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Thread: 50cc Scooter conversion

              
   
   
  1. #11
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    Maybe you have a source. I have not seen motors over 1kW using the two flat, "double D" shaft drive. The design is limited in its torque capacity. Many outrunner (RC) motors use 10mm output shafts (with keyways?). You need to be careful with the side loads with that small of diameter shaft(and bearings) when using a belt or chain drive. Keep the sprockets as close as possible to the motor to reduce the side(overhanging) load.

    Some people have hollowed out the ICE crankcase(removed one side of the case, the crankshaft, and the output bearing); and mounted some of the smaller, high power to size motors in the space. It makes a great mounting spot if the overhanging load mentioned before and cooling problems can be addressed. Usually the stock belt cover can be used.

  2. #12
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    Hi,
    I'm definitely learning but the 3K3 BLDC I have is 'double D' / T8F. I'll post some images later today (if the site allows me)
    VERY valid point re: side-loading - and the very reason I could not see a way of using a belt drive
    I looked at hollowing out the crankcase (machine-shop) but that went against two of my 'starter-for-10' principles : [1] not very DIY (not for me anyway) and [2] increased cost. Ideally though, you are bang on ! Keeping the motor within the confines of the original crankcase would be awesome. Apart form the two 'reasons' I mentioned I could not see a way to hollow out enough crankcase for the motor (107mm dia) but leave enough to maintain strength / rigidity (bearing in mind the swingarm / rear wheel strength is integral to the crankcase ass'y on these scoots).
    I think I may rue the day I set a budget of 800Euro for this, in that the batteries (even 'home made') were +/- 400Euro, the motor/controller pair was +/1 200Euro, then I have the charger and all the 'extras'... I think if I were to start again (although this is a little premature in that it's not a finished / working project yet) but.., if I did... then I would spend more on the motor/controller. We'll see.
    Right, I'm off to see if I can cobble together my pics so far and write some explanatory words for an update here...

  3. #13
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    50cc Scooter conversion - Motor

    Time for an update ! I've made some progress with the motor :
    The motor controller arrived !! Yaaay !!!
    BLDC Motor-KR3Kw72V(250x212px).jpg
    Initially, I removed the cylinder head. Once that was done, the swingarm was next. I found it easier to leave the swingarm attached to the scoot for the major kit removal as it helped support and hold the crankcase etc during the work. So, after the cylinder head, it was the turn of the oil pump, the starter motor and the ignition system.
    I'll need to design some covers / blanks for the holes. I intend to route the motor cables through the square, oil pump hole so will make a blank specifically for that purpose.
    StripDown-CylHd+OilPpRemoved(250x445px).jpg
    Once the cylinder head, oil pump, starter motor and ignition system were removed I began to 'play' with possible motor positions; the crankshaft was 'annoying' me though - it seemed to always be in the way and I knew it'd have to come out for re-working or... something...
    CrankShaft+Starter(250x445px).jpg
    I tried all sorts of ways to remove the crankshaft... and couldn't... In the end, I used a trolley jack - I tried but couldn't move it any other way. The trolley jack did the job in a couple of minutes - live and learn, I guess !
    CrankShaft-Removal2(250x445px).jpg
    The swingarm was placed, upside-down, on the trolley jack and 'tied' down with tie-straps all the way around the outside of the jack. The crank shaft was located centre of the trolley jack 'saddle'. The jack was slowly and pressurised, the 'saddle' extended BUT the swingarm itself was restrained by the tie-straps. Slowly, very slowly, being careful so as not to distort the swingarm itself, the crank shaft popped out - as per the centre image above. The whole lot was then cleaned up.

