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    Charger circuit questions

    I would like to modify this simple charger (for lithium ion cells) so that it will stop charging at a lower voltage.

    The IC used is HX-3H1227. I could not find the datasheet from the internet. I have send e-mail to the manufacturer or factory asking for the datasheet and got a reply saying that they also could not find it.

    I would like to know if somebody can help me on getting the datasheet and/or how to lower the stop charging voltage.





    Attached Files

    #2
    Re: Charger circuit questions

    A couple of things what is the input voltage
    The second thing what is the two diodes that are Zener diodes what are the are the part numbers or the voltage on the output of diodes
    9 PC LCD Monitor
    6 LCD Flat Screen TV
    30 Desk Top Switching Power Supply
    10 Battery Charger Switching Power Supply for Power Tool
    6 18v Lithium Battery Power Boards for Tool Battery Packs
    1 XBox 360 Switching Power Supply and M Board
    25 Servo Drives 220/460 3 Phase
    6 De-soldering Station Switching Power Supply 1 Power Supply
    1 Dell Mother Board
    15 Computer Power Supply
    1 HP Printer Supply & Control Board * lighting finished it *


    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
    2 Hem Saw Computer Stack Board

    All of these had CAPs POOF
    All of the mosfet that are taken out by bad caps

    Comment


      #3
      Re: Charger circuit questions

      Originally posted by tmhobadcap View Post
      I would like to modify this simple charger (for lithium ion cells) so that it will stop charging at a lower voltage.

      The IC used is HX-3H1227. I could not find the datasheet from the internet. I have send e-mail to the manufacturer or factory asking for the datasheet and got a reply saying that they also could not find it.

      I would like to know if somebody can help me on getting the datasheet and/or how to lower the stop charging voltage.
      Paint the circuit board blue -- that should fix things for you! The darker the blue, the lower the cutoff voltage...

      (Sound crazy? Isn't expecting us to GUESS what the circuit entails in order to tell you how to modify it just as "crazy"? :< )

      Your question also lacks specificity -- just how MUCH lower do you want the cutoff voltage to be. And, does it need to be adjustable??

      A charger consists of a mechanism to deliver charge to the cell being charged AND a mechanism to monitor the state of charge (often by sensing cell voltage). There may be other provisions to enhance the charging (temperature monitoring, etc.).

      So, you need to know the level of integration for the charging IC to know if the two functions are independently available on the pins of the device.

      If it's all wired together "internally", then your only remedy is to make the cell appear to have a greater cell voltage than it actually does. I.e., ADD a voltage drop to that of the cell and pick that drop to match the amount of "lowering" that you want. E.g., a Ge diode in series will "trick" the charger into thinking the cell voltage is 0.3V greater than it actually is.

      [Hand-waving as there are other issues in the charger that can bias this decision -- like current flowing through the cell while the voltage is being sensed]

      Think more exactly about what you want and what information you can offer...

      Comment


        #4
        Re: Charger circuit questions

        Originally posted by sam_sam_sam View Post
        A couple of things what is the input voltage
        The second thing what is the two diodes that are Zener diodes what are the are the part numbers or the voltage on the output of diodes
        Input voltage to the charger can be 110-220 AC, and I use 110V AC.
        It is hard to see the no. on the diodes so I better measure the voltages across them.

        When the charger is not charging:
        ZD2: 163.4V
        D3: 5.78V
        D4: 3.58V

        When the charger is charging a cell:
        ZD2: 150.4V
        D3: 7.3V
        D4: 4.32V

        Comment


          #5
          Re: Charger circuit questions

          Originally posted by tmhobadcap View Post

          When the charger is not charging:
          D4: 3.58V

          When the charger is charging a cell:
          D4: 4.32V

          Is this diode next to the battery terminals

          How much lower do you want to make the voltage
          9 PC LCD Monitor
          6 LCD Flat Screen TV
          30 Desk Top Switching Power Supply
          10 Battery Charger Switching Power Supply for Power Tool
          6 18v Lithium Battery Power Boards for Tool Battery Packs
          1 XBox 360 Switching Power Supply and M Board
          25 Servo Drives 220/460 3 Phase
          6 De-soldering Station Switching Power Supply 1 Power Supply
          1 Dell Mother Board
          15 Computer Power Supply
          1 HP Printer Supply & Control Board * lighting finished it *


          These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

          1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
          2 Hem Saw Computer Stack Board

          All of these had CAPs POOF
          All of the mosfet that are taken out by bad caps

          Comment


            #6
            Re: Charger circuit questions

            Originally posted by sam_sam_sam View Post
            Is this diode next to the battery terminals

            How much lower do you want to make the voltage
            I can trace that D3 is connected to the positive battery terminal.
            I want to lower the stop charging voltage to 4.1V.
            Attached please find 2 more photos on the circuit board for your reference.



