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    #21
    Re: Simplest 3S or 4S lithium ion protection circuit?

    Interesting finding

    Try lowering your charging current to like 250 milliamperes and see if that works better

    I have some batteries that there milliamperes are all over place and wondering how I could use them but I do not have enough of any milliamperes value to make a battery pack that I can use

    I guess I going to have to try what I was talking about earlier balancing the cell banks and see how this works in the real world
    Last edited by sam_sam_sam; 11-24-2019, 08:25 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


      #22
      Re: Simplest 3S or 4S lithium ion protection circuit?

      Yeah at first I was depending on the resistance of the power source, so the first couple of minutes of charging it was taking charge at 2+ amperes (!), and it was charging quite fast. But once voltage of the battery got high enough, it stopped and oscillated, much like the theoretical operation of my PoC relay protection circuit, so I guess I have something right...

      After putting that resistor in series with the power supply, the oscillation stopped and charged normally until full. Yes, need to slow down current flow to operate correctly... or rather I should use a CVCC type charger for the pack.

      Comment


        #23
        Re: Simplest 3S or 4S lithium ion protection circuit?

        Some more testing...trying to power my netbook with this 4S pack with a DC-DC converter. Much like before, it seems to cut off in several minutes and stay dead but if disconnected and reconnected, it will run for a while.

        Not charging the internal battery, drawing about 12-18W I think. The condition of the cells are so poor it doesn't last long, but has similar characteristics where it will power a little longer after connection cycling and resetting the overdischarge.

        Now I wonder if i should now hook up the cells from this other laptop pack...and break apart some other packs...

        Comment


          #24
          Re: Simplest 3S or 4S lithium ion protection circuit?

          Are your battery or batteries in your netbook bad if so why not replace them first and then work on the external battery pack because it might make a different in your results

          The reason I point this out is I had a tablet that I tried to do this with an my results where not very good until I replaced the internal battery first then the unit worked with what ever external battery I would hook to it
          Last edited by sam_sam_sam; 11-25-2019, 04:53 AM.
          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


            #25
            Re: Simplest 3S or 4S lithium ion protection circuit?

            Nah, I was just using the netbook as a "real world" load instead of using resistors or incandescent lamps. The netbook's battery isn't in great shape either (says about 60% of rated lifetime), but I think better than these cells in general by gut feel...

            The netbook uses 2S3P config. I tore up a 3S2P pack from some random dead pack I had, as well as the 4S2P "base" pack to play with. Was hoping this 4S pack could be used for other purposes not specifically laptops, was planning on also feeding the output into a boost converter to 170VDC...

            Comment


              #26
              Re: Simplest 3S or 4S lithium ion protection circuit?

              Do you have a battery-charger-load-tester
              Do you have something like this
              This is what I use to check my battery with

              https://www.ebay.com/itm/iMAX-B6-AC-...ry!32220!US!-1

              If not you might want to think about getting one
              This will tell you the status of the batteries that you are working with

              When I do battery testing I only do one battery at a time and write the results on that battery and test the next battery and so on

              I will weld battery packs for some one but

              I will not do the battery testing this take to much time ( this could take any where from 2 to 4 hours to charge/discharge cycle depending on the condition of the battery )

              I barely have enough time to do battery welding but you can see the end with battery testing you have keep eyes on the display screen most of the time

              I setup the charger as follows 1 amp charging/1 amp discharging might be 1.5 amps ( or more so that your screen shows above 1 amp ) sometimes I set it to 2 amp if the battery voltage does not drop fast but if you do this setting then use the temperature sensors and put it on the cell that you are working on and set the temperature settings from 80* to 100* F ( this setting does work on this charger it stops when discharging and it also work when changing )

              I also write down the amount of time when discharging voltage is above ( 3 volts @ 1 amp) (depending on how you want your parameters to be you might want to wait until it reaches 0.75 amps ) to do comparisons of each battery because some protection boards are very picky about voltages between cells

              Yes it is very time consuming but your results are a lot better

              Also if you are going to put battery pack together you might want to think about getting a battery spot welder for this under taking
              Last edited by sam_sam_sam; 11-26-2019, 10:38 AM.
              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


                #27
                Re: Simplest 3S or 4S lithium ion protection circuit?

                No I don't. I'm just estimating by behavior with load and time, doing the math. Need to compensate for constant wattage, but only need to be close enough.

                Comment


                  #28
                  Re: Simplest 3S or 4S lithium ion protection circuit?

                  Give me a little time with that let me see what I can find for you

                  Do not buy this type of salvage bay I did this once and the results were that you get less than 30% useable battery for a lot of work

                  https://www.ebay.com/itm/99-SANYO-18...ry!32220!US!-1

                  Now the seller was nice enough to refund some of my money to make it worth while doing it
                  I have to be fair about it
                  Last edited by sam_sam_sam; 11-26-2019, 11:44 AM.
                  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


                    #29
                    Re: Simplest 3S or 4S lithium ion protection circuit?

