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Questions about Bafang BBS02 on 20" trike

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    Questions about Bafang BBS02 on 20" trike

    New guy here.
    Before I order a BBS02 for my wife's Terratrike Maverick, I have questions I have not been able to find answers for. If you can help, please let me know:
    - Can the Bafang display DPC-07 (default display with the package I am considering) support the 20" wheels on my wife's Terratrike? I will be ordering a programming cable with the package, but I have been told the display supports only 26" and larger wheels.
    - Do other displays support 20" wheels?
    - I plan to use a 52V battery. Can the DPC-09 be calibrated for a 52V battery or will the indicated battery level be wrong. If wrong, a lot wrong or only 1-(48/52) wrong?
    - For mounting on a recumbent trike, I will need cable extensions. I plan to solder custom length cables for the speed sensor/gear sensor/brakes /battery cables? I hoped to save cost, avoid loops of excess cable, and reduce the number of potential connection point failures by soldering my own. Is this a bad idea?
    - Her Terratrike came stock with a single 170mm 38 tooth chainring (and 12-32t 8speed microshift cog). The stock Bafang BBS02 will have a 46 tooth chainring, so I expect she will be giving up torque for higher top end. Can the motor handle the 39lb trike, 20 lb? motor and battery, and a 115lb rider or should I replace the 46 with a 38tooth chainring? She will be using the trike primarily on dirt roads, with minimal trail riding. I'm not looking for more speed, but I also don't want to tax the motor too much.
    Thanks for your thoughts.

    #2
    Soldering the wires that come with Bafang stuff isn't fun. Its super cheap wire that barely has any copper in it and the insulation melting point is barely over room temperature. It can be done its just not as easy as you may think or hope it would be. The other catch is there really isn't a standard for colors. You will want to ring everything out before you start cutting and soldering to make sure you can get it all hooked back to the same places.

    I think if I was doing a trike I would start out with ordering extensions and just coiling it up to start with and make sure it all works and you are happy with the locations of everything. If you are then start cutting and soldering. My thought would be to cut the extensions that way if you had issues you could just buy or make new extensions.

    Displays I don't own any of those. Most of mine are 500c's and I'm pretty sure they had 20" options. I do have an 850 and don't recall if that did or not. If the voltage isn't supported it just seems like the battery gauge is off. The cheaper displays that just read in % are kinda known for not being accurate anyway so probably not a big deal. The better displays that can display volts likely also have the battery options as well as the wheel options. I also really like displays that let you select 9 assist levels. I think having the 9 levels really helps being able to find just the right amount of assist for varying terrain and mood.

    Chainring I would say ya go for the smaller one of speed isn't that high on the list. On a trike you usually have a long chain so the lack of offset with smaller than 40t rings usually doesn't hurt you. The 20" tires help compared to bikes but if the thing came with a 38 to start with there must be a reason. I'm not really a trike guy so I could be wrong. Bicycles usually can get away with a larger than stock ring as long as you can still pedal because the boost you get from the motor makes up for the larger ring. Its only if you are all or mostly throttle that you may have to go smaller.

    Are you not going with the HD just for budget reasons? I know other than budget some people go 02 because its slightly smaller and lighter. Trike I would not think either of those would be a real concern. Do you have some sort of E bike? Or are you a regular biker and she can't keep up? Or does she have some sort of physical limitations? If its physical limitations that could get worse rather than better maybe the HD would be better so if she had to go throttle only there would be more power available? You can always dial back the power but you can't reliably add it. I guess it also depends on the amount of riding she will be doing. Less than 10 miles on flat ground would be different than all day adventures.

    Comment


    • Headdead
      Headdead commented
      Editing a comment
      Thanks for your thoughts.
      She has stability issues, so we just bought the Terratrike. She should be able to supply some torque, and I was hoping the BBS02 would provide enough power, and I don't expect her to go off-road or long trips; mostly flatish dirt roads for 10-15 mile rides. And yes, cost is the reason I don't want to upgrade to the HD.

    #3
    Can't answer to the DPC-07, but the DPC-14, 500C, 860C, and most other displays do support 20" wheels, and some displays go a step further and support circumference (in cm). I rummaged through what DPC-07 manuals I could find, but none gave the wheel size supported info - but I'd find it real hard to believe it doesn't support 20" wheels (just a number in a software array).

    I've grown to prefer the 500C display, with it's "just big enough to read" display but still small bar space used.

    There's also the aftermarket, very capable and compact Eggrider display, which I've tried and can't glance-read.

