Scotts 5th - uh 6th build! now with a video - sorta!
- Thread starter scottclarke
- Start date
scottclarke said:Quick update.
Acceleration between 35 and 55mph was just silly fast - really really quick. Going from 55 to 58 took a long time though - a few seconds into this last phase and I felt a hiccup.
Stats for that whole journey show 32.2V minimum (30V niminal pack!), 126A max - making for what was a truly awesome experience consisting of over 4KW of accel
Scott
I know you have been switching the gearing around a little... What gearing do you have when you made these runs? I'm guessing a 74t rear and 10t motor at 30v nominal?
Thanks, just wondering...
Kyle
etard
100 kW
Finally, it was VERY VERY fast - I would get into all sorts of trouble acceling that fast. That was not the intent - a commuter is what I want - one that is capable of 40mph with a car matching accel profile. It does all that on 24V - the pipedream is over!
You have found the pot-o-gold!! congrats!! How much did the pipedream cost? A final part by part tally would be more than gracious.
You have found the pot-o-gold!! congrats!! How much did the pipedream cost? A final part by part tally would be more than gracious.
scottclarke
100 W
etard,
You have to bear in mind it doesn't have any real accel at less than 20mph. As it is now on 24V it has good fast accel between 25 and 38mph. It is a narrow range but it suits my needs very well. It does require pedalling along with a little effort and gentle throttle use all the way up to 20mph. Or, you could accel REALLY slowly - no pedalling required. I can pedal up to around 33mph with sensible cadence so I will get the fat burning activity I require!
58mph was with a 88 tooth gear and a 10 tooth pinion.
Currently running the 91 tooth along with the 10. Top speed is 38mph according to GPS - measured over a 1 mile distance.
I am not happy with the performance from start to 20mph - thats a fact. Yesterday I had the opportunity to use a fast current logger and it showed spike peaks on the order of 280A. As suspected - this is the reason for the bad low speed performance. Until the motor gets to 3000rpm its basically 'stalled' and draws huge current.
What I would really like to do for a general use version would be to gear it down - say something like 25:1 then bump up the voltage until the current spikes are just below the Jazz's cut-off point (220A it seems from measurements). Geared that way I think it might be possible to have a top speed of 40mph or so with faultless accel.
Thats what I want next - it is very much like my old axi powered scheme which worked fine but drove the pedals.
Thats all on hold now though - as of yesterday I stopped 'developing' this bike. I'll use it as it is.
Scott
You have to bear in mind it doesn't have any real accel at less than 20mph. As it is now on 24V it has good fast accel between 25 and 38mph. It is a narrow range but it suits my needs very well. It does require pedalling along with a little effort and gentle throttle use all the way up to 20mph. Or, you could accel REALLY slowly - no pedalling required. I can pedal up to around 33mph with sensible cadence so I will get the fat burning activity I require!
58mph was with a 88 tooth gear and a 10 tooth pinion.
Currently running the 91 tooth along with the 10. Top speed is 38mph according to GPS - measured over a 1 mile distance.
I am not happy with the performance from start to 20mph - thats a fact. Yesterday I had the opportunity to use a fast current logger and it showed spike peaks on the order of 280A. As suspected - this is the reason for the bad low speed performance. Until the motor gets to 3000rpm its basically 'stalled' and draws huge current.
What I would really like to do for a general use version would be to gear it down - say something like 25:1 then bump up the voltage until the current spikes are just below the Jazz's cut-off point (220A it seems from measurements). Geared that way I think it might be possible to have a top speed of 40mph or so with faultless accel.
Thats what I want next - it is very much like my old axi powered scheme which worked fine but drove the pedals.
Thats all on hold now though - as of yesterday I stopped 'developing' this bike. I'll use it as it is.
Scott
MitchJi
10 MW
scottclarke said:
Hi Scott,
How hard would it be to add something like a Banebots 3:1 or 4:1 to your motor shaft? That would give you 27:1 or 36:1:
http://banebots.com/c/P80A-nnnn-0005-Rn
Or a Neu P62 6.7:1. Its rated for 10k watts and 30k Rpm. Its a little more expensive (about $200):
http://www.castlespecialprojects.com/csp_2200.html
It seems like one of these in your drive line would resolve your gearing issues and make for a much nicer bike. If its not to hard to do and if it is reliable (the Neu seems very likely to be up to the task) it might be worth the effort.
recumpence
1 GW
A planetary would increase his motor length and necessitate a redesign of his system.
