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  • Battery question:how do you determine the amps of a battery pack

    if it is not printed on the battery?

    i have looked at skill/ryobi and ridgid stuff. non of them print the amp hour battery ratingthe batteries. Is there a was to test batteries which would tell me the amps?

    BTW
    Hello

    first post newbie

  • #2
    You have to do some research.

    You have to do some research. Sometimes it is published in the specs. Sometimes you will find the information in a review.

    From memory, the original Ridgid 18V battery was 1.4AmpHr. The MaxHC is 1.9AmpHr. The Max2.5 is 2.5AmpHr and the 24v and 18v Lithium Ion packs are 3AmpHr.

    The original Ryobi batteries were 1.2AmpHr. The latest, One+ are 1.7AmpHr.

    DeWalt's XRP's are 2.4AmpHr.

    Panasonic makes 2, 3 and 3.5AmpHr NiMh batteries for their drills...and now 3AmpHr LithiumIon.

    Generally, cheap tools skimp on batteries. The Kawasaki drill sold at Costco only has a 1.3AmpHr battery. Interestingly, the Sears 19.2V C3 tools, which near clones of the Ryobi One+, only have 1.3AmpHr batteries. If I recall the B&D Firestorm came with 1.3AmpHr batteries as well.

    AmpHr rating is a good A-B comparison of how one battery will run longer in a tool than another, but not necessarilly a good comparison how one tool will compare to another in runtime. Tools have different efficiencies and optimizations of their motors and transmissions.
    Last edited by Disaster; 12-04-2006, 09:26 PM.

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    • #3
      18v 3.0Amp battery

      I've never come across this, do they exist ? is it a myth ?

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      • #4
        Just an FYI: the Milwaukee V18 and V28 Li-Ion batteries use 4.0 Amp. Hour cells inside them. A full size "D" NiCad cell is rated at 4.0 Amp. Hours, but you normally won't find such in a power tool battery.

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        • #5
          I lost the link but I had seen some place that had schematics of how different manufacturers wire their batteries. Kind of interesting to see the difference. I think Bosch and Dewalt used lower a.h. cells of about 1.0 ah each wired in a series then on parallel rows. Milwaukee I believe used the cells directly in parallel to the cells ah rating is directly the batteries ah rating.

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          • #6
            Originally posted by Woussko View Post
            A full size "D" NiCad cell is rated at 4.0 Amp. Hours, but you normally won't find such in a power tool battery.
            They are probably not even made for power tools as I understand power tool rated Li-Ion tools use a slightly different chemistry than run off the mill LI-ion cells.

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            • #7
              If you have a "Batteries Plus" location near you they should be able to show you wiring diagrams and also pictures of the insides of battery packs. Most of their locations are setup so they can rebuild them with new cells. They also make up custom battery packs. As to doing a series or parallel connection, most are series, but you could do both. Please remember that Ni-Cad and Ni-MH cells run in the range of 1.2-1.4 Volts each and Li-Ion in the range of 3.6-4.0 Volts each. Please note that actual Voltage measured per cell depends on the state of charge. Anyway to get say 18 Volts in a battery pack, several cells must be connected in series. For greater Amp. Hr. capacity, they could make up two or more series connected strings and then connect them in parallel, but why not just use larger cells? As to there being different types of cells for light discharge (like some electronics) loads and heavy discharge loads (power tools) there would be a need for internal changes in all types of cells. I'm sure come companies use HYPE ratings.

              To gain more insite to what's inside each battery pack, you might try Technical Support for the product. They might be willing to give some info. I personally like the older DeWalt battery packs that do come apart so the internal cells can be replaced. You need to be careful taking such apart. Please leave such to to battery pack rebuilding experts. You can have a dangerous arcing condition if you just start cutting into your battery packs.

              I'm waiting on Panasonic which is a leader in battery cell technology to come alive with super replacement battery packs and smarter chargers.

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              • #8
                You will only find batteries in parallel in Lithium-Ion Packs.

