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    Battery Charging for Maximum Life

    I recently purchased one of your Bafang BBSHD kits from you, with the 52V PF shark pack... LOVE IT!

    Do you recommend running the batteries until the cutoff kicks in? Or just plugging in and topping off the charge each time, regardless of usage?

    #2
    That is great question.

    If you are charging to 100 percent i recommend not charging until you need to.

    Basically your lithium battery does not like to be too empty and does not like to be too full.....so just try to dwell as long as you can in the fun zone between 90 percent and 10 percent charged if that makes sense.

    I would say that in general a lithium pack has no memory like those crappy old lead acid packs and you are not going to hurt your battery too much by running it all the way down and charging to 100 percent.

    Ride it like you stole it...i would recommend just riding the hell out of it and after it goes bad years from now (it takes most people years to accumulate 500 full charge cycles) it will probably be obsolete anyway and in bad need of replacement with something new and cool (i cant wait to see what future holds)

    If battery life really does concern you invest in a luna charger or a Satiator and charge to 80 percent which will greatly extend the life of your pack.

    Link to Luna Charger is here

    Link to Satiator is here

    Comment


      #3
      [not to get too geeky] But I still have a question?

      I have a 52v 20Ah 25r triangle pack that is 58.8v at 100% charge.

      When you (Eric) talk about riding it within the "the fun zone" - I take that to mean between 90-10% of the 'delta' of my pack. In other words 58.8v (full charge) - 52v (zero/baseline) = 6.8 volts. So if I apply the 90-10% rule then I should be charging my battery to 58.5v (approx 80% charge) and riding till I am at 52.68v?

      Is that what you are saying? Or, are you saying something else?

      Thanks in advance!

      Comment


        #4
        80% is about 4v per cell, 90% is near 4.1 per cell. A 52v battery is 14 cells in series. 14s. 14x4 is 80% 14x4.1 is 90% charge. Each choice can add more cycles, charges to the life. Ride it like you stole it is what I used to quip in my Vespa days. Fits here too!

        Grin did a good article peddling their Satiator. http://www.ebikes.ca/product-info/cy...ced-cycle-life
        We satiate for $200 bucks less.

        Comment


        • Alpinist
          Alpinist commented
          Editing a comment
          Yep that makes it clear. Thanks Louis Luna and Madman Ebikes!

        #5
        For our purpose the info I am providing will suffice for most 18650 cells used in ebike battery packs today - 18650 cells are fully charged at 4.2v/cell (or parallel string), have a nominal voltage (mid point (not actual def)) of 3.7v/cell and fully discharged at 3.0v/cell.

        So if you have a 14s pack ("s" stand for series = voltage) you multiple 14 x 3.7 = 51.8 or 52v nominal. This gives a fully charged voltage of 58.8v and fully discharged voltage of 42v. Though the packs BMS (battery management system) will have the LVC (low voltage cutoff) set at something like 44v (+/-).

        Comment


        • ironjack
          ironjack commented
          Editing a comment
          Hi, this info appears to be close to what I am looking for. I recently purchased the 60v triangle pack Panasonic PF cells.

          Basic questions:

          What is the full charge value?
          What is the fully discharged value?
          What is the bms lvc?
          What is considered a 90% charge?
          80%?

          Thanks

        • Madman Ebikes
          Madman Ebikes commented
          Editing a comment
          you have a pack with 16 cells in series or 16s:

          16 x 4.2 = 67.2v fully charged
          16 x 3 = 48v fully discharged
          do not know the exact lvc but i'd expect it to be 51v +/-
          90% is 4.1 x 16 = 65.6v
          80% is 4.0 x 16 = 64v

        #6
        Thanks! So I'll set the CA lvc to 52v should be good to go.

        I've got another question for you, I live on a hill when I leave the house with a full charge what happens when I engage the regen braking at the bottom of the hill? Does the extra voltage do damage? Is it ignored?

        Comment


          #7
          Are you setting the CA to measure battery capacity or actual LVC?

