The Prince | 12s10p flight-safe Switchblade build

It’s that time of the year again! Carve PDX is less than a month away, and I need a board to take with me to the US! :us: I did a similar build last year (:stars: Northern Light | Switchblade with Reverse-mounted Urethane Gear Drives), but there were a few problems:

  • NESE modules caused the battery to go out of balance, leaving me troubleshooting things mid event
  • I survived Portland on urethane, but there were some close calls. This year I want to step my filming game up, so I need to have a safer board. Pneumatics fo sho
  • I had to assemble my board the day before so that the threadlocker would have time to cure before the first ride. I want to have my enclosure easy to access, like Jackson (@jack.luis) did on his | PlayaHaya | Air Travel Focused Build | Haya Deck
  • Range was barely enough. Jackson and I were the first to run out of battery on rides and need to charge, and when my battery refused to charge fully, I had to be towed a few times to finish a ride. (Shoutout Liam!)

I also had the additional goal of making a board that would fit inside a standard check-in luggage size (Most airlines have a limit of 115 inches for length + width + height). I might approach this problem next year (@IDEA brackets, possibly folding, could be an amazing solution), but this year I’m bringing back a bunch of stuff again, so might as well just pay the oversized luggage fee.

Backstory

I’ve actually had this build in mind for 3 years by now. This was supposed to be my second DIY board, and I wanted to make it special. After owning a 38" Switchblade as my pushboard and @eBoosted making an enclosure for the 40", I knew I wanted to make a sexy ultraboard akin to @Adstars Evolve GTX:

The name for this board comes from one of my favorite songs – “The Prince”, by Madeon.

(It’s also like a big brother to Little Princess Board | Custom FatBoy Nano Gear Drive 1:3 5065 140kv | 6s8p | Landyachtz Switchblade 36” | Untiy | ABEC 107mm )

The original plan was “simple”:

  • 40" Switchblade
  • Black bergmeisters (all the rage back in the day)
  • Surf Rodz RKP trucks (most affordable CNC trucks back in the day)
  • @moon drives
  • Bioboards branded Maytech 6880 motors (with the big bearing to prevent can imbalance)
  • @akhlut axles with integrated mounting plates



But then Akhlut went MIA, and with literally all the parts on hand except for the axles, the build was never finished. Regular surf rodz adapters from Moon wouldn’t have given me enough clearance for my motors. After a while reports came in about the axles I wanted being crap, my motors being crap, bergmeisters being crap, and stormcore 100D issues.

After reading about @Psychotiller’s new HeXL TKP split angle trucks and realizing how TKP extend the wheel-base of a board (I had become obsessed with exploring wheel-bite issues on Switchblades and solutions to the problem), I somehow became aware that @3DServisas had made a custom hanger for HeXL trucks. This would solve the problem with people having their HeXLs bend, and would allow me to use a gear drive again! :smiley: 3DS had also recently came out with an updated version of their SS HD-Mini gear drive, which now offered a 1:4 ratio, and their own sexy CNC hubs! (Keep in mind this was still in 2020, so this was the bleeding edge of esk8 tech at the time)



I also sent 3ds my gen1 100D to have a new external ESC box designed for it

The plan was now to get a bigger battery by MAXIMIZING the enclosure space by building a 16s4p in the under-tray, and mounting the ESC on the tail of the deck as a foot-stop.


But yet again, this build fell through. I didn’t have time to build the battery, and after arguing with people on the forum about high or low voltage, I realized I don’t really gain much by going 16s. Fun fact – did you know that you can actually fit a 12s5p of 21700 with a sane layout in the switchblade enclosure? :exploding_head: (One side has cells vertically, the other horizontally. I think an LTT BMS fits inside as well, but I forgot to take a picture)

Another reason for me not completing this build was that I realized a 16s4p battery probably wouldn’t be enough range for me on long rides, since pneumatics can eat a lot, and I want to keep up with my new friend @Rudi’s Flux.

