Announcement

Collapse
No announcement yet.

Help with battery selection please.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Help with battery selection please.

    Hello Good Peoples.

    First things first.... I am very new to the e-bike world. I actually gave up on bikes many years ago due to my disabilities, but then recently discovered e-bikes. Once I saw what they could do for me I rushed out and bought myself a used recumbent trike (see my profile pic) that had a BMC V3 and Lyen Controller on it. The person I bought the trike from had 8 Turnigy 5S 18.5V 20C - 30C 5000 mah batteries running the system. He had 4 running in Parallel and then those 2 sets running in series for a total of 36 nominal Volts (41V fully charged) and 20,000 mah capacity. I was able to top out at 46Km/h (ran out of room to go any faster) and seem to get approximately 40-75KM run time *depending on how I am pushing the motor, of course*. I loved this and it was great. However, these batteries were old and have since died and my disabilities stop me from being able to save cells and rebuild batteries.

    So I am looking to replace these batteries but am not sure what I should get for replacement(s). I know I want more mah as I want to get a further ride ( hoping to go 40,000 or more mah ) from the batteries, but I DO NOT need more Volts as I find it to already be fast enough for me. Many people have told me to get away from 5S batteries as they are not as common as the others and when I take my journey across Canada it might be a bad situation I am in if I fin myself needing a not so common 5S battery replacement. I was told 3S would likely be better for me if I wanted to go down the same style battery route as I would have a far better chance of finding a 3S over a 5S in random bike shops across Canada.

    I was also told to keep my C rating as low as possible... Although I do not understand why exactly.....

    I will also be adding a 12V battery to control all my lights, horns, blinkers, hazards, etc..... So any recommendations on 12V batteries that will last a very long time using 12V bulbs (LED is still too expensive for me right now) I have my created wiring diagram should that be able to assist in helping me chose a 12V battery that will last.....

    Feel free to ask me any questions you may have that could help make a better decision.

    Thanks in advance to all whom read this and offer their advice :) :) :)

    #2
    The batteries you describe as 5S simply mean "5 cells in Series". this is because all lithium batterys are 3.7 volts. If you connect 5 of them end to end you get 18.5 Volts. Linking 2 of these packs gets you the equivelent of 10S or 37 (called 36 volts ). 8 packs connected like you describe do in fact = 20Ah (20000mAh).

    A 3S pack will only be 11.1 volts so that's a lot less and may not even work with your controller if you built it up the same way you would only have 22.2 Volts..

    Any of Lunas 36 batteries will do the job since they are built the same way, just using 18650 core cells instead of pouch LiPo's. There is currently a 14Ah , a 29Ah and I believe a 30Ah pack available in 36 Volt configuration.

    The C Rate you are referring to is a way of determining how fast you can discharge the pack without it tripping off or damaging it. Your pack for example was 20Ah as configured , So if it was rated at 1C you could safely pull 20 Amps from it max, 2C you could pull 40 Amps etc. A 20-30 C Rate is HUGE. Most eBikes pull under 50 Amps max . I suspect that should mean 20 to 30 Amps pulled not 20-30C.

    Keeping the C Rate low was likely referring to the charging, as the speed you can pump juice back into the packs is measured by C Rate also. Most packs, and certainly packs 15 Ah and larger charge at a fraction of a C rate . My 20Ah pack I charge at 2 Amps or 1/10 C, the slower you charge the kinder it is for the pack.

    Since you have a 36 volt pack, I would do lighting by getting a cheap step down converter and drop the 36 down to 12 for those needs. The draw is minimal as compared to the motor system and would be 1 less charger/battery to add complexity.

    Hope that addresses most of your questions. If you need or want any clarifications or have follow up questions , Fire away... That's literally why we are here. Welcome to the forums and welcome back to the biking world . Enjoy
    Last edited by Bicycle365; 10-12-2016, 02:50 PM.

    Comment


      #3
      The way I was thinking of going in regards to using 3S instead of 5S would require me to have 3 sets instead of 2 which concerns me a little bit as that still doesn't quite equal out to 36V nominally, but is instead 33.3 nominal Volts. This portion has me quite confused as to whether this configuration would work or not. Also I like the idea of it all weighing a little bit less since technically there are less Cells. I now also understand why I was told to go with 3S instead of 5S due to having issues finding them. I live in the Capital of Canada and anywhere I go here has to order them for me and doesn't have them handy on the shelf already, but I see PLENTY of 3S.

