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DeWalt 14v Drill Driver losing power

Discussion in 'Tools and Materials' started by sammy1990, 16 Apr 2015.

  1. sammy1990

    sammy1990

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    Hello, i would be greatful for some advice. I purchased a DeWalt drill driver about 3 years ago, 14v. It worked perfectly fine until about 2 months ago when it gradually began losing power. Now even after a full 1 hour charge the batteries only let me drive in 5 or 6 screws until it loses most of its charge.

    But even when both batteries are fully charged, the drills power seems very weak. A 6mm wood bit barely goes through wood.

    Is this normal on a dewalt which is 3 years old and used lightly 3 or 4 times a week?
     
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  3. ntb

    ntb

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    It's not abnormal with NiCad batteries which I'm going to guess they are? The long and short of it is that your batteries need to be replaced. That may prove to be as expensive as buying a new drill and if you do that, make sure you get one with Li Ion batteries.
     
  4. big-all

    big-all

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    i am guessing they are 1.3ah ??
    batteries tend to loose 10-25% off there capacity every year dependent on quality use and storage
     
  5. sammy1990

    sammy1990

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    Thanks for the replies lads.

    Yes, its Nicad batteries, 1.3ah.

    Do Li-on batteries work better over a long period of time? I dont really want to have to buy a new pack of batteries every couple of years considering im a light trade user.

    Ive seen some sites saying they can refurbish old batteries for about £30, not sure if this is worth doing. Has anyone tried such a service and if so any luck?
     
  6. big-all

    big-all

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    in my opinion
    if you take a battery as a fuel tank and the voltage as the engine
    in general there is an amount off a battery you cannot use as this part overcomes all the resistance in the battery and in the motor and drive train in the drill
    where you have a say 1.3ah battery this may be 20% loss so a lot off the capacity available as new at say .25ah leaving 1ah to power
    i have several 2-2.6 ah dewalts so the .25ah removed from the battery would give you 1.75ah-2.3 ah power available
    now the point i am making is i have 8 batteries 2-2.6ah minimum 5 -12years old giving around 40% power minimum so around the capacity off your battery in year two
    so go for higher power batteries
    are your reviving options new cells ??
    if so go for the same chemistry as you charger [may be nicad or nicad and nmh ]and go for no more than 3ah unless you know your charger will fully charge the capacity
     
  7. sammy1990

    sammy1990

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  8. joe-90

    joe-90

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    I bought an Hitachi 18v drill plus impact driver with two 1.5 lithium batteries for £169. I love it. From screwfix.
     
  9. ntb

    ntb

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  11. big-all

    big-all

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    i always go for the larger batteries unless the cost is disproportionate
    they tend to be cheaper per extra ah as in 2ah say £50 and 4 ah £80 so less than double

    a brand new 4ah battery will give you around 4 times the run time off a 1.3ah battery
    you will also have far more off a sweet spot on the battery
    by sweet spot i mean when you charge a battery in around an hour you get a charge rate off around 20% more than the battery rating so your 14.4 will be around 17v when fully charged for a short while before it drops down towards and then below 14.4v as it flattens
     
  12. Monkeh

    Monkeh

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    Just because it measures higher on a high impedance multimeter doesn't mean you magically get more power.
     
  13. sammy1990

    sammy1990

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    Please explain, as I would assume the higher Amps being generated would translate into more power?
     
  14. Monkeh

    Monkeh

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    Batteries show a high voltage into no load after a charge. This voltage immediately vanishes under significant load, it does not relate to stored energy.

    Under unloaded conditions you'll get a drill spinning faster. As soon as you load it down it becomes irrelevant.
     
  15. ntb

    ntb

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    Yes, the cells are nominally 3.6V but can show 4.1V after a charge. Americans being optimists use the higher figure which is why a 10.8V drill over here is a 12V drill over there despite them being identical.
     
  16. Monkeh

    Monkeh

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    Something they don't get away with here.. something to do with laws about false advertising.
     
  17. big-all

    big-all

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    think off a car
    voltage is the engine
    amps is the fuel tank
     
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