E-Longboard not getting as much power as it should

octane

10 mW
Joined
Nov 5, 2015
Messages
21
Recently i finished by longboard build and have tested it and stuff. It works but its not as fast as i believe it should be. ~18km/h max on flat
I have the following components.
2x Turnigy 5000mAh 3S 20C Lipo Pack (In series 22.2v total)
Turnigy Aerodrive SK3 - 5055-280kv Brushless Outrunner Motor
FVT 120A BRUSHLESS WATERPROOF ESC, 1/10 1/8 RC Car Link:http://www.ebay.com.au/itm/221465739994?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Gear ratio: 14t to 40t
Transmitter: Some rc transmitter that ive had for a while.

On builds that ive been looking at with this motor and similar esc and battery configurations they reach top speeds of about 30km/h.
Im not really sure what limiting my speed. I think the esc could need configuring better (LCD programming card is on its way)
Any help would be great
Cheers.

EDIT: I will be posting my full build once ive completed it.
 

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torqueboards said:
If you haven't programmed it that is most likely the answer.
Okay thanks. What sort of programming would i need as the supposed default settings dont look too bad. Could it be my gear ratio? its 14:40
ive attached a image of the default settings
Cheers.
 

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Hi Mate

Well it depends on your size and weight as well.
Also I am not sure of the wheel size you have there.
With that ratio you are geared for good torque I would say, not highest speed.
There are a few speed calculators out there.
I used one and came up with a theoretical 24km/h - No way you are going to get 30km/h with that gearing unless you use huge wheels.

I personally have just ordered some 97mm wheels, up from my 83mm at the moment. Looking forward to seeing what that does to my ride. speed/torque

Cheers
WeeCh
 
WeeChumlee said:
Hi Mate

Well it depends on your size and weight as well.
Also I am not sure of the wheel size you have there.
With that ratio you are geared for good torque I would say, not highest speed.
There are a few speed calculators out there.
I used one and came up with a theoretical 24km/h - No way you are going to get 30km/h with that gearing unless you use huge wheels.

I personally have just ordered some 97mm wheels, up from my 83mm at the moment. Looking forward to seeing what that does to my ride. speed/torque

Cheers
WeeCh


Cheers for that info. I didnt really think into the gear ratio when i was buying my parts i just went with gearing set that worked i guess. Im not looking for torque as much as im looking for speed (I live in a fairly flat area). I still have to figure out whats limiting my speed i think. In have 93mm wheels aswell which i guess is a bonus if i want to increase the speed while compromising torque.

If anyone has some info on what esc settings i should that would be great.
Cheers
 
torqueboards said:
Your settings on default are most likely Motor Timing - Normal and Motor Acceleration - Low. You can change both these options to higher options.

The manual says that motor timing is set to high as default and accelaration high. Should i set these both to veryy high?
Cheers
 
It's up to you but without the LCD programmer you don't actually know if it's set at those settings.

I would suggest going with the LCD and finding out first. Test it lower and move upwards. If you move upwards to very high, monitor and notice the temperatures of your motors if they are getting too hot. If they are move it downward and/or change gearing and/or add a second motor or more voltage. (of course with a higher voltage ESC)
 
torqueboards said:
It's up to you but without the LCD programmer you don't actually know if it's set at those settings.

I would suggest going with the LCD and finding out first. Test it lower and move upwards. If you move upwards to very high, monitor and notice the temperatures of your motors if they are getting too hot. If they are move it downward and/or change gearing and/or add a second motor or more voltage. (of course with a higher voltage ESC)

Okay will do. I have ordered a lcd programmer that is the same brand as my esc soo it should work. However i ordered the China post snail speed shipping which i regret now haha. I think i might have a solution to my slow speed problem and it could be me being a twat.
Cheers
 
Okay i got it to work properly. I had calibrated my remote incorrectly and as a result my motor was around the wrong way. As a result when i pressed the forward trigger it would engage reverse but it would still go forward (reverse thrust set to 40% soo i was only getting 40% power). Soo of course i recalibrated it and switched the motor leads around and now i get the speed i wanted (~30-40km/h). I also managed to strip the belt which im not sure why that happend exactly. I Think its because the belt might be a bit loose on the gears. Any help? here is a picture of the gearing before the belt got destroyed.
 

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definitely loose. You shouldn't have "bow" in the belt - it should be at least flat when taut.

Also - 3d printed wheel gear? It's easier to slip the belt accelerating hard and braking. I'd suggest 15mm belt width if when it's tight it's still slipping. More teeth in contact (Torque's suggestion that the motor gear may be too small), a tight belt, and wider belt all might help!

GL!
 
sl33py said:
definitely loose. You shouldn't have "bow" in the belt - it should be at least flat when taut.

Also - 3d printed wheel gear? It's easier to slip the belt accelerating hard and braking. I'd suggest 15mm belt width if when it's tight it's still slipping. More teeth in contact (Torque's suggestion that the motor gear may be too small), a tight belt, and wider belt all might help!

