Motor size and ESC questions

F

Fender

10 µW
Joined
Aug 4, 2015
Messages
6
Hi! I am currently researching parts to build an electric longboard. I have read a lot of good Endless-sphere threads and blogs, and I am still having a bit of trouble deciding on a motor and ESC to go with it.

My longboard will be powered by a single motor. Lots of people use Turnigy SK3 63mm motors, but I want something smaller in diameter. I came across this Alien Drive Systems 5065 motor (http://alienpowersystem.com/shop/50mm/alien-5065-outrunner-brushless-motor-270kv-2200wa/). Would it be a good decision to buy this motor over the Turnigy SK3 63mm (lots of which are on backorder)? I live in a hilly area, so would this be able to ride me up and down hills (I weigh about 120lbs if thats relevant)?

I have read a lot about ESCs. I saw an Endless-sphere thread where a guy used a 120A Hobbyking Boat ESC, and another where somebody used a 90A Hobbyking Boat ESC. I really like this idea because it is quiet, cheaper, and provides more subtle braking. My only problem with this is that the HK Boat ESCs are large and rectangular. I've researched boat ESCs that are smaller and more square (like car ESCs), but I cant find one with a "forward with braking" mode. I have no problem with purchasing a 120 HK Boat ESC, but I was wondering if there were any other options. It may be worth noting that I will be using 2x 3s 30C 5000mah bats in series.

Thanks!
 
Weight and how you will ride it are critical to which motor (or motors) you use.

Why do you want to use a single smaller motor vs a single larger motor? weight or clearance?

The other part you aren't touching is kv. How many rotations per volt basically. Lower kv motors are better for torque and hills (combined with gearing which you haven't mentioned). I'd recommend getting a calculator for speeds (motor kv + size wheel + # series (6s, 8s, etc.) + motor gear + wheel gear (# teeth) = top speed). I have set mine up for slower speed which would work better for hills and wanted to limit my top speed to 25mph or so.

So getting a lower kv motor will help with hills, but go slower overall. Simple'ish. I'd recommend a lower kv motor unless you are trying to build something to go super fast. 200kv or less if you can find one in stock somewhere.

My testing (also weigh two of you) was that a single 5065 200kv motor on 6s is SLOW, and doesn't do hills very well at all. That same setup (same wheels, same 6s) with a 6354 200kv motor = much better!

ESC - don't get a boat ESC. Get a car ESC. Seems like the XERUN and FVT with programmer card works pretty well. If you can find one, i'd recommend the VESC as the best option. But you need some computer and basic soldering skills to build/configure it to your best benefit. You have to configure the motor to the individual ESC at the minimum or it won't work or will damage the VESC.

I'd recommend starting with Torque's "how-to" tutorial in the sticky. You might also check out his site which has good proven kits depending on your budget. He won't push you to his site, but his and onloops have great setups you can start with! (Torque's - www.diyelectricskateboard.com or Onloops - www.enertionboards.com). My personal experience with APS was not so great, but ADS - http://www.aliendrivesystems.com (two different companies) was fantastic. Largely would depend on where you are at (States vs UK).

What motor mount, board, and trucks are you going to use?

HTH - GL!
 
for hills and a single motor, you still should probably go 63mm. enertion has one that I have been using for a little while: http://www.enertionboards.com/electric-skateboard-parts/190kv-electric-skateboard-motor/ and diy electric skateboard has some 50mm motors if you still want to go smaller: http://diyelectricskateboard.com/product/50mm-electric-skateboard-motor-5065-200kv/

I'm around 140 pounds, and the enertion 190kv 63mm motor shoots me right up hills even on 6s. on the other hand, I have a 245kv 50mm motor that really struggles to get me up hills on 6s, and runs pretty hot...

for esc's I would honestly just get a car esc... boat brakes in water are very different from braking on land with a 120 pound rider. Again, you could get an esc from diy electric skateboard for $70. its also fully programmable if you want subtle braking: I know its more than the $44 boat esc, but I think its the better longterm buy.

long story short, the boat esc might work fine for a little while, but from the looks of it I think it was designed to be water cooled, and the brakes might not be that great out of water... Without cooling, especially with hills, you run a high risk of burning out you esc- without descent brakes, especially with hills, you run a high risk of hurting yourself...

if I were you I would just change to a car esc of your choice, and then decide on the motor- 63mm if you can do it, but if you really want a smaller diameter, you should be ok with 50mm in the end.
 
I started writing before I saw sl33py's post, but I pretty much touched on what he said, and agree on all his points...
 
Good point from cmatson on the boat ESC and cooling. Especially the brakes part if you are wanting to do hills!

again if you get any of the ESC's that have programming cards or USB programmers - GET IT! You absolutely need to adjust the brakes. ALL CAR ESC's ARE GOING TO NEED ADJUSTING. We are using a car ESC to haul a full size human instead of a couple pounds of plastic!
 
sl33py said:
Weight and how you will ride it are critical to which motor (or motors) you use.

Why do you want to use a single smaller motor vs a single larger motor? weight or clearance?

The other part you aren't touching is kv. How many rotations per volt basically. Lower kv motors are better for torque and hills (combined with gearing which you haven't mentioned). I'd recommend getting a calculator for speeds (motor kv + size wheel + # series (6s, 8s, etc.) + motor gear + wheel gear (# teeth) = top speed). I have set mine up for slower speed which would work better for hills and wanted to limit my top speed to 25mph or so.

So getting a lower kv motor will help with hills, but go slower overall. Simple'ish. I'd recommend a lower kv motor unless you are trying to build something to go super fast. 200kv or less if you can find one in stock somewhere.

My testing (also weigh two of you) was that a single 5065 200kv motor on 6s is SLOW, and doesn't do hills very well at all. That same setup (same wheels, same 6s) with a 6354 200kv motor = much better!

ESC - don't get a boat ESC. Get a car ESC. Seems like the XERUN and FVT with programmer card works pretty well. If you can find one, i'd recommend the VESC as the best option. But you need some computer and basic soldering skills to build/configure it to your best benefit. You have to configure the motor to the individual ESC at the minimum or it won't work or will damage the VESC.

I'd recommend starting with Torque's "how-to" tutorial in the sticky. You might also check out his site which has good proven kits depending on your budget. He won't push you to his site, but his and onloops have great setups you can start with! (Torque's - http://www.diyelectricskateboard.com or Onloops - http://www.enertionboards.com). My personal experience with APS was not so great, but ADS - http://www.aliendrivesystems.com (two different companies) was fantastic. Largely would depend on where you are at (States vs UK).

What motor mount, board, and trucks are you going to use?

HTH - GL!
Click to expand...

Thanks for the great advice! I will definitely use that formula and look into car ESCs now. To answer your question: I will be making my own motor mount in CAD. It will attach to Caliber II 50 trucks and I will be riding a Bustin Boards Maestro 38in deck.
 
Great deck and trucks. I forgot to mention - Welcome to ES! Great community of folks that will help you figure this out.

If you are going to make your own motor mounts you can set the angle however you'd like. One feature i like about Onloop and Torque's latest generation of motor mounts is the adjustability for angle to clear your deck. Worth looking at if nothing else as a starting point to make your own!

If you want to do hills, and only 6s... i think you are going to want the 63mm motors (</=200kv). 83mm wheels, 200kv, 6s, 15/32:
Diameter Motor KV Battery S/V M pully Hub pulley

83 200 6 15 32

Speed= KPH 35.20611
Speed= MPH 21.2085
actual speed 17.81514

There are other calculators online you can find. This was from an xls sheet beetbocks sent me.

Again - welcome! GL!
 
Or spend more bucks and get a 50mm scorpion motor. As strong as a 63 and smaller. Their sizing is different and goes by the stator diameter which is 10mm smaller
 
bigfoot 160 is a great motor from what i hear, but at 245kv it's not as well suited for hills in a single motor setup is it?

Gearing obviously will help, but wouldn't it be better to have a single 160-200kv motor vs 245kv either way for hills (not as fast top speed obviously). At 120-140lbs hills shouldn't be too bad w/ only a single motor. A >6s setup to use full wattage of motor would be even better...

Fender - any luck finding an ESC you like? What's your budget and maybe folks can make recommendations?
 
sl33py said:
bigfoot 160 is a great motor from what i hear, but at 245kv it's not as well suited for hills in a single motor setup is it?

Gearing obviously will help, but wouldn't it be better to have a single 160-200kv motor vs 245kv either way for hills (not as fast top speed obviously). At 120-140lbs hills shouldn't be too bad w/ only a single motor. A >6s setup to use full wattage of motor would be even better...

Fender - any luck finding an ESC you like? What's your budget and maybe folks can make recommendations?
Click to expand...

Sl33py, I'm not quite sure what my budget is because I may be receiving some funding from my school. I came across Enertion Board's VESC. This ESC is expensive, but I think it is well worth buying because of its small size and useful features. I've also been looking into EZRUN 150A pro as its been very successful in a lot of e-boards.

You mentioned using more than 6s to use more wattage. Could you explain this? If I was to buy a 190kv motor, how much more useful is a, for example, 8s setup?
 
Hey Fender. I'll try to explain.

There's a trade-off. Higher voltage usually equals less amps needed (runs cooler), and the higher voltage equals more power output from your motor (wattage). More wattage will give you more torque/power for your single motor setup.

Disadvantages - cost! A much more expensive ESC. Most hobby ESC's are 2-6s, and they get significantly more $ for >8s! Vedder's VESC is phenomenal and very reasonable if you want to look there and can find one for sale (or build your own!). With appropriate DIY skills you cannot go wrong, but do have several steps to build/configure to utilize it fully (or at all).