    There simply wasn't enough space to mount the motor within the engine casing - even if I had the mind to attempt it ! Looking at the various 3Kw motors available I don't think I can get one much smaller regardless of the amount I'd be willing to pay and even then, the mechanical / machine shop re-work would be extensive (and, therefore, expensive !). In the end I began to see that the motor could be mounted in lieu of the cylinder head if I designed a suitable bracket. Out came Sketchup
    Motor+Bracket DesignRear(250x202px).jpg and Motor+Bracket DesignFront(250x211px).jpg
    and then the 3D printer and in an afternoon I had an ABS bracket knocked up (in pieces - much as I would eventually need in aluminium) and welded them together with an acetone/ABS slurry. Effective !
    Motor Bracket Template(250x310px).jpg Motor bracket ABS with Motor-1(250x445px).jpg Motor bracket ABS with Motor-2(250x445px).jpg
    Once I'd determined that the the bracket was correct for the motor, I went about mounting it to the 4 threaded holes vacated by the cylinder head studs - all the time being very careful not to break my template ! And, once I'd done that and noted the correct positions of the 4 x slots in the back panel for the new cylinder head machine screws. I say 'slots' - these are 4 x horizontal 20mm x 5mm slots allowing the bracket to be mounted to the crank case in a way that there would be 20mm +/- of lateral movement to enable future alignment of the motor pinion with the rear, gearbox, sprocket.
    I then cut out and welded the same pieces all over again BUT, this time, in some 'scrap' 5mm aluminium I re-tasked from the skip at the local scrapyard.
    Now I had something like the images below. I actually began to feel pretty pleased with myself... starting to believe the whole crazy idea might just work !!
    Motor bracket offered-up(250x445px).jpg Motor Bracket Alu((250x445px).jpg Motor attached-1(250x445px).jpg
    The three holes in the bottom strengthener / spacer are to enable any water to drain more easily.
    The motor is held rigid by the two pivot bolts at the bottom bracket and then the short arm at the rear of the motor (left hand side in the images) to help prevent twisting. The long arm on the top of the bracket, at the pinion / drive side of the motor allows the whole motor to rotate forwards / backwards (in relation to the scoot) and thereby enable the chain to be tensioned - much like an alternator adjuster-arm.
    To be fair, after a wee bit of filing some rough edges, the whole system mounted up in 15 minutes
    Motor + SwingArm(250x141px).jpg
    My job with the motor was almost done. All I had to do now was blank off the old / no longer used crankcase holes for the starter motor, crank shaft and oil pump etc being careful to route the motor cables through the now empty, crankcase and up towards the back of the scoot where I planned the electrics & controller would go !

    Next is the Gearing, tidying up the electrics and batteries...
    Almost forgot; I created that web-site / blog at www.ianwatts.online
    Last edited by 3DRoboGuy; 04 June 2019 at 0832.

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  5. #14
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    50cc Scooter conversion - Gearing

    An update re: my (rather hopeful?) gearing...

    I'm not sure this will work (given the gearing) but I have to start someplace !
    I figure that it will be easier if I can the existing rear variator / clutch assembly (in some modified manner) to pass the drive through the gearbox to the rear wheel. I'm hoping the clutch / gearbox will be beneficial / not pose any significant problems... although some math with the ratios indicates a top speed of 11kph !! Hmm... To be frank, I think I'm going to need to re-visit this one BUT, at the current time using the existing variator / clutch assembly is the easiest way to get drive into the gearbox... I certainly can't see any way at all (bar a hub motor) of 'ignoring' or bypassing the gearbox - although I have looked at switching gear ratios within it (costly and of (at first glance) limited benefit !

    So, to make a start and fit the new sprocket to the rear clutch ass'y, I stripped down the whole assembly and through-welded the sprocket to the two clutch plates (they will not be needed as the rear section of the variator anymore so...

    I started by removing the nut from the splined gearbox input shaft. The clutch bell housing (right hand side in the image above) may then be removed, followed by the variator itself.
    A large nut will be visible once the bell housing is removed. If you're planning on doing this yourself, then be VERY careful stripping the variator - it's under pressure from an internal spring (image below). I held the variator plates shut (their natural position under spring tension) and removed the large nut. In doing so the spring tries to release - keep that pressure applied, remove the nut fully and all comes apart as per the next image.
    Gearing-1 disassembled(250x126).jpg

    I then stripped the variator guide plates from the shaft and welded the 69tooth sprocket to both plates. To ensure the new sprocket remained central / true I made up a plastic spacer (again, using Sketchup and the 3D printer).
    Gearing-1 spacer ready-to-weld(250x141px).jpg
    Gearing-1 welded(250x238px).jpg

    Reassembly was the opposite of disassembly (above) - apply pressure to the spring and start the nut off on its thread. Lock up the nut and refit the whole assembly to the gearbox input shaft.
    Gearing-1 re-fitted-1(250x445px).jpg

    If I find (as I'm pretty sure I will) that the clutch assembly is just too inefficient / isn't needed then I can always lock the clutch. I can also lengthen the gearing somewhat...
    But... that's for another day !

