Are 50mm OR 63mm Motors Better on V4.12 VESC?

ESK8 Electronics
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True you can hide a systems short comings with reduced gear ratios and low speeds but it doesn’t change the fact that you will have an unbalanced system if using a VESC 4.xx

It has been well established that a single motor build is better with a 63mm motor but you really should be using a hobby rc type ESC that is rated for at least 150 amps unless you plan on going dual VESC. However I have overheated 6555 motors on a single drive board so it really depends on several factors.

There are a lot of different ways you can configure a system but everyone should know the VESC isn’t designed with enough throughput to power a 3000 watt motor to it’s full potential without overheating. Sometime I wonder if you even ride since you were so unaware that the VESC can overheat when limiting the motor current below 50 amps on large 63mm motors. Maybe you just don’t push it hard enough?

I think I have explained the reasoning to leave some headroom in your ESC in regards to the motor. Plenty of info on this topic in several other forums, just a google search away.

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I imagine Aus is pretty flat

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In America bigger is better. 63mm.

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this thread is a completely unhelpful mindfuck for the new guys. thanks fellas

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I’ve only run my VESC’s on single 6355 motors, and haven’t over-heated one. The only VESC problem was a solder joint that vibrated loose…

one is an Rspec on 16/36 gearing 83mm wheels limited to 40 amps with a space cell.

the other is a torqueboards 230kv 15/36 gearing on 100mm wheels limited to 65 amps on 6s

both go about the same speed, and both are around the same temp after long rides; warm to the touch, easy to hold your hand on the motor and not get burnt. I will say it is mostly all flat ground, but there is wind resistance by the river as others have mentioned, and little hills throughout my usual treck.

Now, I’m only 140ish pounds, but my dad is now pushing 210, and he’ll ride the Rspec board for a couple miles now and then with zero problems.

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but why do you insist on wanting to run 3kw into your esk8? I get it that you want to ride at super fast speeds but you already know that it causes problems with VESC.

You are one of the only people on here who continues to push the VESC past its engineered limits… that’s why you installed heatsinks, right?

But now you claim the issue is 63mm motors?..

Why not just use your ESK8 in a safe operating zone with plenty of head room?

Very few people want to ride single motor esk8 up hills at 32mph… I suggest from now on you start publishing your drive train setup & vesc settings with every statement you make, like it or not you are an influencer on this forum, you need to make sure your statements don’t confuse the masses.

Personally, I have no intention of riding at the speeds you like to ride at, in urban areas it’s just unsafe, it’s also well documented that speeds above 45km/h require a huge increase in power to get small gains. It’s inefficient & thats why you have been forced to use such large batteries.

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Here is a nice little instructional blog that may help you understand how to properly balance a system. http://www.modelairplanenews.com/blog/2011/05/29/choosing-a-motor-speed-control-battery-pack-taking-the-mystery-out/

Currently most of us are using the V4.xx of the vesc which has a max constant current of 50amps (1800 watts at 10s) so we need to expand the system requirements from there and work outward to find our motor and battery specs. Once V6.xx becomes available we will be able to use just about any motor we want and just make sure our packs can handle the load. You could of course use a high end car esc now if you wanted.

I completely understand that some lighter riders can zip up hills with ease on just about any setup. At 185-200 lbs I have to say I am jealous. Just accelerating too hard or too frequently will heat up your battery and esc if they are trying to power a motor that can draw more than the system can handle when you are close to 200lbs regardless of gear ratio. Some of us are savages!

It is better to pair the system with a motor close to the same spec and allow the system to self govern. If you have a balanced system and your motor is getting warmer than you want, adjust the gear ratio to reduce the load or go with a dual drive. This goes for 50mm and 65mm motors. You end up with a much more balanced and efficient system.

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Gents, I’m going to insert myself here and try to reel this thing in a little and bring it back to the more common ground for people around here that have a more average situation. Self serving? Sure. But I’m going to do it anyway. And, likely it’ll be good for the community at large. Both of you gentlemen, @onloop and @chaka are respected figures around these parts and both of you guys have a some great products. Even in this thread you’ve both conceded some points to the other. I think this 50mm vs 63mm motor discussion is a good one. And i really think to nail this thing down, maybe we should frame it in the context of a single drive motor and eliminate some variables. Shall we?

Let assume a fairly middle of the road setup with middle of the road aspirations. Our guy, let’s call him J1m0007, wants a top speed of around 20mph and has hills maxing out at 20% grade in his general area. He’s going to build a board in order to work towards those aspirations.

He doesn’t want to go face-melting fast. He doesn’t want to climb Mt. Everest. He doesn’t want to spend the next 6 months tinkering with different drive train components.

He’s going to buy an average board with average wheels, gearing and power: 83mm Wheels 36/14T drive for a 2.57 : 1 drive ratio. EDIT! I meant 14t Not 16 10s – because @onloop and @torqueboards and others make great plug and ride solutions and Li-Ion is dope.

Let’s assume J1m is the weight of the average male in the UK for the sake of argument 180lbs (~81Kg).

If you run the numbers here: http://toddy616.blogspot.be/2013/07/electric-skateboard-calculator.html J1m ends up with just the right amount of speed he desires.

J1m could pick @onloop’s 190kv 63mm Motor (6372) http://www.enertionboards.com/electric-skateboard-parts/6374-190kv-electric-skateboard-motor/

or @chaka’s 50mm 200kv Motor (5065) http://www.ollinboardcompany.com/product/om5065-200kv

Both of which recommend the gearing described above for a single motor setup on their product pages.

So, if J1m wanted to meet his criteria in a board AND protect the longevity of his components (VESC, Battery and Motor alike) heat exposure and related corrosion, which would J1m want to pick and, as @onloop is keen on stressing the importance of, WHY?

