GNG, 1000W 48V BB-drive, $400

spinningmagnets · Aug 16, 2012

edit: although the GNG kit remains useful (especially at 36V), the stock kit has several weaknesses, and Mike/LightningRods has developed a new kit that uses all heavy-duty parts using the same motor as GNG. The thread can be found here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=57720

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http://www.gngebike.com/450wbrushless.htm
Its advertised as the 450W kit, yet the voltage is 48V and the stock controller is 22A max, so the stock kit maximum is at 1000W ("GNG" means "Giant and Great")

The owner is Jon Chan, his business address:
FLAT 2,9/F, WAH LAI INDUSTRIAL CENTRE, 10-14 KWEI TEI STREET, SHA TIN NEW TERRITORIES, Hong Kong

Page 19, from Craigh85

Climbed a seriously steep hill for more than 10min at 21amp, motor and controller were warm to the touch certainly not hot (@ 44V LiPo)

Page 20, from d8vehI

tested mine today at 36V and 25 amps using a KU93 9-FET controller. It had massive torque - about equivalent to a geared hub motor at 40 amps or more. I also tried it at 15 amps with a 6-FET controller and it gave much less torque. With 15 amps it went up our 15% test hill slowly in first gear, but with 25 amps the motor didn't even slow down as I changed up through the gears to fourth...(pg 21) On the open road the system is fairly quiet. During acceleration from a start, it has slightly more noise than a geared hub motor in similar circumstances. At 15mph and above, the wind noise drowns out the motor noise.

from Christerljungs build-log

The power of 12S (44V) was fine, good for pedal-assist combination...pulled wheelies quite easy...[then] at 72V...motor temp gets a little warm (not hot)

Page 121, from Wishes

...This motor likes to rev. I have run it at its stock 48 volt, stock 60 volts, 75 volt and 100 volts keeping the AMPs at 40 max. It runs great, doesn't heat up and is quite efficient...

Reduction:
edit: primary drive is a toothed belt, 14T-80T (ratio 5.7:1) and the secondary drive chain is 12T-44T (ratio 3.7:1) overall gear-down from motor to BB is 3.7 X 5.7 = 21.1:1, chainrings are 4-bolt 64mm BCD, The internal BB width of the mounting bracket is 68mm, Laser-cut steel is 2.5mm thick, BB is 150mm wide. The primary belt is 5mm pitch / 15mm wide. Motor case is 120mm dia / 70mm wide, weight of complete drive assembly is 4.3kg. There's a new thread about just the primary drive upgrades here: http://endless-sphere.com/forums/viewtopic.php?f=28&t=46738

Edit: as of the spring of 2015, GNG is shipping all new belted primaries with a 20mm wide belt, instead of the original 15mm wide.

Jack shaft NO-LOAD output @ 48V = 570-RPM, so with 12/44 second stage no-load cadence will be 155-RPM, the chainring that drives the stock chain to the rear wheel is a 38T (many thanks to ES member "full-throttle"). Unloaded motor kV is approximately 67.

The 36V kit is $80 cheaper and brushed, also it uses the noisy Currie-style metal gear-reduction.

The 48V brushless kit has an external belted reduction to a jackshaft, which also allows an off-the-shelf freewheel (Dicta?). I like the mounting bracket, which should allow it to be mounted to a wide variety of frames (can be easily upgraded to a White-Industries ENO/ACS-Crossfire). Pics of how the bracket attaches to the spindle cartridge on pg 67 http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785&start=990#p686296 Stock belt here: http://www.ebay.com/itm/221012653265?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 if EBAY link is old when you read this, it is a HTD-5mm pitch, belt is 15mm wide and 475mm long with 95 teeth. The Goodyear version of this belt is considered to be better.

Kit does not come with a battery or charger. It appears to be direct-shipment from China, so no North-American dealer, plus, returns would be a hassle.

