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18650 vs 21700 battery packs.

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    That pretty much what I have found with my pack that is in the 20ah range. I don't think I have ever killed it where the 12 ish ones I could and a few times did kill em. With the 20 the ah stands for ass hours and my ass isn't rated to spend that much time on the seat at one time so that becomes my range limit.


    • Retrorockit
      Retrorockit commented
      Editing a comment
      This thing is 24Ah and yes it will wear your ass out! It's supposed to get better after a few charges.
      1- I love this battery. It can feed a BBSHD. Full throttle at the end of a long ride and no low Voltage cuttoff. Perfect!
      Low Voltage cutout in South Florida traffic cam have consequences.
      2- The bracket is a PITA. mid level fabrication skills required. You don't have to be a machinist, but it wouldn't hurt.
      There are probably very few bicycles this bracket will just bolt up to.If you don't have the skill, parts, and tools, pay someone who does.
      The hose clamp option is available. But Bolt On=Bolt Off with that option
      3- The lock is different.Needs to be manually locked to the bike every time.
      Scores- Performance 10, Value 10, Bracket 3, Lock 6

    I pulled the bracket off and took some photos but they"re stuck in my phone. My computer can't find them.
    I'm going to try and describe this mess.
    The metal parts (2) of the bracket are about 2 inches away from each other and only connected by plastic and 3 tiny machine screws that hold the wiring cover on. Structurally disconnected.
    The front bracket is about 4" long with 2-1" slotted long holes. This is the structural part of the bracket that engages the tabs on the battery. You will want 2x bolts here to hold the 14# battery.
    It can only use 5M button head bolts. This will not line up with any normal bottle mounts. It will be up towards the front corner of the frame.
    I was lucky. My 26" comfort bike has an 8" long head tube. Barely enough room to get the job done with normal size drill bits and an angle head drill. Most of you will have to be prepared to install 2x bottle mounts in a very tight space. Probably the size of the battery in most cases.
    The rear bracket will probably line up with one or maybe both holes. But the battery just sits on top of this. One bolt is probably enough here. Due to the plastic cover you can't see all 4 holes at once. It's like 2 separate projects that have to align perfectly when you're done. The battery plug sticks down in between the 2 brackets.
    If theft isn't an issue hose clamps are an option. But the flexible bracket may have issues with that also. It really needs the bike frame to align it.
    My advice is- get some 1'x2" oak or poplar trim and on the work bench-
    1- Make a straight line down the middle so all your holes will line up. You can put masking tape on the board and mark that if you want to.
    2-Drill, on a drill press if at all possible, 2-13/64" holes to match the bottle holes on the frame so you can bolt it to the bike and use it as a drill guide. Counter bore the holes so it sits flat on the frame. If this is difficult for you STOP RIGHT NOW! if you can't get this right in one try, don't go near the bike with a drill. It's a skill and it takes time to learn this. Drilling a hole in wood on a workbench is a lot easier than doing it on a round metal tube inside a bicycle frame. Quit while you're ahead.
    3- Find out where the rear bracket will sit on the frame and mark where the bolt hole is in the slot so you can repeat it on the wood.
    4- Put the bracket(s) on the wood in relation to the existing holes, and mark where the added holes will go. Further in from the end means more room for drilling holes inside of the frame. It also lets you put both bolts in that slot if you need to.
    5- Get your special tools together
    Short length 19/64" drill bit ( McMaster carr, Grainger etc.)
    Short length 1/4" drill bit
    Angle head drill, or 90* drill adapter
    Several steel Rivnut water bottle mounts.
    Rivnut installer tool. This can be done using a bolt and washer with pliers keeping the Rivnut from turning. If you can borrow one, do it. Or have a bike shop do this last step.
    A cheap set of transfer punches. These look like set of drill bits with a point on the end. Chinese ones don't cost much.You will need to cut one down because they're all full length. or an automatic center punch because you wont have room for a hammer in there.
    6- Mark all your holes on the center line of the board, working from whatever hole lined up, and the correct position of the bolt in that slot. You don't really need the 2nd hole in the rear bracket.
    7- Drill the holes you marked to 1/8". A drill press would be ideal. But you can turn the board over so the holes will get drilled into the frame through the marks. Bolt the board to the bike and using the 1/8" transfer punch mark the center of the holes. This is to keep the drill bit from wandering on the round tube. You can make the center punch bigger with a automatic punch to be sure the drill starts
    8- This is the point of no return. if you want to test fit the bracket and battery on the one bolt hole and see if the punch marks line up, do it now. See if you can get a drill and bit inside the frame to make the 19/64" holes where you need to. If you have to, put both bolts in one slot.
    9- Drill some 1/8" starter holes into the frame through the board mounted to the bike.
    10- Remove the board and drill the new holes in the wood to 1/4". Repeat step 9. 3/16" etc.Then 19/64". repeat step 9.
    11- install the Rivnuts. The special tool pulls straight up on the nuts to crimp them inside the frame. If you use a bolt to draw them up, they will want to tun until they grab. The pliers leave marks.
    It;s up to you which way to go. Any bike shop should have the tool.
    When you install the bracket the unused water bottle hole will cause it to not sit flat. Tap over the hole so it makes a mark on the bracket, and drill a clearance hole there. Or file it flat if you never want to use it again.

