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NESE modular jumper - 🐉 Dragon MTB build

After the collapse of my first lightning powered murder machine, I’ve embraced the fact that Houston streets are basically an apocalyptic wasteland that require an all-terrain build. The goal here is to build a capable off-road mtb that I can both use in a minimum-weight configuration for launching off hills/curbs/ramps as well as on longer group rides. I’ve chosen most of these parts either for light weight (deck, drive, hubs) or because they’re interesting to play with (NESE, Davega).

There is a large grassy hill in the middle of a field a few blocks from my house that’s been tempting me for 2 years now…

To that end, I’d love feedback on where I’ve gone wrong with this modular jump build, before it’s complete.

The only novel aspect of this build is using two NESE battery packs. 1x 12s2p P42A ‘jump pack’ that is permanently installed and 1x 12s3p P42A ‘range pack’ that is added or subtracted as necessary.


References

At some point in the planning stage, I was convinced this was not the worst idea. Although I’m having second thoughts. Reference threads:


Build Plan

The plan is to use 60 fresh P42A cells in NESE modules, and wire the two 12s packs in parallel to the ESC. No BMS onboard - Daly 12S BMS will be mounted to the 6A YZPower charger and the two packs will be charged individually. No charge port - everything will use XT90s connectors - must disconnect pack from ESC to charge, but that’s easy with the Nanuk case.

(Obviously, packs will only be plugged in together when both are charged to 100% on the same charger. The range pack would not be added on the fly)

Pack config like this, with ESC permanently mounted under the range pack, bolted to an aluminum enclosure floor plate, which is then mounted to the deck. Each pack has its own balance harness:

(still printing NESE modules)

Alternative pack options I’m considering:

  • Qty 2 x 12s3p NESE packs - would required a bigger enclosure or 3D printing a custom enclosure. This solves the current draw imbalance issue. Not that I need 12s6p but I wouldn’t hate it. ‘Jump mode’ would be heavier than planned
  • Salvage the unused 10s4p P42A (1 year old, ~15 cycles) pack I had in my now dead 1st build - could reconfigure into a 12s2p pack by chopping some connections (probably?). This pack will have higher internal resistance, so may actually be better balanced with the new 12s3p NESE? Unclear here. I’m no electronics rocket wizard.
  • Sell all the new P42A cells and NESE hardware. Wait for sales on gently used 12s2/12s3/12s4/12s5 welded packs. Buy two full packs, swap as needed, don’t try to parallel them.
  • Use second pack as charge-and-ride. I don’t know much about this - more research necessary.

Full BOM:

PART BRAND MODEL DETAILS WEIGHT (g) PRICE SHIPPING+TAX
DECK Haero 2021 Bro 96 Mountainboard Deck Stiff Flex [$325] 2,300 $326.00 $0.00
TRUCKS MBS Matrix II 16.3" width, 6061-T6 Alum, qty 2 [$200] 12mm hanger axle, 1.9lb ea, used 1,800 $135.00 $0.00
BINDINGS MBS F5s 1 pair (540g pair), used 540 $74.95 $0.00
BINDINGS MBS F5 heel straps, used 1 pair 40 $40.00 $0.00
DRIVE Moon AT Moon Drive Batch 6 POM spur wheel Gear (1140g), 4.7 ratio (47:10) 1,140 $360.00 $41.00
WHEEL HUBS MBS FiveStar - white Material: Nylon, Fits 8" & 9" Tires, used 567 $40.00 $0.00
WHEEL BEARINGS MBS Bearings 12mm I.D. X 28mm O.D. ? $19.95
WHEEL SPACERS Boardnamics 12.2mm ID x 22.2mm L ? $14.00 $0.00
TIRES & TUBES - road 6" Clever 6x2 (150x50) tires + tubes set of 4 ? $44.25 $13.52
TIRES & TUBES - knobby 8" AliE 200x50 (8") tire + tube ? $49.68 $11.23
MOTORS Flipsky 6374 Brushless DC Outrunner Motors, 190kV Battle hardened, 3500W, 85A max, 8Nm - already have 1,960 $0.00 $0.00
ESC BKB Xenith V1 (already have) 80a cont 274 $0.00 $0.00
ESC (OPTION) MakerX Go-FOC DV6 Go-FOC DV6 365 $225.25 $13
REMOTE Hoyt St Nylon Puck, Black used N/A $100.00 $0.00
BATTERY A NESE Modules 11 sets 12s2 + 12s3 packs, 10 bus bars 1,422 $98.29 $15.69
BATTERY B Molicel P42A 21700 cells (ordered qty 65, used 60) 3,960 $321.10 $10.92
POWER HARNESS Turnigy 12awg silicone - XT90s, parallel harness ? ? ?
BALANCE HARNESS ? qty 2 22awg, 13-pin JST (daly: 26g ea) 52 ? ?
BMS Daly 12S ebay dickyho N/A $15.00 $7.73
ENCLOSURE Nanuk 905 empty / no foam, Interior: 9.4 × 7.4 × 5.5” 1,396 $48.95 $4.04
TELEMETRY DaVega X Kit used ? $120.00 $0.00
TELEMETRY SPACER - Rubber sealing/wiring pad TPU printed ? $0.00 $0.00
CHARGER YZPower 12S 6A N/A $48.39 $4.00
BRAKE LIGHTS XLITE 100 smart brake light, 38g ea 76 $25.64 $2.12
LIGHT MOUNT Mount to Moon drives custom PETG qty 2 50 0 0

Sweet Pics


Credit to Tarboxx for the super dope artwork. Local area graffiti artist

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I’m loving all of it! You’re gonna have a fun board for sure. It’d be more work and annoying but that 10s4p could make a 12s3p too.

I think you will be in love soon :heart:

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Very true. But without a spot welder, that seemed less feasible than chopping 6x 4p groups in half and soldering.

p.s. @Venom121212 you are definitely a main inspiration for this build! Appreciate the advice, photos, and guides

2 Likes

Bro? Do you even Bro?!?

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that Haero looks so dope dude…
I am not sure if alrrady in the plans but I highly recommend a heatsink…

Have you ridden bindings before?
planning on going out with heel straps from the get go?

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Personally, I would have 2 packs and make them easily swappable. 12s5/6p(or larger) for a cruising pack and use lipo’s for a jump pack. This would eliminate concerns over paralleling packs together.
Nice build dude, awesome artwork!

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This is effectively what I did ^^

12s6p for riding, 12s2p for jump session

2 Likes

Definitely considered this, but I can only mentally/emotionally/financially afford so many esk8 purchases at a time. Modular batteries soothes my need to avoid waste. If I was a smarter man, I would’ve waited until someone (@Taraskasyanyuk) put up a used 12s5p battery for sale and snagged that. Or used lipos, etc etc.

But that also requires buying a lipo charger.

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Now that the experts that be have given the go ahead, that this type of dual pack setup probably won’t do anything too funky electrically, I’ve started building for real:


Nicely enough, the Nanuk 905 case has #3 screw holes built into the sidewalls for attachment. I printed a rigid frame for the 12s2p pack and it mounts quite nicely this way.

The 2p NESE modules do not stay together very well naturally, since the bus bars are alternating top and bottom, and they’re the only thing attaching module to module. It wants to pop apart like an accordion without additional support. The modules have zip tie holes, but it’s not super easy to use these without really long zip ties, or a lot of them.

This case reduces the # of zip ties down to 2 and keeps everything locked in and aligned.

Also, the super important TPU screw caps! Without these, every bolt is electrically live and exposed. Scary stuff. I redesigned the caps to extend out over the tabs, since they did not cover everything and were super difficult to install (very tight fit).

Enclosure mounting hardware is ordered and on the way.

Next up, wiring.

6 Likes

Jump pack done and wired.

