hi everybody!
this all started more than a year ago when not many 4wd builds could be seen and I wanted to build my ultimate painkiller, which would solve all the pains of boards for street:
the pain
- not enough range
- not enough speed
- not enough torque
- belt skips every-fucking-time when you want to break a bit more
- not long enough deck so less stability
- too much tinkering and spending time fixing issues
the solution
building something that solves all of the above
so I ordered redember 44 from @jamie. some time passed and I pulled the plug and ordered gear drives and adjustable baseplates from @3DServisas.
then the deck arrived, in all its 44 inches of dick erecting glory
recently new motors were acquired (173kv, 86/107 rated/max amps at 12S, capable of 18s)
the problems
well, first of all, I got my hands on the deck 366 days after the inquiry. sheesh, that’s a lot of time. this is solved now.
secondly - the battery and the vescs. a number of cells in each P group is certain - as much as humanly possible to stick under the re44 in 2 layers. the number of S groups is first catch.
I see two routes to go - HV and standart 12s.
higher voltage means higher speed and at this point, voltage and wheel size are the only variables I can adjust (kv and the gear ratio is set). at 12s with 150 metro boards tires its close to 60kph which sounds nice, with 8" tires it’s 77kph, which’s manageable. at the higher voltage, the speeds are through the roof and I’m not sure if I want to sacrifice the torque.
-
go higher voltage
- problem 1 - 100ds are not thaaat much tested and I’ve not seen anybody riding them ad 4wd, so it’s not gonna be just no-injury plug&play. also, @Deodand, can you switch both of them with one button?
- problem 2 - @Trampa HV vescs are fucking expensive for 4wd! Ubox could be a solution
- problem 3 - too much speed?
- problem 4 - too much uncertainty of uncharted HV territories?
-
stay at 12s
- problem is which vecs? 60D? trampa mk6? trampa HD? unity? makerX?
I think one more variable I should mention - I chose to abandon the sensors - although the motors have them, I got used to the convenience of only 3 beefier wires and ditched the pain-in-the-ass sensors. a year ago sensors were necessity but after two boards running HFI on unity it seems like more work than use. and I also somewhat remember what happend to @glyphiks when he sanded his wires off.
what I’ve not seen before is the arrangement I plan to have (if battery would be 12s12p):
motivation is space, where vescs at each end take up too much space where the battery should be thickest, and longer phase wires are (what I read, heard, and used) more electrically stable than longer battery wires (due to higher impedance and current spikes). problem might be temperature, but lots of people are riding 2wd without a heatsink and inside the enclosure. there should be less heat dissipated per vesc at 4wd.
and the space in the middle next to vescs will be used for junction of balance leads from the batteries (so that it behaves like one), neptune 15 connection, buck converter for LEDs epoxied between layers of enclosure and reciever/s
I’d love to fit dzus fasteners to hold the enclosure! all the electronics will be mounted to the deck, so for a quick look or debuging something, just turn 8 screws 90° and be inside the enclosure.
I’ll try to build this board slower and more consciously rather than faster and prone to breaking electronics or bones
so guys, what do you think of the vesc dilemma I have? which way would you go?
well you summed it up quite well, I might be more specific - we’re having quite a different places to ride here in prague/czech republic
he’s riding unity, 12S12P 30Q, the same motors and 8" tires