            Attached Files
            Last edited by tmhobadcap; 11-30-2019, 09:14 PM.

            Comment


              #7
              Re: Charger circuit questions

              Ok

              now you have to get the part number off of the diode and put a second one in series
              But depending on what type of diode it is it might need more than one

              The easiest way is to unsolder it from the board but make sure you know which end has the band end
              9 PC LCD Monitor
              6 LCD Flat Screen TV
              30 Desk Top Switching Power Supply
              10 Battery Charger Switching Power Supply for Power Tool
              6 18v Lithium Battery Power Boards for Tool Battery Packs
              1 XBox 360 Switching Power Supply and M Board
              25 Servo Drives 220/460 3 Phase
              6 De-soldering Station Switching Power Supply 1 Power Supply
              1 Dell Mother Board
              15 Computer Power Supply
              1 HP Printer Supply & Control Board * lighting finished it *


              These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

              1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
              2 Hem Saw Computer Stack Board

              All of these had CAPs POOF
              All of the mosfet that are taken out by bad caps

              Comment


                #8
                Re: Charger circuit questions

                Originally posted by sam_sam_sam View Post
                Ok

                now you have to get the part number off of the diode and put a second one in series
                But depending on what type of diode it is it might need more than one

                The easiest way is to unsolder it from the board but make sure you know which end has the band end
                Thanks a lot. I will try that accordingly.

                Comment


                  #9
                  Re: Charger circuit questions

                  I'd say forget about changing the voltage. I think that zener will not affect the voltage at all, and the charger voltage reference and control is within the IC. Thus it will be quite difficult to be influenced externally unless you lie to the chip, but then you lose charge capabilities.

                  After studying my Baofeng's charger, I feel this charger is likewise a crap linear lithium ion charger...

                  ... but don't take my word for it until we find a datasheet.

                  Comment


                    #10
                    Re: Charger circuit questions

                    Originally posted by eccerr0r View Post
                    I'd say forget about changing the voltage. I think that zener will not affect the voltage at all, and the charger voltage reference and control is within the IC. Thus it will be quite difficult to be influenced externally unless you lie to the chip, but then you lose charge capabilities.

                    After studying my Baofeng's charger, I feel this charger is likewise a crap linear lithium ion charger...

                    ... but don't take my word for it until we find a datasheet.
                    Think about you might be right about this I could not find the right information for this chip
                    Last edited by sam_sam_sam; 11-30-2019, 11:37 PM.
                    9 PC LCD Monitor
                    6 LCD Flat Screen TV
                    30 Desk Top Switching Power Supply
                    10 Battery Charger Switching Power Supply for Power Tool
                    6 18v Lithium Battery Power Boards for Tool Battery Packs
                    1 XBox 360 Switching Power Supply and M Board
                    25 Servo Drives 220/460 3 Phase
                    6 De-soldering Station Switching Power Supply 1 Power Supply
                    1 Dell Mother Board
                    15 Computer Power Supply
                    1 HP Printer Supply & Control Board * lighting finished it *


                    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                    2 Hem Saw Computer Stack Board

                    All of these had CAPs POOF
                    All of the mosfet that are taken out by bad caps

                    Comment


                      #11
                      Re: Charger circuit questions

                      I have some of them but never tried to modify one because the charging current is so low

                      500 milliamperes or might be a little bit more
                      9 PC LCD Monitor
                      6 LCD Flat Screen TV
                      30 Desk Top Switching Power Supply
                      10 Battery Charger Switching Power Supply for Power Tool
                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                      1 XBox 360 Switching Power Supply and M Board
                      25 Servo Drives 220/460 3 Phase
                      6 De-soldering Station Switching Power Supply 1 Power Supply
                      1 Dell Mother Board
                      15 Computer Power Supply
                      1 HP Printer Supply & Control Board * lighting finished it *


                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                      2 Hem Saw Computer Stack Board

                      All of these had CAPs POOF
                      All of the mosfet that are taken out by bad caps

                      Comment


                        #12
                        Re: Charger circuit questions

                        Yeah, my Baofeng charger is like 1A max but is package dissipation limited(!)... The chip is a SOIC8 and thus cannot dissipate much heat -- and thus I killed mine... hah.

                        I need to get another chip...or another charger. *sigh*

                        Comment


                          #13
                          Re: Charger circuit questions

                          Thank you very much for all your comments.

                          Comment


                            #14
                            Re: Charger circuit questions

                            Originally posted by eccerr0r View Post
                            I'd say forget about changing the voltage. I think that zener will not affect the voltage at all,
                            That's a likely conclusion.

                            and the charger voltage reference and control is within the IC. Thus it will be quite difficult to be influenced externally
                            Yes, but without knowing the circuit topology, you can't determine if this is "hard-wired" in the controller, or not. E.g., the reference in an LM317 is "inside the chip" yet you can make a '317 act in all sorts of "adjustable" ways!