  6. #15
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    50cc Scooter conversion - Electrics tidy-up

    Next came the original / as-fitted electrics and their sorting out and tidying up.
    Once again, like the strip down, this was pretty straight forward. Unfortunately, the Chinese used a strip, twist, solder and tape method of making joints within the wiring loom. They also had multiple earth / ground connections (using the strip, twist, solder and tape method) which in turn connected at both ends of a common (green) wire to the chassis. None too neat or pleasant to work with and definitely not simple to fault find. The cause of the intermittent spark did become apparent though - just a little too late for this ol' scoot !!
    Electrics_TidyUp3(250x445px).jpg
    All the 'strip, twist, solder and tape' -type joints were removed and each item was individually tidied up. In all cases (there's not a lot of current involved here and it's all 12V) the earth cables were directed back aft to a common earth bolt.
    Electrics-TidyUp1(250x445px).jpg
    Once the cable loom had been opened up it became possible to begin removing cables; the battery cables first, then the ignition and charge system (c/w CDI and regulator)...
    At the end of an hour all that was left was lighting, ignition, side-stand down, fuel gauge, starter, kill switch and low oil cables
    The 'kill' switch was modified (with an additional cable) from connecting the low-tension side of the spark ignition system to earth (thereby killing the spark) to being a pass through switch intended as an interlock for the controller/motor HV relays.
    Kill-Enable switch re-task-1(250x445px).jpg
    The fuel gauge cable was isolated as was the low oil level cable. These will be re-tasked later.
    The idea is (once the scoot is 'up and running') to re-task the :
    [1] low oil (red) warning lamp to be a low Voltage lamp (something like, 72V battery pack below 65V)
    [2] the fuel gauge cable (full scale deflection at 0V / connected to ground/earth) to indicate battery pack voltage and, therefore, a kind of battery level indicator. An AVR Tiny will be used to pulse the gauge at a preset rate depending upon the battery voltage it detects (thereby adjusting gauge needle deflection)... Crude... but I don't like unused controls / gauges and it would be a helpful indicator whilst employing the existing panel gauge. An improvement may be to switch out the programming of the AVR to be a coulomb counter and, therefore, make it MUCH for useful... we'll see... that's a later-date project !

    I have a made a small 12V Li-Ion pack (Panasonic 18650 cells again) (which will be charged by the DCDC convertor) and used to 'power' the ignition switch, via the modified 'kill' switch, and thereby energise the Controller line and two (one HV/72V and one LV/12V) relays / contactors or, in my case SSRs (solid state relays).

    All lights have been switched out for low-power LEDS, including the head light (VASTLY improved over the original headlight). The only challenge here was the standard method of earthing the indicators was 'novel' in that the Chinese manufacturer used the instrument panel indicator 'On' tell-tale as a ground for the active ones. Due to the extremely low power required by LEDs, this simply meant that ALL indicators flash when either direction is selected. The way I chose to work around this was to trace the two, left/right, indicator cables at the panel tell-tale and insert standard 1N4001 diodes into each. This way one indicator direction cannot back-feed the other. Hey-presto - all LEDs including panel lights.

    Finally the new 'loom' was routed through some braided sleeving with cables exiting at their required points along the route.
    Electrics_TidiedUp1(250x445px).jpg
    Now onto the main EV electrics !!!
    Last edited by 3DRoboGuy; 04 June 2019 at 0855.

  7. #16
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    50cc Scooter conversion - Swingarm / transmission cover

    I thought that before I start the main / primary EV electrics I should 'tidy up' a little bit first.
    To be fair, at this precise time, given that I have serious doubts as to the effectiveness (and, therefore, finality) of the scoots gearing, I have decided to carry out the most basic of tunnel / cover modifications. All I did was to mark out the upper and lower limits of the chain drive between the motor sprocket and the, recently refitted, rear gearbox input sprocket
    SwingarmCover_MarkingOut(250x141px).jpg

    and then cut the marked area out with a hacksaw and file. A little sandpaper on the edges to finish and...
    SwingarmCover_CutOut(250x445px).jpg

    Once the marker pen is cleared off with some white-spirit then all will be well for a proper, chain-on test...
    SwingarmCover_ModifiedOpenedUp-Gearing1(250x141px).jpg
    SwingarmCover_ModifiedOfferedUp(250x141px).jpg
    Last edited by 3DRoboGuy; 06 June 2019 at 0447. Reason: picture change

