Scotts 5th - uh 6th build! now with a video - sorta!

[scottclarke]

im a little lost here scott, does the gearing from the motor to the rear sprocket negate the need for a stepdown box like matts? doesn't it mean that the motor takes the full load from the wheel meaning it will get rather hot under load?
i wish i had more brain
it would seem that these RC motors are way cool for use with ebikes but how best to set them up?
I take it that because the rpm is so high there's no way to run one through the gears like the cyclone setups, would this be possible using a bigger sprocket on the motor?
Anyway more pics and some video please - if your cam wont take the abuse on the bike just leave it on a wall or something and do some drive by's???
watching yours and matts build with massive interest!!!!!D

D,

Load is load no matter at what rpm.

I have a step down in the form of the sprocket and chain - its a 9.6:1 ratio as of yesterday which means if the motor span at 10,000 rpm at max volts the wheel would be going 960rpm. I plan to run on 33V as of yesterday which means my top speed is nearer 50mph with motor at 6600rpm - putting me in a bit of a sweet spot at 40mph in the 5000 to 6000rpm range.

If you wanted to be sensible you would need to gear down much further - say 20:1 but I really don't have the space for the gearbox I would need - the motor was chosen because it fits the frame exactly - and for no other reason. At 20:1 it would do 26mph and I am sure - self start just fine as well as having awesome acceleration. As mine is geared it won't self start - it needs to be moving at 1mph or so before it can spin up. This is the reason brushless motors on scooters have a centrifugal clutch fitted - allowing the motor to spin up to 300rpm or so before the drive engages - somewhat gradually.

More later - gotta run!

 

[recumpence]

Actually, the self start issue has more to do with your ESC than anything else.

The start software of higher quality ESCs will handle the startup, no problem. They are costly,though.

Matt

 

[scottclarke]

Actually, the self start issue has more to do with your ESC than anything else.

The start software of higher quality ESCs will handle the startup, no problem. They are costly,though.

Matt

Agreed in principle.

I do have some very cheap controllers that will start a very highly loaded motor - but none does more than 3s - but yeah - £££$$$ usually buys a better start

The start difference between 8:1 and 9.6:1 is quite an eye opener - 8:1 needs about 4mph before it'll run whilst 9.6 is slower than walking speed. Obviously this is when loaded with my weight - take bum off saddle and it starts no problem

Scott

 

[deecanio]

Hi Scott,Matt,

thanks for explanation, i understand that better now, to use one of these little motors on my bike would save me weight well worthy of the investment, having slimmed my pack down to "just enough ah" and joz remaking it to fit inside my triangle im now left with the last issue,a heavy hub.
Dont get me wrong i love my pumas but if i get the same performance from the size you guys are using then it would totally rock 8) not to mention negate the gears problem as my rear wheel would be standard If you add to this size of the controller matt has you could really have something super stealth,super,fast,super cool 8)
Crack on fellas!!! these two bikes are rocking my world!!!


Cheers

D

 

[scottclarke]

D, don't forget - relatively noisy!

 

[deecanio]

yes there is that, how noisy is noisy? any reason couldn't be belt drive?
i think it was fechters scoot had a beaut of a rear sprocket.


cheers

D

 

[scottclarke]

It's not the chain making so much noise on mine - its the vibrations due to the motor mounting method chosen. I have reduced the noise considerably and at 20mph it really is quiet - it gets noisy over 35mph though. At 35 its still nowhere near as loud as a petrol engine - you can actually hear cars approaching from the rear.

EDIT - yes, belt drive - great idea until the teeth in the gears get contaminated with road debris and you need to replace them. It is something I am looking at but 'slowly' due to that issue. In addition, belt toothed gears come at silly high prices and are massively overbuilt since invariably they end up on full scale cars/big machinery! You could turn one down of course but right now I have little chain noise so the cost of that doesn't appeal!

 

[Link]

And a distant relationship to the actual Eminem gets me dibs.

Dude, get out of my mind . . . .

them's battling words.

You might be Eminem's distant-cousin's-friend's-girlfriend's-acquaintance BUT . . . I was touched by greatness. YEAH, I ran up to "Easy E" of NWA fame in LA (before he died of AIDS) to give him my demo tape and he gave me a good swift kick to the curb and I have scars to prove it! How's that for street creds, homey? What do you got, Eminem's autograph? :lol:

I think I met him once. There was this big family reunion thing up in No-Cal a few years back. Apparently one of my parents was having a conversation with somebody who was very big in the rap business at the time. This is back when Eminem was popular. Unfortunately, I was only like, what 10-12 at the time? so I didn't know who he was and to steal his hat or something. :?

You win this round...8)

Oh, and yeah, that is a nice weed-vase. The bike's cool too.

 

[tropmonky]

Oh boy, I can't wait to see some more pics and specs on this! oh, and VIDS! LOL...

Kyle

 

[scottclarke]

some pics just taken - framing is bad since the camera is shot!

will try to grab a vid later today - will be my wife filming from the side though. Thats if it doesn't rain....

Gearing change again - its gone a bit faster - 54mph.

Pedals are now on as are a chain - I have a grand total of 3 gears from a 9 speed cluster due to using a 3 speed chainwheel left hand changer.

BUT - I need batteries - best range I have had at 30mph or so is 9 miles so the bike is somewhat useless now - oh hang on- I can pedal it!

 

[dirty_d]

do you have a link to the ESC you used on this bike?

 

[scottclarke]

Sure do - and its dropped in price - time to order some more methinks!

http://www.allelectricrc.co.uk/suppo-su100a-opto-esc-4-10s-1283-p.asp

 

[lawsonuw]

I have a grand total of 3 gears from a 9 speed cluster due to using a 3 speed chainwheel left hand changer.

