Breakfast Blend: LY DropCarve38 | BN M1 Gear Drives | FS 6374s | Xenith | 10s4p P42A

I started with this smooth acoustic ride:

Project Requirements (SOR)
ITEM DETAILS
Range: 24-32 km (15-20 mi)
System Weight: 9 kg (20 lb) target
Max Load: 100 kg (220 lbs)
Top Speed: 32 km/h (20 mph)
Acceleration: Great ?
Braking: Regen braking
Drive: Dual motor, RWD
Control: Hand-held controller w/ battery level display
Ground Clearance: 6" wheels min
Terrain: Streets, railroad tracks, potholes, grass
Slides: Yes
Deck Flex: Medium flex (bamboo, maple, fiberglass )
Ride Quality: Able to handle terrible urban roads
Ruggedness: Designed for IP54. Rock guards over sensitive / moving parts.
Build Quality: Fully functional for 2+ years, assuming regular maintenance & no major accident
Safety: On/Off switch, protected. Headlight LEDs. Brake light LEDs. Able to pass for non-electric longboard, at a distance. Can be pushed
Ergonomics: Hand-held pocket sized controller. Board carrying strap/handle
Aesthetics Custom grip tape or skin
Budget ($) 1200-1500
Parts List (BOM)

This build is not intended to push boundaries. This build was designed to utilize community-trusted parts and vendors to build a capable, reliable, and fun electric longboard. The entire project was started with a few goals in mind - not only to create a fun, custom esk8, but also to enjoy the build process, and improve my electrical knowledge in the process.

