Same rate, but the 5065 climbs faster because the VESC does not overheat.
In this comparison both motors were 170KV at 12s
In a dual configuration you will likely not pull enough power to find this weak link but the 50mm motors are definitely more efficient.
As far as the vesc, I see what you guys are saying, a bigger motor will be able to draw more current. Are we comparing two small motors to one big motor? Here is a graph I dug up on the interweb from this article
Im assuming this to be general to all brushless motos, can we dig up graphs on real world motors that you guys have used? With efficiency and current data as well?
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If the current is limited in the VESC firmware why would it get hotter on the larger motor? for the same load & same current surely the larger motor handles the load better?
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If you load up a motor on a steep hill it will still overheat the vesc regardless of the current limit. It is definitely harder to induce on a dual drive but possible. You still need to follow some of the guidelines set by the RC crowd. Just because you have a vesc doesnât mean you can be ham handed with your setup if you want an efficient system
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Whatâs the reason there are no heat sinks on the vescs?, new to esk8âs, weight reduction? space? I would assume those mosfetâs can get pretty hot?
@chaka: Your words made me a bit doubtful if my planned setup is good for me.
I ordered a 190kv 6355, VESC, 16/36, 10S
I used a calculator which even involves riders weight and the result was that climbing a 15 percent hill with about 20 kph only takes about 780 watts / 22 amps. So why should the VESC overheat then? My weight is only 65 kilos + board.
What is the max no-load speed of the motor your using? Think about gearing it so half your no-load speed is the speed at which you want to go up the hill at, then you will be on the power peak of your motor as well. If in fact that article is correct and that theory can generally be applied to all brushless motors.
Iâm not sure what voltage you are running but this 2.25:1 reduction ratio is a bit outside my safety zone, big tax on torque. At 10S you are trying to push the top speed up to 32mph. Wind Resistance will start loading up at this speed (at least on the flats)
I know you have a need for speed but have you considered running some more reduction to reduce the load on the single motor? maybe 15/36 & 83mm would be a better option? 28mph is still fast and you will have a more reliable system. Less heat.
I wonder if you will draw the same conclusion about motor size with a higher torque gearing ratio?
is this really about the physical size of the motor or is it meant to be about the max power output a motor can do?
@chaka why does it make a difference for the VESC/ESC: if I have a 1800W Motor with VESC setup to support 1800W or if I have a 3000W motor with VESC setup to support only 1800W? Should be the same for the ESC I would guess, as well would guess that the small motor will run hotter, might be that the small motor spins faster though???
understood, but if I set the limit to 50A I would have guessed max current draw is limited
Sorry i already realized that my post was bullshit especially because @chaka wrote that while climbing you even can overheat the VESC without reaching the 50a limit. Why that?
FWIW the Evolve GT has a 2.13:1 reduction and Iâm using 97mm wheels on 50mm motors. I ride a lot of hills and it doesnât seem to overheat. Though in this case there are two motors.
@chaka wrote that while climbing you even can overheat the VESC without reaching the 50a limit. Why that?
I am not entirely sure why but it seems like the VESC will still allow the motor to pull large amounts of current when loaded heavily. The motor current settings in the VESC should be viewed more as adjusting the throttle and discharge curves rather than absolute limits.
is this really about the physical size of the motor or is it meant to be about the max power output a motor can do?
@chaka why does it make a difference for the VESC/ESC: if I have a 1800W Motor with VESC setup to support 1800W or if I have a 3000W motor with VESC setup to support only 1800W? Should be the same for the ESC I would guess, as well would guess that the small motor will run hotter, might be that the small motor spins faster though???
What matters is what the motor pulls when it approaches âstall torqueâ and that your ESC is able to handle this much power. We also need to be sure our battery systems can handle this much output without heating up if we want our cells to last a long charge/discharge cycle life. The VESC is very good at limiting the current a motor can pull but it is not magic, a motor will still pull huge amounts of current when it approaches a stall scenario. How much it pulls depends on the specs and ratings of the motor.
If you plan on using a big motor with the VESC on a single drive you will want to avoid these stall torque scenarios due to having a top heavy system. If you want to design a system with a long life and smooth operation you need to make sure you battery and motor controller can handle the max rating of your motor/s. Sticking two 3000 watt motors on a 10s3p pack with motor controllers rated at 1800 watts continuous is just window dressing.
It has been established for a very long time that you should always have a pack and motor controller that exceed the rating of your motors.
Well balanced cool running system = Battery>ESC>motor
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Would two of your 50mm motors paired with a Spacecell 10SP4 be a good combination?
When the pack is new it will work fine but as the pack ages it will build resistance and heat under heavy use. In my experience you want to be able to pull 600 to 800 watts at maximum of 1C to have a long lasting pack. This may seem crazy to some people but we have proven that it is possible to fit a pack this large on a board. This is assuming we are building boards as an investment.
If you are building something just to have fun and do not mind wearing things out a little sooner than expected by all means use smaller high discharge packs. If you want something that will not show signs of wear after only 200 discharge cycles you need to go bigger. The trouble with large packs is space and weight, a 23lb board is not the easiest thing to market either.
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If anyone stalls in the middle of a steep hill and continues to try and go up the hill from a standstill (especially a steep hill). You crazy 
Just donât loose your momentum next time going up the hill.
Nobody, should ever do that and youâll have a higher possibility to burn out your components. Your better off walking the hill for 2-3 minutes then riding once your on top of the hill or buy another motor since you fried it. 2-3 minutes saves your wallet.
Thatâs partly why most of these china boards break. People just abuse these cheap boards but flat ground they are most of the time perfectly fine.
Itâs not typical anyone is ever going to burn anything out on flat ground. Uphill causes a tremendous amount of heat.
If your climbing uphill, you should expect to be going up the hill w/ momentum on a single motor and/or go dual motor.
IMO the only benefit for the 6355âs is they are harder to burn out compared to a single 50mm.
Give anyone a 50mm and more chances or not if they arenât on flat ground. Theyâll burn it out if they donât use it correctly.
If the board doesnât go anywhere most people will just âthrottle, throttle, throttleâ.
Different parts for different goalsâŚ
Not even just hills. Wind resistance is also a pretty big factor. My GTâs motors are just a bit warm when traveling 4 miles in my morning commute up and down hills. However, on the way back home thereâs a bunch of headwind and by the time I get home, one of my motors is burning hot (the other a bit warm). I always feel bad for my motors when Iâm going up a hill at less than desirable speeds because I know itâs chugging pretty hard; especially on 2.13:1 gearing.
I also have experienced overheating when riding on flat ground into a strong headwind. That was with dual hub motors.
Specifically it depends on the reduction ratio⌠the bigger the reduction the less chance of your motor drawing high amps and stalling on hills (depends on rider weight and incline).
I know i sound like a broken record⌠but @chaka why donât you try more reduction?.. one single 63mm motor, 2.4 or more reduction with 83mm wheels. Vesc current limit of 50A.
Iâll send you an enertion kit so you can try it?