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  • Ni-Cad Batteries

    Gentlemen,

    I would like to share some information about Ni-Cad Batteries.

    I doubt that it is a secret to most of the people on this site that Ni-Cad batteries have a memory, but wonder how many get the most out of their batteries.

    Case in point: I recently bought one of those attachments that goes in a 1/2 inch drill to raise and lower the knee on my vertical mills. (Best $35 I have spent in a while). It uses some pretty good torque to lift the knee so the maker recommends using a corded drill.

    I also have a bunch of DeWalt 18 volt tools and XRP batteries, some of which are nearly 10 years old. While the old batteries are not up to new standards, they are probably about 70 or 80 percent of new level.

    One of my brothers bought the same kit that I have a couple of years after I bought mine and he is on his third set of batteries. When he needs the drill, he charges the batteries without discharging them first. Bad mistake.

    What I do is when my batteries get too low to be useful for the task at hand, I put them in my vacuum and let them run down until the vac is hardly turning. Before I bought the vacuum, I used the flashlight to run them down. It took longer, but it worked fine. One other thing. I always let them cool down before charging them and again after charging them before use.

    Hope this helps save my fellow HSM'ists some $$$$$$ on Ni-Cads.

    Brian
    OPEN EYES, OPEN EARS, OPEN MIND

    THINK HARDER

    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    MY NAME IS BRIAN AND I AM A TOOLOHOLIC

  • #2
    Aside from the question of the different types of rechargable batteries I think it is important to understand the difference between a 'battery' and a 'cell'.

    A cell is a single unit such as a 'C' cell whereas a battery is a number of these connected in series.

    If a battery is discharged to zero one of the cells will reach zero first and from that point on is being effectively 'reverse charged' which will destroy the cell and once that cell is destroyed the entire battry is useless.

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    • #3
      bborr01 is very correct on that you must fully discharge nicads aprox once a month, Reguardless if your using them or not for best life. 'babying' them is not good for them, they thrive on 'abuse'.

      Its not the so-called 'memory effect' as that does not affect modren cells or even consumer cells period, But crystal growth that results when you charge the cell, this growth is reversed by discharge, with deep discharge being the most effect at reverseing it. Once the crystals puncture the seperator of the cell the battery will self discharge quickly and may even appear as a near short depending on crystal size. (Shorted nicads have been known to be revived by giving them a controled surge of current, but its not something you want to have to do)
      Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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      • #4
        I thought NiCad batteries were being phased out now.

        Allan

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        • #5
          Originally posted by Allan Waterfall
          I thought NiCad batteries were being phased out now.
          Allan
          Oh, they have long since been made illegal for consumer use!...
          Except for power tools, Medical applications, industral applications and anyone else who ever wanted to actualy use nicads over nimh or any other battery type.
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

          Comment


          • #6
            I have had some of these same batteries sit for many months at a time and go so dead that the drill would not even make a noise. Put them in the charger and FULLY cycle them a couple of times and they work pretty good. As I said, some of these batteries are nearly ten years old.

            I have 5 of these xrp batteries in 3 different kits. Some kits like the right angle drill don't get used very often and the batteries just sit. Now I have put them in a row and intend to rotate them so they all get used regularly.

            Brian
            OPEN EYES, OPEN EARS, OPEN MIND

            THINK HARDER

            BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

            MY NAME IS BRIAN AND I AM A TOOLOHOLIC

            Comment


            • #7
              I have a 9.2 V Makita drill that is at least 12 yrs old. Both batteries still hold a charge. I have since scrapped a 12V Dewalt, cause the batteries would not hold a charge. I treated them the Same and have no idea what accounts for the difference in longevity. On another note, I had a 18 V Milwaukee batteries rebuilt for about$40 each. Performance is better than new. Go figure! Bob.

              Comment


              • #8
                Originally posted by bborr01
                Now I have put them in a row and intend to rotate them so they all get used regularly.