  8. #17
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    50cc Scooter conversion - Crankcase blanks

    These are to protect the internals form dirt, grit and water ingress as far as practically possible. In the case of my scoot, I have various cover / blank plates to design and fit :
    [1] Oil pump blanks (I need to design one with a cable (motor) pass-through slot)
    [2] Starter motor blank
    [3] Crank shaft blanks
    I reverted back to SketchUp again and then the 3D printer and came up with these which I then fitted:
    Blanks(250x268px).jpg

    Once designed and printed I trial fitted. Just the second iteration of the square oil pump blank to take the motor cable...
    Blanks_OilPumpFitted.jpg

    and then the others...
    Blanks_CrankShaftFitted.jpg Blanks_StarterFitted.jpg
    Last edited by 3DRoboGuy; 06 June 2019 at 0504. Reason: spelling

  9. #18
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    50cc Scooter conversion - Batteries (2 x 72V@13AHr : 1Kw)

    With most of the 'boring' stuff out of the way I started off trying to work out where to site the batteries I would be making.
    Once the site was chosen I'd have a better idea as to final available / required dimensions. I had already played about with weights etc and pre-set any pre-requirements I had :
    [1] they must be removable for security, off-scoot charging and protection against extreme temperatures.
    [2] being removable they need to be pretty light - around older laptop weights; 1Kg (plus or minus) would be great. For me 'lighter' not only means more easily carried about but less likely to be thumped around when placing them down etc and more manoeuvrable getting them on-off / in-out of the scoot.
    [3] two (or more) smaller packs would tend to suit the previous requirements whilst benefitting from more spaces on board the scoot (there seems to me to be a lot of 'small' spaces available but few large ones) and also lends them more readily to be re-tasked between projects.
    [4] maintain as-low-as-possible a centre of gravity; a top heavy scoot is horrible to handle both in traffic and whilst re-positioning/parking it by hand
    [5] if at all possible, maintain the helmet area below the seat. Having said that, on this scoot any helmet would have to be a pretty small open face or half helmet if it were to fit at all !

    Anyways, I had already selected 72V : 13-14AHr per pack equating to a 20S4P (1Kw) minimum pack power / size. Each pack was to be thermally protected and be able to be individually and / or group charged.

    From the outset, I had hoped to build two 'long and slim' (20 cells long, 4 cells wide) packs and site them under the riders' feet, within the fairing area. Unfortunately, without massive frame mods, there simply wasn't enough space for this to be feasible.
    Battery_MockUps(250x141px).jpg

    Next I looked at using the space vacated by the recently removed fuel tank (although, in reality, too high - from a centre of gravity point of view.). The main (and pretty much insurmountable) problem here though, was that the seat lock bracket was in the way; the two packs would fit (side-by-side) but they'd not be removable. That coupled with the height 'issue' meant option 2 was, again without major grinding and welding work, a dead end too !!
    Then I looked at designing and building two exhaust-style 'cans' - one for each of the battery packs and either side of the scoot... a wee bit drastic but definitely worth investigating. Maybe at a later date.
    In the end I decided to fit them directly above the motor; in the area below the seat, at the very bottom of the seat 'box'. It would mean removing much of the base of the seat-box - so that they could be taken out (for in-house / external charging) and put back in again - but this was the most feasible of the options I'd looked at...
    Once I had the location sorted it came time to make a bracket/shelf arrangement for the two battery packs to sit in above the motor. Initially, I made a mockup in cardboard then in some left-over 10mm EPA foam that was lying around. Once that seemed to be OK, I re-made the bracket so that the original would fit inside it, removed the original and fibreglassed up a shelf unit complete with side and fixing points to locate it securely on the scoot framework whilst, at the same time ensuring the sufficient room for the motor to be rotated for chain tensioning... A bit for sanding and painting and...
    GRP Battery Tray_Mould(250x141px).jpg

    With the battery mock-ups now fitting snugly in their new 'home' on board the scoot I gingerly cut, re-cut and cut again (and again - little by little) the base of the under-seat helmet / storage box to allow their insertion and removal. That all done, it was time to move on to making the battery packs. After gathering together the parts : NCR18650GA batteries, SplitPort BMS, Thermal CB, Charge Plug/Socket & Anderson connector...

    ... I began, with the help of the Spot Welder I built for these 18650 cells, SketchUp and my 3D Printer to build the battery packs.