      As for the C rating I actually do mean the battery discharge rate (20C Constant and 30C Peak ) --> These are the batteries

      I am not sure how to figure out how many amps my bike is pulling. I do know that my BMC is set at 1000W on the current setup. I suppose I could be able to see that on my CA but right now I have no batteries to get that figure from the CA

      I was told the same about stepping down the 36V to also run the lights and such, but I personally would rather it be a separate battery. I likely would only need to charge the 12V maybe 3 or so times on my trip across Canada, where I will be constantly charging the batteries used on the motor almost every day/every 2nd day. I can also use the same charger for both sets of batteries so there wouldn't be a need for a second charger. I was thinking of getting a 12V 10,000 mah for the lighting, just not too sure. I have a Venom Pro Quad 100W 7A 4-Port AC/DC Charger.

      Comment


        #4
        Wow I under estimated the RC LiPo batteries they can pack a whallop !
        33.3V should be OK since it will be higher for most of the charge cycle 37+ at full charge.
        1000w ÷ 36 volts = 27.7 Amps
        1000w ÷ 33 volts= 30.3 Amps
        Lighting battery sound like you have it worked out...

        Comment


          #5
          Please correct me if I am wrong and I am hoping that I am since math really is my weakest, lol...

          You say 1000w / 36V = 27.7A

          but wouldn't have the old battery setup only have been 20A total? I assume that 5000 mAh = 5A and 5A x 4 batteries in parallel = 20A and then in series still only equals 20A as only the Volts double when in series? With this thinking it appears to me as if the previous owner and then myself was under amping the motor? This is where I am really getting confused....

          Comment


            #6
            Welcome! :D

            You're in good company, I ride an E-Bike for fun and exercise, and it helps me more with my chronic fatigue than just about anything I have tried!

            I would really encourage you to get away from Lithium Polymer battery packs, I used Turnigy Nano Tech packs for better part of 7 years, but the lack of BMS and plug & play charging really makes them a hassle and potentially much more temperamental than an equivalent Lithium Ion pack as sold by Luna.

            Also, you're going to generally get more efficiency and less waste heat with higher voltages, and yes, it also gives you potentially more speed, but you can limit that very easily with your Cycle Analyst (it has a top speed limiting feature).

            You might seriously consider stepping up to 48v simply because it will go the same speeds with less stress on the battery which leads to longer life.

            Your Lyen controller is 12 FET? If so, that is a VERY robust and strong controller, and going from 36 to 48v shouldn't be any issue, I have two Lyen Extreme Modder 12-FET controller that I have been using on different E-Bike builds for better part of 6 - 7 years, and since you have the CA to control things such things as low votlage cut-off (the battery will do this for it's self too, but good to have both, as system redundancy) I would encourage you to consider 48V too as your motor will probably run cooler and thus more efficiently.

            I too hope to go on a cross country ride in the spring, (so far thinking of following the Oregon Trail across the USA) I am going for more of a "hot 48V" in the form of two large 52V or 60V batteries as I am wanting about 40ah's of capacity myself, and another thing to consider!

            ALL batteries become weaker over time, and you get lower voltage and capacity as they age, much better to have MORE battery than you need for now so that when it is 3 - 4 yrs old, your voltage sag will be MUCH less noticeable, and since your batteries aren't working as hard, they will perform better.
            Last edited by LI-ghtcycle; 10-12-2016, 08:37 PM.

            Comment


              #7
              Your math is correct for determining AmpHours (size of the bucket)
              The math I was doing is for Amps (how fast you can pour it out)
              The 20C rate tells me you can pull 20x the capacity(5ah) or 100 Amps of current from that (not recommended but you can)


              There is a great article on eBike battery math that can explain it way better than I can.

              These days, awesome ebike battery packs constructed of quality 18650 cells are available to average bike builders thanks to  advances in 18650 DIY pack building  methods and vendors such as Luna Cy…


              Comment


                #8
                Took me a while to find the original email from the original owner. This was what originally had me confused as to what batteries I could buy to give me the absolute most mAh I can possibly get.