                Brian
                I numbered mine and always use them in order. When they won't turn the screw or drill the hole, they go on the charger and they stay there until needed I get years of heavy use out of them. I have 3 batteries right now and depending on what I'm doing, all 3 of them could go through multiple charge cycles in one day.
                I don't even own a corded drill.

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                • #9
                  Originally posted by Boostinjdm
                  I numbered mine and always use them in order. When they won't turn the screw or drill the hole, they go on the charger and they stay there until needed I get years of heavy use out of them. I have 3 batteries right now and depending on what I'm doing, all 3 of them could go through multiple charge cycles in one day.
                  I don't even own a corded drill.
                  Ah, Don't leave em in the charger, That trickle charges em and thats bad. With slow chargers it can be downright fatal to a battery, though some modren fast chargers properly shut off.
                  Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                  Comment


                  • #10
                    Go pay attention to what TA Bodger said.....

                    AS SOON AS the speed starts to slow on whatever the tool is, swap to a charged battery and continue, while charging the "low" one you took out.

                    "Fully" discharged is discharged to the point the voltage reaches a "knee" and starts to drop fast. As TAB said, if you try to get the last bit of use, you almost certainly reverse charge at least one cell, and that kills it fast.

                    Don't worry about "memory".... "memory " won't kill a battery as fast as reverse charging does, and you can always drain it to the "stop using this" point, and let it self discharge from there, if you want.
                    1601

                    Keep eye on ball.
                    Hashim Khan

                    Comment


                    • #11
                      Originally posted by Black_Moons
                      Ah, Don't leave em in the charger, That trickle charges em and thats bad. With slow chargers it can be downright fatal to a battery, though some modren fast chargers properly shut off.
                      Tell that to my batteries that have been abused for years and keep on ticking.
                      My chargers have some fancy cycle that kicks in after 8 hrs and is supposed to "tune up" the batteries.

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                      • #12
                        Some NiCad chargers first discharge the battery, and then charge it. I assume that type is for single cell batteries only. One thing that does puzzle me, however, is a warning on one of my Sears NiCad cordless drill battery pack chargers. The warning is that there are high voltage contacts down in the charger well, and not just the low voltage contacts I would expect. What gives there ? Is that because it's a fast charger ( one hour), and they're using an elevated voltage to charge the 19.2 volt battery pack ? Or is part of the charger circuit inside the battery pack ? I've taken a few of those battery packs apart, and never seen any circuit elements besides the battery cells themselves.
                        Last edited by Bill736; 02-20-2012, 10:12 PM.

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                        • #13
                          Bill, they have multiple cells in series to get a nominal voltage in that range.

                          if you divide the pack voltage by the number of cells in series you'll get the nom. cell voltage (or vice versa for nom. cell voltage to number of cells in series).

                          you probably saw the cells connected + to -, right?
                          -paul

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                          • #14
                            There's no high voltage there, that's just a warning to afford the company a bit more freedom from lawsuits.

                            You might be able to measure something like 30 volts or so, depending on a lot of factors. I suppose that could be described as 'high voltage'. It certainly would be if you look at in terms of flashlights and kids toys.

                            Talking about nicads, I'm starting to see battery packs rated much lower than the typical 1.3 AH which was the standard for decades. It went up from there to the point that you could buy a 1.7AH pack- now I'm seeing 1.0 AH, and the other day I saw a cordless drill with a .8AH battery. Standard size drill and battery pack, but they must really be cheaping out on the battery chemicals.

                            What's the best way to enhance the life of a nicad pack when you know it's not going to be used for weeks or months? (or years)
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                            Comment


                            • #15
                              Originally posted by darryl
                              What's the best way to enhance the life of a nicad pack when you know it's not going to be used for weeks or months? (or years)
                              Discharge it once a month anyway, then recharge it.
                              Perodicly consider discharging it with a very light load that will run when nothing else will untill thats also dead. (Also good to improve capacity of older, tired battery packs)
                              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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