GNG Drive Gen2

Hi Alsprong, I just ordered the Cyclone gear too, but I emailed them first to have a go about the postage, came back to me as $156 inc postage for crank/bb set and the freewheel/chainring (the $98 kit + postage).
Mine flew out the freewheel too (replaced it with a dicta - killed that too, replace with an ACS today), and mine has the wobble on the original crank arm too (so much so now I can't use the bike anymore), and yeah, mine sparks when I hook it up too.

I'm hoping once the cyclone gear gets here, I'll finally have a reliable setup.... :)
 
It's normal for the battery connection to spark when you connect it. Nothing to worry about, although it can wear out your connectors eventually.
 
It is easy and cheap to copy a no-spark circuit that has been posted a while back, if that is of concern.

Some just add a small and cheap "sacrificial" connector in parallel to get past the spark, then make the high-amp connection with an Anderson or XT-90. When the small connector gets too corroded, clip it off and solder on another set...

I don't like the spark due to potential flammable vapors in my garage...rare, but possible when filling mower, etc.
 
Today I had a fantastic 6 mile ride on my GNG v1 Dahon Jack with only one issue, the v1 Primary Reduction pulley uppermost brace is preventing the folding of my Dahon, not huge but a big deal all the same.

The bad news, I have to take the v1 GNG drive off my Dahon Jack :(
The good news, I still haven't gotten around to installing the GNG v2 on my 20" 2012 Nova... Given the smaller form factor of the v2 Drive (and measurements) it will actually fit the look and profile of the Jack better but more importantly it will fit much better and folding will remain an option.

Rebuild of my Dahon Jack will begin in the morning, first tests (using Eagle Tree loggers to analyze the data) will be powered by 10S (36v) then 12S (44.4v) all using the stock controller and measured... from there only the results will point, I have the feeling I'm going to need a new rear hub with a 9t sprocket in the cassette - these are available just not cheap, 11t is just not big enough for pedal along top speed @ 85 RPM pedal cadence.

Oh well... more to come soon...

-Mike
 
mwkeefer said:
... I have the feeling I'm going to need a new rear hub with a 9t sprocket in the cassette - these are available just not cheap, 11t is just not big enough for pedal along top speed @ 85 RPM pedal cadence....
Click to expand...

I even hate 11T sprockets since they tend to eat chains. I prefer using 13T with a big chain wheel. 9T isn't even worth the effort, it's a waste of time.

If you want a drive ratio that really fits your needs, you should try a "dual freewheel jackshaft drive" http://endless-sphere.com/w/index.php/EBike_Motors_Middrive#Jackshaft_Dual_Freewheel_Config
, which should be possible by using special sprockets on the Gen2 drive (i'm not sure here, you have too look where you could get them). Overdrive ratio can be tuned up to ~1.9, so virtual chainwheel sizes ofmore than 80T are possible with this config. Another option, that is more off-the-shelf is a hammerschmidt drive, it's also an overgear drive, it has an overdrive ratio of 1.6. A 48T chainwheel gets 76.8 virtual teeth that way.

Have fun, I really like the Gen2 drive!
 
I posted this in another thread somewhere, but I think it should go here.
I bought one of these controllers fromm Cohismotor:
http://www.conhismotor.com/ProductShow.asp?id=323
It gives more torque than the standard one. I'm guessing about 30 amps, which might be a bit much. Maybe the 500w one would be better.

I can now get 5 levels of PAS, which really suits this set-up. At 36v, cadence and the PAS settings are just about right. The PAS levels affect the crank rotation speed. It's similar to having 5 fixed levels of throttle. You can also switch PAS off from the nice LCD display if you want. The LCD can be set to show actual voltage as well if you want.
 
I've been using my GNG Gen 2 a\ lot recently, and really enjoying it, but here's what happens if you run it with 30 amps. Anybody know where to get a replacement?

 
garfong said:
I was about to put a 48v 45amp controller on mine. What part is that?
Click to expand...

sounds like that's not the best idea if you dont even know what that part above is used for xD
d8veh said:
I've been using my GNG Gen 2 a\ lot recently, and really enjoying it, but here's what happens if you run it with 30 amps. Anybody know where to get a replacement?
Click to expand...

measure the inner dia of the sprocket, guess it is 1/2" or something like this, Email sickbikeparts for a reaplacement when you know the dia.
 
gng have that gear on the site for sale. :wink:
 
That stock item is 9 tooth and may be the issue at hand :) Perhaps moving to either 11 t #35 drive sprocket or as I have been planning, move to #25 11t driving 80t #25 sprocket on the chainrings (80t #25 is available from dozens of places (including electricscooterparts.com and others).

Also, does anyone know the gearing ratio of the internals on these drives? I've calculated (ballpark) 5:1 but really I forgot to write some RPM details down when bench testing so I have no clue if that's right..

