Been a few weeks, feels like time for another update!
Today I present “Opportune 68V Bushings”
Mini IE race
esk8hustle hosted two i2s track days with informal race brackets.
@Ruxx Pushed held me back to 2nd on the first day, but I managed to stay in front on the 2nd day.
Was fun racing with everyone! Looking forward to the next one.
Thanks Michael(esk8hustle) for hosting and giving away an i2s engraved shortboard, trophies and a bunch of other prizes.
Deck Camber
Thanks @andoug for the mbs camber pads! They arrived without a scratch. I cut one apart, then peel and stick. Some Vicious in the middle. Easy as pie.
This is probably the best upgrade I’ve made to my board yet. It’s crazy how massive a change 5 degrees of deck camber makes. Makes me even more confident that I don’t want a binding on this board.
16s!
My board is now two batteries heavier. Not too much else to say 
I also took this as an opportunity to put 1mm adhesive foam on the batteries, to keep them from getting scrapped up against the belly pan.
Plugging the batteries in was more of a hassle then I expected. I fried two AS150s(with very loud pops). I guess 4x G300s at 16s is too much for AS150s. (don’t worry, I replaced em)
I have an old power resistor laying around that I salvaged from some electronics years ago. I touched either end to the male/female AS150 connectors to charge the capacitors, and after a couple seconds, I quickly dropped it and mated the AS150s. Janky solution, but it worked.
Smart Active Balancer
Upgrading to 16s meant that my 12s charging harness is obsolete. (And good riddens, with the design flaw it had. Read about it here:)
Also took this opportunity to incorporate a Smart Active Balancer into the board, letting me charge like a “normal” esk8 (no balance charger required).
It also lets me quickly check all of my cell voltages via iphone app(super nice for quick troubleshooting). I did measure 10~20mV drop over a few days in my testing, so it definitely has a non-negligible power draw. That’s fine though, as I’m riding this board every couple days.
Even with my new bellypan (which has been GREAT), There was no room to put it underneath the deck. The best place to put it was awkwardly wire-tied on top of the rear G300s. Not elegant, but it’s worked great for several track sessions without a single issue. Maybe I find a smaller smart BMS in the future.
I’ve been using a panel-mounted XT60 plug to charge, pictured above in roughly center frame. It connects to a 600W 72V charger, that I’ve adjusted down to 68V.
Here’s the new balance lead harness before I installed it into the board (no more DSUB!). Happy with how this came out. imo solder wire splices are underrated, especially for harness work like this
The big bundle ended up fitting perfectly between the G300s and the central spine of the frame Good luck getting a good view of it tho, this board has so much going on. This is the best I could get
New bushings
Riding on track, I kept wanting to loosen the board. However, I reached a point where any looser would cause me to loose the center. Obvious solution, step down the duro.
My only gripe with 3-link trucks- you need to fully disassemble them to be able to change the bushings.
Massive gigga shoutout to @HAIRYMANJACK for sacrificing his hands to the process (and the help)
Between us, we were able to swap out the front and back in around 4 hours.
Narrower Wheelbase
Considering we had the trucks fully apart, we took the opportunity to narrow the wheelbase by ~
25mm in the front and back. This just required moving the motor mounts closer together to remove the gap between the motors- the wheel’s themselves could be brought in by removing axle spacers.
Small wrinkle, the motor mounts are connected via a threaded female-to-female crossbar.
But nothing an angle grinder and tap can’t fix.
Narrower wheelbase beauty shot
Esk8con Track
We’ve been setting up the @Esk8Con track at the San Diego zoo the past couple weeks. It’s a tight track!! Serious competition coming from @HAIRYMANJACK this year. (His times aren’t mine to share, but they’re quick)
Running with 16s hasn’t made any change to the efficiency to the board (as expected). However, the additional energy capacity has noticeably increased my range, I’m able to ride about 30% more every night.
Also, new personal best for power with 13.57kW. I’m still nowhere near peak performance 
No load test
lol imagine 3.7kW of losses
Yeah, so, uh…I did a no-load test. Here’s the play by play:
- I spool up the motors over ~10 seconds with the board upside down
- The motors went go 30C to 40C.
- I backed off because I got a freaked by the loud gear drives
- I gave myself ringing in my ears and a splitting headache for the next hour.
TIL; don’t spin this up indoors.
All in the name of data…
73.2A * 61.8V = 4.52kW of freespin losses at 81kph(50mph)
F*ckin silly.
What’s ever crazier is right now it’s geared for a max speed of ~80mph(22:78 ratio), so if I understand things right the losses will go even higher if I dared to push it faster.
(I’ve got Vesc eRPM limited to ~60mph, but still)
TIL; don’t spin this up indoors. (Or at all, really).
When Moe posted a video of me riding at i2s OC this past Saturday,
I realized I’ve never posted riding footage. Shame on me!
Thanks @HAIRYMANJACK for capturing this candid, especially my save at the end.
Bonus vid: @MarioChacon taking a lap at i2s intro to garage
The real race board is the friends we made along the way
??? sure why not
Thanks @Lyfe_Of_Jimmy for these great photos! He’s got some great stuff on his insta and youtube, go check him out.