Bro-kie broke MTB (wip) 12s(4p?8p?) Queries inside

Hoping to make a waterproof mtb, i am coming close to finishing up i think, i have a couple things id like clarification on or help with.
First, for soldering, I am planning on soldering the xt90s and 10awg between batt and esc enclosures. if i have flux core im pretty sure i dont need flux? I found flux core 60/40 at the local hardware was hoping i could just use that, but idk if i need specific thickness or anything else i figure its not thick enough i just use more, but idk if theres some chemical reaction barring me from doing so? This is what i have on hand

I am also at a bit of an impasse for my esc enclosure, this is my rough plan atm.
Excuse the dick i will explain.

I was planning on running batt wires in board, under enclosure, into enclosure above esc, and then plugged into esc xt90 on top of esc itself, and then running phase and sensor into the esc from under it, and then plugging into phase beside esc in enclosure. Upon more reading i heard through the grapevine longer wires are no bueno, so i want to plug batt wires in from bottom of esc case, but am slightly worried about clutter, and am lazy and dont want to pull apart geardrives to move motor wires to mount above esc. Again please excuse my childlike scribbling but like so.

Will that save me stress and issues? Please advise :sweat_smile:

I am waiting to recieve batt before deciding on that, but planning on drilling holes for 10awg, putting wires into box, and soldering xt90 inside, rtv silicone any openings in box and the box will be fermanently affixed to board, if i want to do 12s4p, will open box to swap batteries, but with reading i also hear that might not be too highly recommended, so might keep 1 big box still not sure.

Pics of what i have atm

Thanks for reading and any help is much appreciated

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Also planning on putting one of these over the wire between enclosures with some grip over top, hoping it will give me a bit of w concave on the back, if anyone has tried lmk

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Generally that’s correct, some things are easier with flux but decent flux core solder will do the majority of simple jobs

Thickness generally isn’t much of a factor other than really thin gets annoying when you have to keep feeding more solder in, what you have seems fine but as with anything, quality resources make the job easier. Kester solder has been a huge upgrade for me.

While this is technically correct, I’m pretty confident it’s much more of a factor in applications with
1: higher wire resistance
2: longer wire runs
Routing 25ft vs 50ft of solid core wire in a house will make a much larger impact than the difference between 2ft and 8in of stranded wire.

I bet @Pecos could elaborate on that.

I’ve been told not to worry about it.

This is how my wires are routed on this build;

I use baling wire to keep the wires from flopping around. So far so good.

You’ve kinda got 3 options here
1: like you said, drill holes for wires silicone around them.
2: cable glands, 1 individual cable gland for each battery wire + silicone is likely the most waterproof option but also the most work, usually looks kinda ugly, and could get in the way depending on your setup.
3: panel mount an xt90 and silicone around it.

I’m partial to 2 and 3 as it gives flat mating surfaces for waterproofing.

Absolutely no idea how this’ll go I feel like it would be too tall but I have no way of knowing that, interested to hear how this goes.

Good luck with the build!


For battery wires, as long as it isn’t something like a backpack remote battery or anything crazy you will be hard pressed to come up with a way to make the wires too long. Don’t have big coils of wire and generally shorter is better but the resistance difference between 1’ and 5’ of wire is negligible.

The motor wires on the other hand are a little different and you should avoid having feet of extra wire - i am not an expert but if i understand how the motors are driven there COULD be issues with extremely long (in our use case) motor wires creating issues having something to do with the capacitance effecting how the fets switch or creating some kind of feedback but it is beyond me and ive been advised to ignore it beyond just keeping them not unreasonable longer than necessary.


How bad was wiring it all up in the small enclosure? Do you think i would be able to make it neat enough to keep the seethrough lid, or is it going to look like my spintend is taking part in a tentacle porno? :sweat_smile::rofl::sweat_smile:

I feel like i have less space between the motors and the esc than you have in your pic, i could be wrong, but i dont like the amount of resistance when i bend my wires that way how they are currently mounted. I could probably do it but id prefer to rotate the motors 90° for convenience.

