need two race boards. one to fix one to ride. (lord don’t let me have just jinxed mine or dash’s board)
Board’s disassembled, and I’ve got all four wheels spinning. Not sure what the issue was, but reflashing and setting up the four vesc’s fixed it ¯\(ツ)/¯
Aiming to be at inland empire on Saturday, time for the arduous process of reassembly
Sometimes you just have to thank the gremlins for dispersing and button it back up.
Got the board is buttoned up and ready for i2s yesterday, and took the opportunity to make several minor upgrades and fixes.
The theme of this update is “first 100 miles design issues” *
* I don’t have a functional odometer so 100±150 mi
Phase Wire Fix
At AVS last year when I was riding my board to the relay race I heard some grinding when I was turning. Concerned, I hopped off my board and identified the issue. My motor mount had shifted, causing my motors to rub against my box. (If you look at my motors today, it’s why the anodization has been worn off on the front two motors at the top of the cans)
Worse then this, it was starting to slice through one of the phase wires.
With the relay race about to start, I told my team to switch me to go last, then rushed back to our camp. The phase wire was still mostly intact, so I wrapped it in electrical tape and called it good. I re-adjusted the motor mount, did a couple test pulls to make sure it wouldn’t move again, then met up with my relay team on the track.
Taken about 5 minutes later by @s_m_l_s_ :
I raced the entirety of AVS weekend with the bodged fix.
Got home, and… if it aint broke, don’t fix it.
so I’ve racing with this frayed phase wire the past few months. Don’t fire me pls thx.
No more! With access to the G300 terminals, I cut and re-crimped a new connector on.
thanks @HAIRYMANJACK reminding me to do this. I would’ve forgotten if you hadn’t
Bottom Box Bracket
@MoeStooge’s v5 frame is great, near perfect imo. However, it was definitely not designed to have a 5 pound box mounted to the front of the deck
The deck is held onto the frame with rivets, and the most forward rivets are entirely behind the box
(I peeled the griptape back a bit to show you)
This leaves the box mounted on a bit of diving board. My solution for the past 100 miles has been a pair of zip ties that holds the deck against the frame
Worked fine, but there was a more elegant solution. 3D print a braket that loops around the main spar, allowing any force to transfer directly to the tubular frame.
In hindsight, champhering the hole for the bolt was unnecessary and a terrible idea. Literally turns the bolt into a wedge pushing the layers apart.
Oh well, it works well enough. Better then the zip ties, at least.
Something to fix in the future.
I love the front box on my board. It takes up minimal deck space, protects the G300s from impacts, but still makes them visible. Plus, it give a pretty unique character with its silhouette.
But god, from a maintenance perspective, I hate the design .
If you remember, each G300s bolts to a piece of C-channel, which is then bolted to the deck from the bottom with 8 bolts.
If you have the eyes of a technician, you might immediately see the issue. The nuts for the bolts that mount it to the deck(bottom of picture) are impossible to access. Here’s a picture showing just how little space there is(featuring a small crescent wrench).
So crammed you probably can’t even tell what the picture is (it’s taken from the front, looking towards the back).
The first time I assembled the board, I superglued the nuts to try and make this assembly process sane. Of course, the superglue didn’t hold. I had to tape each nut to a crescent wrench and painstakingly thread each one. Imagine threading a nut onto a bolt with only chopsticks (cuz it’d probably be easier then this).
This weekend, I had to disassemble the front box to get at the USB ports to re-flash firmware. I’d be stupid to put it back together like this again, so upgraded to use clinch nuts. These nuts have groves
on them that cut into the metal, holding them in place.
This would’ve been great, if it worked.
Front Box re-assembly
My amazon-quality nuts made out of cheese metal would pop out with the slightest force.
With no alternatives on hand, I got creative with tools and tape to have the board operational by IE i2s.
Putting in the 8 bolts that mount them to the deck took me 2 hours. 15 minutes PER BOLT.
The clinch nuts made them easier to tighten, but I need to figure out a better solution next time I disassemble this. Rivnuts, perhaps.
At some point in the past few months, the box got bent off-axis
(ignore the angled connector, it was unplugged)
When it was disassembled, took some pliers and bent them back to a right angle. Presto
Front foot plate
Visible in the previous photo! Not sure if it’s shown up in previous posts at any point(don’t think so), but last year I 3D printed a small foot plate that slides onto the front box. This functions mainly to give a spot to press my foot against(instead of just the edge of the C channel), but also protects the wires inside.
Initial versions were held on with just a friction fit, and would frequently pop off and need to be put back on. They’d also break at the layer lines after a couple sessions(seen above)
To make the part, I actually took a picture of my foot position after being on track and brought it into CAD to model that curve
I made an upgraded version that bolts onto the front box. This should also stiffen up the front, preventing it from bending again.
Featuring heat-set inserts for frustration-free install.
I haven’t solved the breaking at layer lines issue, but I’m already planning a V3. Going to add a half-binding feature, and probably fiberglass it. (stay tuned)
Charging Harness Fix
The charging harness that I have installed (more detail about it) uses DSUB15 connectors to expose all of the balance pins. This setup plus my powerbutton has been blissful- takes more time to pull the board out of it’s bag then turning it on or charging it.
However, some things are obvious in hindsight. There’s a reason that battery balance plugs have plastic housings.
When plugging in one DSUB15 of the “balance harness” (the one with the blue wrap), the other DSUB15’s pins become live. I plug in this second one not straight, they can short on the metal housing of the other connector. Ask me how I know.
Instant spark, and the pin exploded.
New vs old pin, for comparison (xacto for scale):
Still had continuity, so I continued to used it for a couple weeks. Depin the two damaged pins, cut, re-crimp new ones, and re-insert em. Feels good to have that repaired.