Motor:
Motor is an inrunner about 4-1/2 inches diameter and about 2-1/2 inches wide. A very good size for a BB-drive. Bigger may be better for performance, but a bigger motor would have a hard time fitting most frames. Since the motor size is a limit on whats possible for most bikes (in that frame location), the fact the motors 67-kV is set for a BB-drive @36V-48V is a great choice. Motor internal pics (thanks christerljung): http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785&start=780#p674715 plus some motor specs: http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785&start=825#p675568

Controller:
edit: http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785&start=165#p633397 stock controller is a 9-FET with a fat aluminum bar as a FET heat-sink, the capacitors are 63V max, this controller has been run successfully on a 44V LiPo pack and also 48V. The LVC does not allow a 36V [or lower] pack to work). The stock controller from GNG has been verified as 22A max, so in stock form 48V X 22A = 1056W, and since the motor and controller have not been getting hot (only warm) at this continuous power under load, this is its true rating. It "may" be possible to get GNG to substitute a controller at no extra charge that has it's LVC set for a 36V battery, ask before ordering, and check immediately upon arrival.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=46164&start=15#p695197

I also pulled off the 12T freewheel on the jackshaft and took some measurements. There was a bit of confusion regarding the diameter (some people saying it's 10mm). It is 14mm in the center, but the keyed part the freewheel attaches to is actually 11mm with a key nub. The length of the output shaft is about 22mm long. I decided to pick up an adapter for 11mm keyed jackshafts from BikeMotive to use a 30mm x 1.0 BMX freewheel, and also ordered an ACS Crossfire 13T to mount on it. The gear ratio from motor to chainring is the opposite of what I wanted to do, but it'll give me more freedom with the chainline (motor to chainring). There's also the added benefit of readily accessible replacement parts.

GNG Primary chain conversion thread http://endless-sphere.com/forums/viewtopic.php?f=28&t=46738

GNG kit mods thread http://endless-sphere.com/forums/viewtopic.php?f=28&t=46891

Strong freewheeling crank upgrade http://endless-sphere.com/forums/viewtopic.php?f=28&t=47618

Big Block GNG alternative motor:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483&p=857507#p857507

GNG now has a chain-primary kit advertised as a 60V system (80V caps), found here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=52865

Here's a spreadsheet of all possible gear and sprocket selections, providing the end MPH at 48V
http://endless-sphere.com/forums/viewtopic.php?f=28&t=51263

_________________________________
16 minute Video of GNG kit dis-assembly

https://www.youtube.com/watch?v=mCuwmoT1skE

9 minute motor dis-assembly
https://www.youtube.com/watch?v=WFbMbHrMTIc

redstone02 · Aug 16, 2012

Hello,

Total noob here. Researching GNG's 450w brushless mid drive is what brought me to ES. GNG has a forum on their website and the owner is very responsive to inquires.
I'm very close to making a decision on this; looking at batteries for my 4 mile (one way) commute over flat terrain.

What is BB?

neptronix · Aug 16, 2012

Cool, that looks like a nice mid drive to me. Should be quieter than the currie-style system for sure. The motor looks a lot like a knockoff of a small MAC / BMC, as well. ( ecospeed uses those ! )

I like the mounting system! Using the BB as a mounting point is smart. This is a big improvement over the cyclone kits.
The vendor looks a bit shiesty, going off their web page. But they might be OK.

So who is going to be the guinea pig?

a 450w mid drive is not going to be a barn burner, but it'll be a decent setup.

spinningmagnets · Aug 16, 2012

fabiograssi · Aug 16, 2012

spinningmagnets, are you putting 25A and 48v on this motor now? Sorry if I understand wrong... If yes, what is the performance? And noise?

heathyoung · Aug 16, 2012

Very interesting design, if that inrunner has a good thermal path from the windings to the case, this would be more capable than the cyclone style motors in terms of power handling. Hmmm... very tempting.

Time to look at unite motors to see if this is one of theirs... All of the others look to be unite.

Looks like the motor used on their transaxle - http://szunitemotor.en.made-in-china.com/product/WqhmifFDnIcK/China-Transaxle-Motor.html

They rate it 48V 500-1500W.

spinningmagnets · Aug 16, 2012

I have not purchased one. The motor runs the appropriate RPMs to be a BB-drive at 48V. That has been one problem with off-the-shelf motors. If a motor has a kV that makes it work well at 24V (or in some cases 36V), it will be spinning too fast when using 48V. Since this has a two-stage reduction, there are a couple places where a sprocket could be changed to a different tooth-count if needed, but since this motor already runs at the right speed at 48V, no sprocket search-and-change is needed.