PART BRAND MODEL DETAILS PRICE SHIPPING+TAX LINK ORDER DATE STATUS
DECK Landyatchz Drop Carve 38 Fox deck only, 37.9" L, 9.7" W, 28" WB, 7 ply maple $119.99 $0.00 https://landyachtz.com/product/drop-carve-38-fox/ 1/2/2021 Arrived
DECK BRACES Dickyho Deck Protectors Heavy Duty Stainless Steel Skateboard Deck Protectors washers Set of 2 $4.00 $4.00 Creative Heavy Duty Stainless Steel Skateboard Deck Protectors washers Set of 2 | eBay 1/23/2021 Arrived
TRUCKS Boardnamics BN220 Precision Trucks Hangers, 50/40 baseplates, Riptide Sports 93a KranK barrel bushings and 96A pivot cups. $129.99 $0.00 https://boardnamics.com/product/bn220-precision-trucks/ 1/12/2021 Arrived
TRUCK HARDWARE Loaded Drop Through Strips shock absorbers, w/ washers $3.95 $0.00 https://www.muirskate.com/longboard/risers/3499/0-13-khiro-drop-through-strips-shock-absorbing-risers 1/18/2021 Arrived
TRUCK HARDWARE Bolt Depot Axle Nuts qty 4 5/16"-24 steel nylock nuts $6.40 $5.89 https://www.boltdepot.com 1/18/2021 Arrived
TRUCK HARDWARE Loaded Button Head Flanged Hardware qty 8x flanged button head hex 10-32 x 1.25" screws, qty 8x 10-32 locknuts $6.95 $0.00 https://www.muirskate.com/longboard/products/71945/loaded-flanged-head-hardware 1/22/2021 Arrived
TRUCK HARDWARE Dime Bag Hardware Speed Kit bearing spacers and speed rings $4.50 $0.37 https://www.amazon.com/gp/product/B004QGAJ4G/ref=crt_ewc_title_srh_1?ie=UTF8&psc=1&smid=A3CDEUCT9UACPY 1/18/2021 Arrived
TRUCK HARDWARE Riptide Sports Small washers 3/8" x 7/8" stainless flat washers $1.50 $3.35 Small Flat Washers | RipTide Sports 1/30/2021 Arrived
DRIVE Boardnamics Dual M1 Drive kegel wheel adapter. 64T wheel / 23T motor (straight gears) $160.00 $0.00 Dual M1 Drive | 1/31/2021 Arrived
WHEELS Torqueboards 72a 110mm wheels set of 4, kegel core $90.00 $15.00 110MM TORQUE Wheels (TB110) – DIY Electric Skateboard 1/13/2021 Arrived
WHEEL BEARINGS Bones Reds Bearings 8mm ID, 22mm OD, 7mm W
(8 pack W/Spacers and Washers) $17.95 $1.48 https://www.amazon.com/gp/product/B0798WGCB1/ref=ox_sc_act_title_1?smid=A16ZC15ZGEH7W1&psc=1 2/9/2021 Arrived
MOTORS Flipsky 6374 Brushless DC Outrunner Motors, 190kV Battle hardened, balanced, sensored, qty 2, 3500W, 85A max, 8Nm msx torque, 14 pole, 12AWG phase wires, JST-PH connector for hall sensor wires, M4 mounting screws, 8mm shaft, with keyway & key $162.00 $34.50 Flipsky BLDC Belt Motor Battle Hardened 6374 140KV 190KV 3500W for Ele – FLIPSKY 1/17/2021 Arrived
ESC BKB Xenith VESC dual motor 2x MT60 Motor Connectors, 1x XT60-M 12AWG battery connector, single MCU architecture, 80A continuous motor current $195.00 $0.00 BKB Xenith - VESC Based Motor Controller (High Power) – Build Kit Boards 1/9/2021 Arrived
REMOTE Flipsky VX2 Pro UART $63.75 $13.50 Screen Remote VX2 Pro for Electric skateboard | Flipsky VESC Remote with telemetry data – FLIPSKY 1/3/2021 Arrived
BATTERY esk8life / thisguyhere 10s4p P42A w/ SMART BMS, XT90S female connector to VESC, 5.5x2.1 barrel plug for charging, Pack: 410x150x29 (16.9 x 5.9 x 1.14), BMS: 108x65x10, Inline fuse holder, glass 5x20mm fuses $388.00 $47.00 https://esk8life.com/batt/index.html 1/9/2021 Arrived
BATTERY+VESC MOUNTING 3M 3M Dual lock heavy-duty 250/250 3M Dual Lock Reclosable Fastener SJ3560 250 Clear, 1 in x 6 Ft $14.50 $1.20 https://www.amazon.com/3M-Reclosable-Fastener-SJ3560-Clear/dp/B00JHKTDMA/ref=sr_1_4?dchild=1&keywords=3m+dual+lock+250&qid=1611816860&sr=8-4 1/29/2021 Arrived
BATTERY CUSHION Aliexpress 2mm x 20mm EVA sponge foam, adhesive back to fill gaps and cushion everything inside enclosure $1.65 $3.14 Strong adhesion EVA black sponge foam rubber tape anti collision seal strip 1, 2, 3mm thick|Tape| - AliExpress 1/28/2021 Arrived
CHARGER YZPOWER DC 10S 42V 4A 36V Lithium Ion Battery Charger US Plug, 5.5x2.1 barrel connector (4.2 hrs charging est) $23.32 $0.00 YZPOWER 42V 4A Lithium Li ion Battery Charger For 36V 4AH 5AH 8AH 10AH 20AH Lipo Bike Power Tool Scooter Battery Pack|battery charger|li-ion battery chargercharger for - AliExpress 1/11/2021 Arrived
ENCLOSURE eBoosted / eboards Evolve Bamboo GT 630 x 230 x 33 $125.00 $45.00 https://www.eboardsperu.com/product/evolve-bamboo-gt-enclosure/ 1/19/2021 Arrived
ENCLOSURE HARDWARE SS M4/M5 inserts, GLUE them in M4 button heads screws + steel finish washers + rubber washers + blue loctite 242, 8mm long insert? (measure deck thickness) $5.21 $0.00 20Pcs M4 Threaded Inserts Stainless Steel SUS303 Helical Insert Self Tapping Slotted Screw Thread Repair Insert|Threaded Insert| - AliExpress, 10pcs /bag, Colors Aluminum M4 Flat head Screw Washer Countersunk Head Washers Fender Washer|Washers| - AliExpress Arrived
ENCLOSURE GASKET Dicor Butyl tape Dicor BT-1834-1 1/8" x 3/4" x 30’ Butyl Seal Tape $13.56 $0.00 https://www.amazon.com/XFasten-8-Inch-30-Foot-Sealing-Patching/dp/B06WLQ3WLS/ref=sr_1_5?dchild=1&keywords=butyl+tape+black&qid=1611819741&sr=8-5#customerReviews 1/29/2021 Arrived