Batteries get expensive too when you want to run >6s. You can compromise to smaller capacity batteries to save $ (and weight), but that limits distance. Carrying spare batteries a good way to mitigate if easily swappable. High mAh + higher voltage (say 2 x 4/5/6s in series for 8/10/12s) is the costliest option. Nice not to have to swap batteries, but usually also heavy (my board is ~20lbs currently). I have 8000mAh capacity and 8-10mi range depending on terrain and acceleration.

Be careful getting >6s batteries for parallel (double capacity/range instead of double voltage in series). Most chargers max at 6s lipo, and >6s (8/10/12s) chargers get spendy quick. A good charger is really a must have in my opinion. Quality/accurate balancing of cells equals longer life of your batteries and reduced risk of damage to the cells (less likely to puff/swell/catch on fire). Just research common sense charging safety (ceramic bowl or charging bag, never unattended, etc.).

Don't underestimate gearing advantages - you can gear lower with higher voltage. More torque and still reasonable top speed. I target a top speed of 20-25 generally. Onloop has some nice 3 gear sets to dial yours in, or run your calculator and gear as low as you can with the top speed limited to what you expect you'll need at the fastest.

Tons of ways to slice this... others with a lot more experience than me can likely help more.
 
One more comment on speed. Considering that most people-mover solutions max out around 12mph (E-go, Onewheel, solowheel, etc.), it's surprising how much fun that speed is. More than that is nice, and the nicer store-bought boards (Boosted, Marbel, etc.) usually max out 20-25mph. You'll see some crazy folks here who have gone faster but i'd say reasonably fast is somewhere between 12-18mph. Over that is fun on occasion but not necessarily used frequently. Your skill and pedestrian/car/road conditions obviously might make that easier or harder.
 
sl33py said:
bigfoot 160 is a great motor from what i hear, but at 245kv it's not as well suited for hills in a single motor setup is it?

Gearing obviously will help, but wouldn't it be better to have a single 160-200kv motor vs 245kv either way for hills (not as fast top speed obviously). At 120-140lbs hills shouldn't be too bad w/ only a single motor. A >6s setup to use full wattage of motor would be even better...

Fender - any luck finding an ESC you like? What's your budget and maybe folks can make recommendations?
Click to expand...

You would think 245 is too much, but I have a friend who ways around 230lbs and this motor on 6s gets him up hills. Nothing to big, though.
 
mccloed said:
sl33py said:
bigfoot 160 is a great motor from what i hear, but at 245kv it's not as well suited for hills in a single motor setup is it?

Gearing obviously will help, but wouldn't it be better to have a single 160-200kv motor vs 245kv either way for hills (not as fast top speed obviously). At 120-140lbs hills shouldn't be too bad w/ only a single motor. A >6s setup to use full wattage of motor would be even better...

Fender - any luck finding an ESC you like? What's your budget and maybe folks can make recommendations?
Click to expand...

You would think 245 is too much, but I have a friend who ways around 230lbs and this motor on 6s gets him up hills. Nothing to big, though.
Click to expand...

True - it's all relative. I'm about 40-50 lbs heavier than your friend (6'8"/2m helps), and my goal was similar to the dual+ that accelerates up some pretty good hills with a 160lb rider. Quite a bit more demanding to haul another 110-120lbs up that same hill.

I haven't figured out how to gauge a hill's grade (10%, 15%, etc.). So i can compare with what they claim in marketing. Though riding my buddies dual+ it's pretty impressive even w/ me on it. Except range.

Edit - found a cool "how-to" for determining hill grade. From http://www.bikesatwork.com/blog/how-to-measure-grade
Measuring and calculating grade is simple and requires only a level and ruler. For accurate measurements, you will want a level at least 18-24" (45-60 cm) long. If you don't have access to one that long, you can tape or rest the level on a straight edge instead.

Rest the level (or straight edge) on the ground. Lift up the lower end of the level/straight edge (i.e, the end nearest the bottom of the hill) until the level measures level.
While holding the level/straight edge still in this position, measure the distance between the end of the level and the ground using the ruler, as shown in the image below.
Calculate the grade by dividing the distance measured with the ruler (the "rise") by the length of the level or straight edge (the "run") and multiplying by 100:

% grade = (rise / run ) X 100
measuring the slope of a road using a level and ruler

Measuring the grade of a street
measuring-grade.jpg

In the image above, the end of this 18" long level, when it is horizontal, is about 1-1/2" above the roadway. Using the formula above:

grade = 1.5" / 18" x 100 = 8.3%
Click to expand...
 
Don't see anyone doing that ever. Nice picture. Looks like an optical illusion. I keep looking at ur glove.


kv and gearing are interchangeable. Just get a bigger gear ratio for the torque. The gear combo can be limiting if u have small wheels. Get as small a motor pulley as u can. Look at the gear calculator at the pulley store. U can get like a 14 if ur mount is a bit long. 6 teeth engaging is in the green
 
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