Matt
Matt
Hi Matt,
i've been meaning to ask you for a while now but have been too embarassed
Is there any motor of similair size that you know of that wouldn't require a massive step down?
i would like to try the rc kit over winter (was there a summer in the uk?) but i would like belt drive straight to wheel - i must look at what motor miles used
i like scotts setup because of the simplicity and tidyness (stealth) but he sais that his speed 0-20 is pretty lame, is that because his motor doesnt kick hard until it gets to a reasonable rpm? top speed is a non issue for me, 30mph would be fine but im after torque o rocket
Cheers
D
i've been meaning to ask you for a while now but have been too embarassed
Is there any motor of similair size that you know of that wouldn't require a massive step down?
i would like to try the rc kit over winter (was there a summer in the uk?) but i would like belt drive straight to wheel - i must look at what motor miles used
i like scotts setup because of the simplicity and tidyness (stealth) but he sais that his speed 0-20 is pretty lame, is that because his motor doesnt kick hard until it gets to a reasonable rpm? top speed is a non issue for me, 30mph would be fine but im after torque o rocket
Cheers
D
MitchJi
10 MW
Hi,
I didn't realize it was that tight.
Yes!
recumpence said:
I didn't realize it was that tight.
deecanio said:
Yes!
deecanio said:
He only had so much room on his particular bike and mounting point. The only way to not require as much of a gear down is to get a lower RPM per volt motor (Lower KV). The only way to really get that done is with a larger motor. PLUS, if you read his posts you'll find that the size motor he currently has is on the bleeding edge of overheating due to such a small thermal mass. Being these motors are OUTRUNNER you can't stick a liquid cooled or heatsink jacket around them so the best way to help combat the heat and gearing is to go with a larger motor.
I'm hoping to go with a slightly larger motor rated at 170KV vs Scotts 200KV. I'm also going to be running a 24inch tire/rim combo to help with the gearing (and give me more room to mount the larger motor).
The problem with gearing down is you loose the top end that Scott and I are looking for unless you go with a high voltage setup. I'd rather have a lower voltage setup with gearing than a high voltage setup with a single gear. I'm going to look into some type of transmission once I get my bike where Scott is.
Kyle
recumpence
1 GW
Scotts low end torque issue is more than likely something to do with the small size of his motor and the controller's ability to communicate with the motor (back EMF). I have crazy low end torque with my outrunner (both my expensive Plettenberg and the less costly AXI).
Yes you can go with a very low KV motor in conjunction with lower voltage and run single stage to the wheel like Miles is running. But, you will need a large motor that can dissipate heat and, ideally, a fan as well.
Oh, Miles is running a hand made motor. Good luck finding another one. :wink:
Matt
Yes you can go with a very low KV motor in conjunction with lower voltage and run single stage to the wheel like Miles is running. But, you will need a large motor that can dissipate heat and, ideally, a fan as well.
Oh, Miles is running a hand made motor. Good luck finding another one. :wink:
Matt
recumpence said:
Haha, the harder thing to find is a good speed control for a larger motor.
I've been reading about the Castle Creations 110HV and I like the specs on it. Very programmable, with lots of items good for a ebike like ultra slow starts, programmable low voltage cutoff, and even a amp load cutoff!
Kyle
Hi All,
Thanks guys, that makes much more sense than trying to figure it all out for myself (mostly wrongly)
Maybe i will stick with my hub for a while longer yet until i can figure something out, i cant see me being to able to get a gearbox onboard with my current setup and thats if i could get one made in the first place (looks at matt with envy of his skills).
Cheers for the answers fellas,
D
Thanks guys, that makes much more sense than trying to figure it all out for myself (mostly wrongly)
Maybe i will stick with my hub for a while longer yet until i can figure something out, i cant see me being to able to get a gearbox onboard with my current setup and thats if i could get one made in the first place (looks at matt with envy of his skills).