ELECTRONICS SEAL GE Neutral core silicone II+ sealant GE Silicone 2+ / Advanced $3.77 $0.00 https://smile.amazon.com/Clear-Electronic-Grade-Silicone-Squeeze/dp/B0063U2RT8/ref=sr_1_2?dchild=1&keywords=neutral+cure+silicone&qid=1611125630&sr=8-2 2/12/2021 Arrived
HEAT SHRINK n/a 220mm flat width, 0.15mm thick, PVC, Blue DIY Battery Pack PVC Heat Shrink Wrap Tube Length 3M Width 220±5MM for Big Battery Pack Power $15.36 $0.00 Amazon.com 2/12/2021 Arrived
HEAT SHRINK n/a 50mm dia Polyolefin, Clear Heat Shrink Tubing, 2:1 Dia 2" Sleeving Wrap Cable Wire Electric Insulation Heat Shrinkable Tube Transparent 16Ft (Dia 50mm) $13.99 $0.00 Amazon.com 2/14/2021 Arrived
CONNECTORS Amass XT90S Parts List:, - XT90 Male - replace connector on VESC, - XT90 Male w/ 10/12 AWG pigtail - 3-way Loop #1 - connection to battery, - XT90S Female w/ 10/12 AWG pigtail - 3-way Loop #2 - connection to VESC, - XT90 Male connector - 3-way Loop #3 - bulkhead mount to enclosure for Loop Key, - dust/water cover - XT90 Male, rubber/TPU, attached $12.96 $0.00 https://www.amazon.com/gp/product/B074PTHZ3M/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1 1/11/2021 Arrived
CONNECTORS Amass XT30U 10 pair $8.99 $0.00 2/14/2021 Arrived
CONNECTORS Amass MR60 10 pair $15.99 $1.32 Amazon.com 02/10/2021 Arrived
TAPE n/a Kapton Tape 1 roll, 13mm x 33m $5.99 $0.00 Amazon.com 02/10/2021 Arrived
WIRING SLEEVE n/a 1/4 braided split sleeve $0.00 $0.00 - - Had on hand
ANTISPARK DIY XT90S Loop Key bulkhead mount XT90 male, 3d printed handle w/ xt90s female, 3-way 12awg wire routing, Parts List:, - XT90S Female connector, - 10/12 AWG wire, - 3D printed handle, - 3D printed bulkhead/panel mount plate, - Potting compound / epoxy / JB weld, - Velcro to stick to controller when not in use,
Mount to enclosure, to board, to trucks, or elsewhere $0.00 $0.00 How to make a XT90 Loop key Made
CHARGE PORT FUSE n/a Mini Blade Fuse Holder, In-Line 16AWG, 10A fuse $7.99 $0.00 Amazon.com 2/12/2021 Arrived
DRIVE GREASE Lucas Oil 10005 Red’n’Tacky Grease 14 oz tube $4.99 $0.41 Amazon.com - Arrived
DRIVE LOCTITE Loctite 648 Green Retaining Compound Low viscosity, high strength, high temp, press/close fit cylindrical parts $19.00 $1.57 Amazon.com 2/8/2021 Arrived
AXLE LOCTITE Loctite 290 Green Wicking Threadlocker $15.92 $0.00 Amazon.com Arrived
FASTENER LOCTITE Loctite 243 Blue Medium Strength Threadlocker $5.99 $0.00 Amazon.com Arrived
LIGHT CONTROLLER Arduino Nano From VESC → microcontroller → battery level, remote control commands (brake, accelerate), Microcontroller: ESP32, ESP8266, arduino nano, Teensy, etc, Need ambient light sensor (headlights vs drl), Need IMU for turning (brighter on turn side) Let there be ESK8 lights - #274 by skelstar
LIGHTS - REAR LED strips APA102 strip w/ SMD5050 IP67 waterproof strip ($11.37), 2x short strips wrapping around each gear drive case - (only need red?) - brake lights APA102 Smart LED Strip Pixels Light waterproof 5m 1m 30/60/144 LEDs/m Pixel DATA and CLOCK Seperately DC5V Strip Lights|seperate eggs|seperator filterseperation pad - AliExpress
LIGHTS - FRONT Flashlight / headlamp Flashlight, remotely powered, multiple brightness settings?
LIGHTS POWER Buck converter DC-DC step down buck converter ($2) DC DC Buck Converter KIT Adjustable Power Supply DC DC Step Down Adapter 3A LM2596HVS LM2596HV Step Down Power 4.5 55V To 3 40V|dc buck converter|buck converterdc dc - AliExpress
SKATE TOOL Zeato All-in-One Skate Tools Multi-Function Portable Skateboard Y Tool Accessory with Y-Type Allen Key and L-Type Phillips Head Wrench Screwdriver - Green $10.98 $0.00 Amazon.com
OPTIONAL:
WHEEL LIGHTS motion activated, wireless
GEARS #2 Boardnamics Helical gear set (pinion & drive) 60/22 (helical) - $60 TBD April
POCKET FUEL GAUGE DIY 42v LED display, waterproof voltage / remaining battery display, in 3D printed case, power pass thru, Pocketable Fuel Gauges: pictures and howto [serious] - #4 by b2640https://www.thingiverse.com/thing:4231643 $19.89 $1.64 https://smile.amazon.com/gp/product/B07KS1G585/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1https://smile.amazon.com/gp/product/B08SJM2G52/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 2/15/2020 Arrived
SAFETY - FIRE BLANKET Tonkyo Fiberglass Fire Blanket 47.2 x 70.9 in $19.99 $0.00 Amazon.com 2/10/2020 Arrived
SAFETY - LIION FIRE EXTINGUISHER
SAFETY - HELMET Dainese Use existing helmet $0.00 $0.00 - - Have
BRAKE LIGHT Nkomax Smart Bike Tail Light Ultra Bright, Bike Light Rechargeable Auto On/Off, IPX6 Waterproof LED Bicycle Lights, High Intensity Rear Accessories Fits Any Road Bikes ($24), Power via main pack w/ DC-DC buck converter https://www.amazon.com/dp/B07DF8RTM4/ref=cm_sw_r_cp_api_gE8pBbPBV2KW8
BAG + DECK Bustin Mystery Box ($169) https://bustinboards.com/collections/skateboard-and-longboard-mystery-boxes/products/one-bag-box
SUBTOTAL $1,719.02 $179.37
TOTAL $1,898.39
Parts Arrive

