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Secondary battery install ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by xplosuv, Jul 22, 2002.

  1. xplosuv

    xplosuv 1/2 ton status

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    Im looking at the oppisite side inner wheel well from the passanger side and notice that it seems to have mounting holes that look like you can mount a second battery tray on the drivers side. Is this right? and where do you find a battery try for that side.
     
  2. Sandman

    Sandman 3/4 ton status Author

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    You can just go to your GM dealer and get the battery holder. They were an option on bigger trucks. Thats what I did and it worked out real slick.
     
  3. txbartman

    txbartman 1/2 ton status

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    The diesels come with two batteries. The second battery is mounted in a tray on the driver's side. Find a diesel K5 or pickup and you have your second battery tray. My K20 gas also has the second tray. Or, do what I did. Take a passenger side tray, cut the support off the tray, reposition the support, reattach it to the bottom of the tray, and you have it. Mine is probably sturdier than the factory one!
     
  4. dremu

    dremu Officious Thread Derailer Premium Member

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    There was an option for a second battery from the factory, for diesels or for gas engines in cold climates.

    You can buy the support from the dealer, not cheap. LMC (www.lmctruck.com) has the parts for less -- and the last set I bought from them had GM stickers on them. Lessee, dealers parts at half the cost ... no brainer. I think I paid $50-60 for the whole stack o' parts to put the second battery in my '90 Burb. Heck, the big honkin battery cost me more than that.

    If you know about isolators ignore the next bits ;-)

    You'll also need to do some wiring; on my Burb, I just paralleled the two batteries for now. Down the line I'll probably do a solid state (ie diode) isolator. This allows the alternator to charge both batteries, but you can drain either without hurting the other (ie you can drain your aux battery from lights, winch, cooler, stereo without hurting your starting battery.)

    On my Blazer I went with a mechanical isolator, otherwise known as a big-ass solenoid, which would have been factory in 1974. The parts place didn't have the "correct" one for the Blazer, so I apparently have one to fit a John Deere. (Whatever, it's a beeeg freekin relay ;-) When the ignition is on, presumably meaning the alternator is turning, the batteries are paralleled, charging them both. Turn the key off and the auxiliary battery disconnects from the main, so I can discharge it all I want without hurting the starting battery.

    I have the lighter socket in the Blazer connected to the aux battery, so when camping, f'rinstance, I can leave the cooler plugged into the lighter socket and let it run all night.

    Hope this helps.
     
  5. 502Burban

    502Burban 1/2 ton status

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    When you installed your factory second-battery setup, how did it mount? I too have purchased the support and the tray from LMC, but haven't figured out how the tray is attached to the support. (Sorry in advance if this is an incredibly stupid question. /forums/images/icons/blush.gif )

    I'm sure I'm missing something basic, but the tray just seems to lay on top of the driver's side support bracket. Any insight you can provide will be greatly appreciated.

    And if you have any photos to post of the factory second-battery setup, that would be even better! /forums/images/icons/cool.gif

    Thanks,
     
  6. NITRO

    NITRO 1/2 ton status

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    Mine is a gas '79 K5 that came with the second tray. i just run mine paralell when im offroading. other than that, they stay disconeected most of the time

    NITRO
     
  7. dremu

    dremu Officious Thread Derailer Premium Member

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    aux battery pic

    Here's a pic of the secondary battery in Tankie, my '74 Blazer. Nothing really to see, unless you like relays ;-)

    Without actually pulling the battery, looks like the tray bolts to the support, or maybe to the fender, on the left side (i.e. the outside). Two bolts, anyway, from the tray to something on the left side.

    The support then bolts to the fender, the wheelwell and behind the grille as previously mentioned.

    It's a little weird, as I can pull the engine side of the battery up about an inch, but it hasn't come loose yet -- no real hardcore wheeling, she's bone stock drivetrain.

    HTH.

    If you have an 81+ truck, lemme know and I can snap a pic of my Burb, same general idea except the batteries go north-south instead of east-west. I think I had to move my charcoal cannister or something to get the battery support to fit, but there were lots of holes already there so it was just a case of juggling bits around.
     
  8. 502Burban

    502Burban 1/2 ton status

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    Thanks for posting the pic! Didn't help much with the aux battery install as I am trying to figure out how the tray mounts to the support, but I did like where you mounted your relays. Think I'll put that idea to good use. /forums/images/icons/wink.gif

    Thanks again,
     
  9. dremu

    dremu Officious Thread Derailer Premium Member

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    Well, I woulda had to pull the battery out to get a good pic of the support, and I was actually working on the other truck and just remembered to pop the hood on this one ;-)

    OTOH, the relays went in nicely as there were already holes tapped there, just begging for a sheetmetal screw ;-)

    -- A
     
  10. JP's K5

    JP's K5 Registered Member

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    I also bought my parts from lmc. They bolted to factory holes. I did have to move the charcoal canister. I bought a Perko switch (mainly for marine use) and used it to hook the two batteries together. The switch has four settings, off, bat 1, bat 2, or both. The switch cost about $25 and is great when working on your truck because you can shut both batteries off at the switch.

    Jared
    '89 Blazer
     
  11. 79Beast

    79Beast 1/2 ton status

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    How on earth do you keep you engine compartment so clean....I was looking at the link and it's all black and shiny. Good job....mine is dirty like the trail just up and climbed under my hood....guess that's why I run a K&N.
     
  12. Blue85

    Blue85 Troll Premium Member

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    If anybody doesn't know, this requires a continous duty solenoid (relay). A regular one like a Ford starter solenoid shouldn't be used because it uses so much current and is only designed for short-duty use.
     

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