The Penetrator | A waterproof Evo for commuting in the UK

Backstory

My friend still has two years of uni left in Edinburgh. Due to rent being stupid high, we’ve never lived particularly close to school. I could afford an esk8, but he could not. But I didn’t use my esk8 every day anyway, since it rains very often in Edinburgh, and the strong winds and hills require a powerful board.

Well this sucker my friend agreed to edit a 20-30min long youtube video for me if in exchange I built him a 2000€ electric skateboard for commuting in Scotland. Time = money so the deal makes sense for me. So, how are we going to do this?

Requirements

  • Waterproof
  • Reliable
  • Enough range to get to school / fast charging
  • Easy to carry around campus

Parts

A high-performance skateboard for this cheap ain’t easy. So here are the parts I ended up with:

  • Surf Rodz RKP baseplates used from @BigBen for dirt cheap
  • 3DS FatBoy Surf Rodz 260mm hangers to match
  • 3DS 4:1 SS HD-Mini helical gear drives (Because belts slip and we need that efficiency & torque!)
  • 3DS hubs in gunmetal grey (Not that much more than plastic hubs tbh)
  • LY Evo 40" deck (bought in the US because of availability and price, shoutout @JJHoyt for being the middleman so I could take this back to Latvia)
  • Double stack Evo enclosure from @BigBen (Cheap, and the wide enclosure lips make this ideal for waterproofing)
  • Stormcore 60D+ used from @poastoast for dirt cheap (Reliable ESC with dual UART for a robogotchi and Kami remote) (Shoutout @MrDrunkenMobster for being the middleman)
  • 20A charge port from DuckBatterySystems
  • Mini remote from Nexusboards (dirt cheap, and it’s a trigger remote!)
  • Metal risers from Trampa (Cheaper than Riptide tunnel risers, although they’re conductive so in hindsight this was a mistake)
  • 6.5" Urban Treads from Trampa (larger wheels would cause wheel-bite)
  • Radium anti-sink plates (I was buying stuff from him anyway, and 3DS was OOS on theirs)
  • Maytech 6374 190kv motors bought new from @FreezingShrine
  • Riptide Krank bushings
  • Black MR60 connectors from @PixelatedPolyeurthan
  • Robogotchi
  • 10s4p P42A battery to be built by @Anubis

Building




Marking where to drill the holes on the enclosure was one of the hardest parts. The enclosure isn’t symmetrical at all, so a lot of painters tape at 90 degree angles was needed to get somewhat even hole spacing.

Also, this time I only drilled 4 corner holes in the deck, added inserts, bolted the enclosure, and then marked where to drill the remaining holes. They were pretty spot on this way!


Also counter-sunking the holes for the inserts and using a spare bolt and two nuts to lock the insert to the bolt was required to get these in. Definitely the hardest part of this build.

And I even managed to fuck up once because my tape marker on the drill bit had slipped up and I drilled too far, ruining the beautiful grip-tape :sob:

Also some of the inserts got their inner thread fucked up and then got stuck to my bolts, and got pulled out, despite the epoxy and everything! :man_facepalming:




All was well eventually. I did make the enclosure holes larger (M6) in the end. The washers cover it, it’s fine.

I’m running a 35 degree baseplate up front, and a 45 degree baseplate in the back. With the Evo’s angled ends of ±10 degrees, this ends up a 45:35 split again :laughing:

One large mistake I made was using an LP-20 charge port.

  1. The rubber flap comes off easily, so it gets full of dirt
  2. It’s huge! I only had 1 spot I could reasonably put it, and because of it the ESC sits slightly too far back and I can no longer fit a 12s4p P42A pack :sob:
  3. Good luck finding a 20A charger anyway

I’m now switching all my boards to SP-13 connectors because they’re more sturdy, smaller, can do 13A and most importantly – have a screwable cap on them! You can get them on aliexpress or from Apex Customs.

Anyway, how do we make the motor connections waterproof? Phase wires are easy – epoxy some MR60 connectors and bob’s your uncle. I even added 4mm bullets both on the inside AND outside so that the ESC or motors can be easily replaced.


But the sensor cables? Well, as you’ll see in another build thread of mine, waterproof sensor cables take up a TON of space. Like look at this spaghetti mess!

My solution for this board: A single cable gromet, that I can just barely squeeze both sensor cables through if I depin them from the JST connector!

Oh, and I also conformal coated the hall sensor PCB on the motors. Standard practice for me these days.

To be extra safe, I covered the charge port and power button openings with some sort of white silicone cream on the inside. I also used fabric tape to secure the small wires from sensors and the power button together. All the cool kids are doing it. (Shoutout @mariocontino )


The cable gromet is epoxied in of course, but for safety I also squeezed some butyl tape in there.

I assembled the gear drives with green threadlocker (I’ve found that red isn’t strong enough). Because the bushing seat opening is too small on these trucks (see my green board thread), I’m using cone bushings with the narrow ends towards the hanger. Not buying these trucks again, wish I knew before I had ordered them.

I put some fish-paper on the metal risers from Trampa so that the wires wouldn’t cause a short if they got cut up.

The motor wires go between this riser and the deck, and and connect to the MR-60 extensions I soldered. Once the enclosure is mounted I duct tape these wires to the deck, just so that they’re not hanging loose. The motors leave perfect space for the sensor wires to go up into the gromet. Perfect fitment :ok_hand:



I really like that the motors are forward mounted, yet high up. You can drag the board by lifting the front, and not have to worry about the motors hitting anything. Very practical.

Also, I got some M3 washers so that the plastic gear drive bumpers wouldn’t fall off like they did on my green board. Lesson learned.

I put a 10s4p 30Q battery in to test ride this board. Unfortunately I finished it a day before Latvia would be covered in snow for a few months, so I had to test ride in very rainy/muddy conditions. When it’s fully assembled a layer of butyl tape on the inside of the enclosure bolt holes will keep the enclosure water-sealed, but for this test I just used foam and duct tape. And it survived! :smiley:


I took the board apart and washed it off. Bought shorter enclosure bolts, and added some water ingress detection stickers on the inside, for future reference. @Anubis will be building a 10s4p P42A battery for my friend, which should give him 20km of range. Wish we could fit a larger battery, but this double stack enclosure is really small, and not thick enough for a 21700 double stack really. But oh well, with 10s the top speed is about 45km/h which is fine for my friend, and the torque at 70A per motor is fucking fantastic :smiley:

Hopefully my friend takes some pretty pictures of the board and his adventures when he gets to ride in in the UK in two weeks. The total price of the board, including the 10s4p battery, ended up being 2100€. Not bad for a gear drive DIY build IMO. Thanks for reading! :slight_smile:

38 Likes

you sir are a very nice friend

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uwu :blush:
may the 60D serve well!

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Clean build! Lots of value here!

ftfy

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Great job! Looks like Bioboards jr.

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Excellent build, Raity! Your friend is lucky to have you :metal:

Lol, basically :grinning_face_with_smiling_eyes: If the Jaws had come out 6 months earlier I might have just bought that to save myself the trouble, but all in all this is like a grand cheaper than a comparable prebuilt. Well, maybe China has some offering, but reliability was one of the main goals. Whichever remote comes out first – Kami remote or OSRR trigger version, will be the final remote for this board.

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Now this is one delicious build :yum:
Well done Raisins!
Always dreamed of an Evo high speed pneumatic board
:grin:

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I’m very curious about the range this will have. I have a very similar setup with 10s4p.
Scared i might have to buy the eboosted double stack enclosure and get a 12s8p. $$$
Evo with pneumatics looks good! :slight_smile:

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Did final preparations this evening before handing the board off. Here you can see the inside layout:


Phase wires do a loop, their bullets are held together with fiberglass tape.
Behind the ESC on the left we have the charge-port fuse holder wrapped in foam for silence, and on the right we have the mini remote receiver.

On the side of the ESC I also have the Robogotchi stuck in place.

All connectors (sensor cables, power button, robogotchi and remote) are secured to the ESC using hot melt glue. I find it to be the best to keep connectors in place, but with the possibility to pick and pry at it to get it off when you need to unplug things eventually.

Here’s a shot of all bolts put in (quite short, only 12mm flat-heads!) and a baggie with some spare bolts (slightly longer, in case the butyl tape adds too much thickness). You can see how wide the enclosure lip is! – I wish Eboosted did that. (But you can also see that the enclosure could have easily been made wider :fist: )

Finally, the back truck bolts had come loose, so I added blue threadlocker to all 8 and tightened it well down. Some final glory shots:




Also, because my friend is a cheap-skate, we bought this super flimsy bag from aliexpress meant for xiaomi scooters. Hopefully it’ll survive the airport luggage system :laughing:

Excuse my messy bedroom workshop

5 Likes

great job, lucky friend :stuck_out_tongue:

I’m trying to spot the similarities between our janky desk bedroom setups, so far it’s two of the same lamps, matching Allen key set, remarkably similar pile of packing material/shipping boxes, and general disregard for Feng Shui

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Great build. Those insert threads can really be PITA.

Anyway if you have some other video (preferably 60mins long) that needs editing. I am up for it. Then you can make me 4k build :muscle:

Great thing of you to make this for him.

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I have a 10s4p p42 and I’m super light at 105lbs and I can get 31 miles but if I’m pushing more like 26 so definitely go 12s4-8p.

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Going to update this thread with what’s happened with the board and some pictures.

In March Nexusboards finished the battery build, and my friend successfully installed it, using velcro to secure it in place in the enclosure.



One tiny issue was that the ECS wasn’t responding to the Robogotchi or remote signals when turned on. Turns out this was the culprit:

Those are the e-stop pins on the stormcore!

Luckily thanks the Lee Wright’s stormcore disassembly video I got my friend to open the ESC up and snip those pins off the board. They had likely shorted somehow from the connector getting bent. With the pins snipped the ESC behaved like normal again :slight_smile:

Final enclosure layout was such:

We also noticed early signs that the battery build wasn’t up to the quality we had hoped for:

With that wire insulated and more foam added, it was time for the butyl tape to water-seal the board :slight_smile:

After the threadlocker cured and the mini remote was recalibrated, my friend could finally enjoy the board he’d been waiting so long for :smiley:



Enclosure started picking up scratches due to the Brits not having invented curb ramps yet:

The first real issue we had were remote cutouts. This is when my friend, @RDs , and my little brother learned from first-hand experiences that the mini remote just isn’t reliable in today’s noisy RF environment.

Also my friend was really abusing the fact that this board is waterproof, and riding in the rain became a common occurrence :laughing:


The remote got cleaned and duct-tape added for more weather sealing, but coutouts were still the norm. An upgrade to a puck was inevitable. Luckily Apex stock those, so a batwing puck and receiver arrived shortly. :slight_smile:

Also a lot of the bolts were now completely rusty, likely from riding near the beach.


well yeah… if hes in UK, isnt like one day out of the year not rainy there? :man_shrugging:

wonder what the insides of those motors look like :smiley:

The second issue encountered - one of the motors spazzing out :scream:

This would happen very randomly, and was nearly impossible to make out looking at logs. We opened up the gear drives, opened up the enclosure to check for unplugged phase wires, no luck. Switching ESC sides always had the issue lead back to the same motor. We had managed to pinpoint that the issue was likely a phase wire short, but the question was - where?

Well, after a few months, we finally found it – I had done a subpar job soldering the MR60 connectors, and over time stress on the wires caused the wires to fray and make small shorts :open_mouth: :disappointed:





After consulting with fellow community members, I got instructions on how to solder MR60s with ease and with perfection. It boils down to stripping the 12Awg wire and losing a few strands for an even smaller cross section, tinning the wire to eliminate any stray wires, tinning the cups of the connector itself, and then using a thick soldering iron tip to heat up both so that the wire can be carefully seated in the cup. You also need the male MR30 connected to the female for additional thermal transfer away from the plastic of the connector, to prevent it melting. You also need the stripped section of the wire to be exactly the right length to get a good solder connection, and not have any exposed wires, because there’s no room for heat-shrink with these.

Since the outside wires connected straight to bullets for modularity, I was able to solder up a new set of adapters and mail them off to my friend for replacement. Somehow I can’t find a picture, but they were absolutely perfect :100:

But unfortunately, this was not going to be the last issue.

After replacing the connectors one of the motors would sometimes spin in the wrong direction, or refuse to move at all. I had a pretty good idea that this is due to a sensor issue, and when my friend opened up the board, sure enough, he had put too much pressure on the sensor wires and they had broken off the glued-in JST connectors:

Also we noticed that one of the phase wires internally had almost unplugged. This is crazy, because they connect to epoxied MR60 connectors in the enclosure wall. I guess it goes to show, vibrations will make anything come loose. Use adhesive lined heat-shrink, folks!

After my friend fixed the sensor wires, the motor would still behave weird. Doing motor detection didn’t detect the hall sensors, so most likely the sensors inside the motor had died (despite my conformal coating layer), and now the motor was being run in sensorless mode, which sucks.

I had my friend update to FW6.0, and luckily HFI appears to be a viable solution! :smiley:

However that’s not the end of our troubles; somehow one of the gear drives has gotten loose:
loose-3ds (1.7 MB)

I have 0 clue how that could happen, since I used Loctite 648 on ALL of the gear drive internal bolts, and let it cure for 72h+ at least. So my friend will have a fun time opening up the gear drive yet again and reapplying threadlocker to those bolts :disappointed:

Amid all this, there was a strange issue that occurred one day – the board would not charge! The smart BMS would report that the board was charging, not charging, charging, not charging, almost as if the BMS was blocking the charge current, even though all the cells were balanced.

Help! Daly Smart BMS refusing to charge

Thanks to some back-and-forth among fellow battery builders, we half-guessed half discovered that a loose charge circuit connection could cause spikes that would trigger the BMS to shut off charging. As you can see in the above thread, the solder job done on the battery connections was awful. Cold joints everywhere, that kept breaking loose as my friend was cutting away the fishpaper to take a closer look. Very disappointing from @Anubis

The black wire had come off already on its own lol.


These are unacceptable solder connections, and no wonder they failed. Get a hotter iron, and use more solder @Anubis !!! This is what good solder connections should look like:

Anyway, after my friend did the best he could to solder the wires back and did a few tug-tests to make sure the connections were good, the board successfully charged again :slight_smile:

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