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

Christerljung and speedmd, you mentioned that taking the motor apart and reassembling it (to modify the shaft) is complicated, I would appreciate some more detailed info, as I am planning to do this and don't want do damage anything in the process.
Click to expand...

Hi Ferret

Welcome to the group. LR did a good job of taking you through the teardown. I would suggest you locktite the outer race of the large bearing in the housing when you are getting it back together as the shaft can be pulled out bearing and all if not.

Look forward to seeing what you plan for a gear reduction.

Cheers
 
Thanks!

I am planning to use 2 stages of planetary reduction, something similar to the photos on the first 2 pages of the Dogati thread (http://endless-sphere.com/forums/viewtopic.php?f=28&t=15233).
The gearbox output will be connected by a freewheel to a shaft with a cog that will attached to the main chain going to the rear cassette. On the other side of the shaft, another freewheel with a cog will be connected by a short chain to a chainwheel on the cranks. Similar to the M55 (see attached picture) except the main chain will be inboard and the short one outboard.

According to my calculations this arrangment will j_u_s_t fit between the cranks if I use a 83mm BB.

I am now trying to source the planetary reduction stages. I will probably buy ones intended for Currie bikes (http://www.esurpluselectronics.com/hardware.html) because I can't find anyone selling any other Matex gears (http://products.matexgears.com/viewitems/all-categories/planetary-gears-torque-range-45-300in--lbs-?forward=1). I even tried contacting Matex, but they did not respond to my mail.

Avner.
 
Hi Ferret

Sounds like you have an intresting plan.

I bought the parts you were looking for from Matex a good while back, they will probably eventually reply as they did to my web request,

I was also going to copy the Dogati setup but ended up in a different direction. I seem to remember the noise of the straight cut gears being an issue for some people, even when packed with greese.

The parts are now just gathering dust and surplus to my requirements, shoot me a pm and we can see how expensive they will be to ship to you from Italy.
 
It's possible to actually test all of these theories and that would be worth doing. We should compare the same motor with different reductions and measure actual output vs. the numerical reduction, the dba level at cruise and full speed, the pedaling effort with the motor off and anything else we can think of. It would also be great to know how the normal service life and much power each reduction drive can transmit before failure.

Planetary gear sets are really compact and if you want the cleanest possible minimalist install they're hard to beat. I have concerns about their noise levels, particularly with straight cut gears, and I'm not convinced they are the most efficient or most durable. I was going to say that the difficulty of changing gear ratios is a problem but as long as it is in a multiple stage reduction and there is a chain or belt in that system the overall ratio can be adjusted.

The closest thing I've seen to someone doing this was a comparison between a direct drive hub and a planetary reduction hub on electricbike.com.
 
speedmd said:
GNG motor only needs a single stage reduction to a jack and then you could go straight to the rear wheel as many have done with good success. With something like a three speed gear selection at the jack you could then bypass the crank entirely and have a good speed range for this great little motor. You would be shifting two places, but not have to reduce rpm and then increase them through the pedal system.
Click to expand...

I agree that struggling to reduce a 4,000 rpm motor to 100 rpm and then gearing back up 1:4 for wheel speed is really awkward. It would be great if one shifter could be coordinated to operate two gear boxes as you suggest.

One reality that seems kind of unavoidable is that pedaling along with a 60 mph electric motorcycle is not practical. On really fast electric bikes the pedals are there just to qualify it as a bike. At 1,000 watts and less your pedaling can actually make a difference and the bike drivetrain can handle the power. At 3,000 watts you will shred a bicycle drivetrain and pedaling is pretty pointless.

Since this great little motor can either be an e-bike assist or be over volted up into light motorcycle territory, at some level of watts you are looking at designing a different kind of drive system. For trying to sneak an electric motorcycle past the law as an electric bicycle, your dual transmission idea would work well.
 
The urban commuter store's "M-drive" uses a jackshaft in this manner, but still uses the bikes gears at the rear wheel. It is designed for the Yuba Mundo, so there is lots of frame room for a bulky drive with the added jackshaft and freewheels. One of the big benefits of the M-drive is that it is very easy to swap in various motors, and also easy to change sprocket tooth-counts.

It's impossible to design one drive that can adapt to every frame. But...between the Gen-1 and Gen-2 I think 80% of the bikes out there can have a reasonably affordable mid-drive. I think hub-motors will survive in the long run, but mid-drive has a couple of clear benefits for specific user-profiles...
 
The Schlumpf and Hammerschmidt type drives that crossbreak is using are a good solution to pedaling at high speeds. I think pedaling along helps much more than expected in the GNG type systems. It not only adds power, it lessens the down stream chain losses that can rob tremendous amount of total system power. Sort of like restrictions/changes in direction to piping do to flow the farther you are far from the pressure source. If you keep the whole thing light and the rider is able to keep the motor more in the efficient operating range, the paybacks can be significant.