    With a one piece bracket and 3 long slots in it, you would just stick it on the bike, transfer punch the holes and get on with it. Probably 2 holes would line up anyway. Adding a 3rd would be easy.
    I did this freehand. I've been doing this sort of thing for many years. I don't recommend it in this case. I'll say "I got away with it" this time.
    Last edited by Retrorockit; 01-13-2022, 02:25 PM.


      You can get a look at the bracket in the Haiong manual here.

      The front plate which is loose has to be all the way forward when installed. In one photo it has slipped back. This will give you some idea of all the places it doesn't have mounting holes.



        Here is a drawing of it showing the 2-23mm slots for mounting bolts at the front end. There are slots under the plastic cover But the 50mm plastic section is all that connects it to the front where the battery is supported. When you open the cover the whole front bracket comes off with it. making it a separate operation to mount the back part. The 3 tiny screws on the cover are all that hold the 2 parts together.
        Last edited by Retrorockit; 01-14-2022, 02:43 PM.


          I finally found out what it takes to pull this battery down to 25%.. My long ride to an LBS 2 cities away about 36 miles out and back (I don't actually measure this stuff.) On the way back I had dinner, and then looped back about 1/2 of the trip to add some miles. I was trying to run the battery down so no effort to conserve Watts. Lots of 600W assist, and occasional bursts of full power. About 8 miles from home it got down to the 25% bar. When I got closer to home I tested 600W assist for 1/2 mile, no problems, and at on my own street I did a few full throttle runs. I still haven't managed to provoke a low Voltage shutdown on this thing. So at 25% level this thing has some useful range and power left in it. The 2A. charger it came with does take longer to charge this thing back up. My old battery was always charged over night. This one is taking a bit longer. So an upgraded charger would make sense of you're going to use the full capacity of this very often.
          So this battery lets me use the power of my BBSHD without worrying about range. 48V. vs. 52V. option you lose 15% range. I'm very pleased with the 21700 battery
          The design of the bracket is unfortunate..
          Last edited by Retrorockit; 01-16-2022, 05:13 AM.


            For comparison look at the bracket on the same brand 18650 pack of similar size. 4 slots end to end and the connector at the back end.
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              There are other options "out there" (in China) in 21700 batteries. Here is a 14s5p 52V. 24Ah battery with a user friendly bracket. It's 6" tall which would fit my bike just fine. 70x21700 cells.
              So there is hope for this. Notice this bracket supports the heavy battery along it's full length.


                Well I've got some bad news. My 21700 battery quit. 2 weeks out of it's 90 day warranty. Reads full charge at the charger port, but no lights at all on the battery level LEDS. And not enough to turn on the display when on the bike. Waiting to see what the vendors says. Filed a support ticket yesterday afternoon...................
                Since it's out of warranty I will probably open it up to see what's going on in there. But I'll wait a little longer to see what the vendor suggests.


                • Retrorockit
                  Retrorockit commented
                  Editing a comment
                  I think the problem was me. I was actually having a medical issue starting up. I was hospitalized a couple weeks ago. Thought it was over, but I seem to have a new issue or 2. I took the "O" icon for ON when it means OFF. The manual says leave it on for charging so I never use the switch. I think I just had the switch out of phase, and too much medical stress going on that day (my own, and others in my family) to figure it out. The lights are back on now. I'll take it for a ride and hope it's not an intermittent problem.
                  I didn't know I was having a problem until I sat down for dinner and my resting pulse was 103. Definitely new territory for me. After the hospital everything had been normal until then.

