1hp scott motor ebike

[DeathBlade]

Well, I've been working on a ebike, at first using a 1.5hp winch motor, but now using a Scott 1hp brushed PM motor its much heavier than the winch motor close to 14 pounds. I'm going to drive the rear wheel with a chain with the motor mounted above the wheel. I've got a 9T sprocket on the motor and a 56T sprocket from a gasoline bike kit on my rear wheel. I'm making a homemade controller using a ic556 and a 300amp IGBT module. For now I'm running it with two 17ah AGM SLAs.
Its going ok, but I need a bike with a supsension (I do a bit of trails), and my old diamondback with no supsension is heavy and almost all the parts are broken. So I need a new bike I found a schwinn S40(Links bike) on craiglist near me for cheap. A couple questions I have read that its aluniumium s there any steel parts that could be welded to? or am I going to be using a lot of screws to attach every thing? Are there any mount holes on the rear arm to mount a rack? What kind of weight do you think could be mounted to the rear arm? I need two 10-15lb AGMs a, 3lb controller, and a 14 pounder mtor.

Here are some pictures of the version I had on my old hardtail bike befor I mounted the scott motor today.

The previous idea

The 56t sprocket

The winch motor test mounted

The first diagram of the controller (I changed the resistors and some part since I drew it)

The Scott motor vs the old winch motor.

stationary testing the motor
[youtube]hlt7ZYcspSg[/youtube]

The test ride the the winch motor (the batteries I had just couldn't give it the amps it needed)
[youtube]m_DX0kPPsgk[/youtube]

 

[vanilla ice]

IIRC some of the low end alum frames use a steel swingarm but.. You can braze aluminum to aluminum. Welding is obviously hotter but even at braze temps I'd be wondering about the heat effecting the allys strength.

Steel to aluminum you can't do much. Epoxy is about it other than bolts. If the arm is steel you could do similar to your old bike. If you put a heavy motor back there, prolly want to find somewhere else for the bats.

 

[dogman dan]

The cheap full suspension bikes have steel swingarms. but you won't be able to connect the rack to the seapost anymore, meaning that you will have all that weight hanging off a really cheap swingarm pivot. And you will be overloading the shock spring quite a bit too. Cool build, but you will need to just get a hub motor for a full suspension bike in my opinion. You might be ok if you can carry the batteries elswhere, but with full suspension, you most likely won't have a frame triangle space, and post racks and sla's are a poor mix unless you do some really serious beefing up of the post , post mount, and the rack itself. But you clearlly like to fabricate, so have fun! Again, I suggest keeping the current motor on the bike you have, and do build two on the full suspension bike as you can afford it. Nothing wrong with two ebikes, as most of us have 2 or 4!

 

[DeathBlade]

On the hard tail I was planning to use the 17ah SLAs in saddle bags on the back. But for the full suspension I was thinking of using three dewalt 36v LiF3p04 packs in parallel I have heard they can give me 30 amps so 180amps for a motor that only needs 100max. I think the three batteries could fit between the front tubes. I could make some kind of quick disconnects for the batteries in the rapid prototyping lab so I could take them out when I'm away from the bike so they cant be stolen, or possible it my next few pay checks are good two sets of batteries. For a quick swap! Any thing to get over the gas mileage of my jeep.

 

[dogman dan]

Yer no dummy. I was picturing the 17ah sla's back there on the swing arm. Still, an excuse to have two bikes is priceless. I never gave a thought to how a rear suspension would work with a regular bike rack till I bolted one on. It pretty much doesn't, putting incredible stress on the rack as it tends to turn the bike back into a rigid rear. You may have seen that coming but I never even thought about it till i had the full suspension bike in hand.

 

[DeathBlade]

Threw together another diagram depending on how much suspension travel swing arms have I could mount the motor ontop of the wheel or sideways at more of an angle, all depends on the suspension. The battery mount depends on the room between the front tubes. The green thing is this section of fexible 8gauge wire from a tractor trailer I finally found a use for.
Ok a bit of research the dewalt packs are only 2ah of I'd need something like 6 in parallel so off to ebay to look for a 36v 20ah LiFeP04 pack

 

[gmouchawar]

I have been wondering if you need a freewheel somewhere between the motor and the chain. Otherwise when you pedelling you are also generating current
which will stress your diode in the IGBT.
Have you given that some thought? Where is a good source for the motors that you are considering?

 

[DeathBlade]

I have been wondering if you need a freewheel somewhere between the motor and the chain. Otherwise when you pedelling you are also generating current
which will stress your diode in the IGBT.