                            Of course, given that it's a ONE LAYER board, the OP could have taken the initiative to trace the foils and hacked together a crude schematic (even if he doesn't know what the components are and just draws each as a "two terminal box"). From that, it would be relatively easy to determine how much of the control is provided by "component selection" vs. hard-wired.

                            unless you lie to the chip, but then you lose charge capabilities.
                            It depends on how you "lie". E.g., putting a PN junction in series with the battery offsets the cell voltage without interfering with charging. But, you really only get a couple of possible "offsets" with that approach. (a more "active" solution could get you a greater adjustment range)

                            Again, a crude schematic would tell you a lot...

                            After studying my Baofeng's charger, I feel this charger is likewise a crap linear lithium ion charger...

                            ... but don't take my word for it until we find a datasheet.
                            It's likely a "smart charge controller" with two-step charge profile and some "smarts" to decide when the "battery" is toast (and, possibly, battery temperature monitoring). Again, much of that would be apparent from a schematic... perhaps the OP can find a BLIND MAN to trace the foils for him?

                            Comment


                              #15
                              Re: Charger circuit questions

                              AH, without a datasheet this could be hard. No matter what, I think you risk blowing up your device if you change things. (most likely, killing the mosfet)

                              Honestly, if you wanted to use this as a learning experience I would find a charger with an IC I could get a datasheet on. Most of the time a 5$ charger off of ebay will have one of these chips. Cheap stuff likes to use ic's with good datasheets that have schematics in them, or so I have found. (Might be chinglish, but probably still ok.)


                              Well, beyond those conciderations, here is what I think you likely have:

                              1 switchmode power supply chip with a voltage programmed(either with Resistive divider/zener) to about the right voltage for a fully charged battery. From there, I think you have an overvoltage cuttoff using discreet components. I could be wrong on that, but you can make some pretty "ok" over and under voltage cuttoffs using a mosfet/transistor, a zener, and some resistors. But all of this is a guess, since we don't have a schematic.


                              “Men always seem to think about their
                              past before they die, as though they were
                              frantically searching for proof that they
                              truly lived.”
                              – Jet (Cowboy Bebop) -

                              Comment


                                #16
                                Re: Charger circuit questions

                                Look here for info about your charger using PCB ZJ-3009-25
                                https://raspiblog.noblogs.org/post/2...ttery-charger/
                                IC: HT3582DM (HX-3H1227)
                                https://www.alldatasheet.com/view.jsp?Searchword=HT3582

                                The datasheet of the HOTCHIP HT3582DM is on Chinese and I have to use a Chinese to English Translator.
                                Here are some useful information from the datasheet:


                                - The HT3582DM is an internal reference voltage control chip universal charger with automatic battery polarity, short circuit protection, over temperature protection (of the chip).

                                -- Maximum charge current is 300~350 mA
                                -- Support for 0V rechargeable battery
                                -- Normal mode for three lights' and two lights mode or colorful lights mode.
                                -- No Load Voltage Minimum 4.15V, Typical 4.23V and Maximum is 4.30V
                                -- Saturation Voltage, Minimum 4.17V, Typical 4.25V and Max 4.32V

                                Pin 1 is the Battery Negative
                                Pin 2 is the Light 3
                                Pin 3 is the Light 2
                                Pin 4 is the Light 1
                                Pin 5 is the SW pin, function selection
                                Pin 6 is the GND
                                Pin 7 is the Battery Positive
                                Pin 8 is the Vdd (5~8 +Vin)
                                Attached Files
                                Last edited by budm; 12-01-2019, 07:10 PM.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #17
                                  Re: Charger circuit questions

                                  how does the led operate ? like is it red then green or ?

                                  Comment


                                    #18
                                    Re: Charger circuit questions

                                    If it's something like the Baofeng charger, it's like green when idle, red when charging. Probably will light or blink if over temperature or shorted. It's all chinese to me, no clue...

                                    But I think this pretty much proves it, it will be very hard to change the voltage of this chip. Any takers? I would almost bet no takers here, even with the reference design circuit shown in that data sheet.

                                    IMHO the only way to change the voltage is replace the chip, pretty much... If someone forced me to modify the design to lower the voltage, I would require minimally one or two MOSFETs, few op amps maybe, another zener, and resistors to make an external reference to fake the voltage to the chip.

                                    Comment


                                      #19
                                      Re: Charger circuit questions

                                      Originally posted by eccerr0r View Post
                                      IMHO the only way to change the voltage is replace the chip, pretty much...
                                      The only "thing of value" is likely the case and the mechanism by which it mates with the cell being charged. Remove all of the electronics and deadbug a new charging circuit (of whatever characteristics and complexity are appropriate).

                                      Comment


                                        #20
                                        Re: Charger circuit questions

                                        Maybe this could help you

                                        https://www.youtube.com/watch?v=OU5WQTAtaUo&t=336s

                                        Comment

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