                Originally posted by Retrorockit View Post
                Well I've got some bad news. My 21700 battery quit. 2 weeks out of it's 90 day warranty. Reads full charge at the charger port, but no lights at all on the battery level LEDS. And not enough to turn on the display when on the bike. Waiting to see what the vendors says. Filed a support ticket yesterday afternoon...................
                Since it's out of warranty I will probably open it up to see what's going on in there. But I'll wait a little longer to see what the vendor suggests.
                Here's hoping they come through.


                • Retrorockit
                  Retrorockit commented
                  Editing a comment
                  See my addition to the above post. I think it was me having a bad day.

                • ncmired
                  ncmired commented
                  Editing a comment
                  Glad you figured it out. I've had a lot of medical issues and extended hospital stays, with associated "mush brain" episodes.

                • Retrorockit
                  Retrorockit commented
                  Editing a comment
                  Follow up physical. No problems found. No drugs to take. Back to riding 22 miles for lunch almost every day.
                  My advice. When stuck at home all day waiting for an e bike battery to arrive. Don't drink a quart of nitrous oxide foamed cold brew coffee.
                  I think that's what Wile E. Coyote was running on.
                  Last edited by Retrorockit; 04-27-2022, 09:22 AM.

                After R&R the battery a few dozen times the point of interference became obvious due to the scratched plastic there. I filed it down a bit and the effort to remove the battery is now within the normal range. Whether it's poor fit of the bracket, or lack of precision in my mounting technique, it wasn't too hard to solve. This is the Hailong Mega Shark 21700 bracket. Others have had the same issue.


                • Retrorockit
                  Retrorockit commented
                  Editing a comment
                  I'm very happy with this battery. I installed a Tannus Armour tire liner in the rear. The damping effect allows my hardtail to cruise comfortably at higher speeds than it did before. That combined with the seasonal winds off the ocean here means I'm using a lot more power to get around. If the Tannus has increased rolling resistance it's not obvious. On a 36 mile ride with 20mph headwinds on the way out, and trying to outrun a thunder storm on the way back with it's own higher headwinds I managed to pull it down into the 25% range. The acceleration wasn't as sharp as with a full charge, but fast running without any low Voltage cutout was possible all the way home. My old 17.5Ah batttery would have thrown in the towel a long time ago.

                I finally found the bottom on this battery. It took a 40 mile ride with no regard for range to do it. It was fun too. Lots of full speed runs on the throttle. Good weather, almost no traffic. The usual 20mph headwind on the way into town. Pretty much street slalom all the way home after a couple stiff drinks.I had to pedal it the last mile. My old battery would recover some if I gave it a few minutes rest. This one when it's over it's over.


                • Retrorockit
                  Retrorockit commented
                  Editing a comment
                  With the Tannus in the rear tire cruising comfortably in the 26mph range is now possible. With the headwinds 900W 3/5 assist is now commonly used. I'm finding the 24Ah battery is just the right size. I also discovered that 5/5 PAS is not= full throttle. 32mph 5/5, 35mph @ full throttle.

                I saw this listing for you battery geeks. Samsung 40T3 21700 4000mAh 35A batteiry for $3.99 (was $ 5.99).
                Discover the Samsung 40T 21700 4000mAh Battery. With a high capacity and ultra-high discharging capabilities, this battery is perfect for demanding needs. Buy now!

                The price breaks on the quantity discount list are still based on the $5.99 price. So IDK what you will get if you order a bunch of them?