Begin The Build

All the photos.


image


Finished up the electrical wiring & soldering:

  • Battery pack gets XT90S’s
  • Xenith has XT60s
  • Charge port gets XT30s
  • Wired the loopkey loop
  • Replaced the battery’s glass fuse with a mini blade fuse holder & installed 10A fuse
  • VX2 bluetooth pcb got conformal coated
  • VX2 and BMS bluetooth pcbs got heat-shrinked and silicone sealed (GE 2 Advanced 100% neutral cure).
  • I had to resolder some of the BMS wires to lay along the long edge. Soldered a length of 12AWG to the BMS discharge port for future lights / arduino power (covered in cheap yellow heat shrink)
  • Heat-shrunk the entire BMS






Xiaoxiang android app for the SmartBMS. I adjusted the parameters before the first charge - all to be more conservative. But if anyone wants to review these, I would greatly appreciate a second or third pair of eyes.

Next Steps


Time to build the @mmaner pocket fuel/voltmeter gauge. I’ll design and 3D print a case. I think I can build a slightly more compact version, and then waterproof it.

The big unknown is how to go about shortening the enclosure. The FrostKing 3/4 in. x 7/16 in. neoprene foam tape for the enclosure gasket just arrived. Will check to see if that’ll be enough to mount everything. Right now the wires on top of the battery pack rub first.

I’ve been thinking about dremeling off a ~3" length (will measure) out of the left-center area of the enclosure, so the battery is fully protected by a single piece. Then weld/join the two remaining pieces together with more epoxy + fiberglass mat.

18 Likes

Problems and Solutions…

- PROBLEM - Ground clearance, drive-deck interference, motor-baseplate clearance

Parts: BN Fixed Baseplate (40 deg) + BN M1 Gear Drives + 63XX Motors + Flat deck

The core problem with this combination is the mounting positions available for the gear drives in relation to the truck hanger. There are 15 mounting holes, at 360/15= 24 deg increments, but effectively you only have 2 (forward) mounting positions - drive close to deck (up), or drive close to ground (down), 24 degrees apart. As seen here:

With a flat deck and a short neck, the drive up position causes rubbing between the case and the deck when you start to turn (see black sharpie marks in later photos). It also causes issues with wire routing - if the enclosure is too close to the truck assembly, the phase wires hit the enclosure when you turn.

The drive down position does not give enough ground clearance between motor can and the ground, even with 110mm wheels - around 20.4mm measured.

On wire routing - There are 4 orientations for mounting the motors (up, down, backward, forward) in the BN Gear Drives, with no halfway rotation possible. With essentially no gap between hanger and motor (result of the very tight c-c distance in gear drives), orienting the motor phase wires backward/rearward is not possible. A ground-ward wire orientation would invite damage. That leaves upward towards the deck, or forward. On this board geometry, upward hits the deck in a turn, so forward is the only option. (One more thing to look for in choosing a deck I never expected).

- SOLUTION -

Attempt 1:

  • Use ‘drive up’ position (solves ground clearance)
  • Add riser pads as needed (solves deck & wire interference)
  • Grind down baseplate (solves motor clearance).

Turns out “enough riser” is ~16mm. I printed 6mm rise pads in PLA for testing. I got to 3x pads before I had enough deck clearance. That was too tall for my taste and suboptimal, as it didn’t actually solve the core mounting problem, just acted as a band-aid workaround.

Grinding the baseplate is easy enough, but doesn’t inspire confidence. I also took off more than necessary.

All in all, not a great solution.

Attempt 2:

  • New baseplate w/ smaller angle (solves all 3 issues)

Randal downhill 35 angle baseplate:

This potentially would’ve worked fine, with new Riptide pivot cups to tighten things up. However, I didn’t want to throw out the BN precision baseplate just yet, and I didn’t want to be forced into a 35 degree baseplate angle.

Attempt 3:

  • Drill new mounting holes! (fix the core problem)

Per @b264 on ground clearance:

My experience is 8mm is “extremely ridiculously terrible” and 20mm is “not enough” and 30mm is barely enough to be comfortable but does work.

May as well optimize. Via the CAD model:
‘drive down’ position - 20.4mm clearance
12 deg rotation - 29.8mm clearance (+9.4)
15 deg towards deck - 32.1mm clearance (+11.7)
17 deg towards deck - 33.7mm clearance (+13.3)
19 deg towards deck - 35.2mm clearance (+14.8)

Designed and printed a drill guide for that 30mm clearance. Added 4 new holes to the existing 3 holes, at half increments (12 deg).



Upgraded to zinc plated steel screws and reassembled.


Right on the money.

3D files for anyone else to use:
BN Fixed Baseplate Riser - 6mm.step (25.2 KB)
Boardnamics M1 Drive_Drill Guide - 12 deg.step (71.5 KB)
Boardnamics M1 Drive - Rough Model - v4.step (3.1 MB)

10 Likes

Problems and Solutions…

- PROBLEM - Enclosure is too long.

 Parts: eboosted Evolve Bamboo GT enclosure + LY Drop Carve 38 deck

I knew it was going to be tight when I ordered the enclosure, but I was at least happy that the width worked out perfectly per the calcs.

To choose an enclosure from the limited availability of high quality fiberglass enclosures on the market, I overlaid a stock photo of the deck, calibrated from actual measurements, with a picture of the Evolve.

- SOLUTION -
With the electronics mostly assembled:

  • 10s4p Molicel P42A battery from @thisguyhere w/ 10s smart BMS (charge only)
  • Xenith VESC
  • VX2 bluetooth dongle
  • lots of wiring, loopkey loop, etc

There was still room to spare / cut off in the enclosure.

I plan to mount everything to the underside of the deck, so if the enclosure takes a hit, it won’t immediately transfer to the electronics. I’d rather the enclosure only act as a weather seal and physical barrier, rather than a support structure on top of that.

Laid out the component spacing on the deck and calculated how much I need to chop:

A table saw makes quick work of fiberglass. It took longer to setup adequate airflow and put on PPE than it did to make two cuts.


Test fit:

Now for the fun part - playing with epoxy. After some advice in the Fiberglass Repair thread, I got to work. I decided to have some fun, learn some new skills, and do all the things:

  • Prep: scarf cut / beveled edge on each piece
  • Reinforcement 1 - light epoxy coat
  • Reinforcement 2 - heavy, thickened epoxy coat
  • Reinforcement 3 - fiberglass cloth layers
  • Finish - paint

Materials:

  • System Three Silvertip Epoxy with Slow Hardener, 1.5 qts, $55 - Amazon - Manufacturer
  • System Three 3200A04 White Paste Pigment Coating, 2 oz, $16 - Amazon
  • System Three 3105S16 White Silica Thickener, 1 Quart, $9 - Amazon
  • Bondo 6oz Fiberglass Cloth, $4 - Amazon
  • Plastic mixing cup, 1 qt, $1.50 - HomeDepot (epoxy won’t stick to this, and can be peeled out once dry and reused)
  • Mixing Sticks, $1 - HomeDepot
  • Digital scale
  • Sand paper (80, 120, 220 grit)
  • Disposable gloves
  • Packing tape
  • Duct tape
  • Paint
  • Isopropyl alcohol and simple green for cleaning

Prep:
This did not go well. I attempted to hand sand opposing edges in order to overlap the two pieces. Flat sections were fine, but the curves were impossible to do without some sort of jig. Oh well, live and learn.

Epoxy:
I already had a large bottle of the System Three Silvertip epoxy w/ slow hardener, purchased to eventually skin and frit the top of the deck. This was perfect for the enclosure as well. Easy to mix (by weight, 100:43) and use, even in small quantities, dries clear.