Can you fit the usual right hand shifter on the left side of the bar? It'll shift "backward" and the gear indicator may be hidden, BUT all the gears will work. This is assuming you have a grip shifter or lever shifter. A click shifter might work mounted wrong side on top of the bars?

Anywho, NICE looking bike. Gearing on that motor's a bit loony. Nine miles of range is not too bad. It looks like the system is light enough to just use as a "turbo" booster on hills, etc.

Marty

 

[scottclarke]

Marty,

I had a selection of 30 or so shifters to try - and you are correct - I could have chosen a 9 speed and put it on the left - BUT - my daughter has to be able to use this and the gear indication is essential for her!

In any case - the bike is intended to mostly be doing 40mph+ making any gear other than 53/11 a non option! TBH all I really wanted in terms of gears was to be able to pedal the bike from a stop and help at 30mph or so.

Unfortunately its raining now so I have not had a chance to use the hybrid power train at all! I did give it a quick spin under pedal power only and was pleasantly surprised with how easy it was to pedal

Next on the list - mudguards - but have to be very close fitting to tyres due to speed.
followed by a rear rack seatpost mount - I may end up with batts on this
then lighting - going for a 4 way strobe on the rear with different flash rates shining through a red 'fog' light. Not decided on the front but I do know I need a 20M throw so it can't be some 20W affair!

Scott

 

[knoxie]

Hi Scott

Looking really nice there!! will get up and see you in the summer (when we finally get one!!) been an awful day again today so I doubt there has been any video, looking forward to it though! might be an idea to get a chain guard for the motor drive side as well stop it pulling your trousers off! :lol:

Really clean build as well, you may be able to use the Headways if you parallel them up? If I were to use them I would go with at least 2 in parallel, maybe 3, then they should be ok, may just go with life batts though and make it a bolt together affair, nice and clean.

Soon as the roads dry get some video! want to see and hear that thing running!!

Knoxie

 

[scottclarke]

Knoxie,

I have a chainguard! It was the last thing I cut out admitedly but the fact it wasn't fitted was the reason for the last ride being pedal power only - no desire to be eaten by the motor!!!!

I can come down to you again but its up to you - roads round here are really busy all the time unfortunately

If I do decide on a 2KWH pack I suppose I could ride down to you then do a 1 hour charge on arrival - watch the leccy meter fly round What'll be that then sir? Methinks about 18p - not bad for a 35 mile?? forget now - trip!

See and hear it running - yeah right you'll hear it no worries! I've just applied a load of contact adhesive around in strategic areas - have a very delux type of foam thats going to work wonders!

Scott

 

[recumpence]

What are your thoughts on the long wiring from the bottle to the motor? I seem to be struggling with wire heat and I am only running a few inches of wire to the motor (maybe 7 inches or so) and 16 inches from pack to ESC. Your harness is quite long (clean layout, I must say).

I really like the build too. :wink:

Matt

 

[dirty_d]

why cant you use a 114 tooth rear sprocket? i cant see anything that the chain would hit. that would give you better acceleration and limit the insane top speed

 

[johnrobholmes]

Very nice build! Makes me want to convert my santa cruz bullit to an E machine!

Do you have rear brakes?

 

[scottclarke]

What are your thoughts on the long wiring from the bottle to the motor? I seem to be struggling with wire heat and I am only running a few inches of wire to the motor (maybe 7 inches or so) and 16 inches from pack to ESC. Your harness is quite long (clean layout, I must say).

I really like the build too. :wink:

Matt

Matt, I have used longer wires from esc to motor on a couple of ducted fan jets - admitedly less power but I never had any issues. I have some EV's at work that are brushless (well, 48) and these all have wires in excess of 24 inches long - that carry over 1000A peak - now - they do occasionaly blow controllers but this is looking more like a quality control issue rather than induced faults.

I used a too narrow gauge initially - just didn't have anything bigger lying around and keen to run it! I had problems - mostly associated with too high current resulting in a warm cable. This was most evident at the connectors with the connections to the esc coming away - not actually desoldering - but coming away. I have changed to some very heavy gauge now - essential when running on 36V really. It seems to have cured the esc solder problem (if any) and now I have zero wire heating.

Given the relatively low cost of wire (in terms of overall build) - I say - use as thick as you can - you won't lose anything except money doing so!

HTH

 

[scottclarke]

Dirty_D,

You maybe can't see what the chain would hit - but 96 tooth is the largest that will fit - I promise!

John,

No rear brakes until the cush drive is finished. Not a biggie since I rarely use rear brakes on a bike anyway

Scott

 

[johnrobholmes]

I normally don't either, unless I am in the middle of a turn and can't use full front brakes without a skid.


You say you are using go-kart chain and sprocket? Care to share the brand or where this stuff could be gotten? Looks plenty strong for what we need.

 

[scottclarke]

I normally don't either, unless I am in the middle of a turn and can't use full front brakes without a skid.


You say you are using go-kart chain and sprocket? Care to share the brand or where this stuff could be gotten? Looks plenty strong for what we need.

A turn you say - whats that then?!? No seriously I do of course need a rear brake before I get past the 'testing it' stage but right now its still very much in prototype form so, much like the gear cover - its all over the place!

Its regular kart chain and sprockets as found all over - my supplier is only 5 miles away...

http://www.kkckartshop.com/index.php?navigation=10

these are used with motors over 20HP so it should be plenty strong enough!

 

[Miles]

The new Extron sprockets might be a good choice: http://www.accelerationkarting.com/219.html

 

[vanilla ice]

A local kart shop, stewartracing, was blowing out some lightly used #219 rear sprockets. Going out of biz inv. sale. Anybody looking for a cheap rear sprock can try emailing stewrace at stewartracing dot c o m to ask what he has.