                  I ran this battery all the way down again. I took a longer than normal ride. Davie to Ft. Lauderdale for brunch, a ride to Dania Beach pier (26mph into 10-15mph headwind (riding faster than before due to Tannus tire liner in the rear on the HT), back to N.E. FTL, then back to Davie, They've installed a small traffic circle on my return route which requires a full throttle blast so cars aren't trying to pass me going into it. This is where I find out how much battery I have left. It didn't shut off, but PAS1 the rest of the way home. Done riding for the day since it takes 12 hours to charge this back up. I my need to invest in the 4A charger. The only place i tried to conserve the battery was running PAS2/5 instead of 3/5 for about a mile. Due to a tailwind I was still running 24mph.
                  I could have ridden to all these places if I had gone straight to Dania from Davie and made a single loop. But Sunday brunch had to happen first. I could have done the visit to N.E. FTL any time, but they're open Sunday so I added some miles to this already long ride. The Davie to Dania direct run is on a road that's know for motorcycle accidents. Mostly head on left turn stuff. I prefer to take the long way around the airport..
                  I could have done the Brunch, N.E. FTL visit and then Dania Beach in that order and come straight home. The MC crashes are mostly weekday rush hour stuff.
                  I'd say the BBSHD and 24Ah battery are about an even match. The whole run east into FTL and Dania was at PAS 3/5 due to headwinds off the ocean..
                  Last edited by Retrorockit; 08-22-2022, 07:10 AM.


                    I found this seller listing a few 21700 battery packs that specify Panasonic 21700 cells from a US warehouse. I have no experience or connection with this seller.
                    They show 5000mAh for each Panasonic 21700 cell.

                    48V 20Ah 40A triangle pack, and 52V 20Ah 40A triangle pack. Both are in the drop down menu.

                    This one looks like the battery I have with the funky bracket in 52V 20Ah instead of my 48V 24Ah (which I much prefer).
                    H HAILONG 48V 20Ah ebike battery lithium Li-ion Battery for 200W-1200W E Bike. H HAILONG 52V 48V 36V 15Ah 20Ah Lithium Battery for 750 1000W Ebike Motor EBike. H HAILONG 48V 20Ah battery for 1200W Power Ebike motor lithium Li-ion Batterry.

                    It may be that 21700 cells are new enough the copycats haven't tooled up for them yet. Just a guess on my part. I'm sure it won't be long.

                    There are some 21700 brick batteries on this page up to 30Ah. The sizes vary quite a bit with capacity and the 21700 are thicker.
                    12V 12AH Deep Cycle LiFePO4 Lithium Iron Phosphate Battery for RV car electric. Capacity (amp hours) : 12Ah. Usable Capacity (AH): 12AH. Applicable to electric bicycle: 48V 100W 200W 350W 500W 750W 1000W 1200W 1500W 2000W motor.


                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      It looks like no one in the US wants to offer a 48V 24Ah,40A. Mega Shark 21700 battery any more. The guy listed above stops at 20Ah. I doubt if I have the only one, but it's the only one I've seen for sale. The 21700 really comes into it's own at the end of a long ride.Especially if I've been fighting 20mph headwinds both ways.
                      Nothing wrong with my old 17.5Ah 18650 battery when new. But 3 years old it was maybe 12Ah.and probably not making it's whole 30A either, or not for long anyway. If after 3 years this is still making 16Ah and 30A I'll be real happy.
                      Last edited by Retrorockit; 11-03-2022, 05:51 AM.

                    • calfee20
                      calfee20 commented
                      Editing a comment
                      2170's are available inside Dewalt 6 amp Batteries. I bought a stupid amount of them. Maybe I will start to work on them if I can get my other million projects done.

                    I saw your formula for range Wh/20=Miles. So here it is 48V.x24Ah=1152Wh/20=57.6 miles.
                    So a 45 mile ride with headwinds and an occasional top speed run are all in a days work.
                    My original 18650 battery 48Vx17.5Ah=840Wh/20=42miles. Obviously some compromises would have to be made along the way.
                    30 mile range was realistic for my conditions.
                    3 year old battery 48Vx12Ah=576Wh/20=28.8 miles.
                    In my world a 22 mile ride to lunch and back was about it towards the end.
                    Last edited by Retrorockit; 11-03-2022, 07:23 AM.


                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      It's often followed by rain.
                      I suppose this thread could be considered as being about the pros and cons of getting a 24Ah battery. 21700 cells are just how I came to own one.
                      It's a very nice thing to have for me, and might give an extra years useful life making it cost effective. Time will tell.
                      Last edited by Retrorockit; 11-03-2022, 09:53 AM.

                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      I guess this is how I got there.

                    • stts
                      stts commented
                      Editing a comment
                      waste of time
                      Last edited by stts; 03-24-2023, 05:31 PM.