    I don't know that any of the Bafang displays will correctly indicate the battery remaining percentage with 52 volt batteries. Some displays can't even register the full 58+ charge voltage. I think "Bafang does not support 52 volt batteries" is still a true statement. But, 52 volt batteries is all I own personally, and I get by just watching the volts, mostly when it drops below 50. I use the percentage as kind of a "1/4 tank left, dear" indicator.

    Making your own, reliable, custom length cables depends on your skill level. The wire gauges are small, and skill with a quality, low and/or controlled wattage soldering station would be best. Some of us have done it though.

    On your gearing situation, my knee jerk would be to gear down lower than the 46, but it's hard to judge "real world". Note that gears below 42 tooth kick the chain line out quite a bit, which is usually undesirable. So, with that rolling weight and on dirt roads, I'd first try the inexpensive Bafang BBS02 44T. There are also 104BCD spiders available, opening up use of the teensy gears. If you need to tuck as close to the motor as possible, there's the Lekkie 40T (expensive) and 42T.

    P.S. You didn't ask, but I suggest NOT skimping on your battery purchase - buy it from a reputable source, and buy more capacity than you think you'll need.
    Last edited by ncmired; 03-22-2022, 10:05 AM.
    BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

    Comment


      #4
      I've never used a dpc 07 display so I don't know if they even have a wheel size setting, the only online manual I looked at didn't show one.
      I know my p850c display has a 20" choice.

      My BBS02B on 48v hauls 325# gross weight with no problem. I believe the newer B series can handle 52v without issue, the older versions couldn't accept a fully charged 52v battery. Always check with the seller to be sure.

      The smallest chainring bafang sells for 01/02 motors is 44t. There are after market options to go smaller, 42t from Lekkie being the smallest to keep a normal chainline. Anything smaller moves the chainline to the right significantly. I suggest starting with the bafang 44t (46t if you absolutely have to) chainring then decide.

      I also suggest that before installing a mid drive you should install a new chain and examine the rear cassette/ freewheel closely for wear. Another tip is to make sure the gears shift perfectly. If it has any shifting problems they will only be made worse with a mid drive.

      Comment


      • Headdead
        Headdead commented
        Editing a comment
        Chainring: I will order a spider and reuse the 38t that came with the Terratrike  I can always change if need be (it looks like the kit will come with a 48t ring; all others are out of stock) .  With the huge chain length on this trike I don't' expect chainring alignment to cog will be an issue.  
        Luna support says their stock display, the DPC-07, will NOT support the 20" wheels on this trike, which I find very surprising.  As ncmired mentions,  "it's just another number in an array."  If anyone has real-world knowledge please chime in.

      • Dshue
        Dshue commented
        Editing a comment
        Luna support is probably correct. That display looks to be made for a production bike.

      #5
      And a note about battery capacity. I generally recommend to buy the largest capacity that you can afford or reasonably fit on the bike. I run my BBS02B on a 48v 20ah battery and on flat trails at my 325# gross weight I can easily get 60 miles on a charge with very little effort. Or I can get about 28 miles on throttle only give or take. 15ah is about the smallest that I'd go with. But make sure it's a quality brand.

      Comment


        #6
        +1 on the cables and soldering them being a pain - I would only attempt if you have some decent tools and plenty of practice. It's another thing I wouldn't bother with though - it's likely to be much more reliable using extension cables plugged into connectors. I wouldn't get too grumpy about service loops - it's really not that hard to clean them up with self-amalgamating silicone tape (don't use electrical tape!), heat shrink, tie-wraps, etc. and I long ago learned to live by the adage better a foot too long than an inch too short....

        The HD is likely more appropriate for a trike, especially if ridden by someone who doesn't turn the crank real fast - not so much because of the extra power but more for the ruggedness... and on the same not as Dshue mentions, you likely want to go with a large battery on a trike, especially if on dirt/gravel roads which will require a more power than smooth surface

        Comment


          #7
          Some sort of a bag/pack is a good way to hide excess cables. There are tons of fairly small bags these days with various mounting options. I have seen some pretty nice looking installs where they just stuffed all the extra wire and some of the connectors into a small bag/pack.

          Trikes should have more mounting options than bicycles for battery(s). Also a trike doesn't have the annoyance of getting the weight of the battery too high.

          Do you have an E bike? Or is this your first? Others have brought up the battery and that is a mistake we see new people make is buying more or less the lowest priced battery they can find. For sure you want to get it from North American vendor that has a good reputation. The quality batteries are all pretty similarly priced so if you see one that is claiming similar specs and is priced significantly lower there is most likely something not right. Lots of batteries out there that claim name brand cells and high capacity that cost less than if you were to just buy the raw cells.