The controller is easily upgraded, but the mounting bracket does not easily allow a different motor to be swapped in. If the motor has neodymium magnets, I am leaning towards buying one of these. I don't know what the amp-limit is on the stock controller, but if it will allow 25A, it would save me $50 (it will likely cost $50 to get a different controller).

The 48V Cyclone kit costs twice as much as this, and it is likely to be noticeably noisier. The primary drive here is a belt instead of a chain, so it "should be" quieter.

spinningmagnets · Aug 16, 2012

Found their Ebay store:
http://www.ebay.com/itm/48V-450W-BRUSHLESS-MID-ELECTRIC-MOTORIZED-E-BIKE-CONVERSION-KIT-NEW-CRANK-SET-/190694746581?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%26itu%3DUA%26otn%3D5%26pmod%3D200653249950%26ps%3D63%26clkid%3D1380233566145987562#ht_3787wt_1186

redstone02 · Aug 16, 2012

spinningmagnets said:
redstone02, if your commute is truly only 4 flat miles, you have many options. You might be well-served by a cell_man geared hub kit (its worth looking at before you spend real money). You can decent performance from an affordable 36V battery if the commute is as flat as you say. Going to higher volts cost more, but it improves power and hill-climbing. The people who has mentioned that they are willing to put up with the hassles of a BB-drive (noisy, complex) often state that they have serious hills. If you do get the GNG kit, please post about it.

Thanks for the reply spinningmagnets.
I have looked into hub drives and find, at least for me, they are not aesthetically pleasing and seem like a trade-off for what I am looking for: overall efficiency and easy on the battery. Direct drive hubs draw high amperes getting under speed and geared hubs almost meet my needs but at sounds levels that I figure a BB drive will produce. The BB set-up suits my needs but hey that could change as I learn more. Using the bike drive train and gearing allows quick starts and the motor operating in a better part of its efficiency curve at start-up and underway speeds.
My commute has segments of road where I have a need for speed just to get the hell off that part of the route. I have a telescope that uses a 24 volt drive system, running parallel 6S1P packs will work. A 48 volt with two series wired 6S1P setup just clicks better for me.
Getting long…. don’t mean to highjack your thread…. I’m about six weeks out from a purchase.

Timbuck · Aug 16, 2012

Well....
Just got a kit over here in Australia. No drama's , the process was great , shipping was fast.

Quality looks great.
I'll let you guys know how it goes.

Tim.

heathyoung · Aug 16, 2012

Sweet - I'm interested in the total cost, looks like a better thought out design than the cyclone as well.

Lots of pics please

AussieJester · Aug 16, 2012

Timbuck said:
Well....
Just got a kit over here in Australia. No drama's , the process was great , shipping was fast. Quality looks great.
I'll let you guys know how it goes.

Tim.

Be very interested to see how get 0n with this kit on Tim, would like this for the girfriends
bike...Not in West Australia by chance are you?

KiM

full-throttle · Aug 16, 2012

Timbuck said:
Well....
Just got a kit over here in Australia. No drama's , the process was great , shipping was fast. Quality looks great.
I'll let you guys know how it goes.

Tim.

Nice!
Welcome to the forum

heathyoung said:
Lots of pics please

.. and videos

PS just ordered one
mmm less unsprung weight, gears

Hyena · Aug 16, 2012

Good man full throttle, I was just about to buy one myself after aussie jester sent me the link but you've saved me the trouble.
Be sure and report back how it goes

Thats a bargain price for something with a belt drive like that an such easy mounting.
My torque test for it would be to see if it could take 30 amps on 18S lipo

I'm sure the 450w is underrated and it'll do 1000w with ease. The controller looks like a 12 fet which you wouldn't both with for anything under 20 amps.

neptronix · Aug 17, 2012

Guys, i got a weight spec from the seller.

Entire kit is 8kg / 17lbs. Without the crank, it's 6kg/13lbs.