          It is my personal preference not to set the LVC when I have a pack with a bms. However, please do whatever you feel is best for your circumstances.

          Regen - No, it is not ignored and probably best to wait a mile or so before using, especially if hot of the charger at 100%. Damage, possible but not likely. That said, depends on the size of the hill and at what level you have regen programmed.

          Comment


            #8
            I know it sounds stupid but sometimes I think there needs to be a faq or a book on how-to ride/maintain an ebike!

            The regen at 100% charge problem sounds like another reason to only charge to 90% or 80%. Does the bms regulate the regen current on the discharge port? or is it unregulated?

            So you're saying let the batteries' bms handle lvc and not the CA. I can assume the bms will cut the battery before overdischarging the cells. Is there anyway to use the CA lvc as sort of a reserve gas tank? Set it to 56v say and when it kicks in and kills the bike - sort of a dummy light - could you then get into the CA and set the lvc to 51v and maybe have enough juice to get home?

            Comment


              #9
              So I was trying to keep it simple but...

              For pack w/ a bms- the bms is designed to bleed down the cells/parallel string to the preset hvc. So if your pack is reaching/exceeding the hvc the bms's job is to remove this in the form of heat - its mA (milliamps) not amps but it does the job. Now, even large hills (not mtns) I wouldn't expect more than a 100mA total regen (which is not critical by any means). So I wouldn't think twice about using regen in those circumstances, but I'm trying to provide good/best practices and being conservative is not a bad thing. Now if you had a huge motor, max regen, lipo, and heading down a mtn - different story. Answer rest later.
              Last edited by Madman Ebikes; 02-26-2016, 07:51 PM.

              Comment


                #10
                Quick one, yes you can use the CA as reserve if that suits you. Just remember there is voltage sag and setting the CA to high would cause power loss way before expected.
                Last edited by Madman Ebikes; 02-26-2016, 08:02 PM.

                Comment


                  #11
                  I have a large enough pack that on my short commute I only use half the range round trip (only charge at home). Even so, I have set my controllers LVC to 42V in my 52V / 14S system, so if I ever go on a longer ride, I will be draining the pack down to 3.0V per cell. I certainly don't recommend for anyone to drain their pack down to 3.0V per cell every day, but...on my rides with a large pack...I have never hit LVC so far.

                  I also purposefully charge to 80% every time to enhance pack life. On rare occasions I might charge to 100% if I knew I was going to be providing test rides, because...once you let one person test-ride, a crowd gathers.

                  Comment


                    #12
                    [What is better for the battery lifespan?]
                    I have a 52v 14s 20Ah battery and a 30mi round trip daily commute (mostly flat) and I can do all but the last mile or two on an 80% charge - which is kinda nice to charge only at home and not schlep my charger....
                    I wonder what is my best option for battery life?
                    • Stop being a 100% throttle mad man and pedal more and make it last? (not as fun, but...)
                    • Charge to 90%
                    • Charge to 80% and then charge again at work to again 80%?
                    In other words, will I get better lifespan by charging once a day and using 80% charge drained down to 44v cut off..... OR...... charge 2x day and always run my battery between 80% and about 40%?

                    My concern is, that with a commute 5 days a week, will I go through my pack's lifespan too quickly if I charge it 2x a day or is draining it down like described above worse?

                    Hope this is a legitimate question that can help other newbies like myself. Sorry if it is a dumb question.

                    Thanks for the help!

                    Comment


                      #13
                      first off, on here, there are no dumb questions.

                      read this article, it explains how different factors affect battery life.

                      for me, i'd buy a second charger (even a cheap one) to leave at work and continue to ride hard. don't spoil the fun :-)

                      Comment


                        #14
                        I would recommend you charge twice a day to 80%, and use a low-amp setting. Using low amps will not get the battery hot, and it is the heat that plays a major part in degrading the lifespan

                        Comment


                          #15
                          Thanks for the help. I'll take your advice!

                          Comment

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