                You will only find batteries in parallel in Lithium-Ion Packs. In NiCad and NiMh packs the batteries will be in series. Depending on the size of individual packs, sometimes Lithium-Ion packs are in series and parallel.

                One interesting thing about NiCad/NiMh packs is manufacturers now "cheat" on larger packs compared to how they used to report them. On the largest, flattest part of the drainage curve they produce about 1.2V. It is easy to determine the cells of packs up to 14.4V just by dividing by 1.2....which is 12 individual cells. But sometime...not sure when...manufacturers started calling 14 battery packs 18V...should be 16.8V. The TTI/Craftsman 19.2V packs actually have 15 batteries and should be called 18V packs. Likewise, the 24V packs I opened only had 19 cells...not 20 as you would expect.

                Note this discharge curve (borrowed from a website where the author was testing different cells) for a 4 battery pack. The flat part of the curve is almost exactly 4.8 volts.



                You will find some other interesting things when tearing apart cheap, vs. expensive NiCad battery packs. In more expensive packs the leads will be larger to carry higher current. The individual cells will be rated at higher AmpHrs. There will often be cooling channels or vents. Some will actually attach heatsinks...like the Bosch Bluecore. Heat is a killer of NiCad.

                Lithium-Ion is a very different animal. As was mentioned cells are rated, not only in capacity, but in maximum current capability. You can purchase 1amp...or 10amp cells....and all levels between, above and below. Tool batteries require higher amperage cells.

                The next technology in Lithium-Ion...which will greatly extend pack life, is individual cell charging/balancing. I'm not sure if any of the tool packs/chargers are that sophisticated yet.

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                • #9
                  It was shown on the MaxSelect sign at Home Depot.

                  Originally posted by sandhu49 View Post
                  I've never come across this, do they exist ? is it a myth ?
                  It was shown on the MaxSelect sign at Home Depot. The sign stated the MaxSelect tools will work with three batteries, the Max2.5 NiCd, the 24V Lithium-Ion and the 18V Lithium-Ion.

                  Unless it is a flubbo by marketing I suspect an 18V Lithium-Ion cell is coming. I'm guessing it would work with the older tools as well...since the new MaxSelect tools work with the older MaxHC and smaller 18V NiCads.

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                  • #10
                    Originally posted by Woussko View Post
                    As to there being different types of cells for light discharge (like some electronics) loads and heavy discharge loads (power tools) there would be a need for internal changes in all types of cells. I'm sure come companies use HYPE ratings.

                    There are indeed several different types of cells depending on the application. Most common Li-ion cells used in electronics are cobalt based chemistry. They have the highest energy density but are not well suited to high current applications such as power tools. Power tool cells are usually manganese based which don't have as high energy density but are suited to high drain. They have the advantage they charge faster. Dewalt is using a new phosphate chemistry which seems to be the newest biggest things in Li-Ion. Its supposed to have higher density than Manganese and even better recharge speed. I don't know if it they do but they claimed the first 80% of the charge was done in the first 5 minutes some times ago.

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                    • #11
                      Originally posted by Disaster View Post
                      You will only find batteries in parallel in Lithium-Ion Packs. In NiCad and NiMh packs the batteries will be in series. Depending on the size of individual packs, sometimes Lithium-Ion packs are in series and parallel.
                      Milwaukee uses seven 3.0ah cells rated at 4v wired in a series to get 28v. Bosch and I believe Dewalt too, use two rows of 10 cells. they are 3.6v per cell at 1.0ah each. Every pair is wired parallel across rows and then in series for a 2.0ah 36v pack. Makita does the same but with 10 cells to achieve 18v.
                      As for individual charging, I'm pretty sure makita already claims to do this. Their batteries have a large multiple point connector besides the + and - contacts.

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                      • #12
                        Here is some additional NiCad battery info....

                        Here is some additional NiCad battery info/links I posted in another thread but which is probably more relevant here.



                        Energizer info on NiCads

                        http://data.energizer.com/PDFs/nickelcadmium_appman.pdf

                        More info from Red Scholefield, a NiCad expert.

                        http://www.uoguelph.ca/~antoon/hobby/nicadred.htm

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