I don't see it as sneaking into motorcycle territory but more of maximizing the power resources. I am most definitely glad I got the ratios close for pedaling with the power band of the motor. I was able to stomp with it all the way up my favorite climb the other night. Roughly a 1000 foot elevation change with most of it over the last few miles and averaged some 30 MPH the whole way of some six miles. Most of the time I was flat out with the throttle, but lifted a bit and downshifted as needed to keep the revs relatively high. Nothing close to hot ( I slowed down stopped pedaling and the motor while rolling briefly reaching down to feel it at several points) and totally impressed by this little motor.

Lightening Rods, count me in for a few of the hopped up version of the motor when you get to that (fat wires, High temp wire insulation and magnets, temp sensor). We will have to see about this definitive cooling stuff on a super version of the GNG1.

cheers
 
budwahgreg said:
Hi guys just FYI Powercycles in Melbourne are selling this kit free postage Australia wide for $400 aus. On Ebay.
Greg.
Click to expand...
The seller user ID you entered was not found.

got the link m8 as i can not find the seller or any listings for the gng
 
I'm curious what battery set ups people are using here with the stock or modified GNG controller. Ever since modifying my GNG controller to put out 35A, I've killed my Hobby King LiFePO4 pack. That 30C rating is definitely 10x overrated. :(

Anyone who's pushing out more than the stock 22A using LiFePO4? I ride the metrolink (public train) and park my bike in my office in a Federal building, so LiPos are a no-go for me.
 
skyungjae said:
I'm curious what battery set ups people are using here with the stock or modified GNG controller. Ever since modifying my GNG controller to put out 35A, I've killed my Hobby King LiFePO4 pack. That 30C rating is definitely 10x overrated. :(

Anyone who's pushing out more than the stock 22A using LiFePO4? I ride the metrolink (public train) and park my bike in my office in a Federal building, so LiPos are a no-go for me.
Click to expand...

I use the turnigy Lipo's , been using Lipo's since 2004 in RC airplanes and Helicopters without issue and was building custom lipo's for 1/4 scale airplanes ( big packs) when I worked for Dymond hobbies, common sense , being particular with assembly and mounting and following " the rules" when charging makes them safe. periodic inspection for swollen cells and making sure they are balancing ( I balance charge every 5 cycles) is key.
I've pulled up to 45 amps from these but normally run 36 amps.
The turnigy's come with connectors which allow you to combine packs with out having to solder, I run two packs in parrallel consisting of 2ea 5 cell and 1ea 4 cell 5000 MAH packs plugged together in series for 14 S and two of these units are connected together with a simple harness to obtain 10AH capacity , the only real pain is building a a setup to balance charge them, I also use the Hyperion 1420i net 3 charger which will balance charge 14s .
I dont think Lipo's are anything to be afraid of if used properly.
This is a pic of 14s 1 p turnigys connected without soldering anything which I was using while setting up the controller and throttle.
I know this doesnt really answer your ? but thought I'd put it out there anyway.
 
Thanks Denise, I'm probably going to put together a Turnigy LiPo pack for fun time. :lol:

I just want to see if there is a LiFe option out there that wouldn't potentially ban e-bikes from the Metro and the Federal buildings. I understand the likelihood of a fire these days is minuscule with proper upkeep, but there is still potential of external damage being a catalyst.
 
Denisesewa,
I have been using Hobbyking Lipo packs in RC (cars) for quite a while has well.
In my experience the stock bullet connectors are very poorly soldered in most cases. I would resolder the connector (in fact replace them with 5mm bullets for high amp draw applications).

Avner
 
justlooking said:
just a thought, but if the belt sprockets are to close together, couldnt another be used to link the 2 together ? so there will be 3 in line ??
there is a brown reverse wire on the motor , i take it that it will reverse the rotation that the motor will turn ??

i may be looking at this the wrong way ,,, but its just a thought
Click to expand...

Did anyone try to reverse the motor with the stock controller?

My build plan will require reversing the motor. If it can't be done with the kit controller, I may be better off not buying the GNG kit at all, trying to source the motor from Mr. Tao and get a programmable controller (Kelly? Lyen?).

Mr. Tao seems like a good deal, but I am hesitant because of the problems mentioned in this thread.

http://www.mistertao.com/taobao-vendor/lindachangshihang/price:desc-1.html


Is there any way for me to tell eif all these motors are the same?

Avner.
 
ferret said:
Did anyone try to reverse the motor with the stock controller?

My build plan will require reversing the motor. If it can't be done with the kit controller, I may be better off not buying the GNG kit at all, trying to source the motor from Mr. Tao and get a programmable controller (Kelly? Lyen?).

Mr. Tao seems like a good deal, but I am hesitant because of the problems mentioned in this thread.

Avner.
Click to expand...



there is a brown reverse wire on the motor , i take it that it will reverse the rotation that the motor will turn ??



file.php
 
skyungjae said:
Thanks Denise, I'm probably going to put together a Turnigy LiPo pack for fun time. :lol:

I just want to see if there is a LiFe option out there that wouldn't potentially ban e-bikes from the Metro and the Federal buildings. I understand the likelihood of a fire these days is minuscule with proper upkeep, but there is still potential of external damage being a catalyst.
Click to expand...