Epoxy doesn’t adhere to packing tape, so it works well for created a boundary. Although packing doesn’t stick well to the rough surface of the enclosure.



After the first application to stick the two sides together, I realized I had large gaps at the curves.

Enter silica thickener:

This stuff is amazing. With carefully additions of silica powder, I was able to turn the liquid epoxy into a peanut butter consistency and smear it into all the gaps and crevices of the enclosure.


(Duct tape + packing tape combo solves the previous oozing problem)

If you overdo it it turns to clumpy oatmeal…

After ~12 hours it’s cured enough to remove the tape and sand.

Fiberglass:
What repairs fiberglass better than more fiberglass?

2 layers of cloth:

10 Likes

Paint:
The theme is red, black, and white. Classic. So we can have some fun with a blood red interior no one is going to see. (~6 light coats)

Followed by a nice textured black for the exterior. (~6 more light coats)

Oof that’s a beauty

Maybe a white stripe to turn that scar into a highlight.

now back to:
Problems and Solutions…

- PROBLEM - The underdeck graphic started pulling off when I was repositioning the rubber gasket

Parts: LY Drop Carve 38 + solid neoprene rubber gasket + Barge contact cement


That didn’t inspire much confidence in it’s staying power over time and barrier to water ingress.

- SOLUTION - Refinish the bottom of the deck.

An orbital sander makes quick work of the thin graphic. (hand sanding is the worst)

Pulled the grip tape off the top with a heat gun while I was at it, to prepare for eventual skin+frit.

Thaaat’s not black. Well fuck. Thought I could get away with Varthane “Espresso” stain+poly.


This is also way way too much stain. I don’t know how to stain.


3/18/21 Update:

Resanded the bottom of the deck and stained with ‘Ebony’ Varathane Premium:

May have taken off half a ply in the process, but the finish is much nicer. 1 coat of (indoor) stain + 4 coats of spar urethane for all weather protection. Drying now.

Enclosure update - the stripe is a bit thick, but hopefully it’ll look good when all assembled. A clear / tint might have worked better, but it can always be repainted if I don’t love the final look.

3/20/21 Update:

The black stained maple grain turned out really nice. It’s tough to capture on camera, but I’m really digging it.

Time to epoxy the drop-through holes. Why? Because it’s fun to play with epoxy. And it’s the ultimate truck-deck reinforcement. Sand all faces and seal with packing tape on the bottom and edges:

Mix ~20g epoxy resin + ~1 drop white liquid pigment + (20x43%) ~9g slow hardener (in that order). Cut fiberglass cloth into strips. Stuff into hole and slop in resin mixture with popsicle stick. We do this in two stages because the epoxy resin cure reaction is exothermic and pouring more than 1/8"-1/4" at a time can cause problems. I managed to fit maybe 6 layers of fb in this first stage.

The next day - as hard as a rock.

Underside

Second layer, with thickener to conform to the slight curve of the deck

Sanded:

Mock reassembly

21 Likes

Excellent work dude. And amazing job with the documentation. This is a build to watch, for sure!

11 Likes

Wow, great work on the enclosure surgery!

8 Likes

4real

3 Likes

I really appreciate your thorough write-ups! Definitely following this build. With your drilling guide file, even an idiot like me stands a chance at getting it right if I have too! Thanks for that. It would be cool if Kevin offered an update to these drives with the extra adjustability already in place.


@Boardnamics - Do you think adding these extra holes compromises the strength of your design or is this just better adjustability with less weight and no drawbacks?

3 Likes

Fantastic Build I wondered about BN drives not being that flexible. epic build.

1 Like

Wow! I’m stealing the format of this post! Fantastic build, something you’d find in a DIY esk8 textbook.

1 Like

I know he’s thought more about the tradeoffs between adjustability, part count, holes, etc than I have. There’s no free lunch. The downsides to my approach is 1) unequal spacing on the new mounting holes, and 2) open holes into the drive case.

You’ll notice there aren’t more mounting holes on the blank side close to the pinion gear. That’s because they’re blocked by the motor. This is the reason I went up from the original 3 (evenly spaced) mounting holes to my 4 biased holes. Because of the forces involved, I believe there won’t be any appreciable drawbacks, but if I was designing these for volume manufacturing I’d probably think deeper.

On downside 2), I’ll have to come up with a way to block the holes. It’s not a big deal, and easily solved (and the drives gears aren’t waterproof anyway), but still a downside nonetheless.

Thanks Brian. I have to say, I think I’m leaning hard into the epoxy-all-the-things camp. It was much easier than I expected, and enjoyable to see (and feel) the end result. Also, not terrible to sand and fix when not perfect. It’s really versatile stuff.

