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Battery Voltage

Discussion in 'Commercial Snow Removal' started by rrs26ja, Jan 27, 2003.

  1. rrs26ja

    rrs26ja Junior Member
    Messages: 3

    I just had to put a new alternator in my 1997 Chevy K1500. Even after installing the new battery, the voltage drops from 14 to around 10 when raising the plow or changing the angle. This is the 2nd year for my Fisher 7 1/2 plow. Seems like the electric motor is drawing a lot of current. Any ideas?
  2. OffRoadPlow

    OffRoadPlow Senior Member
    Messages: 247

    Is the alternator stock? That may be your problem, not saying that is could not be the plow, but the alt in my friends 1500 draws heavy, the friend then put in an aftermarket with a higher rating and does not see the draw he used to. Just a thought.
  3. hyperpack

    hyperpack Senior Member
    Messages: 108

    voltage drop

    I have a 120 amp alt on my old Dodge with a boss V Plow, When I raise it voltage drops to about 9 or 10 volts.This is normal,I can plow continuously for 24+ hours with no problem.I think most pumps draw about the same for plows of similar weight, If your voltage raises to about 14 volts a few seconds after running the pump it sounds like the alternator and battery are working good.
  4. Mick

    Mick PlowSite.com Veteran
    from Maine
    Messages: 5,546

    I have a Fisher that puts a pretty good draw on a battery. When my son took the truck to his shop for maintenance, he had a new battery put in. He said it was a "heavy duty" battery. I told him "not good enough" cause it would show a drop to around 10 volts when raising the plow and had him replace it. So far it seems to be doing well. Runs lights, radio, heater and the plow without any discharge.

    It might be your battery. I think the new one is a 1000 CCA.
  5. Earthscapes

    Earthscapes Senior Member
    from WNY
    Messages: 577

    The voltage meter in the truck game,, are these things accurate ??

    My 90 stays around 13 volts. Move the plow and it drops to 9 volts. I was always worried about the 13 volts,but when i hooked it up to a real gage,,it shows 14.5 with a drop to about 11

    My 02' runs 15-16 on the truck gage and when i hit the plow it drops to 12,,except for last nite 3 degrees below ZERO it dropped to 10 volts.

    That is with both trucks running lights,radio,heater and rotator.
  6. fordman

    fordman Senior Member
    Messages: 327

    The voltage on my truck drops 2-3 volts when lifting the plow and I run dual batteries. Plows do draw quite a bit.
  7. Arc Burn

    Arc Burn PlowSite.com Addict
    Messages: 1,141

    I run a 130 amp alt. and dual batteries on a 99' Chevy and it also drops from 14 to 10ish.
  8. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    In the extreme cold we have been having,the draw is very high,due to oil being so thick.If it still does this when the plow is warm,after about 1/2 hr of use,Id be concerned.If its undr 20 degrees much,you should be getting the low temo plow fuild this will help a lot.You can take the truck to a good shop,they can check the battery,and do an amperage draw test on the plow motor,then compare it to the specs.If its within specs dont worry about it,if not replace/rebuid pump motor,or battery which ever is problem.
  9. SnowGodFather

    SnowGodFather Member
    Messages: 330

    157 amp alt dual batts and mine does the same. The lights barrily dim.

    You charging system will charge your batt. at 14.5 volts +/- 5%.

    When you hit the "starter" motor on you plow (just like starting the truck) you drop your charge from 14 to about 10 because you are putting a "draw" on the system. This is all normal.

    Now if you were pulling more then your motor on your pump could be bad or going out.

    There is not much difference with the plow system and that starting system except the obvious that the engine is running and warm.

    Now if you were not charging the batt then you have a diod problem.

    Batt not taking charge batt bad

    From what you told us all systems working normal. You are taking an 150 amp draw and about a 4v drop.

    As long as you don't drop to much under 10v you are A-OK.
    Last edited: Jan 27, 2003

    from NJ
    Messages: 196

    I've got a 200 amp alternator and I too still get the voltage drop when using, raising, or angling the plow.. But the voltage jumps back instantly when I take my finger off the plow button.. It runs at 14.5 or 15 ish, and when I hit the plow it drops to like 12... My 150 does the same thing , but that has a stock alternator and a dual batt setup... But the batts are isolated.. gotta change that ..
  11. fastjohnny

    fastjohnny Senior Member
    Messages: 654


    Check this right away. It sounds like you've got battery cable problems. Check the tightness of the positive connection on the battery, the double cable on the sidemount terminals has a tendency to loosen up. In fact, on my truck, it has gotten loose more times I can count. I can tell when it is happening, because I'll see the battery voltage drop more when I raise the plow. I have read about this on a chevy page. Apparantly, the lead gets squished down, and won't allow full torque on the battery bolt. Consequently, resistance increases, and I've seen pictures of the lead terminal actually melting. Mine melted the rubber casing off.