I thought of that I was going to use large SPDT relay to insolate the IGBT from the battery NC contact there is a large diode blocking current from going to the motor from the battery but with the throttle applied the NO contact the IGBT is in play.
Or just a diode connected between the positive battery terminal and the motor. Both for a junky regen-ish circuit

 

[Link]

The front fork on the S40 is steel. The frame and swingarm are aluminum. I'm thinking a kind of clamp thing affixing the motor support to the arm would probably the easiest way to do it.

You'll almost certainly have to reconfigure any pack you get (or get raw cells if you're willing to get a BMS/charger separate), since there's not much room in the frame. That suspension pivot and spring take up a bit where it would be most useful, and there isn't much space there to begin with.

 

[DeathBlade]

An aluminum swing arm makes things different, Was planning on making the framework for the motor from some welded 1/2" tube. I guess I could make it out of some 1x1x.25" aluminum angle I have and just weld that to the swing arm. Was looking in my checking and I have $52.12 to hold me over to the end of the month I think I'll be sticking with three 15am SLA for right now there small enough.

 

[DeathBlade]

Found out what I thought was alumumium plate was magnesium, dont ask. Till I get another electrode holder for my Tig, I'm going to keep the S40 a bike, bike for now and mount the motor on the old diamondback I used originally and see if I can upgrade the front fork to something with disc breaks and shocks.

 

[TPA]

Found out what I thought was alumumium plate was magnesium, dont ask.

Is it still burning? :lol:

or maybe the flash caused this...

 

[DeathBlade]

Well, I'm back to using the old diamonback. I'm seeing about getting a new front fork with disc brakes and shocks. I've mounted the Scott motor to the back, ran all over creation looking for a halflink. I was welding up a sadle bag type frame for my half U batteries when on of them fell off my bench and cracked the case. Since they where old-ish I'm going to buy some new batteries. Saw these on ebay http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170272574374&ssPageName=MERC_VI_RCRX_Pr4_PcY_BIN_Stores_IT&refitem=170277453486&itemcount=4&refwidgetloc=active_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_widget&_trksid=p284.m184&_trkparms=algo%3DCRX%26its%3DS%252BI%252BSS%26itu%3DISS%252BUCI%252BSI%26otn%3D4
I was going to pick up 4 of them but then I though should I over volt my 24volt motor to 48v and have a 48v 18ah pack or a 24v 36ah pack? Just looking over some things I though I saw somewhere if you increase the voltage you drop the amp draw.
If so if you double the voltage would you half the amp draw? so instead of drawing 41amps @ 24volts for 1hp it would be 20.5amps @ 48volts?

Was planning on mounting the battery brackets on the back two batteries on either side of the rear wheel.

 

[DeathBlade]

Well I'm finally working on my ebike again!, I've decided to jump the voltage on the scott motor from 24v to 48v. Going to modify a 36volt YK42 controller and cut the shunts inside down to limit the amperage so I get the same watts at the motor.
currently it 1hp @ 41amps * 24volts = 984watts, soon 1hp @ 20.5amps * 48volts = 984watts
I have four 'half U1' 18ah gruber AGM SLAs on the way. As as I'm doubleing the voltage the rmp will double as well right?(currently 3000rpm@24volts so 6000rpm@48volts)

So I've changed from a 6.22 gear ratio with a 9t/56t to a 13.82 with a 9t/20t(20T is a freewheel) for 2.22 gears turning the previous 6.22 ratio 9t/56t gears.

3000 / 6.22 = 482 * 79" = 38102" / 12" = 3175' / 88 = 36mph
6000 / 13.82 = 434 * 79" = 34298" / 12" = 2858' /88 = 32mph
Ok I get a decrease in theoretical max speed, I could always swap out the 20 tooth free wheel for a 18t later.

I've ripped off the frame I welded to the bike in the picture in the post above and have fabbed up a peltzer clone of the mount and have the first sproket set and motor tucked up under the seat. And now for the picture.

 

[DeathBlade]

Well I got home from class today and found a box from TNC scotters on my porch hurray! my YK42-3 and throttle arrived! so I got them out and got a pic

And a minute after taking this pic I noticed that my thumb throttle was not a thumb throttle they sent me a foot throttle that wont work, So I call them up and they say 'opps' and that I "need to buy another thumb throttle and they will put a return lable in the box for me to ship it back to them and then once they get it they will refund my money" that pisses me off Moving on to thing that make me less angry.

