matched Alan's examples but it was good to actually see the physical connection points. Not the most 'OCD" install but it will work...checkout in next couple of days..but power is in for two different feeds. There was only three feeds on the positive side 1. Starter 2. Sensor 3. Fusebox. There where two on the negative side 1. Chassis Ground 2. ELD Sensor (Electrical Load Detector). On my 2018 Forester you cannot access the actual physical chassis ground side of that sensor (it is encased within aluminum tubing), but the main chassis ground that I used will do with no ill effects...that is according to Subaru's Head Tech...good enough for me.

    Firewall-Access.jpg RoutingThruFirewallToBatt.jpg ChassisGrd.jpg DirectToPosTerm.jpg
    Last edited: Feb 12, 2019
  10. AI7PM

    AI7PM Ham Member QRZ Page

    Yes, the Hall sensors are found on the negative side.

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