Mixed mAh lipos OK?

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  • Tony
    Senior Member
    • Feb 2008
    • 413

    #1

    Mixed mAh lipos OK?

    Hi guys.
    Will two lipo packs with diff. mAh work in series ?

    7.4v 3300mAh 25C and 7.4v 4000mAh 25C
    Last edited by Tony; 05-07-2009, 09:45 AM.
  • Doby
    KANADA RULES!
    • Apr 2007
    • 7280

    #2
    No.
    Grand River Marine Modellers
    https://www.facebook.com/search/top/...ne%20modellers

    Comment

    • ED66677
      Fast Electric Addict!
      • Apr 2007
      • 1300

      #3
      NO...
      and YES but...
      having two different capacity in serie will cause some problem, the smaller capacity pack will be overdischarged before the ESC cut-off acts, this will kill the pack!!!
      the rule is to always have same capacity pack, no matter if they are connected in serie or parallel!
      Emmanuel
      I'm french but I doubt I really am!
      http://pagesperso-orange.fr/pleindetrucs/

      Comment

      • bustitup
        Fast Electric Addict!
        • Aug 2008
        • 3071

        #4
        NO

        it might work for a bit but something is going to fail
        SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
        EX President of the Offshore FE Vultures Society

        Comment

        • Doby
          KANADA RULES!
          • Apr 2007
          • 7280

          #5
          No, ,,,,,,,What Ed said!

          The lower capacity pack will not survive for long.
          Grand River Marine Modellers
          https://www.facebook.com/search/top/...ne%20modellers

          Comment

          • Tony
            Senior Member
            • Feb 2008
            • 413

            #6
            I'll just have to buy another 3300mAh lipo to run with the pack i have now. My other TP pack wouldn't charge correctly due to "wrong polarity, and wrong voltage" .... Anyways, thanks for the info guys. e"

            Comment

            • Flying Scotsman
              Fast Electric Adict!
              • Jun 2007
              • 5190

              #7
              Just , a note you can run different Mah packs in PARALLEL. There was a discussion on this very subject on another forum and Professor Bill-SOCAL weighed in and stated Ohms law.

              Douggie

              Comment

              • Himalaya
                Senior Member
                • Apr 2009
                • 251

                #8
                That is correct, run different mAh packs in parrallel has no issue, as long as the S numbers are same, and the discharge capability(C rating) better be close. I run 2600mAh and 2200mAh 6S packs in parallel without a single problem.

                Comment

                • Tony
                  Senior Member
                  • Feb 2008
                  • 413

                  #9
                  Originally posted by Himalaya
                  That is correct, run different mAh packs in parrallel has no issue, as long as the S numbers are same, and the discharge capability(C rating) better be close. I run 2600mAh and 2200mAh 6S packs in parallel without a single problem.
                  So, parallel = more run times and less speed
                  series = more speed and less run times
                  correct?

                  Comment

                  • Flying Scotsman
                    Fast Electric Adict!
                    • Jun 2007
                    • 5190

                    #10
                    Originally posted by Tony
                    So, parallel = more run times and less speed
                    series = more speed and less run times
                    correct?

                    It comes down to volts and amps

                    2 2S1P 2500 mah 20C in parallel= 7.4v 5000 mah

                    2 2S1P 2500 mah 20 C in series = 14.8v 2500 mah

                    Douggie

                    Comment

                    • Ocean Racer
                      Senior Member
                      • Sep 2007
                      • 502

                      #11
                      Dougie maybe Im missing something but did you forget to change something on your chart?
                      Failure is the First step to SUCCESS

                      Comment

                      • bwells
                        Senior Member
                        • Jan 2009
                        • 842

                        #12
                        I'll bite! The C rating would change on the parallel example, yeah?

                        Comment

                        • Himalaya
                          Senior Member
                          • Apr 2009
                          • 251

                          #13
                          Douggie is right, C is a constant showing how well the pack handles high current, never changes unless it's getting old.

                          Let me continue Douggie's equations:

                          2 2S1P 2500 mah 20C in parallel= 7.4v 5000 mah 20C, good for 100A*7V =1400W

                          2 2S1P 2500 mah 20 C in series = 14.8v 2500 mah 20C, good for 50A*14V = 1400W

                          make sense ?

                          Comment

                          • Tony
                            Senior Member
                            • Feb 2008
                            • 413

                            #14
                            Originally posted by Himalaya
                            Douggie is right, C is a constant showing how well the pack handles high current, never changes unless it's getting old.

                            Let me continue Douggie's equations:

                            2 2S1P 2500 mah 20C in parallel= 7.4v 5000 mah 20C, good for 100A*7V =1400W

                            2 2S1P 2500 mah 20 C in series = 14.8v 2500 mah 20C, good for 50A*14V = 1400W

                            make sense ?
                            2 2s1p 7.4v 5000mAh 20C in series = 14.8v 5000mAh 20C, good for 100A*
                            Is 100A* good for a 32" cat running a 9xl, ETTI 125 esc, x642 prop?

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