    I ended up :
    ...Building the packs - 20S4P configuration...
    I decided to spot-weld (not solder) and fuse the cells (top and bottom / anode and cathode). I also decided to go with a split-port BMS and a thermal, 50A circuit breaker for output protection.
    Battery 20S4P Thermistors(250x141px).jpg

    I designed in 2 x thermistors and placed them 1/3 of the way / 6 cells rows in from each end-cap. The cables were routed to the CB end-cap and left insulated for a future date add-on project. The idea being to enable battery cooling / heating during charging and battery cooling when running and too hot. I haven't gotten round to this just yet but, when I need a break, I am programming and testing the AVR code.)
    ...Printing out, building and connecting up the end caps...
    Battery-20S4P_EndCapConnections(250x141px).jpg

    (I designed the end caps with three ridges - for the heat shrink to grip onto)
    ...and putting them all together before applying 3mm foam protective sheet and heatshrinking the lot...
    Battery-20S4P_OpenedReadyToHeatShrink(250x141px).jpg
    Battery 20S4P CB End Cap(250x444px).jpg

    NCR18650GA cells are 'C' rated at 3340mAHr. 'C' effectively equates to capacity (measured in AmpHours).
    In the packs (designed & built above) there are 4 x NCR18650GA cells in parallel. That produces a total of (just over) 13AHr. They are rated at 3C continuous (10C max) discharge and 0.7C designed charge current which equates to a 9A charge current PER battery pack, therefore, a 10AHr charger would be fine (seeing as a 9Ahr charger isn't readily available and 1 additional AHr shouldn't cause an issue) for these packs.
    Furthermore, whilst each pack has a 'C' rating of (just over) 9AHr, the PAIR of packs onboard the scoot will have a 'C' rating of (just over) 18AHr, so a 20A charger COULD be used IF the battery packs were to be charged as a pair (with a similar caution as per the 10AHr charger for a single pack).
    I purchased (quite a while ago) a 72v 5AHr charger, however, should I wish to install an onboard (on the scoot) charger than to minimise charge time a 20AHr unit would quadruple the available charge current and (a little simplistically) speed up the re-charge time accordingly - if the room is available at the end of the project.
    Either way, I don't foresee an immediate need to have 'high speed' charging and intend (at this point in time) to use the 5AHr charger for both onboard (dual / paired pack)and in-house (single pack) charging. As as 'aside' the 5A charger I purchased was $60 (USD) whereas a 20A version would be around $160 (USD) - not a huge increase for a far quicker re-charge - if required. The real 'downside' is :
    the 5A charger comes in at around 1Kg and has dimensions around 200mm x 110mm x 60mm
    whereas
    the 20A version comes in at around 3+Kg and a ballpark size of 330mm x 175mm x 115mm.
    Finding enough room for the 20A charger onboard the scoot would be much more difficult - in my case ! At some point I'll do a more in-depth study and comparison of 5A, 10A, 15A and 20A chargers... but not today... I'm still on a mission to finish this scoot !
    Last edited by 3DRoboGuy; 06 June 2019 at 0605.

  10. #19
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    50cc Scooter conversion - Controller installation

    This week I've been busy with the last major part of the conversion: siting the controller and associated components.
    The original ICE kit has been removed.
    The original wiring has been serviced / repaired / updated to remove no-longer required cabling and modified to re-task cabling to suit the new electrics and add any new / additional cabling for the imminent electric conversion.
    The 3Kw BLDC electric motor has been fitted on a custom, adjustable, aluminium bracket and the cabling routed aft and up to the intended controller position.
    The belt driven vari-drive has been modified for a chain drive with rear sprocket and the clutch has been left insitu (to start off with but I have my doubts here...).
    All lighting has been switched to LED.
    The battery pack tray has been built and installed.
    The 2 x 72V, 1KW battery backs have been built, charged and tested.
    The fuel filler cap has been replaced with a 3D printed charge point complete with waterproof cap (still need to update here with pics etc).
    Controller+Parts(250x149px).jpg

    The next step was to design and build the controller 'tray' and then mount the controller before adding a 2nd tier shelf arrangement on which to mount the other electrical / electronic components (fuses, relays, DCDC convertor, 12V battery etc) and connecting the systems up prior to testing. Now it's becoming exciting...

    Controller tray
    Now that the batteries were sited directly above the motor, there was enough space (with a little modification) to site the controller (and ancillary parts) in lieu of the petrol tank / aft of the rider's seat. This are is a quite 'unforgiving' space in that the rear wheel is directly below (don't go too deep) and the fairings are immediately above (don't come too high). To boot, access to the rear / brake light is from this area too (don't go too far aft) and the front end is limited by the seat-lock bracket (don't come too fare forward)... BUT... all-in-all this is controller space !! Dry and well cooled...
    Having decided all would be well, I set to designing and fabricating the tray. This was no job for SketchUp or the 3D printer - just cardboard, scissors and tape before moving on to foam and then fabrication with fibreglass...
    Controller tray template(250x141px).jpg
    Controller tray test-foam(250x141px).jpg

    It quickly became apparent that no matter how much I dislike cutting holes where not absolutely necessary and no matter how much I 'squeezed' or moved the controller or how I oriented it (within the constraints that I had) I HAD to cut two holes in the seat support bracket to enable the cables to pass through and, thereby, allow the controller to move far enough forward to facilitate access to the tail lights. In this case though I couldn't see how the holes would weaken the overall structure so... I cut the holes, rust proofed them, glossed over and trial fitted the controller...
    Controller Tray_Fitted+BracketCut(250x141px).jpg
    Controller_BracketNoleCut+Painted(250x141px).jpg

    All looked good so the next step was to mount the controller and the two SSRs with their heatsinks. I guess the 'norm' here is to use HV contactors / relays but Solid State Relays use so little power when 'On' and have the advantage of being so very flexible with their energising voltage that I thought I'd give them a go. They have worked great in other projects (like my Spot Welder) so they deserved a chance here too... especially as, having no moving parts, there can be no contact bounce / accidental disconnect due to the higher vibration of the scooter... Anyways, I gave them a go !
    Two of them, one for the low voltage (12V) / controller energising and one for the high voltage, (72V) motor.

    The recently removed fuel tank had been through-bolted at four points - top and bottom left and right of the recently-fitted controller tray. These were to be re-tasked to locate the "ancillary components shelf" which (because it allows me to see the controller & SSRs below and because (I think) it looks super cool - not that, when all the fairings are back in place, it will be visible !) was to be made form 8mm clear Acrylic sheet...

    After test fitting the controller tray and acrylic 'shelf' it was time to drill 2 additional (corner) holes in the tray for drainage (there's just bound to be some water ingress) and finally fix it to the scoot frame.
    PerspexPanel_Bare(250x445px).jpg

    I ended up with the painted black, GRP tray housing the controller, the 2 x SSRs and their heat sinks. The tray is angled down toward the front of the scoot (towards the bottom of the image); this is where the 2 x 10mm drain holes are situated.

    The SSRs screw to their (black) heat sinks and the heatsinks are through-screwed into the base of the controller tray. The two holes previously drilled in the seat-lock bracket enable the controller HV input (thick red and black) and motor phase cables (thick blue, yellow and green) - both right hand lower corner, together with the control cables (thinner, multi-coloured) - left hand lower corner, to exit the controller tray without chafing etc...

    Now, things began to move really quickly !
    This was the part I'd been really looking forward to !!
    The first job was to finish siting the SSRs and connect the 2 x battery hook-up cables (terminated with Anderson connectors) The DCDC convertor was fitted next, followed by the Li-Ion 12V battery, the shunt (I think I'm going to want to know charge / discharge current and voltage etc) and then fuse holders. I added a pair of (red / black) banana connector sockets to measure the battery / DCDC convertor voltage and to connect an external 12V source / charger in case of 'flat battery'.

    Two SSRs :
    ... both energised by the Li-Ion battery via its fuse, the ignition switch and the kill switch.
    One 10A SSR (left hand side) for the low voltage (12V). This unit feeds 72V to the DCDC convertor.
    One 60A SSR (right hand side) for the high voltage (72V, motor / controller). This unit feeds battery pack 72V to the LV / 10A SSR (which feeds the DCDC convertor) and the controller.
    One DCDC Convertor :
    Connections to the HV SSR output, shunt ground and the 12V fused rail.
    One diode :
    In-line between the fused 12V rail and the Li-Ion battery The purpose of the diode is to enable Li-Ion battery pack charging whilst preventing back-flow from the battery to any on-board items - except the DCDC convertor (for charging)
    Three fuses :
    DCDC convertor (all onboard 12V)
    Ignition / controller enable (basically, kill switch OFF and Ignition switch ON puts 12V onto the 'power lock' / controller enable.
    Onboard lighting / horn electrics
    One shunt :
    One side of the shunt was connected to both battery -ves, whilst the other side was connected to motor controller -ve, DCDC convertor -ve and chassis ground.
    Final steps : the motor cables (green, blue & yellow) were connected via a 50A terminal block to the controller. The controller / motor hall sensor connections were made (plug'n'play)...
    PerspexPanel_PopulatedConnectionsAlmostThere(250x445px).jpg