                    Thanks, but don't worry about it, I don't think I'll be buying any charger system, was planning on just depending on the protection board for the most part, then math for the rest. I was thinking I just need a mass number of not so great but passable cells and go on from there.

                    As for welding, yeah, I wish I had one. Plus the metal strips, but I think I will have to resort to solder, try to get it done as fast as possible to minimize damage.

                    Comment


                      #30
                      Re: Simplest 3S or 4S lithium ion protection circuit?

                      There is another way to test batteries but it is not as accurate and is to use a MR16 50 watt light bulb and a volt meter and a stop watch and wait until the battery voltage get to 2.75 volts plus the time it takes to get to this voltage

                      Your amperage will start off at about 1.5 and drop down from there

                      I have done this before and results are decent on a scale of 0 to 10 and 10 being a brand new battery and 0 not testing the battery at all I give about 7
                      Last edited by sam_sam_sam; 11-26-2019, 12:20 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


                        #31
                        Re: Simplest 3S or 4S lithium ion protection circuit?

                        That's the thing sort of, the cells need to be cheap, whatever the source is. The two packs I have that I've gutted so far for this project had the "right price" else I probably wouldn't even look into it.

                        I do have car lamps to use as dummy loads, though I was hoping to do away with the stopwatch and have a computer program deal with that along with measuring voltage and current.

                        the "right price" was that the packs were discarded trash picks

                        Comment


                          #32
                          Re: Simplest 3S or 4S lithium ion protection circuit?

                          Here what I would try if I was doing this

                          I would find a micro controller that is easy to program if you have played with them before
                          that a plus

                          I would use a ac to dc converter ic chip ( unless your micro controller might have it built in ) and time clock ic chip ( I would not use a do loop to do this ) write code for each ic chip

                          Read start voltage
                          Start counting timer
                          Turn on load
                          Read voltage
                          In do loop until it gets to discharge voltage level that determine by cutoff voltage in parameters in your program
                          Turn off load
                          Read voltage
                          Stop counting timer

                          Display results at the end of test

                          If I start doing more used batteries I will probably build a controller to what I have above

                          When I had a above ground pool

                          I build a pool timer controller with a Parallax Basic Stamp 2

                          And here a sample of how I wrote this program

                          I use a time clock chip
                          I used LED as light sensor
                          ( yea I know what you think you can not do this but yes you can with creative programming )

                          The program when like this

                          Start
                          Look and see if the sun is out playing
                          If so start timer turn on pool pump
                          If not go to start
                          Loop for 2 hours
                          Then turn off pool pump
                          Loop for 2 hours
                          Exit
                          Go to start

                          Or

                          If you do not want to use a micro controller to do this
                          There is another option but it takes a bit more work and you have to do some hacking

                          Find a kitchen timer and modify the start and stop buttons
                          Car headlight bulb
                          Relay
                          Zener diode at 3 volts

                          And set it up so that when you hit the start button that would start to the timer
                          Have the Zener diode setup so that when the voltage hits 3 volts turns off the timer and turn off load
                          Last edited by sam_sam_sam; 11-26-2019, 07:50 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


                            #33
                            Re: Simplest 3S or 4S lithium ion protection circuit?

                            I figure I can use the code I wrote for my failed project, a software SMPS using an AVR.

                            I think it was using pretty much all the goodies on the AVR, using the ADC channels to monitor voltage and current, using the PWM to control voltage, LCD status and UI with pushbutton menus, and even had a software clock and remote RS232 CLI control, though I was cutting the CLI out as it was using a lot of memory.

                            Alas the system was too slow, even with doing my best to not have an interrupt storm from the software clock as it was a tradeoff from interrupts or ease of computation. Main interrupt that must be done is the PID controller based on ADC samples, and the timer had to be second priority. I figured that I could execute a few more instructions to correct accuracy issues for not getting a more frequent clock pulse, though I recall that I ended up with some strange fractional interrupt frequency like 28.125 Hz due to the dividers.

                            Took a few iterations but got the 1Hz needed to update a clock, both to enable a timed shutdown and to help out with key debouncing/repeat so I don't have to pound the up/down button 100 times to change the setpoint a few volts - just need to hold down the up/down button.

                            I guess the exact frequency for the clock pulse wasn't that critical, but it was good to finally get it working to within a few seconds per day, probably due to crystal tolerance versus the software problems I had initially (I had it losing several seconds per hour initially!). Might have been easier to get the frequency right if I had chose a crystal for the clock but rather I chose the crystal to ensure I get RS232 baud rate generator, though ended gutting most of the CLI anyway.

                            The LCD driver ended up being second fiddle. It was a busyloop and updated whenever it had free cycles, turned out there was enough free cycles to update smoothly. I just needed to make sure that the PID recompute interrupt doesn't take too long and crash into the next PID interrupt...

                            Too bad, gave up. I think I could work around the problem with a larger inductor and filter cap, but oh well.

                            Comment


                              #34
                              Re: Simplest 3S or 4S lithium ion protection circuit?