          As for capacity on a bicycle I usually like to use 2 miles per amp hour for a rough estimate. Assuming a trike isn't much worse that means the common 12-14 ah packs should be reasonable for that 10-15 mile range. Things that decrease range is more stop and go, higher average speed, and less pedaling. Getting into the 17-20+ ah packs cost maybe 1/3 more but many of us have found that those have more capacity than the other ah rating which is ass hours. Many of us here have reported that once you get the right seat and other stuff set up on your bike you can be comfortable for longer than the 13ish packs can go but usually are just tired of being on the bike before you run out a 17+ pack. Other than the weight if you are trying to do technical off road stuff I have never heard anyone say they wish they had got a smaller battery.

          Comment


          • Dshue
            Dshue commented
            Editing a comment
            On my mountain bike I have a small saddle bag that mount on the top tube under the handle bars that excess wire tucks neatly in one side. In your case it could be mounted below the seat or wherever the main motor harness ends. The hydraulic brake switches are what I recommend, I don't think the bafang brake levers have the correct cable pull for mountain bike disc brakes. The hydraulic cut off switches will mount to the stock levers and the added benefit is the wires are longer than the bafang levers, substantially.

          #8
          I appreciate this advice. One more thing before I order:
          On the trike, I hope to mount the BBS02 rotated as far rearward as possible, to minimize the large mass cantilevered forward and add a bit of protection to the motor.
          I have seen torque arresters to keep the motor from loosening under load. Are they necessary? A more elegant solution might be to file/cut 1-2mm indents or notches in the bottom bracket housing to better seat the motor? It is in my skill set, but is it necessary or a bad idea?

          Comment


            #9
            The motor will want to lift up under load. On a normal bicycle you try to mount it so its basically hitting the dowtube so there is no where for it to go. IF you can mount it on the top of the trike that would do the same thing. If not then yes I have seen others that have made little notches to align with the teeth in the bracket that comes with it. Personally I have not had any issues with motors moving after I bought and started using the socket vs the crappy wrench everyone sells.

            Looking at a photo looks like the hydraulic brake cutouts will work. Those levers look to have plenty of flat areas to mount em and you don't want to loose the parking brake function.

            Battery mounting I'm not so sure about. I have seen other designs where there was more options than that one has. Rear rack maybe? Unless yo could build something that kinda put it behind and at the angle of the seat back? If you did the rack maybe get a rack made for a 29er and hang a regular battery underneath the rack? That would still leave the top of the rack open for regular packs. Grin (ebikes.ca) has the eZee flat packs.

            For a throttle it doesn't look like there is room for the stock one on the left and you have the grip shift taking up space on the right. The left thumb throttle has a fairly narrow band and should be able to sneak in on the left side.

            Comment


            • Headdead
              Headdead commented
              Editing a comment
              I thought I would mount the battery under the main tube, behind the seat. For the riding she does I think it will be high enough to be protected. But as you note there are other options.
              The parking brake is necessary to hold the trike while she mounts/dismounts, but what do you think about 1 stock parking brake with NO motor cutout and one Bafang non-parking brake WITH motor cutout. That would allow the gear-shift cutout to connect to one of the brake cables (I think), simplifying the wiring. I think she could learn to always brake with the cutout brake (or both.)

            • AZguy
              AZguy commented
              Editing a comment
              While some may disagree I'm anti-brake sensor for the most part, they don't make sense to me for something while riding - I wouldn't want my moto or car to turn off the motor just because I'm on a brake after all...

              However in this case I do see a really good use for the brake sensor and that would be for the parking brake since you never want power while it's engaged and frankly bumping the throttle or pedals while mounting and dismounting a trike might be an issue

              So instead of connecting the non-parking brake sensor (which I see as more a liability), I'd consider just connecting the parking brake side and gearsensor to other input - unlike the brake sensors (most everyone I ride with never installed them or in the end disconnected them) I find the gearsensor highly beneficial

              Of course everyone is different, has different riding styles and equipment (a different electric bike "mission") so there is clearly no one-size-fits-all and a trike is well outside my experience...

              YMMV

            #10
            Looking at the picture it looks like that doesn't have a rear brake and each front has its own lever? That seems like a not very good idea. I thought there was usually a dual cable for the pair of wheels then the other lever did the single..... not that that matters much for this isssue.

            If it is one front wheel each I don't think I would want to mess with changing one lever. The levers being slightly different may effect how they operate and an imbalance between the left and right may be a bad thing. Just the way the levers grip could make a difference as well as their geometry and how much movement causes how much brake movement. I would just get the hydraulic sensors and do both. AZ had a really good point about the parking brake one having a sensor that would disable the throttle when getting on and off. They sell Y cables if your BBS02 doesn't have the gear lead but I thought they started coming that way. Since you were planning to solder anyway you can just make a 3 way if you have to.

