Perko Switch easy DIY?

Discussion in 'Boating' started by takirb, Apr 26, 2009.

  1. takirb

    takirb New Member

    Messages:
    179
    State:
    South Carolina
    I have a new to me old to others pontoonand want to install a Perko Battery Switch. I have the standard cranking battery already that came with the boat. I'll be purchasing a deep cycle for running my accessories at night. I'd like to place the deep cycle in a battery box and store it under the rear seat for easy access, along with the battery switch (pro's or cons on this location?)

    Am i correct in thinking that all i need to do is -

    1) take the cables that are currently on the positive terminal of the battery and connect them to the COM terminal of the switch
    2) run some 8GA wire from the positive terminal on battery 1 to #1 on the switch (same for batt #2 and position #2 on switch)
    3) run some 8GA ground wire to same grounding point as current battery

    I'm hoping to test out the panel switches soon (boat's still at the boat dealer) and make sure everything's wired correctly, and i'll need to install a 12v cig lighter port to the dash as well (which i'm thinking is just going to pos and neg terminals behind the switch panel).

    Is any of this correct? I'd like to save myself some money as the dealer charges $85/hr for labor
     
  2. catoon

    catoon Board Clown!

    Messages:
    1,387
    State:
    whiteville
    well i dont know im basiclly a dumb ars good luck and some one will be around and know
     

  3. tufffish

    tufffish New Member

    Messages:
    1,196
    State:
    Texas
    i am wanting to put in a perko switch also. i am waiting to see what answer you get and i will not have to ask the same question later.
     
  4. biga

    biga Well-Known Member

    Messages:
    2,112
    State:
    evansville
    STOP!!! what you have going there is totally wrong .. and really for what you are wanting to do a perko switch may not be the answer! it sounds like you are mainly wanting to charge the 2 batteries in your system correct? the perko switch lets you select what battery you are running the engine off of but its only going to charge the battery it is switched to but if you switch to the other battery thats the one its going to start off of and 8ga wire will not hold the amperage that a starter draws....so if you had a dead battery you could switch to your trolling battery to get you back home... 8ga wire is way to small for that application 4ga would be minimum to reduce voltage drop,overheating the wires and possible fire! a battery issolator would be a better choice if you charging system is up to the task of bringing up a discharged battery [MOST OUTBOARD SYSTEMS ARE NOT UP TO THAT TASK] they are designed to maintain charge... if you still want to use the perko switch i can send you the wiring schematics
     
  5. centexcop

    centexcop Well-Known Member

    Messages:
    3,035
    State:
    Texas
    I'm not sure about an 8 gauge cable. If it were me, I would go with a minum size of 6 maybe even larger. You can get bulk welding cable at your farm/home stores. The 8 would probably work, but if for some reason you did a lot of cranking on the motor, the cable is going to get hot really quick.

    It's the same principal as jumper cables. If you try to jump start a dead battery with a cheap pair of jumper cables, you're going to have to leave the cables connected for several minutes to get enough voltage built up to start the vehicle with the dead battery. With a pair of heavier gauge cables, you're going to get more voltage into the dead one quicker.

    As far as the 12v accessory outlet, you are correct. Red to positive and black to ground. I would put an inline fuse on the positive side, just in case whatever you're powering ever has any problems. That might keep you from totally frying the device you're powering and at worst case scenerio buring of wires or fire.

    This is just what I'm thinking. There may be others out there that are more expierenced at this than me.
     
  6. biga

    biga Well-Known Member

    Messages:
    2,112
    State:
    evansville
    you never want to use a smaller wire that the main load wire in the system and most starter wires are #4 on outboards so i would never go less!! the boat i am building now will have #2 thu the whole starting system...
     
  7. GaryF

    GaryF New Member

    Messages:
    3,649
    State:
    O.P., KS
    Here is another discussion of the Perko switch, with a diagram that may help. Also read through the thread for some alternative ideas:

    http://www.catfish1.com/forums/showthread.php?p=1359553#post1359553
    http://i258.photobucket.com/albums/hh271/garyf_bucket/Lowe/BatterySwitch.jpg

    Adam is right about not skimping on the wire. My 60hp Mercury uses 6 gauge, and that is what I used for the switch... but my wire runs are very short, just a couple of feet. Anything much longer and I would have stepped up to 4 gauge.
     
  8. takirb

    takirb New Member

    Messages:
    179
    State:
    South Carolina

    Thanks! I didn't know that 8GA was too small, so i'll play it safe and just use 2GA as long as the current wiring is smaller. As for the charging aspect, using the switch to charge 1 or the other, or both was just an added comfort. I plan to remove the deep cycle after i return each day/night and charge externally. That's one reason why i wanted to put it under the seat so it's in a convenient location to get to. My main concern is being able to use up my accessories battery with the comfort of knowing that my starting battery hasn't been drained. Though I am a little concerned about the alternator being able to charge both batteries while running. I get mixed reviews on whether or not i should even try the "both" selection while the motors running for any type of recharge on the deep cycle.

    I know nothing of outboard motors on a boat, and i don't physically have the boat near me to reference any of the wiring. But i was thinking, logically, the switch controls the source (battery), so anything currently going to the positive batt terminal now should just be wired to COM terminal on the switch. Then just wire up the positive poles to the switch terminals 1 and 2 respectively.
     
  9. biga

    biga Well-Known Member

    Messages:
    2,112
    State:
    evansville
    thats correct on the wiring but just use 4ga.. i am using 2ga because my trolling batteries are at the front of a 22ft boat..
     
  10. takirb

    takirb New Member

    Messages:
    179
    State:
    South Carolina
    Thanks for the links! I actually read that post when i first joined and didn't understand it till now :) VERY GOOD INFO there! It seems weird to me to hook the second negative battery terminal to the current negative terminal only though. Id have thought that it would hurt the starter battery with a seperate battery going through it for grounding. My motor is a Johnson 48 Special (or something or other) so maybe 4GA will do. I just plan on mounting the switch inside the wall of the seat compartment since it's wooden, and hopefully that'll keep all my wiring out of the way of the environment the best.
     
  11. takirb

    takirb New Member

    Messages:
    179
    State:
    South Carolina
    Thanks for this! i felt dumb asking but boats are foreign to me so i didn't know if there was more to it than that :embarassed: I've done automobile wiring before but for some reason i look at boat wiring/electronics as being a totally different ballgame.
     
  12. CatHunter24

    CatHunter24 New Member

    Messages:
    715
    State:
    Dayton, Ohio
    may be late, seems the answer has already been given, but doc lange, a boc member, has a section about how he wired his perko and he used the welding cable, his site is hookedoncatfish.com lots of other useful tips as well.