                              Well if a few seconds off and hour is not so bad for what you would be do with it as long as it is conscience on each battery tested which would be the more important thing

                              I would be using a Basic Stamp 2 only because I have work with them before
                              Last edited by sam_sam_sam; 11-27-2019, 04:28 AM.
                              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


                                #35
                                Re: Simplest 3S or 4S lithium ion protection circuit?

                                I've never used Parallax's offerings before, but I knew I did not like Microchip's PIC that I used for another project... Yuck Yuck Yuck. It wasn't the fact that I had to program in PIC-assembler versus C for the AVR (I programmed assembler for the AVR as well), but the nuances of the PIC...EEIIEEW.

                                It broke my heart that Microchip ended up buying out Atmel, it should have been the other way around and that braindead General Instruments/PIC blown to smithereens, though there's too big of a PIC following as well.

                                Comment


                                  #36
                                  Re: Simplest 3S or 4S lithium ion protection circuit?

                                  The Basic Stamp was very easy for me to learn I find that the Atmel was hard for me to understand but

                                  I guess because I started with the Basic Stamp and because there are so many example to be found on Parallax website and there was a Nut and Bolts magazine they had a contributor that had example code every month ( now this person writes a monthly code for the Parallax Propeller micro controller chip ) and can still be found on the internet

                                  I have a Basic Stamp code for the DS1302 time chip where I could cause the time chip to start and stop it count and could also save the time count in the time chip

                                  I learned how to do this because I had a project for a company that I used to work for that has a silo that held product for a sand blaster machine and they need a way to know how much product they had in the silo so poor soul would not have to climb to the top of the silo and look inside

                                  If you are interested in the post what the finished product look like you can see it in this post

                                  https://forums.parallax.com/discussi...t-in-the-works

                                  If you want to look at the code written for this project you can look at it here

                                  https://forums.parallax.com/discussi...ReSet_Demo.bs2 ( just hit the view button)

                                  The way this code went is as follows

                                  If the air gun trigger was pushed the time chip would start counting

                                  There was some math that would take the time count seconds and the amount of used product ( 50 pounds of product how long it took to use this amount of product to be use up and how many seconds)

                                  When the trigger was released the time chip would stop counting

                                  Then I would save the count results in the time chip

                                  I going to take this code and modified it so that I use it for battery testing in the way that I show in the example I gave earlier

                                  But I going to modify the charger / discharge controller that I gave a link to as the load controller so I do make it more complicated than it needs to be

                                  If I do this project it would make testing batteries a lot easier your post got me to think about this problem I was having testing batteries

                                  One note I have not use a Basic Stamp in about two years so there is going to be a little bit of refreshing my coding skills again

                                  Here is the code for the pool timer project

                                  https://forums.parallax.com/discussi...ool-pump-timer

                                  https://forums.parallax.com/discussi...Pump_Timer.bs2. ( just hit the view button )
                                  Last edited by sam_sam_sam; 11-28-2019, 08:54 AM.
                                  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


                                    #37
                                    Re: Simplest 3S or 4S lithium ion protection circuit?

                                    Yes these coding projects took sometime months to finish because I would work on them when I had time to work on it

                                    I am not very fast with writing code so it takes me some time to figure out how to write the code the way I want it to function and then I test the hell out of it to make it fail if I can make it fail
                                    Last edited by sam_sam_sam; 11-28-2019, 09:46 AM.
                                    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


                                      #38
                                      Re: Simplest 3S or 4S lithium ion protection circuit?

                                      Originally posted by eccerr0r View Post
                                      I figure I can use the code I wrote for my failed project, a software SMPS
                                      Could you please explain in little bit more detail about how this was going to work and what you were going to use it for


                                      Originally posted by eccerr0r View Post
                                      Too bad, gave up. I think I could work around the problem
                                      I find myself doing a lot of this crap and if it becomes to complicated I run in another direction or table it
                                      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


                                        #39
                                        Re: Simplest 3S or 4S lithium ion protection circuit?

                                        Nothing special about it at all, it's just another control system. I only did it to learn/Proof of Concept. It "does" work, not like it's completely useless, though it has very poor transient response and had a host of other problems that I learned greatly from - which was its original intent.

                                        In the end I was able to use it as a CC/CV battery charger that I could tell it to shut off after a while. Too bad it wasn't good enough to use as a general purpose bench PSU, which was the initial goal.

                                        Comment


                                          #40
                                          Re: Simplest 3S or 4S lithium ion protection circuit?

                                          Originally posted by eccerr0r View Post
                                          I only did it to learn/Proof of Concept. It "does" work, not like it's completely useless, ***** had a host of other problems that I learned greatly from - which was its original intent.

                                          I have done this quite a few times and yes you do learn a lot about a concept weather or it will work or not

                                          Here is a EBAY listening for 18650 batteries for a little less than a dollar a battery

                                          https://www.ebay.com/itm/FAST-Lot-of...8AAOSwHIBd0HsM
                                          Last edited by sam_sam_sam; 11-28-2019, 02:29 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

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