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I personally think that planes are going to handle power draw quite differently to skateboards, and wouldn’t be throwing that article out here… maybe an RC car one, but not planes.

my dad is over that range, and has a skateboarding/roller blading past- he knows how to ride fast, and does. Not once has he over heated the battery or VESC in the settings above.

I just don’t think as @onloop mentioned that many people want to go 30+ mph uphill.

My main point: it seems like before you started selling 50mm motors you never made a fuss about 63’s, and the general consensus on the forum was that people should buy the biggest motor they can afford. Now you start selling 50mm motors, and need some way to get people to buy them… how to do that? scare them into believing their VESC will fail with larger motors!!!

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Great question,

Firstly, there is no need to use 16T motor pulleys. It doesn’t put more teeth in mesh & it reduces your reduction ratio. I can’t think of any reason to use it, unless your centre distance is 53mm or less (which is likely impossible)

You should always try to maximise reduction ratio. 15T - 36T is the perfect setup with 5mm pitch belts at approx 66mm distance. Any smaller than 15T motor pulley and you should try to use an idler to get more teeth in mesh.

Every 50mm motor i have ever used has failed, mostly due to overheating.

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hey @onloop my bad I meant to type 14t! Thanks man.

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LOL…

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I hate the new guy they put in to replace Jon

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I have no intention of getting into an argument, but I believe the point that Chaka is trying to emphasize is NOT that 63mm motors WILL 100% kill your VESC. I believe he is simply trying to outline the fact that the V4.xx VESC are not optimized for larger motors and lack the “headroom” you need to really get the biggest bang for your buck out of 63s. @50A, the current iteration of the VESC is not designed to provide enough juice to coax the full potential out of those motors. So if there is not enough output from the VESC to power them optimally, it just makes a lot more sense that a smaller motor would be more efficient in that regard. It just seems really obvious to me that if the ESC is underpowered that you would not pair it with a motor that is too current hungry. From the link that Chaka posted from Modelairplanenews.com, “It is always better to have an ESC that is rated slightly higher than the amps you really need…,” Makes sense to me. This is aside from gear ratios. Yeah, you can def make it work. That was his point as well. Just be aware of the possibilities that an unbalanced electrical system can bring to the party. This knowledge could potentially prevent a serious injury as well. Remember the old saying, “Everything is fine, until the day it’s not.” :wink: Chaka has been generous enough to give us the inside information that he has accumulated from his studies and practical experience. You can bet that I check his work and cross reference it with as many sources as possible to verify the truth. Every time I do that with something that he has posted either here or on Endless Sphere, I find it to be true and it usually leads me down a very useful path in my studies. This is an opportunity…Not an argument, fellas. Watch and learn!! Test everything and hold tight to the good stuff! :smile: :v:

So based on the known and easy to reference fact that an ESC should be rated to exceed the spec of the motors…Then it’s safe to say that 50mm motors are indeed the “better”, more efficient, option for use with VESC 4.xx, based on it’s rated output limit. I think that is a fair statement. :wink: Real world application you want? You guys have seen this Ollinboardco vid, right? Singledrive>5065>170kv@12s and roughly 200lb dude. (Def not little dudes club!) LOL … Owning hills … Def worth 3 minutes of our time!

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That video is great but it’d be better if a laser thermometer was beamed at the motors at the end of that run and displayed in the video

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What I have a problem with is the assumption 63mm sized motors need so-much-more power to be efficient/work well, this is unfounded.

Has anyone actually got data to back this theory up? So why assume that a 63mm motor needs 3kw to operate efficiently?

As @chaka likes comparing esk8 with RC planes it would be worth using some of RC Plane industries common “rules of thumb” when determining how many watts can be fed into a motor without damaging it.

A common rule I have found HERE is the GRAM-to-WATT rule, it states 2-3 watts per gram of average outrunner motor is the target for safe long-term use, without risk of overheating.

2 Watts Per Gram is run-all-day constant current & 3 watts per gram is pushing the motor and only suitable for Bursts.

I have noted the weight of some common motors and compared that to the rated 50A continuous power output of the VESC

Pasted image870×1112 292 KB

*THIS IS NOT TAKING CONSIDERATION OF VARIABLES SUCH AS COOLING, MOTOR EFFICIENCIES & REDUCTION

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Really like that vid too. Yes, and the temp of the electronics as well. Info on temps of everything when It shuts down going up a hill would be good as well.

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In a perfect world what temp data on the motor and vesc need to be monitored?

Would make some interesting graphs to settle the question.

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Thanks for the data. Looks like the 50mm motors I am distributing are up to the task!

One very important point you continue to ignore is the fact that motors “pull” power. Another point you may not even be aware of is the fact that everytime you accelerate there is a burst of current, the amplitude of that burt is directly related to the size of the motor you are using. This burst is even more apparent when you apply braking current which explains the prevalence of abs-overcurrent faults on the 4.xx vesc when using larger motors.

The VESC is a wonderful device but it does have limitations and if you go past these limitations too far you are increasing the chances of a hardware related failure due to limits in processor speed in relation to amperage spikes.

@cmatson I have access to every motor available. I chose a 5065mm motor simply because it was a better fit for the V4.xx VESC. I am not forcing anyone to buy my motors and I still provide repairs for people who run larger motors on the VESC’s I build. I have always been open and truthful with my marketing and do my best to stick with the facts rather than fluffy window dressing.

There will always be times when my findings do not jive well with someones marketing strategy and those people will obviously lash out and try to twist the information into an argument. This will not stop me from continuing to push the limits and find the weaknesses of the VESC throughout it’s development and I will always freely share my findings.

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