The long term solution involves switching to a connector that doesn’t have this issue. I’d love to switch to the aerospace MIL-38999 series connectors we use at my job, just for the meme, but I’m not about to drop hundreds of dollars on two connectors
Anyone has suggestions for a good 13+ pin connector that can be panel mounted?
With all these repairs, the boards preformed admirably as IE i2s saturday. Had a super fun race against @Ruxx for top dog (I’ll beat you one of these days)
Thanks @MarioChacon for the photos!
(Shoutout to Aaron in 3rd, who managed to be within a few seconds of @Ruxx and I with a COTS board and flat tires. Respect!)
As with any project, still have a list of improvements to go!
- Still having bellypan scraping issues, might need to make a new one. I was comparing mine to @Ruxx’s yesterday, and it’s stark how differently ours are. It explains why I have issues and he doesn’t.
- Front Foot mount/hook/binding/composite thing upgrade
- Fix the split 3D printed Box Bracket
- New BRP tires. Time for the Ankle Wreacher B O L D
- Fix balance charging shorting issue. New connector? Custom PCB for mounting JST-PH? tbd.
PS, plugged my values into @Shadowfax’s calculator. I’m part of the 1000N club
PPS, I earned 12th place in BOTY 2024. Honored to have taken part, I feel accepted by this community. Thanks all who voted!
PPPS, I’ve taken to editing the 1st post with links to all my major update posts, for your browsing pleasure.
Pinging @frame to see if he has one.
That harness is a beaut.
Always fun to have mini races at I2S. Congrats on second.
SD20 14 pin
Beat me to it
This is genius for a rolling build thread
Captive nuts are your friend, my friend.
- Design a simple 2d plate with hexagonal nut pockets lined up with the mounting pattern. Have that laser-cut from SendCutSend out of whatever metal.
- 3d-print a cap that will hold the nuts in place in the metal piece (so they cant just fall out).
- Glue the 3d print to the metal captive nut plate, populate the captive nut plate with high quality nylock nuts (so you dont have to worry about servicing them anytime soon), and glue the whole assembly to the underside of your board lined up with the mounting pattern.
Now, when you have two or more bolts threaded, the bolts themselves will act as a wrench keeping the nuts tensioned, so you can tighten the bolts as hard as you want. And the captive nut plate will keep the nuts from falling out when you remove the bolts.
The “Road interface” Update!
I’m having fun with these names I’ll stop if it’s too much
Huge thanks to @MoeStooge for a new bellypan!
Might be the IKEA effect, but it looks siiiiiick. Excited to get a coat of paint/wrap/something onto it.
Measuring the flat bottom, It’s about an inch narrower then my old one and the sides are at a shallower angle. Haven’t ridden it yet, but can already tell it’s fixed the scraping issue. I can’t get anything to touch the ground even if I try.
Not only that, but we sized it so another two batteries could squeeze in there. Because why not.
16s, here I come.
YES, I know it's kinda stupid...
b/c it probably won’t fix my overheating issues(see post 49) which is likely being caused by iron losses.
I’ll also be pushing vesc ERPM limits (I calculate 178k, G300 max is 200k).
It’ll add even more weight to an already heavy raceboard.
so like, yeah
That acknowledged, I feel the need to explain myself;
A) I could use the additional energy capacity
B) It’s my understanding that going 16s won’t hurt anything, assuming an identical mechanical configuration?
C) two more batteries isn’t expensive (relatively speaking)
D) I see new motors in my future anyway
E) When has more lipo been a bad thing
F) [insert irrational rationalization #6]
It wouuuuld let me brag about my board being geared for 80mph, not that I’d ever want to go that fast…
Or I could throw 10T pinions on and have a 2+kN board. The possibilities are endless.
BRPs arrived last week
Fess posted a picture better then any I’ve got at the moment.
I’m now running 4x BRP 45A wides. Makes the “normal” BRP tires look like BKBs in comparison.
Still unsure if I’m going to keep this config. I’m going to race with it for a few weeks, see if it feels stickier (or if I struggle to heat them up).
I’ve been thinking about this comment weekly for the past several months. But every time I do, either my board is dead or it’s the middle of the night (apartment complex + 4x open gear drives don’t mix well). Better late then never, I guess.
Board was upside down and pinned at full throttle for several seconds.
58 battery amps at 48.5V.
2.8kW in losses in freespin
Looks like you’ve got the cursor on the high point of that graph before it drops and levels off. Is that high point your start-up current to get the wheels spinning, and the low leveled of part the actual no-load portion? Or is that high point the entirety of the test, and the low leveled off portion is after you let of the throttle?
HV no powah babeh. Lol. Look forward to hearing results
Yup yup. I was seeing comparable numbers on the display when it was running
Looks like you did the test at 12s so here’s a thought before you buy more lipos.
Moving up to 16s will make the iron losses worse than they currently are. Your free spin load could easily jump to 3.7kw.
Assuming you gear down the system with a smaller pinion, to keep the 50mph top speed, your motors rpm will be 33% faster than it currently is, all the time. This means more heat and worse efficiency.
Of course, I could be wrong about the source of your efficiency issues, but given the 2.8kw free spin, I think iron losses at speed are a safe bet. It seems unlikely you’d see high copper losses (resistive losses) with 4wd and those big chonker motors.
If you do move to 16s, it will be an interesting experiment to see if my theory is right or wrong. Very easy to test too. Just repeat your freespin test.
Yup, fully concur.
Probably won’t run a smaller pinion for this reason (except briefly for the meme)
Good point! I could plug 4 of my batteries in series right now and see how bad it is
he can then move to 8s4p if iron losses get worse. lol.
Working on stuff tonight