GNG 117v 12fet Devinci Magma freeride

[bee]

Here is where I am with my GNG kit. Not sure what the LYEN controller is currently programmed with, only getting about 60km/h due to the gearing but it gets there very fast

Parts:
2002 Devinci Magma: http://www.bikepedia.com/QuickBike/Bike ... odel=Magma
GNG v1 450w kit: http://www.gngebike.com/450wbrushless.htm
4x ZIPPY Compact 5800mAh 7S 25C Lipo Pack
LYEN 12 FET 84-132V High Voltage Racing Controller
148mm DH ISIS BB 4848T chainwheel freewheel crank set

Mods:
Replaced my 15t cog with a 16t single speed Surly which I use for 99% of my riding: http://www.wiggle.com/surly-13t-to-16t-cassette-cogs/
Replaced primary belt with 11:80 #25 chain conversion:
11t sprocket: http://tncscooters.com/index.php?route= ... uct_id=139
80t sprocket: http://tncscooters.com/index.php?route= ... uct_id=131
80t sprocket freewheel mount: http://tncscooters.com/index.php?route= ... uct_id=389
#25 chain: http://tncscooters.com/index.php?route= ... ath=38_103

I mounted the 11t sprocket by filing down the motor shaft using Denisesewa's method: http://endless-sphere.com/forums/viewto ... 50#p674409

The 80t sprocket is a bolt on with the freewheel, just need some bolts and washers to align the chain properly. This means I have a freewheel on each side of my jackshaft, which is redundant, but it was the easiest way to mount the 80t sprocket.


To do:
Chain guide for the 48T chain ring
Get some proper forks

[jman]

Is it just me or does something look bent on that gng?

[mwkeefer]

Great design - looks like #415 primary with freewheel in large #415 pulley - so yea you have to pedal against the jackshaft load but I imagine that's not so difficult

Great build, hoping for more details - parts list... I've got a Gen1 I'd like to do something similar too.

You may want to replace the bottom mounts with Lightning Rods (Mike) lowers, they are much more stout and should handle your power levels much more reliabially!


Regards,
Mike

[Haste]

range?

[o00scorpion00o]

I've a cat exactly like that !

[christerljung]

I like that frame!!
Be carefull to lock the GNG/phanpy freewheel. It wants to unscrew itself. I got mine locked with weld and locktite. It holds up fine for high power thou.
Mount a Little torquestrut and the sheets will stay straight.

[bee]

Is it just me or does something look bent on that gng?

It totally looks bent. I've measured the tolerances a half dozen times now after coming back from rides because I was convinced something had bent but it's all aligned and straight, it just looks like that because the jackshaft is offset by about a cm.

Great design - looks like #415 primary with freewheel in large #415 pulley - so yea you have to pedal against the jackshaft load but I imagine that's not so difficult

Great build, hoping for more details - parts list... I've got a Gen1 I'd like to do something similar too.

You may want to replace the bottom mounts with Lightning Rods (Mike) lowers, they are much more stout and should handle your power levels much more reliabially!


Regards,
Mike

The original freewheel is still there and works fine, so I'm not turning the jackshaft when I pedal. The freewheel I added is redundant and was simply the easiest way to mount the 80t sprocket.
I added a parts list for the primary chain conversion to the OP, let me know if you need any more details.
Waiting on some lower sheets from LightningRods, I haven't had any problems with the stock lower sheets at this power level but it would certainly be nice to lose the idler.

I like that frame!!
Be carefull to lock the GNG/phanpy freewheel. It wants to unscrew itself. I got mine locked with weld and locktite. It horlds up fine for high power thou.
Mount a Little torquestrut and the sheets will stay straight.

I'm not sure what you mean about a torquestrut? I'll put a few spot welds on the freewheel next time I'm working on the bike, so far it has worked reliably.

One of my new zippy packs died after the first charge. I came back and the pack was quite warm, the balance connector showed one of the cells at about 1v and dropping, and the multimeter showed different resistance across this cell compared to the others. I charge the pack with the balance lead unplugged and the damaged cell got up to about 2v but started to lose charge again when I unplugged it and got warm again, so I left it in the tub and checked it again the next day, and the cell was dead at 0v.