Extended all the motor wires. Now time to print some dragon foot tunnel pads:


Edit:
Tried a few footprint designs. I couldn’t find one that didn’t look over the top. Went with a simple scale pattern.



Edit 2:



Not too bad. Got the deck edges spot on. For how large the scale holes are, it’s very supportive / not a ton of flex. TPU is awesome stuff. It’s very 2D right now - I could add some chamfers at the edges to improve the looks

Need to find some clear grip tape…

11 Likes

Time to tackle mounting the enclosure…

I still use this trick, all the way from grade school art class. Rub a colored pencil over the edges to imprint the bottom of the enclosure onto a piece of paper. Throw the photo into CAD, calibrate, and boom, got ourselves a perfect fit design.

A couple iterations later and I’ve managed to nail down the variance in height between the Nanuk 905 feet and my mounting screws and the curve of the deck.


I assumed the little mold nub in the center of the enclosure bottom was perfectly centered… and drilled it out (foreshadowing)

As I plunge my drill bit through the enclosure, rendering it’s waterproof qualities moot, a thought occurs:
What if this nub is not centered. maybe i should measure. it’s probably centered.

Shocker, it was not centered… Future-me will have to plug that hole somehow.

Drilled out the board and countersunk with an imperial bit - close enough. No idea where to get a 90deg countersink bit at a brick and mortar. No going back now.

Very nice. Test fit is perrrrfect. M5x30 flatheads are just barely long enough.



The enclosure is now super stable and I love it. Getting close!
If that MakerX DV6 doesn’t staying cool enough inside the enclosure, I’ll replace this TPU spacer with an aluminum heatsink/mount plate and cut out the enclosure bottom.

@ShutterShock, I remember you talking about printed enclosure mounting standoffs. So here’s mine.
For anyone’s use:
Nanuk 905 Mounting Spacer v2.step (531.1 KB)
Nanuk 905 Mounting Spacer v2.stl (376.3 KB)

12 Likes

That’s damn evil of them not to center that nub

2 Likes

Right?

I’m channeling you hard on this build brother. I put in two PG11 and one PG9 gland <chef’s kiss> perfect fit for the motor wires. Just barely enough thread on the back side of those to tighten the plastic nuts down.

Time to crimp the sensor wire pins. Using a 6 conductor cable is so much nicer than individual wires.

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Run that motor detection before sealing everything up! I learned the hard way :expressionless:

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That build is nasty!!! Great job.

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Looking nice! Yeah I have a similar one on my build, same idea, different implementation

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Well I’m a dummy.

Bought these (free shipping 6X2 tyre 6 Inch Scooter Tire & Inner Tube Set Electric Scooter Wheel Chair Truck Electric Scooter F0 Pneumatic|tire 6|scooter tirescooter tires free shipping - AliExpress) 6x2 roadie tires assuming they’d fit MBS hubs. No dice. The super stiff sidewall and smaller ID means these are a no-go, unless someone’s got a trick I don’t know about.

Anyone need tires?

Nah, unfortunately there are 2 diameter sizes of pneumatic hubs we use:

  • Mbs, trampa, kaly, sunmate, etc style wheels that have a ~100mm or 4" hub diameter

  • bergmeister, six shooter style wheels that have a 71mm hub diameter

If you need some 6" ones that fit mbs hubs, you’re looking for the metroboard 155 tires, mboard tires, etc


6" Mboard wheels on sunmate trampa clones on the left, 8" mbs tires on rockstar 2s on the right. I can swap tube and tire between the 2 hubs no problem.

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Man I hate supporting mboards, but they’ve got the right price. Where you do pickup your tubes with the perpendicular valve stem?

Edit: these are quite nice:

I use that first link often but you’re going to need 150 x 50 tubes if you want to use the 6" tire size.

It was stupidly cheap on black Friday. $67 for a set of 4 tires and tubes was too nice to pass on :grimacing:

1 Like