            Comment


            • Headdead
              Headdead commented
              Editing a comment
              Yeah, only the 2 front wheels have brakes, and I probably shouldn't mix the levers. I will probably add the hydraulic brake motor cut out cables, or possibly hack a parking brake feature onto the Bafang cables that come with the kit. I need to get the parts before I decide.

            • Dshue
              Dshue commented
              Editing a comment
              The difference between the bafang brake levers and quality levers on a setup that uses mountain bike brake calipers of any sort is large. The brake force you get if you pull the bafang levers all the way to the grip is equivalent to a quality lever at half stroke.
              The bafang levers have a cable pull that falls directly between what is ideal for road calipers/cantilever and mountain calipers.
              Honestly $20 more from Lunacycle for the hydraulic brake switches is far and away the best way to go.
              If you decide to go with the hydraulic brake switches many here can help you to set them up. It's not hard. The basics are to make sure the magnet is very close to the sensor and that before you glue the magnet on you have it orientated so that you get the best magnetic field. The sensors come with double sided tape. Find the spot where the sensor and magnet fit best and stick the sensor on. Then find the best field orientation for the magnet and mark it with an arrow. Mix some 2 part epoxy and glue the magnet in place. Check for proper operation, if it works properly then remove the sensor and clean off the adhesive. Clean both the sensor and the area of the lever where it goes with isopropyl alcohol. Find a good way to clamp the sensor after gluing, tape or light spring clamps work well. Once you have a good clamping system worked out mix up some epoxy and glue the sensor in place.
              Another way to mock up the switches is hot glue. But using the double sided tape on the sensor and hot glue or superglue on the magnets isn't what I consider permanent. For me the double sided tape lasted a year.
              Hardware stores usually carry neodymium magnets if replacements are ever required.

            #11
            I like these brake sensors.
            https://www.amazon.com/gp/product/B0...IW8D2PLKT&th=1
            They appear to operate similarly to the gear sensor - the brake cable goes through the housing, rather than taping/gluing the unit/magnet to the brake lever.

            Comment


              #12
              I rode a recumbent trike a couple times. The one thing I recall is it would easily jack up on 2 wheels if you tried a sharp turn at any kind of speed. Recumbents are known for being fast and a motor would increase that. Maybe a hub motor kit would be worth a look? I also don't like them for road use because they're hard to see in traffic. A guy I know got killed doing that.

              Comment


              • Retrorockit
                Retrorockit commented
                Editing a comment
                Being aware makes a big difference. But others being aware also is more problematic.I do ride in one of the more difficult environments so my solutions might not be correct for others.The daytime strobe is a good idea. Lights work much better than flags or reflectors.I also prefer faster pulsation rate for fast Ebikes. Be warned if you have 2 lights it can confuse drivers and make them think a motor vehicle is doing "something" unusual. Reactions can be very unpredictable.

              • BK Xray
                BK Xray commented
                Editing a comment
                I have many thousands of miles on trikes. I have found them to be safer than regular bikes in most road situations. Recumbent trikes are unusual enough that they get drivers attention. They give us much more space than when riding a 2 wheeler. The only time I have trouble is in parking lots where it is hard to be seen because of tightly packed cars. Drivers can see things like potholes and maneuver around them and a trike is much more visible. Inattention is what's dangerous, so riding something that gets driver's attention helps.

              • Retrorockit
                Retrorockit commented
                Editing a comment
                Riding street in South Florida is like a high speed parking lot. Except with fewer rules. Trikes are too wide for tight urban environments. If you have a safe place to ride them they could be lot of fun. I've had to hit the brakes too many times to avoid being squeezed up against a curb (sometimes intentionally) to ever try riding one around here. You have a lot more exit strategies with a narrow 2 wheeler than a trike.
                Last edited by Retrorockit; 03-27-2022, 08:33 AM.

              #13
              I have installed multiple Bafang and TSDZ2 mid drives on recumbent bikes and trikes. I'm putting one on my new ICE Adventure right now in fact. I wouldn't worry about the 46 tooth chainring being too big. With the 20" wheel recumbents, I usually use a 50 or 52. She will have no problem with it at 46. (I used a 40t for our tandem trike) The only lines I had to lengthen were the speed sensor and battery cable. I only used one of the brake cut offs so I could keep one of the parking brakes. I have had no problems using the Bafang brake handles with V brakes, disc or drums. I use these mounts to install the battery: https://ebikes.ca/bottle-bob.html

              Comment


                #14
                I got my Terratrike Maverick A week ago I’m waiting on the bafang motor kit.
                I have some questions.
                The speed sensor where to put it and how to attach it?
                A mounting bracket maybe ?

                Comment


                  #15
                  like to see some pictures of the work

                  Comment

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