I'm going to make a wild guess and say that the motor/reduction unit / mount system comes in at about 10 pounds; the rest may be controller/throttle/bottom bracket weight.

heathyoung · Aug 17, 2012

Hyena said:
Good man full throttle, I was just about to buy one myself after aussie jester sent me the link but you've saved me the trouble.
Be sure and report back how it goes
Thats a bargain price for something with a belt drive like that an such easy mounting.
My torque test for it would be to see if it could take 30 amps on 18S lipo
I'm sure the 450w is underrated and it'll do 1000w with ease. The controller looks like a 12 fet which you wouldn't both with for anything under 20 amps.

Yep 1-1.5 kw wouldn't be out of the question with the physical size of that motor - as long as the stator is well thermally coupled to the case - it could take more!

I'm thinking of getting one to play with for that price

neptronix · Aug 17, 2012

I'm thinking about getting one too, lol.

full-throttle · Aug 17, 2012

Hyena said:
Thats a bargain price for something with a belt drive like that an such easy mounting.

I just don't have the time and tools to fab it all. Looks nice in the photos. Hopefully it's well made.

The (lowish) power level doesn't bother me so much as I'd rather have long battery range and sub-30kg bike than the torque and speed of a motorbike. If it allows me to ride a DH bike as easily as a hardtail I'd be happy.

neptronix said:
Entire kit is 8kg / 17lbs. Without the crank, it's 6kg/13lbs.

Thanks

Hyena · Aug 17, 2012

Yeah it'd be great for offroad, being able to select 1st gear for big hills and tight technical stuff. And they're not exactly a slouch anyway, they claim a top speed of 50-60km/hr. I dunno what rear sprocket that is but with an 11t it should be capable of decent speeds.
I noticed on their forum a guy had converted the belt to a chain drive, to use a smaller ring for higher gearing. He is seeing 70km/hr with his.
It'll be interesting to see how it compares to your BPM which is probably similar overall weight once all is accounted for. 8kg is heavier than I was expecting though. When they say they crank is 2kg I assume that's the arms, chain wheel and BB ? Either that or they're cast steel arms! I dunno what the fighter chain wheels are made out of but I was amazed at how light they are when I had mine apart. It literally weighed about as much as a piece of cardboard in my hand!

If I go get one I might see if the guy can include a second motor. It'd be good to really put some decent power through one and see what they can take.
I'm surprised at how much power Sydney ES member sayian is putting through his stock drive train, he's using an 800 golden motor that's designed for trikes I think. It's fairly chunky - probably 3 times the size of this one and is rated at 800w (on 48v I think) . He's putting 5kw through it on 74v and it's not getting that hot considering the input power is over 6x rated. More remarkable is that his stock freewheel hasn't exploded. Yet... :lol:
Obviously 5kw through a standard drivetrain is pretty severe and asking for trouble but I reckon if it could take ~2kw with access to all the gears it'd be a slick little performer. I've ridden true 450w mid drive motors (supposedly 200w but I measured 500w+ with a watt meter) and it was very uninspiring.

fabiograssi · Aug 17, 2012

Yeah, a second motor on the hub! Overkill! :mrgreen:

spinningmagnets · Aug 17, 2012

If I go get one I might see if the guy can include a second motor. It'd be good to really put some decent power through one and see what they can take

If I may be so bold as to ask...please insert a temp probe and data-log when the motor starts to melt? (in the stator if possible, or even just the surface of the housing). Either way, thanks for anything you post about these...

Haste · Aug 17, 2012

I just purchased one aswell..

Knowledgethirst · Aug 17, 2012

Hi Guys,
I notice that this supplier also has an apparently planetary reduction on one of their offerings (48V600W brush-less motor US$225.00+85shipping).
Does anyone have experience of the noise level generated by a metal planetary gearbox at bicycle drive speeds?

Craigh85 · Aug 17, 2012

Dohh moment of weakness, just bought the 48v 450w brushless kit aswell. Fingers crossed the motor will handle a little more juice.

Punx0r · Aug 17, 2012

How much oompf can you put through the chain line before you start breaking things?

GNG, 1000W 48V BB-drive, $400

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