                As quoted from email " Turnigy C20 lipo batteries (current setup is nominal 37 volts, fully charged to 41 volts. Motor and controller as setup can increase to 55.5 volts nominal, 61.5 volts fully charged " <-- This kinda and kinda not makes sense to me...... LOL.... I understand I can increase the Volts to 55.5, but do I need to do anything else other than add batteries is where it looses me, lol

                It is indeed a 12 x 4110 MOSFET Extreme Modder Controller LYEN Edition

                I want the HUGE mAh for distance. I am more than happy with the speed it is at now ( ** I maxed out at 46Km/h before I was forced to let off the throttle ** I was not yet at full throttle either ** ) In fact I would be extremely happy to find a way to ensure at full throttle I do not go over 50Km/h ( I plan to add something at some point for a sort of cruise/throttle control so I don't have to hold the throttle every time I use it. ) Although I was told I needed the new CA to do this *still have to research this part. If I remember right I have CA v2.3*

                3S, 4S, 5S, 6S, 7S ..... Which bloody S to get, LOL

                Also, again please correct me if I am wrong, but from my understanding the lower the C rating the better?

                Comment


                  #9
                  Saw this after I posted my last message.

                  MultiStar High Capacity

                  They look pretty nice to me and I would only need 6 of them to hit 60,000 mAh but it would bump me up from 36V nominal to 44.4V nominal.

                  Does one really need a BMS if there is a CA ?

                  I also noticed I forgot to add another key note that I noticed in the difference between the lipoly and the Luna....

                  6 X the above = 60,000 mAh and total weight is 32lbs.

                  The Luna battery was only 29,000 mAh for the 36V and I would need 4 of them to come close to the mAh (58,000) as the lipoly with a total weight of 50lbs

                  This puts the lipoly batteries in at 18lbs lighter and 8.4 nominal Volts higher..... Even if I added a BMS to each lipoly it would still be significantly less than the Luna batteries.

                  Comment


                    #10
                    Yes you still need to ballance your pack. If you dont charge though a BMS. Charging lipos need to be ballance charged. Cells charged over 4.2 volt can swell and are potential for fire when charging.

                    Comment


                      #11
                      Oh yes, of course. I already would have that taken care of since I already own a Venom Pro Quad 100W 7A AC/DC Charger

                      **Edit** Now that I think about it.... With my current charger that would mean 7S is out of the picture, unless I upgraded to a new charger which I would rather not do, lol.
                      Last edited by GothPaw; 10-15-2016, 10:10 PM.

                      Comment


                        #12
                        That's good to know that you're educated on lipo.

                        Comment


                          #13
                          Originally posted by GothPaw View Post
                          Took me a while to find the original email from the original owner. This was what originally had me confused as to what batteries I could buy to give me the absolute most mAh I can possibly get.

                          As quoted from email " Turnigy C20 lipo batteries (current setup is nominal 37 volts, fully charged to 41 volts. Motor and controller as setup can increase to 55.5 volts nominal, 61.5 volts fully charged " <-- This kinda and kinda not makes sense to me...... LOL.... I understand I can increase the Volts to 55.5, but do I need to do anything else other than add batteries is where it looses me, lol

                          It is indeed a 12 x 4110 MOSFET Extreme Modder Controller LYEN Edition

                          I want the HUGE mAh for distance. I am more than happy with the speed it is at now ( ** I maxed out at 46Km/h before I was forced to let off the throttle ** I was not yet at full throttle either ** ) In fact I would be extremely happy to find a way to ensure at full throttle I do not go over 50Km/h ( I plan to add something at some point for a sort of cruise/throttle control so I don't have to hold the throttle every time I use it. ) Although I was told I needed the new CA to do this *still have to research this part. If I remember right I have CA v2.3*

                          3S, 4S, 5S, 6S, 7S ..... Which bloody S to get, LOL

                          Also, again please correct me if I am wrong, but from my understanding the lower the C rating the better?
                          Actually, since the C rate directly refers to how high of discharge or charge current (and thus fast for charging, and how high a controller current you can use while riding or discharging) you want the higher number.

                          Many people buy price point batteries with lower C rates because the cost is lower, and if you use a high capacity (high AH battery pack), then you can get away with it, and save lots of $$$.

                          *** NOTE ***

                          I do NOT recommend going for price point on LiPo batteries however, because 90% of the people who have trouble with LiPo batteries break three major rules IMHO.

                          1) Cheap is good and cheaper's better (cheap LiPo is needed to be tested from the beginning because many are defective when they reach your door!)