I will also probably steal the reflector back light idea as im too lazy, broke, and dumb to set up battery lights :sweat_smile:

As for the battery box, my initial idea was to set up#3 with the xt90 connector, but then battery should have female xt90 no? Putting a male out the battery, i am the 3rd of 3 idiots living in my house with a dog, and i wouldnt want anyone shorting the male xt90, and female is less waterproofable from my reading. So i have kinda ruled that one out, and i thought about 2, but i figured id just run both wires through 1 gland :sweat_smile: so thank you for that insight.

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It’s not awful but it’s certainly not something I’d want on display lol, a bit of effort and it could probably look pretty nice.

I think there are 3dp place holders you can use to protect the exposed pins when the battery isn’t plugged in, I have a cover over mine. That said if you have an on/off button for your ESC you should be fine to leave it in pretty much all the time, it’s pretty protected if it’s plugged in.

IME this is sub optimal, you’ll need a pretty oversized cable gland not to pinch your wires, plus the open space around the wires is a potential spot for water ingress.


Also, didnt think about this until now, i know ugotta balance tires on a car, but how do i go about balancing 3ds rims? No bearing seats? All the guides i seen assume i have bearings :sweat_smile::sob::sweat_smile:

Also, anyone passing by, whats the general consensus on uboxes catching fire? Is it worth just going the stormcore/makerx route? Might fix my wire mess problem too :sweat_smile:

Also will post solders for a consensus when i stop stressing and get around to it

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Ok, come shit on me one and all, cause idk about you but it looks like shit to me, pretty sure i knicked a couple strands stripping the wire

Gimme a min and ill solder them together poorly too :sweat_smile::rofl::sweat_smile::sob:

Fucked up trying to remove extra solder

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Do you have solder wick or a solder sucker? They were both really cheap and useful purchases for me

I’m personally scared of them but I know @haven and @Pecos are both (somewhat nervously if I recall correctly) running uboxes

I mean, you can’t really get a stormcore anymore except for if you get it from BKB, and I think there’s some consensus on not really trusting BKB to have sorted out the issues.
makerX has been good for me aside from slightly more complicated setup. The DV4S and the DV6S would both be a good candidate for this setup IMO.


I dont have solder wick, ill look into that, i have also been warned ill probs need a diff. tip or a better iron, so thatll be added to the list.

From my reading it seems as though its generally a fw/setup problem, so if i get it working im not too worried, unless someone else knows something i dont? gonna test off board first in case it does spontaneously combust, i wont have to rebuy multiple things :sweat_smile:

Not from bkb. i have a tab open always here with some stormcores fs, i keep debating, but i know the gf would probs kill me if i get more shit now :sweat_smile: but the idea of a black stormcore is overkill but kinda cool, and i dont need a 100, so i could always go the 60d route, if i were to get from bkb it would have to say xenithcore 100d in stormcore font instead of bkb in big ass letters for me to consider :sweat_smile: but at that price :grimacing: idk i could make a board entirely out of flipsky parts for that much?

Just my experience but I could not get anything except 5.2 to run stable on the ubox. I may have had some additional can issues because mu bms can was terminated incorrectly for the vesc which is also not terminated per can spec but whatever it was - not using can and rolling the fw to 5.2 has been very stable and as reliable as vesc can be on the ubox. I don’t push the limits on it - 60a battery 90a motor and fault time at 80ms. GL


my v1 ubox has been flawless on 5.2/5.3, never bothered upgrading firmware since I didn’t see a need

i run it pretty hard lol, 120 motor amps per side and 65 battery… for that reason I’ll soon be swapping to a DV6pro and then using the ubox for a lower powered thane build

however, that’s not to discount the many cases people have had with uboxes breaking or catching fire - it does seem to happen more than with other VESC options lol

but, fwiw, my ubox just refuses to die. love the thing, remote receiver/BT is built in for my model, plus it has lighting control


Thats good news to me, im pretty sure mine is also v1, with micro usb :sweat_smile::rofl::sweat_smile: i dont plan on pushing it too hard, so im hoping ill be safe. Not a huge fan of the uni1, was also debating getting a voyager from spintend cause im pretty sure it retains all capability, not that im planning horn or lights atm. But maybe eventually :sweat_smile: