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Battery to small

Discussion in 'Introduce Yourself to the Community' started by alesv, Nov 27, 2013.

  1. alesv

    alesv Junior Member
    from NY
    Messages: 17

    I have an 02 silverado i just put a 7 1/2 ft MM on.
    The lights dim when positioning the plow. I was thinking of going with dual batteries when I discover the truck has a under size battery in it. The book calls for about 750 cca and there is a 570cca in it. I plan on plowing only about 3 to 4 hours per storm.
    My question is "When" I put the biggest CCA battery my truck will accept (i'm looking at a 800CCA /1000ca) will it be enough to handle it. Also the ALT is 105 amps
  2. grandview

    grandview PlowSite Fanatic
    Messages: 14,609

    Just put in the biggest battery you can. If you want to move the plow around do it when you moving the higher rpm's will help.
  3. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Well the lights will dim a little. Thats normal. If your really worried you can also buy a small battery charger and plug it in before and after
  4. Rc2505

    Rc2505 PlowSite.com Addict
    Messages: 1,245

    Upgrade the alt. and install 2 batteries. I have done that on all of my trucks, and I don't have any problems. Lights, warning lights, plow, salt spreader, cb, wipers, heater, and radio all running at one time, and the everything works great.
  5. jasonv

    jasonv PlowSite.com Addict
    from kannada
    Messages: 1,122

    The brightness of the headlights is related directly to the electrical system's voltage. In order for a battery to charge, the charging voltage (alternator) has to EXCEED the battery voltage, so you usually have 14-15 volt charging for a 12 volt battery.

    The plow motor will draw more current than the output of the alternator, so when you're running the plow motor, REGARDLESS of how large the battery is, the net current will flow OUT of the battery, which means that the "whole system" voltage will drop by 2-3 volts minimum. The bigger the battery and higher the alternator's output current, the lower the drop, but the drop will ALWAYS happen unless your alternator puts out way more power than the plow pump draws -- which is never going to happen.

    You can always see the 2+ volt drop by the headlights dimming.

    Now if your battery is incredibly small and alternator output is low, the voltage drop will be greater, could be around 5 volts drop. Much more than that, however, and the vehicle's ignition will fail.
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Anything that charges at 15 vdc is bad. It should never charge that high just fyi
  7. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,403

    No it's not. 14.5 is the minimum you want usually
  8. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    15 volts is high. 14.7 14.8 is about right
    13.8 is sufficient
  9. upplowin

    upplowin Member
    from UP/MI
    Messages: 54

    I have a 2005gmc 2500hd, and I have a western ultra mount, Its a two battery system with two 800cca batteries. It works good and the volts going down when you operate the plow is normal but should also recover quickly...I would just go with your set up, a new 800cca battery & see how it works for you. You should be able to go to any auto store in your area, and have them load test your bat/alt. Its free of charge and they will let you know if bat or alt needs replacing...
  10. alesv

    alesv Junior Member
    from NY
    Messages: 17

    Thanks for all the advice. When doing more checks the voltage drop as around 4 volts which is way to much. Also when I say the lights dim so does everything else like the heater and radio displays flickers.
    I talk to my local Alt and Starter repair shop and he was telling me that the alt dont charge that much if any at an Idle (which is where we plow at) and putting a smaller pully on alt would in turn make the alt think its at 1500 rpm and it would put out maxamium amps.
    Also the battery that the previous owner put in is only 590 CCA and 710ca which is used in 4 cyl trucks.
    I'm am going to install the largest CCA Battery called for my silverado and install the smaller pully and see hoe that works before going to a 2 battery system. If I go to a 2 battery system I have to start with the correct battery anyways and install same make model and size.
    I will post with results as I get them.
    Thanks For everones input.
  11. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    I personally would t do the smaller pulley. It's still only a 105 alt. Invest in a bigger alt and call it a day
  12. jasonv

    jasonv PlowSite.com Addict
    from kannada
    Messages: 1,122

    What 4-cly truck would you put a battery that small into?
    Toyota Tacoma 4-cyl comes from factory with 750 CCA / 850 CA.

    Don't go for the largest battery "specified". Go for the largest battery that will PHYSICALLY FIT.

    Also, something even more important that current (amps), is the battery's RESERVE CAPACITY. This is a number that basically specifies for HOW LONG it can pour out a certain current, before it is dead. Even a battery with a fairly small current can run the plow pump adequately, but the larger the reserve capacity, the longer it can run the plow pump. Reserve capacity measures the number of minutes that the battery can output 25 Amps. Reserve capacity is conceptually similar to the [MILLI]AMP-HOUR rating that you are probably familiar with in dealing with things like cellphones. I.e., a 2000 mAh battery will keep your phone operational for twice as long as a 1000 mAh battery. Similarly, a 150 minute reserve capacity will run your plow pump twice as long as a 75 minute reserve capacity.
  13. jasonv

    jasonv PlowSite.com Addict
    from kannada
    Messages: 1,122

    Yeah, because 14.8 is *so much lower* than 15, so it must be worth picking a fight over 0.2 volts...
  14. coldcoffee

    coldcoffee Senior Member
    Messages: 776

    The smaller pulley will generate more heat and decrease the life of the unit. Also, depending on the effectiveness of your belt tensioner, you could potentially cause belt slippage.

    Also, some units have a temp sensor inside which lowers output in order to keep it from overheating. Once the unit reaches it's high end temp, the output will drop.
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Yea it is. 14.8 all day long at 15 that's high. Testers generally start saying faulty equip at 15
  16. jasonv

    jasonv PlowSite.com Addict
    from kannada
    Messages: 1,122

    Nope, not 14.8. Faulty if its over 14.79376.
    But thanks for trying.
  17. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Ok. Thanks for letting me know.
  18. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,380

    I've heard some guy's running battery isolators
  19. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    No real need for an isolator
  20. JCByrd24

    JCByrd24 Senior Member
    from Maine
    Messages: 232

    I highly recommend you start with just a new single battery, and that it be an AGM battery. I run a single Sears Diehard Platinum which are made by Odyssey, which are very well known and used by the military. I just read an ad in popular mechanics that Interstate is now making an AGM battery as well, probably Odyssey as well. They are more vibration and cold resistant, and much more tolerant of deep cycling and high current draw, which the plow motor will do. My stock AC delco battery that was only a couple years old (combined with GMs computer controlled charging system) was allowing voltage to drop low enough to cause ABS system message in the message center. The new battery fixed that problem and also reduced dimming. Also verify you're wires and connections are in good shape and connections clean. Any money you spend on batteries and alternators will not help if connections are bad and wires too small. I followed advice here and added an extra wire from the alternator to battery (fused), and upgraded the ground path as well.

    I would suggest you only really need a bigger alternator if you've added continuous current draw in addition to the plow motor, such as lots of lights, electric salter, etc. The plow motor is pretty intermittent and should not alone require a bigger alternator than you've got.
    Last edited: Nov 28, 2013