                          2) Bulk Charging with very seldom balance charging (Everyone I know who has had problems with LiPo has had them because they flog the crap out of cheap LiPo, and then either have to replace them regularly (every 6mons to a year depending) and usually buy large quantities and cull the bad ones even when new!)

                          3) Charging them to 4.2v (Charging LiPo to 100% is a great idea if you are flying a RC plane and need the maximum just to get more minutes of time in the air, for a LARGE E-Bike battery it is doubly bad IMHO, because especially with cheap LiPo, things go wrong at high Voltage mostly while charging, but also when dis-charging. In around SIX YEARS I have never had one problem with my LiPo getting dangerously hot, but I charged them always to around 80 - 90% max, and never got them too low, in all this time all I have had is one cell on one pack go bad, got warm when charging and wouldn't take full voltage. I also know of many with house/garage fires because they broke these rules. LiPo IMHO is just too high maintenance.)

                          For example, I used 25 - 50c (Discharge so capable of 300a continuous, 600a burst) Turnigy Nano Tech batteries that were 6s 6AH (6000 mAh) often in an 18s 12ah pack (so 3 packs in series, 2 parallel) and used a controller that only drew around 25 - 30amps, therefore, I had batteries that were reasonably priced for the value, that NEVER saw even half their rated out-put, and used them for 7 years, yet with the very high charging C rate of 5 (or 60a at 66.6 volts, my Hyperion 1420i Net 3 only goes to 550watts, so again, at max charge rate of around 6amps @ 66.6v or 18s, I am nowhere near rated, and thus never had a problem! : ) ) I got lightweight yet VERY powerful batteries that never did more than stretch their legs.

                          However, these days, to avoid all the laborious charging & balancing, I use high quality Li-Ion cells packs, and honestly, 6 or so years ago when prices were MUCH higher for much lower rated cells, I wouldn't have considered the average Li-Ion pack, Luna Cycles has changed all that.

                          Now you can get top rated Li-Ion packs that are pretty much worry free, plug & play, and I believe I have flogged mine more than most as I both use a 72v 11.6 ah pack (currently out of stock or otherwise not showing up on their online store) of Panasonic PF cells to haul a 150lb+ trailer to work most days, AND go fast when I am not, topping out at 40mph on my 114lb E-Bike (I weigh 176, so 290lbs gross, and this is with just my 25amp 12 FET Lyen Controller, I haven't broke the surface of the potential of this pack as it has a 50a constant, 70a burst BMS!) when I am feeling froggy.

                          In the past, the main reason people I knew stuck to LiPo was the huge C rate so they could use high amp controllers, now we have VERY reasonably priced plug & play packs with VERY high amp BMS!

                          I have a customer that has been using one of the 48v 11.5ah Shark Packs:


                          Now for about 9 months or so, and she has a hub motor E-Bike (so not very efficient to begin with), pulls some kids and/or groceries on a regular basis, AND climbs a steep hill, and her only regret is that she didn't get a BBSXX powered kit, as at the time, the lower cost of a hub motor kit was more attractive.

                          At the risk of sounding like a commercial, I have issued this challenge on Endless Sphere also, I DEFY ANYONE to find a better deal for quality of service, product, and affordable price on Luna Cycles products!

                          I know this is a bold statement, but it's really true that they are offering these things at wholesale prices to the public!

                          If not for Luna Cycles, I might still be playing the very time consuming and annoying balance charging game with LiPo batteries, each to their own, but I'm never going back. :D
                          Last edited by LI-ghtcycle; 10-17-2016, 07:25 AM.

                          Comment


                            #14
                            That there is part of the issue *for me anyways*..... You won't find a better deal in terms of price, although I truly doubt they are selling them at wholesale unless they are manufacturing them; otherwise they wouldn't make any money from them, but that really isn't the issue... This is the main reason I am choosing to stick with Lipo. The sheer fact that I can double the Ah for a little more money. I don't doubt the performance of the Luna batteries, but as you yourself have said, you used yours for like 6 years without issues. My opinion in that area is that it really depends on the person charging/using them. Mine were always charged full, but I also rarely used full throttle. With 8 batteries not one of them ever got hot at all. The original owner used these batteries for 6.5 years and I used them for a year myself before my stupid roommate put my lipo battery bag outside in the shed during the winter thinking it was something else. I had just finished putting them into a storage charge so 2 months went by before I noticed the bag was gone. By that time it was by far too late and all the batteries had been killed, which is expected when outside in -10 to -40 degrees Celsius weather over the course of 2 months. If this had not have happened I am more than confident they would have lasted me another year at least.