Cheers for the answers fellas,
D
recumpence
1 GW
Kyle,
Yes, they are very good controllers (up to 4,000 watts).
D,
I am working on the reduction unit. I just finished a 3 month long job shop project for a doctor. So, now my shop is freed up for reduction R&D. :wink:
Anyway, I do not want to hijack this thread.
Back on topic.
Matt
Yes, they are very good controllers (up to 4,000 watts).
D,
I am working on the reduction unit. I just finished a 3 month long job shop project for a doctor. So, now my shop is freed up for reduction R&D. :wink:
Anyway, I do not want to hijack this thread.
Back on topic.
Matt
MitchJi
10 MW
recumpence said:
Hi Matt,
I don't know very much about this so...
I'm pretty sure a bigger motor or more gear reduction would do the job.
I am not sure about a better controller with the same motor and gearing.
Is the AXI a bigger motor than Scotts? Didn't you have 25:1 gearing with the AXI?
Thanks!
Mitch
johnrobholmes
10 MW
It certainly sounds like the motor is just overgeared. You need more motor or more geardown!
recumpence
1 GW
Mitch,
Yes, my AXI is bigger than Scott's motor.
I agree with John, Scott's system is just a bit overgeared. That is the main issue. He is very limitted because of the space he has to work with for his motor and sprocket.
Matt
Yes, my AXI is bigger than Scott's motor.
I agree with John, Scott's system is just a bit overgeared. That is the main issue. He is very limitted because of the space he has to work with for his motor and sprocket.
Matt
scottclarke
100 W
Wow, has it been this long??!!!!!
Overgeared for sure - but the aim was for 35mph or so which is almost exactly what 24V gets me.
I fried a few more of these motors but have been running the same one for the last 2 months with no issues. I have had to mod the endbelll to accept 4 fan blades. These draw air in at the endbell and pass it out the 'stator' end (where it fixes to the mount). I have not tried it again on 36 or 48V for 2 reasons. Firstly I don't want to burn any more motors and secondly 35mph is more than adequate for around town since the limit is generally 30mph or less. This modded motor does run a lot cooler - without the blades it would rise about 50C on an extended run up-hill. On a warm day that was problematic since once the bell passes 78C the motors are toasted. With the modded bell the rise is more like 40C.
Oh yeah - the 10,000mfd cap I added has sorted the start-up issues - it now pulls without glitch from a standstill but I do prefer to pedal to 3mph or so before peddaling - for obvious reasons
Scott
Overgeared for sure - but the aim was for 35mph or so which is almost exactly what 24V gets me.
I fried a few more of these motors but have been running the same one for the last 2 months with no issues. I have had to mod the endbelll to accept 4 fan blades. These draw air in at the endbell and pass it out the 'stator' end (where it fixes to the mount). I have not tried it again on 36 or 48V for 2 reasons. Firstly I don't want to burn any more motors and secondly 35mph is more than adequate for around town since the limit is generally 30mph or less. This modded motor does run a lot cooler - without the blades it would rise about 50C on an extended run up-hill. On a warm day that was problematic since once the bell passes 78C the motors are toasted. With the modded bell the rise is more like 40C.
Oh yeah - the 10,000mfd cap I added has sorted the start-up issues - it now pulls without glitch from a standstill but I do prefer to pedal to 3mph or so before peddaling - for obvious reasons
Scott
MitchJi
10 MW
Hi Scott,
I'm very interested in your Velo.
When you have some time it would be great if you'd post information and pictures, either here or better yet in a new build thread
I'm very interested in your Velo.
When you have some time it would be great if you'd post information and pictures, either here or better yet in a new build thread
mud2005
10 kW
Wow, I cant believe I missed this build! Looks sweet, what is up with the #25 sprocket?? how many teeth? aluminum or steel? where did you get it? I haven't seen one like it. 
sorry if its mentioned somewhere I didnt have the patience to read 13 pages of posts :|
edit: never mind I found it, kart sprockets not #25 coooooool.
sorry if its mentioned somewhere I didnt have the patience to read 13 pages of posts :|
edit: never mind I found it, kart sprockets not #25 coooooool.
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