Another Spintend blows up.
I was just running motor detection, the motor on that side froze, and it blew. Luckily I had my hand on the loopkey and pulled it fast.
I can replace the fet the pcb underneath it is fully intact, I can replace one of those other little chips there are solder pads under where it was, but there is a crater where another used to be, not sure if it was 100% necessary. Could it live again this way?
Alternatively does anyone know of a cheap Ubox that’s blown up on just one side or has an intact power stage pcb?
Alternatively I might be able to reverse engineer a couple new pcbs from jlcpcb or somewhere because they only have a 2 digit number of components on the whole power stage. But why could this have happened?
Spintends would suit what I want to do for a
race-ish board in the future
Next up.
I want to go to esk8con maybe in 2 years, so I will need a different battery I can fly with. I believe some airlines allow 20 batteries up to 99Wh on the carry on, so a 20S7P with realistic Wh numbers is perfect and fits well. Being able to disassemble it will work perfectly with how I want to use an offset stack, make the series connections in the awkward space in the middle and use copper instead of nickel tabs due to how I am connecting the corner and not middle. Can I just bolt together each copper tab?
I can hear “What if it flexes?” I router a slot in the deck for steel.
VESC + inrunners?
20S is too much for my controllers and a waste on my motors, so I will change to 17S/18S/19S8P which will unfortunately take another 6mm of clearance in a turn. I could take this as a good excuse to swap the mosfets for some stronger higher voltage ones like DSU011N08N3A (data sheets linked) instead of FDBL0150N80 The rest of the controller is good for 18S if not more, and I am pretty sure these Uboxes have been used on 18S in Kalys and the mosfets are 80v. Encoders, short wires, fast gearing, extra capacitors and charging a little lower can’t hurt. More on this + rheostatic braking later.
And customisable kv.
A normal charger and bms is new to me and actually really expensive, I have been getting compact adjustable volt/amp charging at 1.3kw from 2 server power supplies I got for <€20 and LiPo chargers I already had.
I want to compete in drag races and maybe borrow a racebox at esk8con.
17-19S8P of Bak 45D (tabless 21700s) will handle more than enough amps, a Ubox will do 110 battery amps per corner for a second, with 110T mod 1.5 gears I can gear down lots, so maybe I can set some good 0-30mph times without much max torque. I am pretty confident if I get it tuned decently or use encoders I can run 150A motor or more, my 63100s are very well battle hardened and the Spintend is rated to 180 and has been used much harder by some. Don’t get me wrong normally that much current will have momentary spikes to like 270A which would be a fatal blow to the flipskies but with encoders I can get it down a lot.
Build format + enclosure
I am going to wet lay CF my own enclosure so I can fit the extra thin and narrow pack down to the curve of the cell.
I have been doing the CAD to make sure it might fit under a Deathwish which would be great for the extra standing platform but I do quite like how brackets look and I can get a lot of drop without ending up 5ft long. I think the Trampa 8x4-3" slicks will be great.
Did you know an offset stack with a bottom cell moved to the top is actually better in a turn than a normal offset or an overall smaller wider single stack? It will be a max of 40mm tall and 126mm wide at the tallest part. I am tempted to do a wide single stack which is worse in a turn but good for ground clearance.
I want to use these typically 16S VESCs on 18S so I plan to find a ubox already used for 18S with rheostatic braking stuff included from an old Kaly for the front controller (long battery leads and most of the braking). I am hoping to get one from a Kaly XLR that also has those adjustable dampeners that tighten at speed w/ the VESC servo plug.
This is what it looks like under a Haero Bro which is a good bit shorter for example, so doable with a custom enclosure but I might loose access to an inner truck position or 2. It would be great to get the files for a Deathwish 42 I made some rough ones myself from pictures but proper ones including concave would be awesome. I am pretty sure there used to be a Deathwish 45 one of those would be great. If I can’t fit 2 Uboxes lengths and 9x 21700 lengths and 2 motor widths between the hangers it might just need a top mount VESC box.
Gears and motor mounts
4wd will be great for the extra top end power and no longer always skidding on the brakes, I already have 2 extra sets of motors I just need to trade for some lower Kv’s. Reckon throttle and brake simultaneously with a dual trigger will do a burnout or instantly explode?
I may as well make spur gears because 3 sets of belts will pay them off, I am lasercutting motor mounts anyway, I want more torque than speed on high rpm motors w/ 8" plus. I also made my 80T pulleys way too heavy.
Largely because of Project Endgame not accelerating faster with more amps and how I think it’s because of radial forces messing up gear alignment or something in the wheel hub or motor, I want to make the gears as big as possible to reduce the radial forces, slow wear and achieve big gear ratios for inrunners. I am designing the motor mounts to fit the base of the spur gear and I think I should have a bearing inside the spur gear as well. I think lasercutting from 2-3 mm Hardox 500 and stacking layers is going to be best. Will probably be 110 tooth mod 1.5.
I am cheap, lasercutting gears anyway and need the c2c smack in the middle of Idea mid and large sizes. I will buy some 20x20 clamps from Boardnamics unless someone has cheaper, measure the hole spacing and make some plates that bolt on.
This is largely inspired by the earlier Raceboi, I am ripping off some of Split Decision with the split angle drop brackets atm and then doing the same enclosure process, as well as the Dream Chaser truck and deck combo. There are a few things I would not have thought of without Bog Roosh like an extra internal layer for battery waterproofing, adhesive on loose motor wire strands and the headlight foot switch.
But first I want to rack up a few thousand kilometres.
Rated to 180A phase 110A batt 18S / side, has been used to much more by some, possibly plus an improved Alu pcb, cheap, servo outputs, rheostatic braking, and I don’t think there are any really more reliable options available and if I can make and replace power stages easily it wouldn’t be an issue to kill some.