Noob question thread! 2020_Summer

I have a flipsky 6384 and a FSESC 6.6, the motor came with a sensor cable that don’t fit into the ESC. There is a extension from the sensor cable with another ending but it also doesn’t fit into the ESC. Do I need to buy another extension for the sensor cable or am I missing something?

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Can you give us pics of your motor sensor cable and your ESC sensor port? Cant really advise without knowing what you’ve got.

There isnt one standard connector for this in the RC world (though in esk8 JST PH is fairly standard on VESC based ESCs), so you’ll see all kinds of shit on both the motor and the ESC sometimes.

Nope, its less efficient.

The higher your gear ratio (AKA more torque) the less hard your motor is having to work.

Spinning a BLDC motor faster takes a marginal current increase. Getting more torque output takes a hefty current increase. That increased motor current needed to get more torque not only consumes more energy, it also heats your motor and ESC more, which in turn means you are loosing efficiency to heat.

For best efficiency you want the highest gear ratio you can get for the top speed you want. If you want your esk8 to go 25mph and have enough torque to climb trees, then gear for 25mph. If you want your esk8 to go 35mph, then prepare for worse efficiency and higher motor current.

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You can simply not connect the sensor cable and use HFI.

What is HFI and how do I use it?

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Thanks! Can I also use this on motors without the sensor cable?

yes

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Thanks, so there’s no downsides in keeping the throttle pegged all the time in terms of efficiency? If I were to do a gear change, what top speed should I aim for? The one time I did check amps usage was going uphill at about 75% throttle, which was around 4A, so I think I should have a reasonable amount of headroom. The motors are barely warm after a half hour ride.

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Well now, i didnt say that :sweat_smile:

On the same gear ratio, running at full speed is somewhat less efficient than running at a lower speed. This has more to do with air resistance increasing as you accelerate, but it also had a bit to do with the efficiency curve of our motors. There’s an RPM which your motor is most efficient at, and it ain’t 100% lol. (I dont know what it is for your motor, so dont ask :joy:)

That’s a personal question :man_shrugging: How fast do you want to be able to go, and how much torque are you willing to sacrifice?

That number seems highly suspicious to me. Still, pumping up the motor amps to get torque back isnt exactly hard. It’s just worse for your motor, and less energy efficient.

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I do remember seeing that core losses and iron losses balance out somewhere in the middle of the RPM range, which is why I was thinking it would be more efficient to run a slightly higher speed gearing and just stay in that efficient zone. However, I think that assumes constant amperage?

Yeah, but I was just wondering how fast people tend to go in group rides or in traffic. What’s the slowest you feel comfortable riding in 35mph traffic? I’m personally thinking 28-30, but I’m having trouble finding a 13T sprocket :smiley:

Me too, although that’s what I remember was displayed on the remote telemetry for both battery and motor amps. The entire thing seems suspiciously efficient compared to what I expected in terms of range. Granted I haven’t charged my battery to full yet or did a range test, but a 6 mile mixed terrain ride in 45 degree weather went from 3.8V to 3.6V, which seems low for a 620Wh battery on knobbly pneumatics. The remote’s dying way faster than the board is.

About to buy a multimeter for something non-Skateboard related but figured I could try and make sure it’s suitable if I need it for skateboard repair/DIY. Will a standard 10A fused multimeter be ok? Or do I need to fork out for something better?

Thanks

It will be fine. Make sure it can measure DC voltage up to 100V

You’ll almost never or actually never be measuring current above a few amps.

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What’s the best way to store small tires such as some Bergmeisters I have stashed away…

Vacuum bags kept in an indoor closet?

i usually just keep mine in plastic baggies with some chalk smeared on them; it keeps them from sticking together

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How could I go about creating a 3d model that mirrors the curvature of a deck? Is there another way (i feel like there is a way with math) to find the curvature without having a contour gauge and plotting points on a grid to get the rough curve?

Get a stiff flat material like cardboard or wood, hold it perpendicular to the deck, and trace the deck profile onto it with a pencil laying on its side on the deck. That should get you an outline of the contour, which you can then take a picture of and trace again in CAD.

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What is a good height to aim for from the bottom of the enclosure to the ground?

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can i replace 6900 (22x10x6) bearing with 608 (22x8x7) bearing in a pulley that uses 2 bearing each side? im 100% sure that the bearing seat won’t be deep enough for 7mm width unless i lathe it, i just need to know if it is workable in that way, i won’t be running them in high speed or anything, will be sub 25km/h speed for its lifetime

@b264 maybe u know?

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When I connect R+ to battery positive and R- to battery negative there is a pretty large spark every time. It is a 13s pack charged to 49v. What am I doing wrong?