5 Likes

I personally would epoxy grub screws into those, if they’re tapped

It took me a while to enter the camp, but now I understand why all the highest-tech items like spacecraft and aircraft and racecars and top-tier-bicycles are all made heavily out of composites. You really can make amazing things happen with them.

2 Likes

They’re thru holes, and the wall is thin. I’ll come up with something 3D printed most likely. It would be nice to not lose the original mounting holes.

Edit:

You really can make amazing things happen with them.

Oh, also, tomorrow I’m going to fill the drop-through cutouts with white pigmented epoxy. Very excited. I see no downside. Could throw some fiberglass in there. I have tons.

2 Likes

- PROBLEM - Wire routing from motors to enclosure

Parts: Flipsky 6374 sensored x2, loopkey, 5.5x2.1 charging port, LED strips x2

More specifically, routing wires from inside to outside the enclosure AND maintaining some level of water resistance (and full functionality) takes carefully planning.

System design drivers:

  • Maximum water/weather resistance
  • Some level of maintainability (i.e. no permanent mounting)
  • Smart choices for charge port, loop key, LED positioning for ergonomics & usability
  • Reduce unnecessary wire length inside the enclosure to converse space
  • System longevity

- SOLUTION -

Custom tunnel risers to allow cleaner routing

I started by designing and printing an XT90 mount in PLA that attached via the existing truck screw.

After some tweaks, I incorporated it into a riser pad. The 6mm thick pad included a diagonal wire channel for a deck-top mounted charge port. (mid print here)

Final version, in 100% infill black PETG, cleaned up the design by sticking with a more simple central tunnel. This tunnel goes the full length, allowing the charge port wiring to route through the large central hole, as well as LED wiring from the end of the truck. I also closed off the slit in the XT90 mount - it now requires the connector to be soldered around the mount, but it makes for a more robust and visually pleasing design.


Mock mounting shows the locations, and the tunnel.


The generous 10mm dia tunnel should allow two sets of small gauge wire.

Files attached for anyone’s use:
Baseplate Tunnel Riser - 6mm v2.stl (420.2 KB)
Baseplate Tunnel Riser - 6mm v2.step (75.8 KB)
Baseplate Tunnel Riser with XT90 Mount - v2.step (503.2 KB)
Baseplate Tunnel Riser with XT90 Mount - v2.stl (1.2 MB)
Loopkey Holder - v2.step (364.9 KB)
Loopkey Holder - v2.stl (1.3 MB)


5/19/2021 Update

I ended up scrapping the rear truck baseplate mounted loopkey design, because I needed the room for wire routing.

Taking advantage of @ducktaperules cable riser from his Double Trouble build (that he so nicely provided the files for):
image

I repurposed it will some modifications. It allows for routing:

  • qty 2 x MR60 connectors, with 6 phase wires
  • qty 2 x JST connectorsm, with sensor wires
    -and now, additionally-
  • center charge port wiring
  • 22awg-4 conductor LED wiring pass through
  • loop on either side for a 180deg route for all motor wires
  • MR60 “lids”

I also modified the front tunnel riser (aka Power Riser) a bit for fun:


Also with a 22-4 cable pass through.

With so many lofts, radii, extrusions, planes, etc the MR60JST riser was not my finest CAD work. Eventually I had to stop fine tuning and just print it. It required a small amount of dremeling afterward, but otherwise it worked.

Filled all connections with neutral cure silicone sealant to be safe. It’s a very tight fit in there. Once the trucks are mounted on top of the riser, nothing’s going nowhere. Silicone wires allow for pretty tight bend radius.

7 Likes

- PROBLEM - Enclosure needs waterproofing.

Parts: Fiberglass enclosure, solid neoprene rubber gasket, silicone sealant, foam tape

I’m designing towards an IP54 rating. Of course, I hope to not have to test this, but it’s inevitable.

- SOLUTION - Stack solid rubber, firm foam tape, and butyl tape to allow adequate height for the battery pack and conform to the curvature of the deck. Add silicone sealant to seal around holes. Make sure enclosure mounting holes are SURROUNDED by waterproofing barrier. Route wires through the waterproof barrier, seal around wires.

Enclosure layering stack-up (from the ground up):

  1. Fiberglass enclosure
  2. 3/4" wide x 5/16" thick - closed cell foam neoprene tape, to soak up height differences
  3. Butyl tape (used wayyy too much) to seal
  4. Solid rubber neoprene riser, 1/4" thick

I started with a solid sheet of rubber in order to have an uncut, continuous ring gasket (and it was the same price as strips).

