2009 gmc sierra slt battery location and 2nd battery tray

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by LAURASDAD, Feb 24, 2011.


    LAURASDAD New Member

    Hello all,

    Just bought a 09 Sierra 4x4 slt crew cab and love it so far. I just noticed the battery is located in a horrible location. The negative post is very difficult to access. Not sure what I would do if it needed to be jumped.

    Also, it appears to have an empty 2nd battery tray at the front on the drivers side. How difficult is it to wire and install the 2nd battery? Am I correct that this empty tray is for an auxillary battery?

    Look forward to adding Line X and a Loredo tonneau soon.

    Thanks very much

  2. troutbug

    troutbug Rockstar 100 Posts

    I did it on my '08. It's not difficult to do, but you are going to want to buy some sort of isolator to keep your main battery from draining if the aux. battery gets weak. I bought a smart isolator from Cole Hersee that is rated at 200A, and I have a deep cycle as my 2nd battery that I run accessories off of. This isolator also allows you to wire a momentary switch so you can jump your main battery from your aux. battery without cables. It's not hard to install at all. Run a fuse from the new battery to the isolator, run heavy wire from the juction block on the firewall to the isolator, and that's basically it. The alternator will automatically charge the 2nd battery when the isolator connects the two. The CH smart isolator is kind of a hybrid solenoid/microprocessor type. There are also diode-type isolators, but I don't know much about them. I have read that most have a voltage loss when charging, not allowing a full charge to the batteries.
    If you want to forego the isolator, you could wire the batteries in parallel (+ to +, - to -), but I personally would only do so with two brand new batteries of the same make, preferably from the same lot. If one battery is weaker than the other, it will draw the stronger battery down over time.

    You'll be happy with the Line-x also,...great investment.
  3. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Hey Sal, not including the batteries, how much does a set up like that cost?
  4. troutbug

    troutbug Rockstar 100 Posts

    Mike, I think I paid about $125 for the isolator, and I had some 2 GA welding cable already. I paid about $15 for a small marine fuseblock for accessories, then I just had to get battery terminals and a high amp AMG fuse (just a few dollars). Fortunately, my dad gave me the battery from his camper, and we reconditioned it with his battery-minder.
  5. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Interesting set up and sounds very reasonable for the added function it brings. Thanks!

    LAURASDAD New Member

    How do you guys connect a jumper cable to the main battery? Don't u think its sort of tucked way back there and hard to get to the negative post?

  7. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    For me, my jumper cables have two different type of contacts/connectors....One of them is the traditional clamp and attached to it is another smaller clamp that attaches to the nut on top of the battery post cable. It is the smaller one that fits.

    However, for the negative connection, you do not need to use the battery to attach the jumper cable. Just clamp you jumper cable to any metal that grounds.

    LAURASDAD New Member

    Thanks for the reply. Can I use grounding metal under both scenarios: I am being jumped (my battery is dead) AND if I am jumping another vehicle?

    thanks again

  9. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Yes...the negative post of a battery ends up grounding to the frame anyway.

    You're welcome!

    LAURASDAD New Member

    1 last question. How can I be sure the metal is suitable for gounding? thanks

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