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Zenith SupersPORT battery rebuild

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    #16
    Originally posted by GiGaBiTe View Post

    For NiMH batteries, I'd just get name brand. Energizer, Rayovac or Westinghouse. They're more expensive, but you only have to buy them once instead of experimenting with the Ebay lottery. Walmart, Home Depot and Lowes have their house brand NiMH batteries for garden lights in capacities between 1000-2000 mAh for AAA and AA sizes. C and D cells will have higher capacities, but I don't regularly buy those.
    I see.


    Oh dear heavens no, don't attach Lithium batteries directly to the existing charge circuitry, you MUST use a Lithium battery protection board unless you want a fire or exploding batteries. To clarify my above post, build up a battery pack with a Lithium battery protection board and then attach the output of the battery protection board to the existing charging circuitry in the laptop. This way would better ensure that the laptop didn't do anything funny from getting unexpected behavior from the battery.

    Just be aware that since regular lithium ion / polymer batteries voltage doesn't match up with NiMH, so it may cause the batteries to wear out faster. A 4 cell battery board will give you a voltage of about 16.8 volts, which is 1.8v higher than 10 NiMH batteries at full charge, so the Lithium pack would never be fully charged. Lithium Iron Phosphate batteries (LiFePO4) would give you 14.4v in a 4 cell pack, which is just under the max 15v charge, which would work better. You would need a different charge protection board though. Don't use LiFePO4 batteries on a regular lithium battery board or they'll be grossly overcharged and go on fire or explode.

    ok. Thanks for the info. Still a little fuzzy on the point about the 15V though, why would the lithium pack never be fully charged? I don't think the laptop itself does any regulation of the battery at all.

    Comment


      #17
      The picture of the inside of the battery shows some circuitry with what looks like some sort of regulator. Once the batteries are recharged, a good charging circuit will maintain a float charge.

      Where I get the 15v from is the total voltage of all of the NiCD batteries in series. The battery circuitry is going to put out somewhere near that to keep those batteries charged, or it should anyway.

      The reason the lithium battery pack would never be fully charged is if the existing battery circuitry only puts out 15v, and the lithium batteries expect 16.8v, you're not fully charging them and will lose a lot of capacity. I'm making assumptions of how the battery pack works since with the bad batteries, you can't see the full charge voltage.

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        #18
        Oh ok I'm with you. I'll take a better picture of it in a minute.

        Comment


          #19
          But if I was just powering the lithium charger from the original circuitry wouldn't it just charge the lithium battery normally regardless of what that voltage regulator circuit was doing?

          Comment


            #20
            11EDF198-C6A1-4A2A-B5B6-3E68CFBADD96.jpeg 56F09347-8E0E-4E7B-B011-79A8C83955C3.jpeg 3E15D115-2C54-4A23-859E-C596372DAD45.jpeg

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              #21
              That last picture was just to show that the power supply goes straight into the battery. When it's powered, the pack passes the power through to the laptop while presumably charging the pack also.

              Comment


                #22
                Oh, the power goes directly into the battery and not the other way around, weird. Well there definitely is something going on with those regulators being in there.

                If you can find what voltage comes out of the connector with the red, black and white wires WITHOUT the batteries connected, it'd let us know what could be rigged in if you want to use lithium batteries.

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                  #23
                  5D65DF96-73E4-4D37-BE00-7F9B1CE54571.jpeg D876CD95-C8D6-435B-AFA8-7191E780810C.jpeg It did seem to be reacting to what I was doing. See attached. I also noticed when I pulled the connector that there is a lot of corrosion of the wires and the solder A71EBB4B-B162-49AA-9589-FF7708C11745.jpeg joints look bad. Any chance the cells are still ok? How could I check?

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                    #24
                    (ignore the minus, I was moving the probes around)

                    Comment


                      #25
                      Originally posted by GiGaBiTe View Post
                      Oh, the power goes directly into the battery and not the other way around, weird. Well there definitely is something going on with those regulators being in there.

                      If you can find what voltage comes out of the connector with the red, black and white wires WITHOUT the batteries connected, it'd let us know what could be rigged in if you want to use lithium batteries.
                      Yeah it's a really interesting/unique design! The whole battery pack clips on the back of the laptop and it has a plug sticking out that goes into the laptop where the power adapter normally plugs in.

                      Comment


                        #26
                        So you're getting 15.6 volts and it drops to 12 volts when you move stuff around? Your suspicion would be correct if that's the case, battery goo has seeped into the board and damaged it. It looks like it may have wicked up the inside of the wire to the connector and spilled out. You'll need to pull the board out and inspect under it. You're going to need to clean the board and fix the solder joints. You'll also need to make a new battery cable and connector to use with newer batteries, that one is toast. Fortunately that connector type is still common.

                        I'd also replace that capacitor with a new one with a higher voltage rating of at least 25v, 16v is too narrow of a margin with the voltage being 15.6 volts.

                        Originally posted by thenzero View Post
                        Any chance the cells are still ok? How could I check?
                        Those batteries are what, 30-35 years old? None of them are going to be good, even the best batteries don't last that long. You can tear the battery tube apart to look at the cells, but I suspect most of them are going to have leaked. The reason the pack won't charge is because one or more cells has either shorted out, or has such a high internal leakage that they drain the charge faster than it comes in as waste heat.

                        15.6 volts is closer to the voltage of four lithium cells, but still not there. Lithium batteries wouldn't be used efficiently if you want to go with that type of battery. The least amount of fuss would be going with 10 NiMH batteries and you wouldn't have to add a battery protection board. Cell imbalance may be an issue though, you'll want to make sure all of the cells are at the same voltage before making up the pack.

                        Comment


                          #27
                          That makes sense. However, as you pointed out up thread the nimh replacements are very expensive. I'm leaning towards taking out the existing circuitry and completely replacing with some kind of cheaper/alternative setup. As an example I could hide a battery powered UPS in there, off the shelf for maybe fifty bucks. Any drawbacks to doing something like that?

                          Comment


                            #28
                            That said, I just priced the name brand D cells on amazon and it looks like $50 for that as well. And then I need some tabs and some kind of special solder maybe? Any tutorials on how to put them together that you would recommend?

                            Comment


                              #29
                              By the way that third wire was attached to something (hard to tell because it was corroded), maybe a capacitor? and then to the positive lead of the pack. It was putting out maybe seven volts or so. Any idea what that was for?

                              Comment


                                #30

                                Originally posted by thenzero View Post
                                That said, I just priced the name brand D cells on amazon and it looks like $50 for that as well. And then I need some tabs and some kind of special solder maybe? Any tutorials on how to put them together that you would recommend?
                                You need nickel strips like this: https://www.amazon.com/dp/B07PQP55CM/

                                Another option is to get some stranded copper wire, like 18 gauge. Strip a long section of it, twist it tightly and then hammer it into a flat strip. An issue you may have is that the copper will be a lot thicker and make the battery assembly longer, which may not fit into the case properly.

                                You'll also need some fine sandpaper to lightly sand the battery tabs so that they'll take solder. You can use any kind of rosin core solder, I prefer the 60/40 leaded stuff because it's a lot easier to work with.


                                Originally posted by thenzero View Post
                                By the way that third wire was attached to something (hard to tell because it was corroded), maybe a capacitor? and then to the positive lead of the pack. It was putting out maybe seven volts or so. Any idea what that was for?
                                don't really know without seeing where all three wires go.

                                Comment

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