    ... and then onto the throttle, brake, reverse and power lock cables... but those are for tomorrow... (mostly because it's late and I note that the throttle cable is terminated with a different plug-type to the controller socket !

    To be frank, I also have :
    the High / Low speed connector to make (naturally I only need the HIGH !) but (if only for testing) i'd better make a PAIR of connectors - one for Hi and another for Lo speed - or I could add a Hi/Lo switch...

    the 'fuel filler' / charge port to connect. I have designed it (SketchUp) printed it (3D Printer), fitted the matching 72V charge connector into it and test fitted it on the scoot but I need to add the diode protection, connect up and fit it...

    dry test the lot...

    reassemble the scoot and let my son test it for me... receive his 'review' / critique and...

    and... probably, a load of other small jobs I haven't remembered to write down here...

  11. #20
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    50cc Scooter conversion - Fuel filler / Charge port

    This was some fun ! I took some measurements and started designing (SketchUp, again) a replacement fuel filler neck & cap some weeks ago.

    First I thought I'd use the same Anderson connector as was on the batteries I intended to build (and have since completed). I can't, right now, remember why but I changed my mind and used the XLR 4-pin socket to match the plug that arrived with the charger... the same sockets in fact as I fitted to the two batteries for charging - keeps the parts list simple
    ChargeSocket_V1InHousing(250x344px).jpg
    ChargeSocket_V1OnBracket(250x199px).jpg

    During first fit though, I decided to change the design (again) to a 3pin IEC mains 110/220V AC socket - as per the mains cable between the wall outlet and the charger input. This was mostly because, having a drink at the bar, discussing charging one night, we all agreed that the charger would always be required to charge the scoot (obviously). My idea was that the charger should be carried in a back-pack / ruck-sack or, if space wasn't too important, under the seat ! It was pointed out to me that the charger would then need to be connected to both an available wall outlet and the charge socket, behind the seat. Seemed pretty obvious to me... what wasn't so obvious was that everyone agreed it would be simpler just to connect the bike to the wall socket - no charger to play about with or fall off the seat (or wherever else it had been balanced) and break. Seems reasonable ! In addition the space under the seat (on this scoot) is pretty poor anyways (I think I've already mentioned that somewhere along the line...) so... why not use it for the charger ? ? ? As a bonus, the charger is always dry under the seat - it wouldn't necessarily be so, balanced on the seat / next to the scoot during charing...So... why not indeed ? !
    And, as it transpires, there's still some space left over for documents, tools and gloves etc...

    The 'downside' to this approach is that the scoot will have a fixed / permanent mains AC item wired in at all times and although it won't (obviously) be live at all times, I'm unsure as to any safety regulations with this approach. Having said that, the IEC connector could always be swapped out for the XLR connector in around 10 minutes... so... What's not to like with this approach ?

    The final connector, fitted on the scoot with the fairings back in place, looks like this :
    ChargeSocket_IEC(250x188px).jpg

    The design incorporates an 'O' ring on the lid / cap and a large overhang to reduce the chances of water ingress. It has two large drain slots built in (semi-circular, forward and aft of the raised, central, IEC socket, to prevent water build-up if any gets in.
    ChargeSocket_IECWithLid-Off(250x188px).jpg

    The mains cables (L, N & Earth) are soldered and heatshrunk before being liquid silicone sealed. The cable terminates in the under-seat area with the original IEC plug for the charger. The charger output (XLR connector) connects to the, now redundant, original XLR socket thereby keeping it all fully removable for service etc...

    A little smear of silicon grease on the 'O' ring and the lid / cap is a simple friction twist fit !
    ChargeSocket_CapOn(250x188px).jpg
    Last edited by 3DRoboGuy; 10 June 2019 at 0403.

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