New GNG Mid Drive Brushless 60V650W

[speedmd]

Hi Wishes

I posted this also on the build thread.

Looks like they used the wrong chain (Looks like 8mm chain) and boxed them selves into a taller ratio. You can just pedal faster.

You need to swap out the sprockets for some #25 sprockets or mount the jack shaft further away. Most can fit a 11 or 12/72 (6 times reduction) with the 25 chain (same or more than stock). I made some eccentric bearing cups for the jack on mine and could go still much larger than the 72. Lighteningrods has adjustable plates for the jack which will allow use of a larger sprocket if you want to stay with a longer pitch heavy chain, but you still most likely will need to swap it out for a 219 pitch setup or run a very large diameter gear. The 25 pitch (quater inch) is the most compact of the bunch. You may want to go to a 50 or 52 on the secondary side also if you want torque.

 

[speedmd]

so its got a reduction of 5.0:1, but if a 13tooth will fit then it will have a better reduction of about 4.29:1

13 tooth would be going very far the wrong way.

 

[crossbreak]

this mot runs 5:1 to jackshaft and 4:1 to cranks. At 85rpm crank cadence that are 1700 motor rpm. Who wonders why this is load? At this motor speed the smallest feasible sprockets are 13T or larger.


Motor has still 70KV, so the crank speed of max power

for 60Volt is around 3000rpm @motor /@150rpm cranks.
for 36Volt is around 1800rpm @motor /@ 90rpm cranks. ballpark figure


The right reduction to the cranks would be over 30:1 at 60Volt , so it has max power at 90rpm cadence.
Feasible primary reduction is 7.5:1, with a 13T you need a 98t sprocket on the jackshaft

 

[1KW]

what kind of top end increase with these kits?

 

[crossbreak]

what kind of top end increase with these kits?

just use your calculator...

80/14= 5.71

55/11 =5

increase: 5.71/5 = 1.143 = 14.3% increase

 

[speedmd]

12/88 or 7.33 will work with the longer jack shaft support plates. 12 /52, or 4.33 on the secondary, would bring it to almost 32 to 1. That is where I am thinking I would start if you can find and fit them. here is a 80T http://www.ebay.com/itm/Rear-Sprock...920?pt=LH_DefaultDomain_0&hash=item4613091c68

 

[crossbreak]

90T #25 sprocket http://www.monsterscooterparts.com/90-tooth-25-chain-sprocket-schwinn-izip-mongoose-gt-scooters.html

90 / 13 x 56 / 12 = 32.3 ballpark

 

[Wishes]

kifukarider wrote:

Wishes wrote:It burned out at 67 volts.

Wishes



The GNG v1.1 stock controller has 63v capacitors. It sounds like the new 60v controller still has 63v caps if it's failing at 67v.

Wishes, did you happen to check the low voltage cutoff before testing the "high voltage cutoff" of the new 60v controller?



Doh, no i did not. Hmmm, I guess I'll take the time to change the capacitors and test it. Back with the info shortly.

Wishes



Hmm, I stand corrected, i just opened it up. And the caps in it say 80 volts. I don't know whats wrong with this controller then....... Something else must have died in it. The caps do not look popped.

***** copied from the GNG thread.

 

[Wishes]

Here it is opened up.

While you have it open, what is the model number on the controller board? My 48v controller is XHWDZ-9MOS-B.

XHWDZ-9MOS-B

You can't tell from the picture, but the fet are YP17575C.

Wishes

 

[speedmd]

Sometimes caps short and do not pop apart. They do look just a bit puffy. 80 volt units should not have shorted anyway. They will show a constant resistance if shorted. I would look for bad solder joints or other bad/ loose connections in the system.

 

[dan974]

so how much do you think we can safely apply to them ? 80-10% ? 70V ?

 

[bee]

You can't tell from the picture, but the fet are YP17575C.

Wishes

Is that a typo, can't find those fets on google.

 

[speedmd]

I would say on electrolytic 5- 10% over is commonly safe. Poly type are much more robust and self heal if minor shorts develop.

 

[bee]

My controller came with a "60V 700W" sticker

YPI7575C fets






(click pics for high res)

These are 51-100v fets so we should be able to do around 80v on these controllers before needing to upgrading the caps.

 

[Wishes]

My controller came with a "60V 700W" sticker

YPI7575C fets


(click pics for high res)

You got yours!!! I am curious to see what you think of the noise level difference between this and your old converted #25 chain kit.

Wishes

 

[heathyoung]

Probably 75N75 FET's with another label - 75V fets. Nothing interesting or special.

 

[spinningmagnets]

I am weak on electronics, but I am trying to learn as fast as I can.

Concerning capacitors: Christerljung was the first to run the GNG motors at 72V-100V that I know of. He of course used a third party controller (perhaps Lyen?). However, if the only restriction to using this 60V kit at 72V is the capacitors, an acceptable capcitor should be fairly easy to find and very cheap to purchase. Prices for low-resistance capacitors (Low-ESR) are typically less than $2 each.

Back in 2010 (the year of the RC friction-drives), there were discussions about adding capacitors to the power inputs of RC controllers (ESC's). How many, what type, what criteria should be used to select between two choices?

The closer the voltage rating of the cap is to the system voltage, the better the performance spec of the cap was, so...don't use a 100V cap for a 48V system, a 63V cap will have higher-spec options and perform better in a 48V system.