After separating the dead cell, I noticed that the dead lipo cells bag filled with air after separation which leads me to believe that a hole developed in this cell after the first use, causing it to die.


Some quick surgery and I've got a working 6s pack:


I don't really know what the range is, I got about 25-30mins of hard riding with 2 battery packs and the stock controller, I would say it's around 40-45 mins now, and way more fun

[christerljung]

This is what i meant with a torque-strut. It will prevent the hole assembly from twisting when the 6kw peak-power wants to reach the ground.

strut.jpg (168.9 KiB) Viewed 8600 times

[bee]

Ah that's a good idea, I've been meaning to take some video of the motor/jackshaft while riding to see if any flex was happening. The jackshaft is very rigid on my bike because of the rectangular lower section of the frame.

[mwkeefer]

I like that frame!!
Be carefull to lock the GNG/phanpy freewheel. It wants to unscrew itself. I got mine locked with weld and locktite. It holds up fine for high power thou.

Are you talking about the 12t freewheel nut inside? I've lost one already and didn't even notice till I pulled the drive off the bike.

Mount a Little torquestrut and the sheets will stay straight.

Nevermind, I just looked up at your example

-Mike

[bee]

I was getting a lot of bending with the higher amps from the lyen controller so I had to make a torque strut like christerljung suggested:





I also swapped the 80t primary reduction sprocket to a 65t, and installed a cycle analyst & new shock.

[bee]

Here's what my secondary chain looks like after about 50km of putting too much gear reduction (11:80) and amps through the primary reduction (black chain is the old one):



Since my e-thirteen chain guide only goes up to 42t and I've been dropping the chain constantly with the 48t chain ring, I designed a quick chain guide that would work with any chain ring size:

[speedmd]

Hi Bee

Great work. I am seeing some significant stretch also on the secondary chain. Much more than the #25 primary chain. Looks like I will need to add some more adjustment , or guild block to the secondary side long term to take out the little bit of slop.

[christerljung]

Looks like a perfect chainguide! 3d-printed? could you share the opens-cad or .stl-files?
Are you happy with the power now?
What do you Think about eddicurrent loss in high rpm?
At 100v i get a feeling of strong power in the first half of rpm-register, then a Little dip and then she comes back and screams hard until it flattens out at the top.
Would've been great with an accelaration diagram.
There is almost no need for cassette gears with this broad-band motor.
I also had the sec. red. chain exchanged aftar a while.

[bee]

Yes, 3d printed on a reprap prusa in pink ABS with a .5mm extruder, .3mm layer height, and 60% infill.

I'll post up the source code once I've put a few km through it and made any necessary changes.

I feel a power plateau/loss when hitting the higher RPMs, it doesn't seem to recover once I hit the limit.

I'm pretty happy with the power of the motor, this seems about as far as you can go with standard bike parts so my next build will be a left hand drive with go kart parts.

After swapping to 11:65 on the primary reduction and a 48t/48t setup at the pedals I am reaching a top speed of 63km/h, I'm sure it will go higher once I put the stock cassette back together. The 16t single speed Surly sprocket that Chalo recommended is not engaging very well, it's skipping under pedal power even with a new chain. Not sure why, the chain seems to seat well on it. It seems that the mountain bike sprockets have a sharper curve on the teeth which is helping them hold the chain better?

I can do some data logging with my cycle analyst if there's anything useful I can produce, I haven't played with any of the software yet.

2 speeds would be awesome with this motor, I find myself switching between 3rd and 7th gear a lot depending on the terrain.

edit:
Just got back from a test ride. The chain guide works excellent, I've posted the source here: http://www.thingiverse.com/thing:118578
I was seeing peaks of ~3600-3650w on the cycle analyst while accelerating hard uphill,it seems like when the motor starts to 'bog' at higher RPMs, the watts drop too.

I'm also using this backpack now: http://www.bikeradar.com/gear/category/ ... pack-14623
It fits the 4x 5800mah 7s packs great, and the 3L water reservoir keeps my back nice and cool when the batteries heat up.