In either case, the second stage is going to have more torque and likely caused that 9t driver to split... What is the stock current of the controller? 30A isn't much and at 36 or 48 (or higher) you should be able to use 30A no problem... presuming that your not SLAMMING the throttle after coasting and letting the drivetrain basically Bomb Drop itself :)


Stock Secondary #35 Chain: 38 / 9 = 4.2222 : 1
Stock Replacement #25 Chain: 80 / 19 = 4.2105 *Much more wrap here, wont split as easy
Upgrade to allow over volting: 80 / 13 = 6.1538 *This is about the maximum reduction I would use, 13t may be too small anyway

As you can see, for a bolt on replacement option going to #25 makes sense and for upgraded or increased reduction and again... bolt on compatibility with no fabrication or machining :)

Well that's my .02 for now :)
 
The shaft is around 11mm (maybe 7/16"), so standard ones won't fit. Jon Chan from GNG has offered me the one on their website, which is 13T, but I think that will be too high. The gearing was just about right for the power/speed at 36v with 9 teeth. I think 11 teeth is about as high as I'd want to go.
 
I got my 13T sprocket today. naturally I had to lengthen the primary chain a bit to fit the new sprocket. It works fine on throttle now, but unfortunately the cadence is now completely wrong for the PAS control that I mentioned in a previous post. I'm really disappointed because it was so nice before. The cadence perfectly matched the PAS level settings on the LCD display, but now level one just gives full power, so no point in using the others. Also.the motor's turning the pedals too fast now for me to keep up because I have to use lower gears so that I don't over-stress the motor.

To summarise: Unless you want to ride your bike without pedalling, don't fit the 13T drive sprocket. Unless I can find a 9T one somewhere, the motor will be relegated to the shed.
 
d8veh said:
I got my 13T sprocket today. naturally I had to lengthen the primary chain a bit to fit the new sprocket. It works fine on throttle now, but unfortunately the cadence is now completely wrong for the PAS control that I mentioned in a previous post. I'm really disappointed because it was so nice before. The cadence perfectly matched the PAS level settings on the LCD display, but now level one just gives full power, so no point in using the others. Also.the motor's turning the pedals too fast now for me to keep up because I have to use lower gears so that I don't over-stress the motor.

To summarise: Unless you want to ride your bike without pedalling, don't fit the 13T drive sprocket. Unless I can find a 9T one somewhere, the motor will be relegated to the shed.
Click to expand...

I realize there is an odd output shaft diameter and finding another #35 9T is difficult but between McMaster/Carr and SDI/SDP I think sourcing it would be possible even if it needs bored or if the shaft needs to be shimmed with an adapter.

Personally I would go a bit further (have the parts, haven't had time to finish testing stock 48v setup - but it's installed) the endgame here is #25 drive, if the #25 isn't strong enough for the torque it can be doubled up but again I figured using 80T 4bolt chainring (available from many places) replacing the driven sprocket, I would suggest 13t for the driver minimum - but... you could go as high as 16t and still have a better ratio than stock of 4.22:1, the #25 driven by 16t would yield a 5:1 and engage plenty of teeth at the drive sprocket side... many more than a 9T.

My setup will likely after calculating loaded cadence and my desired cadence for a particular build 15t -> 80t outer ring for a secondary ratio of 5.33 : 1 which is a good improvement over stock 4.22 : 1 and will permit higher voltages than even 48v and will maintain decent cadence :)

-Mike
 
d8veh said:
The shaft is around 11mm (maybe 7/16"), so standard ones won't fit. Jon Chan from GNG has offered me the one on their website, which is 13T, but I think that will be too high. The gearing was just about right for the power/speed at 36v with 9 teeth. I think 11 teeth is about as high as I'd want to go.
Click to expand...

Just looking at this again...

Since the Gen2 is 2 x 38t 4 bolt style chainrings and there are bolt holes which are perfectly 135mm BCD, an easy solution to use the 13T #35 as a driver would simply be to drill out the 5 bolt holes on the outer chainring and then mount a 54t or 55t 135mm BCD chainring (widely available).

This would result in an identical cadence and reduction as stock but with much more engaged teeth on the driver side, may require a spacer from the downtube mount to properly space the chain to allow for a 54t sprocket.

-Mike
 
The GNG 9 tooth sprocket is exactly the same as the Izip, ezip or Currie drive sprocket, and is also fitted to those little scooters that use the same brushed motors. Loads of suppliers in the USA stock it for about $12. The problem is that they want from $50 to $100 to ship it to the UK! I can't find a UK supplier for it.

Has anyone got one lying around on a dead motor. I can pay by Paypal.
 