So, I decided to use the parts I have to turn this build into my new flight-safe one. Starting by selling the bottom enclosure away to @EreTroN

The plan

I want my battery to be flight safe, and look legit. NESE modules were okay, but we can go fancier. Introducing the 10s1p flight safe battery packs from @hoytskate

https://cdn.shopify.com/s/files/1/0077/0673/8747/products/IMG_30313_1200x_941f20f7-d5ba-4154-8bbd-d6e869aaaa3b_590x.jpg?v=1656620792

Using 10x Samsung 25R cells each (10 x 3.6V x 2.5Ah = 90Wh), these sexy and sleek battery modules are flight safe and super quick to connect. Each module is its own battery pack with an individual BMS, so it’s just as reliable as a regular battery.

However, last year I had a 12s3p of P42As (544Wh), so I would need 6+ of these large Hoyt modules to get an equivalent capacity. These batteries don’t come cheap, especially if they were to be shipped to Latvia for me. So instead I got in touch about buying 12 empty cases, with the plan to populate them with cells myself. All my family’s boards are 12s at the moment, so 10sXp wasn’t an appealing option. 12s10p it is :sunglasses:

I’m also using Molicel P26A cells, which gives me a bit more capacity (93.6Wh), and a LOT more current capability, which should result in a lot less sag, and thus more range.

(Fun fact: Most airlines allow a passenger to carry up to 25 lithium ion batteries. So me carrying 12 isn’t that extreme. Okay maybe a little :laughing: )

After building my mountainboard I was inspired by the practicality of having a top-box in the middle of the board, and decided that would be the best way of storing 12 of these batteries. (Hey, a top box works for @MrDrunkenMobster’s With Morning Comes Mistfall - The Duck’s first eMTB build)

I didn’t want a super high box, and need room for my feet since I’m not using bindings, so I decided to find a slim box for the middle, and keep my ESC at the back.

After searching for days online and ordering potential hard-cases, I settled on the Nanuk 910 case. The advertised internal dimensions were a bit off, but after measuring with some legos and a bit of dremeling, all 12 modules fit! :partying_face:



Unfortunately I cannot use the same wire exit hole as originally intended, so I will have to drill an extra one on the narrow side. Then all batteries will connect with a single wire-harness which will also have a LLT BMS for charging!

Speaking of charging, you already know I had to get the Radium 12s 12A charger. It’s small, and has a switch on the back to switch between 110V and 220V, nice.

Anyway, building this battery is gonna take me a while, but I want this board tested thoroughly, so yesterday I assembled the drivetrain and put it on my green Switchblade, since I had broken a motor on it. Some notes on the drivetrain:

Adjust your backlash by putting force on one side of the wheel gear. It sways back and forth a bit (due to the bearings used), so you want to test the max lean angle to avoid too tight of a mesh.

Put washers on the bolts that hold the bash-guard, because the plastic can jump over the bolt heads otherwise.

And walla – I have actually made my first Ultraboard :joy:


I still haven’t tried the trucks out, so tomorrow when the threadlocker has cured I’ll go on a first ride :upside_down_face: (I do know that the drivetrain is solid, it’s the same one I used on my friend’s build The Penetrator | A waterproof Evo for commuting in the UK | Best build under 2000€ ?, and I absolutely love how smooth and powerful these drives are.)

Also shoutout to @janpom for the 3d-printed spacer under my Davega so that I can drop-through mount the trucks! It’s actually a milimeter too thin unfortunately, but looks better than it just floating for sure.

Anyway, before I go into the battery building process, I do have some questions I’d love to get people’s input on:

  1. How should I route the power wires from the battery box to the ESC enclosure? I kinda want to use it as a footstop, so I’m thinking I’ll drill new holes in the box so that they don’t come out right where my foot will be. Should I route the wires under the deck? On the sides? Under the griptape in dug out channels?
  2. I want to keep the case somewhat normal looking for getting through airport security, but I don’t want to keep it open while riding to let the power wires out. Should I drill a hole at the very bottom, or do you think I could epoxy an XT-90 in the middle where the pressure gauge is and they won’t notice?
  3. Do I route a Davega cable to the front of the board? :sweat_smile: I plan on using a puck remote because OSRRs are out of stock, and when in Portland, do as the Hoyt boys do, ya know.
  4. I plan on attaching the battery box to the deck with some straps. But they’ll probably want to slide all over the place. Any recommendations? Do I add some grooves / standoffs under the deck for the straps to sit against? Would rubber pads work? Anything particular I should know about straps? Will scavenge amazon I guess…
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Building the first battery module

Since I have a 10p pack, I figured I might as well build this battery for high current capabilities. I pull 80A from my urethane build, so 90A I would be very happy with.