Cut the outside with an exacto blade

Marked out the component spacing and cut the inside

Test fit - looks good, too bad I need more height for the 21700 cells against the curved deck

Tried 1/2" thick neoprene foam tape. Too thick.

Laid down one full layer of butyl tape around the entire length of the base gasket. This is too much butyl tape.


Butyl tape is impervious to pain, to curses, to your futile cries of anguish. Also, you cannot drill through butyl tape - it gets everywhere.

After ordering probably 4 different rolls of neoprene foam tape, I finally settled on 5/16" thick as the perfect height needed.


How to get wires through the wall of the enclosure?

There’s a few ways to do this. Traditional options include:

  • Drill holes in the enclosure, mount connectors, and epoxy/screw in place
  • Drill holes in the enclosure, mount cable pass-through
  • Cut a large hole on one edge of the enclosure, feed wires under, forget about waterproofing
  • Route a wire channel into the deck itself. Seal wires to deck.

I went a different route for a few reasons. Mainly, I didn’t have enough room for large, bulky, waterproof connectors between the enclosure and the motors/trucks. At 7 plies of canadian maple, I also didn’t trust the deck to begin removing material to route some channels. Lastly, waterproofing is a must. Dead electronics kill the fun.

I decided the create a single piece, multi-cable pass through, and seal it to the deck, and around it on all sides. The cables themselves have the smallest cross-section, vs large connectors, and require the smallest holes. One potential weakness to this approach is that it’s possible to get water traveling inside the wire jacketing via capillary action, if the ends are exposed to the elements.

Initial attempt to drill nice holes directly in the solid rubber gasket with a 3D printed drill guide. Spoiler: you can’t drill rubber with a normal bit. This did not work.

Redesigned, single piece, cable pass-through. Cut a space in the rubber gasket for this to fit.

Test fit. It’s wider than the gasket on purpose, and just slightly shorter in height.


Permanent installation:

I sealed the outside with black silicone sealant, to blend in with the deck, enclosure, and wiring.
I sealed the inside with clear silicone sealant, to allow for easier inspection to ensure no leaks/gaps.

11 Likes

- PROBLEM - Full electronics wiring in a very tight space

Parts: 

- SOLUTION - Route motor cables backwards under the truck and 180 degrees around into enclosure.

The wiring plan

For the most part, scale and layout accurate:

2021-04-11 Update
Revamped the wiring entirely. Will write up summary soon. Here’s the end result:




Re-ran VESC tool motor detection and everything works! Small victories.

11 Likes



Oof

Specifications

ITEM DETAILS
System Weight: 27.8 lbs (12.6 kg)
System Dimensions: 37.9” L x 9.7” W x ??” H
Ground Clearance: 1.2” (30 mm) to motors
Range: untested (16-32 mi calculated)
Loaded Speed: untested (28.5 mph calculated)
Max Speed: untested (31.7 mph calculated)
Max Torque 15.7 ft-lb calculated (21.3 Nm)
Acceleration: untested
Power Consumption untested (Wh/km)
Motors: 2x 190kV 6374 Brushless DC Outrunner
Battery: 605 Wh - 10S4P 21700 Li-Ion
Drive: 4140 steel spur gears, 2.78 ratio
Wheels: 110 mm diameter, polyurethane
Trucks: 6061-T6 aluminum, 11.7” (297mm) track width
Deck: Canadian Maple, 7 plies, mild concave
Electronics Enclosure: Fiberglass
Control: Wireless controller w/ basic on-screen telemetry
IP: Designed for IP54 (untested)

New helmet, who dis


https://www.smithoptics.com/en_US/mainline-tech.html

Smith Mainline MIPS
Downhill certified
770g total weight
super breathable
Way more streamlined than my Shoei RF1100 , much lighter, fits like a glove.

First real ride, 10.3 miles.

Found some local hooligans to cruise with. Probably should’ve fully charged the battery first. I had to dip halfway through and limp back home on fumes.

Also, that VX2 battery bar is deceptively small. I went from ~60% batt to ~20% in the blink of an eye.

Had speed wobbles starting around 22-5mph. I’ll have to put the cup washers back on the trucks and tighten everything up. Also… need some grip tape.

5 Likes

How can you deplete that much of the vx2 battery in just one ride?? I can do 60-70 km in a week and I don’t normally go below 70%

Not the remote’s battery, sorry. The center bar readout for the board’s battery pack on the LCD screen. It’s so small, it’s like an oldschool cellphone.

image

2 Likes