New crank arms seem to have fixed problem , although the third freewheel I bought sounded remarkably smoother than the last two I had . I have had almost 200km of trouble free riding and then the chain snapped , well at least three links on one side, not completely snapped , but unuseable. I also noticed that the mounts for the motor had bent slightly , possibly twisting under torque , I found one of the outer bottom bracket nuts had come loose , which may have allowed the extra movement . My kit is stock so I was a little bit shocked that it would have shifted , so hoping that after retightening everything and replacing the chain I get further than 200 km !
Anybody find it unusual to break a chain so quickly ? Well oiled and tensioned, maybe placing too much load on it ? ( I was worried I'd be snapping spokes )
 
Neiler106 is getting a Gen-2 running, and has posted some of the issues he had to fix:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=49594
file.php
 
spinningmagnets said:
Another pic for the files, from "Vims":

http://endless-sphere.com/forums/viewtopic.php?f=28&t=47642&p=744661#p744661
file.php
Click to expand...

This is interesting, anyone else notice a difference in the Gen2 - there is now some additional bracing between the mount brackets and the centerpoint of the hub motor. I presume because they needed stiffening.

I've got my GNG gen2 v1 - without the reinforced BB mount and while there is a ton of wobble and runout in the free wheeling crankset, and the motor gets HOT at top speeds... on 48v LiFePo4 the sucker is rid-able on the 26" jack.

Monday I went a total of 12 miles on < 6AH
Yesterday was a wash out
Today I have gone about 4.11 miles using 2.3 AH of power so far.

The brackets need tightened, need to figure a way to remove chainring axial run out and a few other bits before I call it a Beta install but so far so good!

-Mike
 
Using metal that is not re-cycled Chinese beer cans will help, and also a better bracket shape that includes thicker steel couldn't hurt either. I have been bugging LightningRods to make a Gen-2 bracket, and he said after the Gen-1 is fully developed (available soon), he will consider it.
 
spinningmagnets said:
Using metal that is not re-cycled Chinese beer cans will help, and also a better bracket shape that includes thicker steel couldn't hurt either. I have been bugging LightningRods to make a Gen-2 bracket, and he said after the Gen-1 is fully developed (available soon), he will consider it.
Click to expand...

Sounds like either I have to pressure Mike to build new mounts (With square inner taper bolts to allow chainring to be torqued without rubbing on Bolt Heads), the stock mounts are a joke. If he won't make em, I'll at least remove mine and have them cut in 3-4mm steel as he does for the lowers on my friends sand cutter.

The heat level after a ride scares me a bit (since I would call it an easy ride).

I think also we need to make a spacer for between the bearing face and inner race of the chain ring bearing then it should never rub and it will (hopefully) sit flush and square.

Other than that - fantastic!

Oh and spin, look at yours then look at the one you just posted - the brackets have changed, looks like an improvement... who knows.

-Mike
 
P1012767 wee freewheel.jpgAfter about 8 months of fairly casual use, the freewheel on my gng2 has worked loose and the initial wobble of the chainwheel been exacerbated to the extent where it now throws the chain. In fact the chain has broken twice. I probably should have tightened the freewheel earlier, and though it still works, the ball bearings seem to be all shoogled up and out of place. Will try getting a replacement chainwheel and crank set from Jon Chan at GNG though I doubt these guys are geared up for/ sympathetic to product failure and reparation. Will let you know. Here's a photo, any ideas or sympathetic comment appreciated.
BTW, was using 12s2p lipo and K123 controller to 1500watts peak. cheers :)
 
To be honest, I would look at replacing that freewheel with a 16T ENO and just grinding down the flanges for removal (it can still be removed but)... another option is just to replace with an ACS Crossfire 16T freewheel and rebuild the freewheeling crank.

I've found all the aftermarket freewheeling cranks leave something to be desired, to the point where I'm looking at setups for tandem bikes again as a way to hopefully have a more bullet proof freewheeling crankset - these tandems have been in development for many, many years and I presume their designs are a bit better...

I'm too busy and lazy to disassemble my entire setup on the GNG gen2 v1 right now, packing and cleaning (kids are coming for fathers day weekend).

Glad I didn't go for a capacity test on the V Power 20AH 48v - since I've only been charging it up to 54.6v when now I see it should be charged up to 58.4v... whoops (3.65v per cell x 16 cells)... I did achieve 12 miles though at good speeds with power to return home - adjusting charger now to see how well it works at 58.4v - I should be able to get a constant 40A out of it and bursts of 60A which would be great if it didn't weigh in at around 27 lbs.

Since this was new when I got it and had a bad BMS - I will continue to test it out, if it works and delivers 18-20A at 1C (20A) it would make a great pack for someone needing 40 - 50mi range, at the stock 20A controller on a 26" I saw approx. 2 AH per mile riding hard the whole time, average speed 17.8 mph, max speed (on flats) 31.7 mph @ 6AH for 12.4mi according to GPS and cycle analyst both.

So if this pack still tests as useable, I will likely offer it up for sale on ES once I confirm it's status.

Remember I was driving a GNG gen2 and BTW... seeing average between 400w and 1000w on the CA with stock controller just in case anyone wants to know :)

-Mike
 
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