Dont miss these nice hardcase lipos:
http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html
They are under a special cathegory at hk, didnt see them until Adam gave me the hint.
 
christerljung said:
skyungjae said:
Thanks Denise, I'm probably going to put together a Turnigy LiPo pack for fun time. :lol:

I just want to see if there is a LiFe option out there that wouldn't potentially ban e-bikes from the Metro and the Federal buildings. I understand the likelihood of a fire these days is minuscule with proper upkeep, but there is still potential of external damage being a catalyst.
Click to expand...

Dont miss these nice hardcase lipos:
http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html
They are under a special cathegory at hk, didnt see them until Adam gave me the hint.
Click to expand...


Unfortunately they show negitive 20 in stock and wont let you add them to your shopping cart.
 
Yep you need to be quick, stock usualy don't last more than a few days... I signed up for email alert and they stock up quite often. Beware of duds tho, last time i got 1 bad out of 8. Cells are fine as checked from the balance leads but the power wires show 0V :lol:

I'm reposting from my thread but I was really impressed by the performance and efficiency of the GNG motor on 100V on Christer's bikes, he used about half the Wh's than my bike and his motor was not overheating while mine was!

This motor geared for 45k single speed with 100V5ah hot swappable battery on a ligthweigth frame is the best setup I can think of rigth now!
 
ferret said:
Mr. Tao seems like a good deal, but I am hesitant because of the problems mentioned in this thread.

http://www.mistertao.com/taobao-vendor/lindachangshihang/price:desc-1.html

Is there any way for me to tell eif all these motors are the same?
Click to expand...

I've bought a few things off of Mr. Tao and have gotten everything that I have paid for. It is a bit slow because they are buying off of the TaoBao or Chinese eBay on your behalf. I do not think they're dishonest. The one thing that I don't like is that you have to fund an account to even try to buy goods and there is no easy way to get money back out of that account other than spending it. It's not PayPal.

I've bought 'GNG' motors from a number of sources in China. First off, the motor spindle that GNG uses is unique to them. Most Chinese regard this as a tricycle motor, not a bicycle motor. It usually drives a two speed transmission through a long transfer case. There are several widths to this same motor, some involving a larger armature and others with just a larger external case. There is also a version with the motor spindle exiting the motor cases on both sides. One side is the drive spindle, the other side is a shaft for an external cooling fan. The spindles that I have seen in the nonGNG motors of this design are much better quality than the one GNG made or had made.

I have had no luck at all with this particular vendor, "lindachangshihang". When I try to order from 'her' I get notices about "is forbidden sell item termed "gear"". What in the hell ever that means.
 
Denisesewa said:
The turnigy's come with connectors which allow you to combine packs with out having to solder, I run two packs in parrallel consisting of 2ea 5 cell and 1ea 4 cell 5000 MAH packs plugged together in series for 14 S and two of these units are connected together with a simple harness to obtain 10AH capacity.
Click to expand...

I have four Turnigy Nano-Tech 22.2v 8ah batteries that I'm about to make a pack from. The bullet connectors that come with the Turnigys make it so easy to series them together. They male/female positive/negative down the line adding 22.2v every time. Simple. And then you just take two of those series chains and do a two into one parallel connector at either end for 16ah.

And then I read these posts from the 'Sparkys' (that's what I call you guys who are really smart about electricity) saying that we should parallel first and then wire those parallel packs in series. Well that just turns into a bloody mess! Is it possible to explain in anything resembling English why there is a problem with daisy chaining the packs neatly and simply using the connectors and then connecting them in parallel at either end?

I hooked my packs up as Denise describes. In a few minutes I was able to easily configure both a 44.4v 16ah and a 88.8v 8 ah. It doesn't really have to be hard to work well, does it?
 
I "think" the whole "parallel first, then connect the parallel strings in series to get final voltage" was to make balance charging easier. A 12S 44V group can be split into to two strings and charged with two 6S chargers. If you bulk charge the entire pack with a 44V charger all the time, then I "think" you can parallel or series in any order that's convenient.

I am willing to be convinced otherwise by anyone with a persuasive opinion.
 
Hi LighteningRods

I had the same question on my pack build and laced just the center female bullet connectors of the parallel bricks together with one bare 14 gauge copper strand and soldered it to the outside of the female bullets after striping off a small section of shrink tube. Either end of the pack has both bricks going parallel into a single power lead so it is not needed there. I understand this to act more like two six cell batteries in series and will help stop one of the parallel bricks from working more or less than its parallel mate. One small jumper is all it takes at each series junction.

I would like to get a few of the GNG motors to hot rod also. If you have not purchased any yet let me know what you need for minimums to possibly spec some of the upgrades to them. Stub mounted Fan sounds interesting. I am interested mainly in possibilities for some high temp wire and magnets, and some heavier phase wires as well as the possibility for a temperature sensor. Let me know if any of the contacts will entertain /discuss it.

cheers
 
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