I opened up my controller and every thing looks good save that I have an extra two pin connector with black and yellow wires that isn't listed on the spec sheet. I'm trying to think of what size resistor I'll need to use the controller with 48volts I have some 100volt 400uf caps I can put in to replace the 63v 330uf caps.

Now just for my batteries and thumb throttle to come in and I can get this thing on the road!

 

[DeathBlade]

Well I've built a gauge box to fit next to my speedometer on my bike, I got a 200volt and 100amp panel meter and rigged them up with a 7805 regulator and some nine volt batteries (I should of just got the 9 volt version)

 

[DeathBlade]

Well over christmas I cut the old motor mount off my bike and I just welded up a new one thats more adjustable, and found I can mount my YK42-3 behind the motor leaving me more room for batts in the triangle. I took it out for a ride with some 7ah SLA and it was :? I hooked up my amp meter the SLAs could give me enough amps, only got 19amps out of them and the 36volt pack sagged down to 29.5volts.
So I need to get new batteries still cant decide on which brand of halfU1 18ah SLAs I want to buy its either gruber or BB wish I could afford LifeP04

But on with the pics.

 

[vanilla ice]

How far do you have to go, maybe get some 12ah bats? As has been said before, 12ah x 36v is about the limit for SLA bats for a normal bicycle before becoming ungainly. And you've got that huge motor. 7's are more like 4's at <1hr rate, 12's are more like 8's..

 

[DeathBlade]

I'm going to use three 18ah half U1 batteries should be 37 pounds of batteries. Two mounted near the front on either side of the triangle, and the last in the triangle at the back.

 

[DeathBlade]

Got some problems. I'm setting it up stationary with three 7ah sla's and the YK42 and using the brake as a resistance load to simulate going up a hill (its pittsburgh we have lots of hills) once I increase the speed to about just over 1/2 it throws the chain, I'm not putting on full brake about half, just enough to give it some resistance (it draws 36amps)
The second problem is if I test it with no load (tire in the air) that the throttle doesn't go to full speed, I'll start moving the throttle and it will accelerate till about 3/4 throttle, after which it will slow down not getting to full speed. Is it throttle or controller?

 

[JohnH]

I'm setting it up stationary with three 7ah sla's and the YK42 and using the brake as a resistance load to simulate going up a hill (its pittsburgh we have lots of hills) once I increase the speed to about just over 1/2 it throws the chain

How's the chain line? I can't really tell from the pic, but is your final drive cog exactly the same distance from the centerline as the driven cog on the wheel? It's a pain to measure this, I know, but on fixed-gear and SS bikes chain-line issues are common causes of chain loss. In this case, "exactly" means within ~2mm - you *might* get away with 4mm, especially with a well-placed idler, or you might not.

HTH,

John

 

[buzzfirst]

Hi, I have been following the thread, nice build. I like simple a lot. How is your mount supported on the chain side of the bike? I can't really see from the pictures. Is it possible that the mount is flexing causing a misalgnment? You may add some lateral stability by continuing the leg on the right side of the motor frame down to the next bar of the bike frame(don't know the name of it). If the chain side is not supported you may consider adding one to keep the downward flex to a minimum. It wouldn't take a lot to cause the chain to go. Good Luck with it.

 

[DeathBlade]

Its been a while since I could even think to type, had/have a bad cold. Wasn't feeling to bad today so I got some shots of the bike/motor/mounts.
You were talking about 'chain line' not really under standing the question but I think you mean the sprockets being out of line side so that the chain is at a angle. I through something together in MSpaint so which diagram, left or right? I believe my chain is currently similar to the left diagram.

Here are some more pics of the mount, I dont think it could be the mount flexing making the chain jump, I made it out of 1/2" steel tube and welded the mounts to the frame. Anybody see any problems I'm not?

 

[recumpence]

Your jackshaft output sprocket is not in line with the chain. The sprocket is leaning down (slightly clockwise when viewed from behind). This makes the chain want to skip off. Without load, it may be fine. But, with any added load, that angle increases because of the chain torque and makes the chain come off. The jackshaft (or entire motor assembly) needs to be tilted sltightly to the left to eliminate the sprocket misalignment.

Matt

 

[DeathBlade]

I'll throw some washers under the right side to tilt it to the left. But I just looked at it and I think its a optical illusion in the photo.

Or I could throw a thin fender washer behind the top bolt of the mounting plate, It would have to be a thin wide washer though.