    The solution is to add a washer or two, preferably brass or non corrosive material, to the battery bolt, between the two cables, and retorque. I ve been meaning to do this. Just too tired after coming in from the route, and usually in a hurry to get to the other job.

    Good luck

  12. bgrover

    bgrover Member
    Messages: 49


    Which truck is your 200 amp alt. in? Where did you get it? I'm looking for one for my '95 F250 460 but the biggest I've found is a 135 amp.

  13. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Bill, powermaster sells a 200 amp for a lot of trucks.It is a Gm 140CSI alternator rewound for 200amps.I swapped a140 into my 89 GMC,its a strong alternaotr stock,must be an animal rewound.
  14. CPSS

    CPSS Senior Member
    Messages: 334

    The Fisher motor is rated at just over 1000 watts. At 12 volts thats 85 amps of current. Its pretty normal for the voltage to drop 2 volts under that load. The problem is if your headlights, warning beacon, defroster motor and radio are also on, you might be drawing more current from the battery than you are putting in. We run the dual alternators and dual batteries in our PSD's, I think that is the ultimate set up. You could always swap the stock alternator out, or at the very least, increase the battery size, or ad a second one.
  15. GVLawnCare

    GVLawnCare Junior Member
    Messages: 22

    Low Voltage

    Here's one thing to keep in mind. Plow motors draw ALOT af amperage. I have a 8' Western on a '95 F-250. I hooked a meter up to my motor and it draws around 175 amps. The manufacturer sais it's supposed to draw 183 amps. Thats alot of power considering you are running other things at the same time. (Heater, headlights, warning lights, radio, etc.) It is completely normal for the volts to drop while raising or angling your plow as long as the volts come right back up to a normal range right away. :D
  16. porkhead1

    porkhead1 Member
    Messages: 70

    Your trucks electrical system takes a beatin when you're plowing....lights on.....heater on...wipers on ( maybe)...Brake lights when stopping to back up.....+ everytime you manuver the plow your drawing another 175 + amps.....yes, your volt gauge will drop...... But, make sure its coming right back up when you release the controls for the plow. All systems have 12volts reguardless of vehicle......the differences are in the amount of "push" that voltage has = amps. Even with high-amp alternators, you'll still see a voltage drop. Alternators are rated at rpms above what you're plowing at so you're not getting the full amperage at "plowing speeds". Some suggestions.....make sure your battery (or batteries) have a lot of "Reserve Power" ( rated in minutes)....its kind of like "stored energy"....keep your terminals corrosion-free for better electrical connection....make sure your alternator belt is in good shape & not slipping or shiney... keep your battery(ies) full of water.....you may want to even put them on a trickle-charger to make sure they're fully charged when you start out...... Install a good brand name "Amp" guage to keep an eye on your alternator & make sure its working.
    I'm sure I missed some things, but I hope you get the idea....you can't spend hours pushing snow without putting some time back into making sure your truck's ready for the next snow event...

    Good luck.....
  17. SnowGodFather

    SnowGodFather Member
    Messages: 330

    Word would be "draw".

    All systems have 12volts reguardless of vehicle

    Now a days unless it's 24v. BUT your charging system reads 12v then you have a "problem". It must read over 14v. If it's reading 12v then you're not charging.

    make sure your battery (or batteries) have a lot of "Reserve Power" ( rated in minutes)....

    CCA + reserve minutes, must have both. a 1000 amp batt is no good if it has a 400 CCA and 30 reserve minutes.

    keep your battery(ies) full of water

    Most batt's are maintenance free and won't have a place to even check to fill them.

    you may want to even put them on a trickle-charger to make sure they're fully charged when you start out

    Once an automorive non deep cycle batt. has not been fully charged it will not ever reach it's full capasity like when it was new. The moment you use it once it goes down. If you have to trickle charge it you better start looking for a replacement.

    That's all good so called preventitive, but some of it is wasted time, and your better off buying a new $60-$70 batt.

    5 years in the tire and batt biz.
  18. wxmn6

    wxmn6 PlowSite.com Addict
    Messages: 1,037

    Actually porkhead1 is correct. Voltage is the difference in amount of "push" but a proper term would be "electro motive force." The higher the voltage that the system has, the less current it will draws. Load in the electrical circuit "draw" current, not voltage.
  19. SnowGodFather

    SnowGodFather Member
    Messages: 330

    An electric motor "draws" amps. Apms = load. Load = a "draw".

    There is no "push" in electric termanology.
  20. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Porkhead,welcome to plowsite! A lot of good advice,here,btu one thing I did want to comment on was the amp guage.I do not use them,mostly because the require you to run the full amperage into the cab and thru the guage and back to the battery .There is to much of a chance of a failed guage,or connection problem running it into the cab and i dont like running wire that thick into the cab,with a 200amp alt you'd need to run a 0 guage wire into the cab.I preffer a voltmeter,if its lower than usuall you have a problem,and it can be wired with 22 guage wire,and a 3 amp fuse if you'd like.