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Dual Battery and Alternator insite

Discussion in 'Truck & Equipment Repair' started by ptrkptz, Nov 29, 2008.

  1. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    I am looking for advice from the expert...

    I bought a '74 chevy pickup last year and put a plow on it... the 'backup'...

    I ended up using it a few time this last year... but I start to lose battery power. I end up shutting the headlights off and run off park lights and still push the limits.

    I have asked mechanics and auto parts place... no one can give me a straight answer.

    So I hope that someone can help me out... i need advice on the type, size of batteries and alternator.
    Thanks in advance
  2. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    you can get a alt from a newer like pontiac transport with rear air i think is the model. its a 140 amp unit. and super close to direct bolt in.

    www.ck5.com has some good info on it . i cant recall much on it as my stuff runs newer style stuff.

    went over and checked for ya. here is a search with some good threads in it.




    Last edited: Nov 29, 2008
  3. MeeksCo

    MeeksCo Senior Member
    Messages: 214

    I am no expert... I will say that.
    Though, I added another battery to my system. I have a 96 K1500 Cable operated Western. I took an old battery from my garage upto Autozone and had them charge it.
    I crossed over another positive cable from the other battery and grounded the extra battery to the frame. That extra battery alone has given my original battery (which is not that new anyways) so much backup its incredible. I am planning on beefing up the alternator but it seems like just by adding this battery i'm ok.

    If your altentor is not charging the battery back up after you rev the engine, then you may need either a new battery or a newer altenator. It doesnt hurt to add an extra battery. Go to your local junk yard and buy a used refurbished battery for like $25 and a 2' black cable and a 4' red cable all for like $35-40 bucks total.

    My 2 cents....
  4. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16


    So the alternator that is currently on there is 63 amps... i can put on a 140 amp alternator w/o doing anything else (except adding the other battery)?
  5. As long as it will fit you sure can.

    I just upgraded my alt from a 90amp to a 130amp and it made a huge difference. I'm going to buy a second battery and add it as well.
  6. MeeksCo

    MeeksCo Senior Member
    Messages: 214

    Yea...like the other guy said. If the newer altenator will fit...you may just be ok with that. Though, in the longrun, I recommend adding a backup battery for tons of reasons. You can just keep it in all year long.
    You will still be at 14-14.5 volts if you look inside your truck (which is what is normal)...though you times that by two...because it will take double the amount of energy to kill two battery's then one.
    It's a cheap and great preventive maintenence.

    But get the new altenator first!
  7. adksnowo

    adksnowo Senior Member
    Messages: 370

    You should always replace-install dual batteries together unless you are running aux. battery through isolator. Dual batteries should both be purchased @ the same time & be of same type. Otherwise parasitic draw will ruin the batteries, batteries will charge improperly and can ruin alternator.
  8. juspayme

    juspayme Senior Member
    Messages: 116

    its a must in my book, had the engine stall many times in the olden days . get the 2nd bat.
  9. snowandgo

    snowandgo Senior Member
    Messages: 143

    A second battery will get you a long way. You should be able to get a 100 amp or larger alt. from NAPA or Auto Zone for your truck. I never had trouble plowing with a 100 amp and a big single battery. You might get away with just a larger battery. Two would be better, but then you have to buy extra cables, rig up a mount, etc.

    Maybe your pump motor is going bad and drawing too much juice.
    Last edited: Dec 4, 2008
  10. adksnowo

    adksnowo Senior Member
    Messages: 370

    Not just plow drawing power. There is a lot of juice being used on our trucks. Defroster so you can see, beacon, strobes, lights, aux. lights, back-up lights and sat. radio:).
  11. Duncan90si

    Duncan90si Senior Member
    Messages: 602

    This is how I set my trucks up.
    Two batteries.
    Good quality 4 ga wire connecting both batteries from + to +.
    Run a 4 ga ground from the 2nd battery to the motor or frame.
    I'm surprised I didn't see this posted in this thread yet.... Run an additional 4 ga wire from the + terminal on the second battery to the back of the alternator. All the batteries and big alternators in the world won't make an enormous difference until you run a bigger charging wire to take advantage of the increased amps of the alt. and/or increased capacity of dual batteries. The factory 10ga - 12ga wire is not sufficient.

    My opinion.
    The way I look at it is, power cables on most plows are around 4 gauge, correct? Plow manufacturers use that large of wire because obviously the plow uses enough electricty that its needed. Well combine that with your lights, heater, radio etc, how do you expect the battery/batteries to charge fast when they are being supplied with power from the alt. through a wire thats 1/3 the size of the cable that just the plow is drawing through, not to mention all the other electronics being used.

    To give you an example:
    Just today actually I rewired my K3500 like this. It already had 2 new batteries in it. The second battery was wired + to + and - to - onto the 1st battery. At idle with the heater, lights, roof light, wipers, radio etc. on it was reading high 12s to low 13s on the factory volt gauge.

    I then eliminated the ground cable between the batteries and grounded the 2nd battery to the motor. I then ran the 4ga cable from the alt. to the + side of the 2nd battery. Now with all the same accessories on, it reads slighty about 14v at idle.

    Hope this info makes sense and helps someone out.
    Last edited: Dec 4, 2008
  12. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Use the search function on the gray line above the post. Search "charging" "Duel Batteries" etc. It's beat to death every couple of months. There should be hours of reading there.
  13. jonniesmooth

    jonniesmooth Senior Member
    Messages: 296

    I have an '85 chevy, it's a 4 speed.
    got a alt, isolater, and all the essentials from these guys:


    they know their stuff

    RODHALL Senior Member
    Messages: 374

    if you don't have an isolater in the system your going to burn something up.
    regulator, alt, batt all work togather. what will happen when you add a second batt is regulator tells the alt how much charge to send to one batt, second batt will either over charge or under charger, under charge it is usless over charge and it can explode. if one of the two batts over charge it could back feed and make the alt and or regulator stop working al togather.

    jacking a second batt in truck improperly has caused more then one fire...

    an 80 amp isolater is like $40...
  15. In2toys

    In2toys Senior Member
    Messages: 319

  16. Duncan90si

    Duncan90si Senior Member
    Messages: 602

  17. In2toys

    In2toys Senior Member
    Messages: 319

    kool thanks

    IGETPLOWED Junior Member
    Messages: 13

    Will upgrading to a higher alternator give you any electrical problems? I was told you could 'overcharge' your electrical system.

  19. festerw

    festerw Senior Member
    Messages: 986

    If you put an isolater in you may as well just run one battery for a plow truck, the extra reserve capacity is what you're looking for and the isolater destroys that.
  20. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    As long as the "Voltage regulator" is working right it will not over charge the batteries. If it is an external one, buy the heavy duty one if you replace it. The alternator is regulated by the total system voltage. If the load is pulling from the batteries the voltage drops. The "Voltage regulator" senses this and sends 12 volts to the field part of the alternator. This causes it to put out voltage / amps over what is being drawn up to the rating of the alternator and the RPM it's total output peaks at. keep in mind an alternator only puts out 1/3 of it's rated output at near idle RPM'S. Most trucks plow at near Idle speeds. Combine low amps-high draw, low air flow and coolant flow. You can see why Plow Trucks have charging and cooling problems. Your battery system should be about 12.6 + volts with the truck not running. With it running it should be 13.5 to 14.5 volts.
    A stock OEM dash gage is for the most part is useless. If you really want to keep an eye on your trucks voltage status. Install an after market Volt gage with a good volt scale on it. Don't even bother with amp gages, they are useless, they just show you it has output or not. You can be on the plus side for days, but if the battery is bad, it will not be in a charged state to start the next day.