                            I don't seem to understand why you think balance charging lipos is an annoying game. I simply plug mine into my charger and it balance charges the lipos for me without hassle. As for time consuming. Yes it would take longer to charge than a Luna battery, but then again I can safely charge "all" of my batteries in the same amount of time it would take me to charge 2-4 Luna batteries. I would only own one charger if I had Luna or lipo batteries as all those extra chargers means added weight for me. Weight is a big deal for me as I will be travelling across Canada. Depending on how much of the TCT is ready by the time I leave I could find myself travelling up to 24,000 KM....

                            Originally posted by Bicycle365 View Post
                            Your math is correct for determining AmpHours (size of the bucket)
                            The math I was doing is for Amps (how fast you can pour it out)
                            The 20C rate tells me you can pull 20x the capacity(5ah) or 100 Amps of current from that (not recommended but you can)


                            There is a great article on eBike battery math that can explain it way better than I can.

                            https://www.electricbike.com/%E2%80%...rs-watt-hours/

                            The way I had it setup was for 20A (4 X 5000mAh) + ( 4 X 5000mAh) = 20,000mAh - So wouldn't it be 20C is 20x (20Ah) ? *Edit* Unless you were speaking of just one of the batteries by itself *End Edit*
                            You say " (not recommended but you can) ...... Doesn't this mean that the lower the C rating the better? This is what this says to me, but yet Li-ghtcycle says I want higher C rating....

                            I don't want to HotRod the machine or even close to it. I simply want the higher mAh so that I can go the greater distance.... IF I have 44.4 nominal Volts with 60,000mAh that should get me 215KM full throttle from what I read on the link you gave me. I would almost never use full throttle so I "personally" would more likely expect to get 250KM range which for me would be astoundingly perfect.

                            In terms of " Speed " ..... I really really do not wish to go faster than 50 kph (30 mph) when at " FULL " Throttle


                            Doesn't Higher C Rating mean Faster Discharge ? If so then that's not likely something I want if I am trying to get the most distance.

                            Comment


                              #15
                              Oh man! I would be soooo mad with my room-mate! That's potentially $100's of dollars! (Time to get a new room-mate! j/k hehe ;-p)

                              Think of it this way ... if your battery was a water storage tank, then the "C" rate would be the size of the pipe going in to fill at the top for charging, and the discharge the size of the pipe at the bottom where it comes out.

                              The larger the "C" rate, the larger the pipe, so when charging or "filling the tank" it is quicker and more efficient. Same goes for the discharge, and yes, you can definitely "empty the tank" faster with with a larger discharge pipe or "C" rate, but you don't need to have your throttle on full all the time to get the best performance necessarily, a good controller won't require that.

                              So staying with the same "water tank" analogy, having a lower "C" rate not only limits how fast you can charge and discharge, it also means that the lower the "C" rate, the harder it is on the battery to put out a given rate of current, i.e. a 2c battery putting out 25amps of current will be work much harder than a 10c battery of the same voltage and capacity.

                              Higher "C" rate batteries cost more because they perform better at for the same work with out getting as warm, and that means less resistance, thus greater efficiency.

                              If you're happy with LiPo, more power to you, but if you bulk charge them, including balancing them in bulk, your going to have a problem with a weak cell sooner or later, it took 7 years before I had a "problem" meaning I had a cell actually die, BUT! The batteries were only giving me about 60% of their original capacity, and with-in 3 - 5 years, battery technology advances considerably, so if I had to do it over again, I'd much rather do it with a pack like Luna's.

                              Also, where ever you are storing your LiPo, I really hope it's in a fire resistant pouch or better yet, a metal container in a fireplace or concrete flood, because they are a lot more energetic, and that means also a lot more prone to thermal runaway, i.e. fires than the Li-Ion.

                              I have mine in metal boxes stored in a garage's concrete floor , but not really needed as much with Li-Ion, but I still store/charge in a "fire safe" area as ANY battery can have a malfunction, and a good high energy & capacity battery has a lot of characteristics with a bomb. ;-)

                              Comment

                              Working...
                              X