Each pack is actually slightly taller than an XT-90, so that + 10AWG wires it is. The problem – the cell layout.

As you can see, the space in each box for the wires is parallel to the cells. This was fine for the original 10s1p batteries, but this means I don’t have easy access to the ends of the cells. Space is limited height wise, and I don’t have copper braid, so to get enough current carrying ability I need to be smart with my nickel placement.

This was my first idea – to use a 25mm x 0.2mm nickel strip on top of the pack. This would have been good enough for 30A per strip IMHO, so 60A total. But then I realized I could fold the strip I weld to the cells as well, and thus have 2 such strips carrying the current –

So that’s what I did.

  1. First I glue the cells together with hot glue

  1. Then I add fishpaper

  1. Weld the first nickel strips


(Lot of welds because I was experimenting with settings still)

  1. Add solder on top of the strips, and then melt the 2nd layer of nickel on

  1. Drill + dremel the slot on the side for the wire exit, and a bit of junk off the lid

|

  1. Do a bunch of soldering

7 Glue the original wire exit shut

  1. Glue the cells in place, add some kapton tape and close the box with 4 M3 bolts :slight_smile:


Then repeat 11 more times :sweat_smile:

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This is SO SEXY
I’m a bit more mitigated about the actual build ^^ but life is what it is ^^
I’m curious of how pratcicable is the top mpunted box on a street deck though, I love the idea but I recall your last try wasn’t that succesfull

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My last try was on a short-board that required kick-pushing :sweat_smile:

I’ve tried standing on the board with the boxes on, it’s not bad!

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Excellent build thread Raitis! Was a pleasure to read, and I’m looking forward to seeing it at Carve!

I used hard rubber sheets to make wire channels under my grip tape, it works great! Whatever you do with them, make sure they are totally protected in case of a crash. For that reason, I advise against running them under the deck or along the edge.

This is the best way that I can think of. Take into account the possibility of vibration shaking your panel mount connectors loose.

Theoretically you can get by with just checking your LLT BMS for voltage readings, but having the HUD with all that data and range estimates would be more convenient.

If you decide to do this, I suggest making a new UART cable with much thicker wires. The stock davega cable is really thin and seems to break down over time when it’s under your grip tape. Mine was laid into a channel with solid rubber on either side, and it still shit the bed eventually.

@jack.luis just re-did his box mounting on Vantablack. He 3d printed a pastic piece to roughly match the deck on one side and be totally flat on the other, which bolts to the deck. Then on the flat side you put a big sheet of velcro. That way there is a flat mating surface for the sheet on the deck and the sheet on the box.

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Correct except I didn’t 3D print shit, I used shear to cut a thick sheet piece of ABS :joy:

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Watching / Subscribing / Following / etc. Cool stuff @rusins ! Looking forward to seeing what you come up with at Carve.

Function over form all the way. I wouldn’t worry about the aesthetics of the top boxes. I think @MrDrunkenMobster has some keen ideas for the implementation, prioritizing safety.

Wishing you much success! You’re gonna have the highest-capacity flyable board I ever did see!!

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Only 9A on 120V US power :sob:

Still kick-ass for how small it is.

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Ah yes, the range anxiety Switchblade! Dope build. About the modular power pack - have you considered using LiPo pouches instead?

as both a lipo and liion user

lipo is less Wh dense for the same volume compared to liion (just about 1/2), although it is better for A output

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Does this account for form factor?

form factor?

With Li ion cells we’re always losing some volume due to their round shape. For EV’s this seems to be beneficial as it allows for better cooling, but in our case it’s pretty much wasted space.

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nah, not accounting for form

i can fit a 6s2p in the same volume as a single 6s 4500mAh lipo, so with P42A, das about 2x the Wh

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Got it. Thanks for the clarification!

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anytime :smiling_face_with_three_hearts:

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Two things:

  1. This is a cool build and a fun read!

  2. They just announced that there are other decks than the Switchblade.

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While you were out partying, @rusins was studying the Switchblade.

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And I’m a hypocrite, since I just used a Switchblade clone to build a shitty commute board.

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