The 80V caps in the stock 60V GNG controller suggest that if you are using the 3.6V-4.1V per cell charging protocol, an 18S LiPo pack would provide 64.8V when low, up to 73.8V when fully charged (20S would be 82.0V).

So...let's just say that the Low-Voltage-Cutoff (LVC) in this controller is set for 55V. If we track the pack voltage (State-Of-Charge/SOC...Depth_Of-Discharge/DOD) by other means, we could theoretically swap in several better caps ($10?) to run this stock controller at 18S-20S.

The 80V caps shown are generic "no-name" mass-produced Chinese capacitors, and personally I feel that since you only need one cap to "pop" to ruin a great day on the trail, I would not risk this controller at 18S in stock form, I would stick to 60V.

But...if you own a 100W soldering iron, and several upgraded caps are only $10, which one are worth trying because you want to experiment at 18S-20S?

You want resistance (Impedence) in milli-Ohms (mOhm) to be as low as possible.
You want the ripple-current rating (amp-flow capacity) to be as big as possible.
The physical size in Micro-Farads (uF) is unimportant, bigger is not better, just harder to fit.

Here are two choices I found (there are likely many other good choices)

26 mOhm, 3.86A, 100V, 820uF http://www.digikey.com/product-detail/en/100ZLJ820M18X40/1189-1048-ND/3133977
27 mOhm, 3.51A, 100V, 680uF http://www.digikey.com/product-detail/en/100ZLJ820M18X40/1189-1048-ND/3133977

Concerning physical size, the two cap types shown in this pic are 1000uF and 3900uF, so both of the listed 100V caps above are smaller than the small cap in this pic. If anyone finds a link to purchase a 100V cap that has a lower mOhm number and a higher ripple-current amp number, please post it here.

 

[Wishes]

I took apart the primary drive side today. I'm going to change the required parts so that I can use #25 chain and sprockets. Which will enable me to get my old ratios back. Its cheaper to buy the sprockets and chain, than start changing up my chainrings and back wheel cassette to compensate. Besides, I already had the parts for it to upgrade my v1.0 kit.

gngV1.0 Stage 1 had 11-80 pulley
gngV1.1 Stage 1 has 11-54 sprockets

I'm going to replace both the small and large sprockets to use #25 chain and 11-80 tooth count.

The small sprocket is held on only by a bolt.

Once removed, the shaft has a 10mm diameter and 8mm on both flats.

You can see both the new and old large sprockets with their corresponding smaller sprocket. The small #25 sprocket in the pic was for my v1.0. I've found an exact fit for this shaft. http://www.electricscooterparts.com/sprockets25chain.html and http://tncscooters.com/index.php?route=product/product&path=63_89&product_id=131

If I'm left with having to replace the whole chain system, then the only thing this kit is better for is to save you the trouble of filing down the main shaft. Off the shelf sprockets can be found as direct bolt on for both large and small sprockets.

Waiting on the 11T sprocket to finish the install.

Wishes

 

[bee]

Gng chain kit 54÷11=4.90909091

Gng 1.0 80÷14=5.71428571

80÷11=7.27272727

80:11 was too much reduction IME

 

[speedmd]

The closer the voltage rating of the cap is to the system voltage, the better the performance spec of the cap was

Voltage rating will not change system performance assuming it is high enough not to short out. Capacitance is the factor to watch. More capacitance will buffer more and allow a smoother flow of current on the PS side. (like having better long travel suspension does) It will also change switching frequencies in a LC circuit so you have to be careful going up or down in capacitance much.

The little electrolytic type capacitors here are used because they are compact /cheap. If you want best power supply and filter performance, you want a polypropylene film type cap. They are much bigger, but way better if they can fit. Not even close in performance

 

[spinningmagnets]

If you want best power supply and filter performance, you want a polypropylene film type cap

You definitely sound more experienced than me at this. Would you be able to dig up a couple of reasonable cap options with links? 100V should be fine, any higher and a builder really needs a better controller than the stock GNG.

 

[dustyearlobe]

has anyone built a duel motor with these ?Whats the noise levels compared to a cyclone

 

[speedmd]

Would you be able to dig up a couple of reasonable cap options with links? 100V should be fine, any higher and a builder really needs a better controller than the stock GNG.

I posted this on the 48v thread. I am assuming they are 470uf

Something like these should hold up /fit.

http://www.ebay.com/itm/NTE-NEV470M...pt=Vintage_Electronics_R2&hash=item53fd560af1

 

[bee]

has anyone built a duel motor with these ?Whats the noise levels compared to a cyclone

I haven't seen any dual motor gngs, if I wanted more power I would get a wider motor and a frame with a wide BB

The noise coming from these kits is very low as far as decibels go, they are small chain links that are designed to mesh well. People don't like the TONE of a high RPM motor, which is the same issue I have with my scooter. WOT at 28s on the gng is an annoying sound to some, but high rpm is the best way to squeeze more performance out of a small motor.

Tuning 2 stroke engines taught me to stay below 10,000 rpm if I want to avoid tickets for annoying people with pitch, what RPM does the gng reach at 118v? It certainly sounds close to 10k RPM.

If you want a lower pitch/tone, stick to non-geared hub motors.

 

[ferret]

A 67 kv motor running on 118v should reach a maximum of 67*118=7906 rpm (unloaded).