[bee]

Whoops:



Time for a single speed conversion so the chain can get some proper tension!

[christerljung]

How can that be that the Power is 3kw on yours 28S system when i got 5kw on my 24s?

The gearing differs between our bikes:
There is 12/72 , 13/48 and 48/34 or 48/28 on mine.(most common is that i use the two biggest gears in the cassette)
Then it tops at 70km/h
(phase current is set at 45)
A very conveniant way to go between trail and highspeed is to use the Three-level programmable powermodes in the lyen controller. Then you just use the Electric switch instead of the cassette.
After 3 months of constant hard riding wheelies, accellaration and so on. The shimano HG40 7/8-speed still holds up fine. There is no cogg slipping in the cassette except for the smallest 11tooth. (But i only use that when pedaling)

Also the wheelie capabilities you observed is the same as mine. On the bighit fram the rear suspension had a huge compession when trying a wheelie. Then i popped back when you eased the throttle. Impossible to wheelie on that frame, at least for me. This phenomenon is less brutal on the kona frame and the wheelies is under better control now.

Gonna print out that chainguide when im back from holiday.
Thanks!

[bee]

I think my controller came programmed for 35A, I haven't tried programming it with higher values yet.

My cassette and chain appears to be in great shape.

This is the second derailleur I've destroyed in this way, I'm not really sure what happened, both times I was cruising slowly and then hit the throttle hard. This surge of power seems to cause the chain to spin quickly until it matches my cruising speed and the freewheel engages. When the freewheel engages, a lot of shock goes through the fast spinning chain and I suspect that the spring in the derailleur isn't strong or fast enough to pull then chain away from the large chain ring and so the chain stays engaged and pulls the derailleur towards the front of the bike.

Increasing the shock stiffness helps with wheelie control. Trying to balance a wheelie on this bike has been a fun challenge, it's so much easier on my Yamaha BWs.

[speedmd]

Hi Bee

Most likely, the chain is twisting/ binding up some way between the pulley wheels. You may look for/ make a more fully enclosed pulley cage that may help this. Good thing you have a replaceable hanger or the frame would need some hot wrench activity.

[Wishes]

Hi Bee,

Thanks for sharing the details of your build. I used many of your suggested parts in my build. Got love this forum for the volume of information people are willing the share.

I had a question about the CA and the Lyen controller. Did you have to fine tune the advance settings of the CA to specifics of the GNG motor?

Wishes

[bee]

I just had to enter the shunt value into the cycle analyst and disable the throttle output limit. I still need to reprogram the controller to try higher amps, currently I'm limited at the stock 35A.

[beast775]

Those chain guides are the bizz!

[bee]

Destroyed the 1.0 GNG jackshaft so I ordered a new kit to have a motor in reserve and put on the new jackshaft with LightingRods' new adjustable sheets.





I needed a new torque strut with the new position of the motor so I redrilled the old one and welded a washer in the new position to save time.





The included screw + tube at the top of the lower adjustable sheets was a little too high and interfered with my frame so I put a short screw on each side instead:



I also put a larger single speed sprocket (22t I think) on the rear and replaced the 48T at the pedals with a 44T to make the gearing less harsh, which has made pedaling easier at lower speeds, improved motor torque, and should reduce wear on the components.



Finally, I've modified my broken derailleur with a skateboard wheel and tightened the spring to add much needed extra tension to the final drive, which should last longer than the soft rubber of the DMR STS tensioner I was using which got cut in half by the chain.

[1KW]

awesome, what is the torque/top end speed like of the single speed sprocket? Im sure with a single speed rear, and LR sheets/parts this is a bullet proof reliable setup?

[bee]

The torque is insane, I've geared it to practice learning power wheelies and so I break traction in the dirt and drift

The top speed is probably lower than what I got at 2000w with a 9 speed casette in the rear, but that is the trade-off when going to single speed.

I've only ridden a few hours on it so far, but it's been solid in those few hours, whereas with the previous jackshaft and gearing I had to readjust all the chains and alignment after an hour of riding.

I'm currently using an 18fet Lyen controller set to 40A (4500w).