I want to mount a battery far away from the VESC but I don’t want to kill the controller. I was looking at adding this cap:
https://www.mouser.com/ProductDetail/EPCOS-TDK/B43415C8308A000?qs=Aj7me2ELROLn2v1mSJjLdQ%3D%3D
Would that work for about a 5ft run of wires? Any better suggestions for caps? I thin I need about 220uf per 4 inches.
Metric is your friend.
dont need that expensive cap. few of these or similar will do: https://www.mouser.se/ProductDetail/Nichicon/UHE1J681MHD?qs=sGAEpiMZZMvwFf0viD3Y3Qfkdtx73YnmMXJ9t2r2sgk%3D
make the phase leads long instead if you can. I just read an article detailing why. Pretty sure the problem will manifest itself as “ABS_overcurrent” errors and possible poofing. the caps are a band-aid, but the cure is short batt leads. lemmie see if I can find the article…
Can somebody explain to me why long battery wires are a problem? I’ve always used short ones because of how i build boards, and generally keep my phase leads short as well if possible but have found that the length of phase leads doesn’t matter much within reason, jake has some over 2 feet long on his old board.
Sounds like a backpack battery with 4ga wires going to the board
Inductance (magnetic field) built up in the battery wires (Just like in a motor) creates a voltage spike when collapses. So when disconnecting there’s a high voltage for a fraction of a second. On the motor side of the esc it’s not a problem for some reason
And the shape of the wires also effects how much inductance is produced. With battery wires that have both black and red as close as possible i think reduces both the inductance and also possible radio interference it can produce.
Tell me if I’m wrong someone.
It’s an inductance thing, the way electronics work is that some components (including long wires) have enough inductance that spikes of current draw take a long time to subside so you have more current trying to force it’s way into the ESC than the ESC wants to draw and it isn’t good. Think of it like the momentum of the electricity
You can reduce the inductance by tightly binding the battery leads together, the magnetic fields overlap and it cancels out to a degree
here is one explanation
Those guys at rcgroups know everything. The plane guys study every minutia related to their stuff
Their batteries are too small and they don’t have all the fancy mechanical stuff to deal with…they have nothing else to do but be nerds while their lipos charge
@hummieee @ZachTetra Thanks! I can wrap my head around that now. So i assume the caps are there to buffer the spike.
Ok so maybe jake burning out every ESC I’ve ever given him was because of this. His boards are huge, his batteries are never near the ESC… Things are adding up, his last for weeks, maybe months if lucky.
They really utilize their stuff and get the most power out of these motors possible. I feel like all the motors we use are more so designed for them with thin back iron and not much magnet fill. Good for spinning super fast and being light.
We have definitely been using model airplane motors this whole time.
I started out on NTM 270kv 5055s after i ditched the 50xx R-Specs.
Is there that much of a better way to make low kv motors? I know the small can and high kv motors run really efficient but it that a law of brushless motors or just the specific design that they are based off of?
Was looking into making some “skate” specific motors
