[Tuning Stage] III:THE EMPRESS | Apex Bro / Airs / Chain Drive | 6384 140 kv 5:1 | 12s2p P42A | DV6 | | 8" Rockstar II

After over a month it is UPDATE TIME

Captured double Loopkey
So the main goal of this build was to be able to have a lightweight board that could be extended in range for the purpose of getting to the jump/riding destination. In order to do this I needed to find a way to be able to attach 2 battery packs to the board safely. I initially thought about doing parallel packs but that only works for the way there, because both packs need to be the exact same voltage when plugging them in. So you could only use them when paired as “one” pack and you could only remove the range pack and not add it back after the small pack is drained. I came to the conclusion that just having 2 completely separate packs would be the best scenario, and in order to have an internal pack, and an external pack I designed:

The Captured Double Loopkey:









This way I can have my internal battery for jumping and short rides, and then have an external battery for range if I need it. Thanks to @sleepless for the original captured loopkey design here. Still need to sort out the details on how I am going to do the external battery but that is a future me problem :grin:

As of right now it functions pretty well, a bit sticky on sliding out due to the resistance from the XT90, not sure how much that could be improved. I would like it to be more smooth but not quite sure how to go about it. Ideally I would also like a bit more of an air gap between the middle position and the outer, but this was the max amount of space I could take up on the apache case.

Progress on the build
Internal Wiring:

Here is where I did something very stupid and put the charge port where the lid latches closed…





The charge port is now off to the right of where the buckle comes down

Loopkey wiring




Here is how I joined up the 2 wires before soldering. I used a box cutter to cut away a section of the outer sheathing, then wrapped one wrap above where you start and the rest below. That joint is now covered in silicone rather than electrical tape.




Wayyy too much thermal paste, had to scrape it off the sides


Finished internal wiring, everything is either smushed between foam or held down with tesa/gaff/VHB tape. It is a VERY tight fit between the battery and the ESC, just snug when you close the lid. Not sure if I need to add a barrier between the cables and battery but suggestions are welcome if you see any shortcomings.

Cable extensions:
Nothing too fancy to see here





Using some jst extensions that I got off amazon.

Unpin them

Solder

Done

Do it again

Silicone to keep everything in place

Heatshrink everything together, ran out of big heatshrink for the extensions but getting some more soon. Also need to design some cable management. Gaff tape is holding everything in place at the moment.

Footpads:
I wanted to do something a little more elegant (and serviceable) than just running the wires below the grip tape so I decided to make them out of sheets of 3/16" and 1/16" thick rubber.
Really like the blue tape to cut out method, works flawlessly:

I measured out a line on both sides of the deck that was 50mm from the center holes for mounting the top box to give myself a point of reference, this way if anything could be flipped and used on the other side I would.


Cut out the first one (I used several passes with a large box cutter to get consistent lines)

Then reuse the cutout to make the pad for the opposite side

Re-tape the tape on and mark hole locations because you forgot to initially. I drilled out these with a step bit.

To get the correct hole locations for the other side you will need to put more tape down to mark that side’s locations. Since I had the reference line everything ended up lining up very nicely.

For the side with wires going under I wanted to have a layer that bridged over them for just a little bit more protection, that is what I used the 1/16" rubber for. I just laid the wires over the top and taped them on either end, then just traced them with a sharpie to get the cable channel outline.



Used the same tape to cut out the thin rubber

Then I just lined everything up and got ready to glue the 3 pieces together





All glued up


Now time for grip tape! Side note, this shit hurts! I scraped up my hands like 3 separate times working with it.

Cut out with box knife again


Drill holes from underside (again)

ezpz footpads that take about an hour or 2 to make.

Vinyl Skin
I ordered the skin from WePrintWraps, they were pretty quick to ship, and I just gave them the total length of the board and the area in the center that I wanted the art to be in.

Applying the wrap was a pretty painstaking process as I have not skinned anything before, but I just took my time, used a heatgun, and wasn’t afraid to rip it up and reapply if I was unhappy with an area and I would say it turned out pretty well:

VESC Settings
I tried to initially setup with metr but ended up just using the pc vesc tool
Motor amps: 60A/side
Battery: 30A/side
Regen: -12A
Throttle curve: Linear for now, going to tune this later
IT LIVES!!!

Initial Impressions
I had a bit of a crisis when first getting the bindings setup where I thought I had setup everything for the wrong stance but it turns out that bindings just feel so weird to me that I thought I was riding opposite from what I normally do. After angling the front binding a bit more outward it felt much more natural, but I still definitely have to get used to them as I had a bit of a spill at about 10mph on my first ride. Butt is scraped and bruised but not more than my dignity. I bought some triple8 bumsaver pads for learning how to properly ride this thing as I foresee much more falling in the future :sweat_smile:.

Power impressions are great though, so much torque and brakes are muuuuuch better than my old board. I took it up to about 21ish and it was rock solid, I don’t ride super fast and the board’s top speed is only like 25 anyways so this is great for me. I do think I want a bit more carve though. I weigh 125lbs and with the default bushings at the loosest while still being snug I felt like I needed more turning ability still.

Consumption is also pretty good? 19Wh/mi over 4.5miles of mixed street and gravel is pretty good in my book. First ride was 87% to 54% (30% usage) so hopefully I will get around 14 miles out of this little 12s2p.

Also free roll is INSANE on this chain drive, sooo nice to be able to cruise without the board slowing you down so much.

Conclusion and future plans:
I absolutely love this board and can’t wait to learn how to use it to its full potential. Shout out to @ApexBoards for making some phenomenal products. My other main conclusion past the hardware is that I need to start working out and stretching so that 1. I can actually jump with this thing and 2. So that if I fall I don’t instantly tear or break something :sweat_smile:

Next steps:

  • Heatshrink for sensor wires
  • Blue loctite all the bindings in once I figure out how to properly set them up, anyone got any good guides for binding setup? I know they are generally supposed to be ran a bit more loose.
  • Replace truck mounting hardware: Got some stuff from McMaster because I didn’t like that the M5 bolts I got use an M3 hex instead of M4, strip out super easy.
  • Let a bit of air out of the tires: I am running about 45-50 psi and I think I wanna drop that down to 40 to see how it feels. I would like things to be a bit cushier on the tire side of things.
  • Anti sink plates (Looking like @SabreDynamics claw mount at the moment)
  • Make the epoxy look better somehow? Grey on black is not great and I would love to make that a bit nicer.
  • Tune bushing setup: bought some 84a krank bushings from @RipTideSports to try and get a more carvy setup. Got a couple different shapes to try out.
  • Tune VESC settings: I like where it is but feel like I could make it a bit smoother to ride, right now it feels like a lot of power that could be smoothed out a bit.
  • Design some cable management to 3D print for the phase/sensor wires. A piece of gaff tape is not up to snuff for how much time I have spent on this build.
  • Figure out how to go about the external battery. Not sure if I want to do something underslung or something akin to a hat that sits over top.
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