GL!

torqueboards said:
jakeyb2525 said:
Im no Expert but that definitely looks a tad on the loose side to me buddy...

Ditto.. It does look really loose. Gearing might be too small too.

Okay thanks guys.
I think ill order a 15t gear to replace the 14t and i think that should fix the problem (hopefully). I had 3d printed my motor mount with a distance of 70mm inbetween the the centres of the 2 attach points (The motor centre and the centre of the truck hangar) soo the dimensions might be off slighty.
To sl33py I did 3d print my gear attachment and it works very well and is stable aswell. Full credit to this guy for the gear. :http://www.thingiverse.com/thing:545345 . Its probably cheaper to go and print this at a local 3d print shop ( or print it yourself if you have one) than to buy the gears and attach them.
 
octane said:
psychotiller said:
Are you positive you have your batteries in series and not parallel?

Yes i ended up fixing the speed problem. Thanks anyway.

what was it? :p
 
Okay i got it to work properly. I had calibrated my remote incorrectly and as a result my motor was around the wrong way. As a result when i pressed the forward trigger it would engage reverse but it would still go forward (reverse thrust set to 40% soo i was only getting 40% power). Soo of course i recalibrated it and switched the motor leads around and now i get the speed i wanted (~30-40km/h).
 
whitepony said:
octane said:
psychotiller said:
Are you positive you have your batteries in series and not parallel?

Yes i ended up fixing the speed problem. Thanks anyway.

what was it? :p

I said this above "Okay i got it to work properly. I had calibrated my remote incorrectly and as a result my motor was around the wrong way. As a result when i pressed the forward trigger it would engage reverse but it would still go forward (reverse thrust set to 40% soo i was only getting 40% power). Soo of course i recalibrated it and switched the motor leads around and now i get the speed i wanted (~30-40km/h)."
 
octane said:
sl33py said:
definitely loose. You shouldn't have "bow" in the belt - it should be at least flat when taut.

Also - 3d printed wheel gear? It's easier to slip the belt accelerating hard and braking. I'd suggest 15mm belt width if when it's tight it's still slipping. More teeth in contact (Torque's suggestion that the motor gear may be too small), a tight belt, and wider belt all might help!

GL!

torqueboards said:
jakeyb2525 said:
Im no Expert but that definitely looks a tad on the loose side to me buddy...

Ditto.. It does look really loose. Gearing might be too small too.

Okay thanks guys.
I think ill order a 15t gear to replace the 14t and i think that should fix the problem (hopefully). I had 3d printed my motor mount with a distance of 70mm inbetween the the centres of the 2 attach points (The motor centre and the centre of the truck hangar) soo the dimensions might be off slighty.
To sl33py I did 3d print my gear attachment and it works very well and is stable aswell. Full credit to this guy for the gear. :http://www.thingiverse.com/thing:545345 . Its probably cheaper to go and print this at a local 3d print shop ( or print it yourself if you have one) than to buy the gears and attach them.

Okay ive sorted the problem i hope. I printed out some HTD 5m 15,16,17 tooth gears and found that the 16 or 17 tooth worked great. I couldnt get the printed gears to stay on the motor shaft properly and have soo far broken 3 of them. Im going to order metal pulley's online. What should i go with? Both the 16t and 17t fit but the 17t fit tighter. Is tighter the better in this case? Cheers
 
Tighter is better to a certain point. If it is too tight (no vertical movement) then you'll just be stretching your belt. Also I have found that when my belt is super tight It is more prone to breaking due to trash getting in between it and the pulley. I do some off-road riding though so maybe it's just me.
 
First off, thanks for pushing the envelope! 3-D printed gear and mount is something I would not have expected. Wasn't nylon nylon? Or PLA....

Loose will be wasted energy and faster wear and so will tight. See if you can perhaps figure out some adjustability. What starts off just right will wear to loose.
 
astilwell611 said:
Tighter is better to a certain point. If it is too tight (no vertical movement) then you'll just be stretching your belt. Also I have found that when my belt is super tight It is more prone to breaking due to trash getting in between it and the pulley. I do some off-road riding though so maybe it's just me.

Okay thanks for that. Im having a bit of trouble finding a 17t gear with the right dimensions soo i might just get the 16t and hope for the best.

NyOliver said:
First off, thanks for pushing the envelope! 3-D printed gear and mount is something I would not have expected. Wasn't nylon nylon? Or PLA....

Loose will be wasted energy and faster wear and so will tight. See if you can perhaps figure out some adjustability. What starts off just right will wear to loose.

Haha cheers. I printed a mount using abs plastic with 100% infill and it pretty strong. I attached it by drilling 2 holes into the trucks (4mm) about 1/3 into each side then slid the m4 bolts through the holes on the printed mount and into the trucks where i superglued them in place. There in no up and down movement but a tiny bit of side to side. I need to buy some more epoxy to stabilize it better.
Also cheers for the gear advice.
 
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