Strange oscillation in GT16

[Scatcat]

The new board is subtly different from the old.

One thing is the implementation of a power-alarm and tilt-back. If you get over like 80% or so of available power, you get a double beep and tilt-back. It took me by total surprise, and I'm quite happy the tilt-back in the GT16 is not the violent kind.

I'm not certain I like it unreservedly, it seems to trigger on peaks as much as steady power. While that is pretty safe, it may be overly conservative. I've just had one occurrence, so I'll reserve my judgement for now. I have a tendency to accelerate pretty violently, but not go at very high speeds - seldom more than 22mph or so. But this triggered when I made a brutal acceleration from almost stand-still to maybe 15mph, suddenly I got a double beep and then the pedals leveled to horisontal. A fat reminder telling me to back of or else...

As I said, the event in itself was more surprising than scary in any way, the tilt-back is so smooth that the only effect is you not doing whatever you were doing to trigger it anymore.

The "walking mode"/cruising mode seems slightly softer than on my old board, and it nudges you to take it easy with small tilt-back tendencies if you try to push it to hard. Not tilt-back in the normal sense of the word, more like catching you from over-leaning by acting like some sort of spring suspension. There was some of that in the old version, but it's more pronounced now.

"Playing mode"/Hard mode is nippy as ever.

One very happy thing is that the alarms are MUCH louder than on the old board.

Other differences is the feeling the power use is slightly more aggressive and/or that the motor is in better condition. When I go up slopes that was in no way a problem before - then now they're even less of a challenge, to the point I hardly notice them. Especially going up at slower speeds there isn't even a change of sound in the motor to signify more power used, and the pedal response hardly changes from flat ground. I can slow down, speed up, carve or go straight, like it was flat rather than 15° uphill.

The new motor is less noisy overall, both the noise of rotation, and the high-pitch hum is distinctly lower. Still loud, mind you, but not AS loud.

So all in all, I recognise my EUC, but I also feel there are some differences between 1.2 and my current 1.4...

[Hunka Hunka Burning Love]

1 hour ago, Scatcat said:

There you are.

Could you tell us what are the numbers/letters on the sensors themselves if you are able to make them out?  I'm glad to see that they use a small PCB board to help support the insulated sensor legs rather than solder wires directly to them.    

[meepmeepmayer]

The hall sensor picture (they have their own board!) and the description of improvements from revisions of all the parts make me think Rockwheel quality > Gotway quality now. They seem to know what they are doing...

[Scatcat]

4 hours ago, meepmeepmayer said:

The hall sensor picture (they have their own board!) and the description of improvements from revisions of all the parts make me think Rockwheel quality > Gotway quality now. They seem to know what they are doing...

I think quality is not an issue as such. GT16 has some design problems, and some of the same problems other designs are plagued with, but I can't really see that they are any worse in QC than let's say Gotway.

What they lack is a good sales and support organisation. And the design-problems that I think are most in-your-face are the waterproofing and how difficult the GT16 is to take apart and service. Too many nooks and crannies, too many parts you risk breaking when you dismantle it. But it is not THAT hard, I'm a f-ing amateur, and I've taken it apart at least ten times by now. I could wish the design was easier to handle and a bit more sturdy, but it works.

They should probably both take a leaf from Kingsong's books and lacquer their boards, as well as set reasonable and hard limits.

All of them should also study best practices when it comes to heavy duty electrical engineering to avoid overheating, melting insulation, popping FETs, arching plugs, broken hall-sensors and so on. They should up the margins of error as well as margins of physical fatigue. They should make sure the support for the rider is adequate, with larger pedals, better padding and a reasonably natural stance when riding.

It sometimes pisses me off to know how close they are to building the perfect EUCs, and then they don't.

Think about it, how much more expensive would it be to build:

• Motors with inch-thick shafts, which wont break and would give ample room for...
• Battery and motor cables of 10-12AWG and silicone insulation.
• Hall sensors that have good support from a pcb, and can take high impacts and vibrations.
• Heavy duty FETs with redundant circuits.
• Triple gyros, where one can fail, and the two other will override it.
• Waterproof battery packs, cabling and board.

Personally I think that would be small change compared to the total cost of manufacture. Yes it would be a few dollars more expensive, but who wouldn't buy that EUC given it still had the rest of the things we want? That is, torque, speed, stability, agility, responsiveness and range. Cool design too of course, but none of the big brands fall short in that category, not really.

[meepmeepmayer]

4 minutes ago, Scatcat said:

It sometimes pisses me off to know how close they are to building the perfect EUCs, and then they don't.

I don't think you're alone with this on this forum. Nothing more frustrating than to see inexplicable, absolutely unnecessary, and straight counterproductive behavior from the manufacturers. And they all do it! It's like a curse...

[Scatcat]

6 minutes ago, meepmeepmayer said:

I don't think you're alone with this on this forum. Nothing more frustrating than to see inexplicable, absolutely unnecessary, and straight counterproductive behavior from the manufacturers. And they all do it! It's like a curse...

Yeah, i really loathe that "good enough" attitude, it's neither good, nor enough.

[esaj]

On 8/1/2017 at 1:19 AM, Scatcat said:

 

On 8/1/2017 at 2:27 AM, Hunka Hunka Burning Love said:

MOSFETs and caps look different as well.  Maybe the version you received before was some sort of very early prototype that they wanted to sell off?

Nicely spotted, the MOSFETs have been changed to another manufacturer & model (HY5012). Couldn't find a datasheet, here are some specs:

HY-N-MOSFET ??HY5012 ????

Part    HY5012 
Vds Min (V)     125 
ID@TC=25?(A)    300 
RDS(on) Max 10V(mOhm)    3.6 
RDS(on) Max 4.5V(mOhm)    N/A 
PD@TC=25C (W)    500 
Vgs(±V)    25 
Vth (V)    2~4 
Ciss Typ(pF)    16305 
Qg Typ(nC)    352 
Configuration    single - N 
Package Code    W 
Package    TO-247-3L

 

 

[PriestHood]

Scatcat, My GT16 gives FULL Tilt-back at 40% battery. RE-setting alarm & tilt-back to a lower setting helps only a little. I still get FULL / Complete tilt-back. Is this Normal ? 

[Scatcat]

10 hours ago, PriestHood said:

Scatcat, My GT16 gives FULL Tilt-back at 40% battery. RE-setting alarm & tilt-back to a lower setting helps only a little. I still get FULL / Complete tilt-back. Is this Normal ? 

Sounds strange, but frankly I haven't gotten down to 40% with my new board yet. Since I assembled it, there have been precious few days with nice weather, and the longest I've gone at once was when I wen't about 25-30km to buy a protective jacket. Cruised around a bit and got down to just above 40%, maybe 45% or so. Had no strange behaviour at that level.

I'll be sure to report back if there's any strange stuff happening at lower charges, or for that matter to report if there ain't

Yi Chen noted that the only "mode" that is truly compatible with GT16 is "playing mode". I have had some strange tilt-back situations in "walking mode", but only with this board, not the old one. This board also seems to have a lot more safety features built in. Is your tilt-back in "walking mode" and have you tried switching to "playing mode"?

[PriestHood]

I haven't tried the other modes. I only (always) set my wheels to Hard/Player modes. Will have to try the other modes to see what it does and report back. In any case... the wheel does Revert back to Beginner Mode at Random.(But, I only notice this when I re-connect the app)

Yi says will get back to me when he asks technician about my wheels behavior.

If this is normal, I may not upgrade. I am really looking forward to the 96v version. So. This better not be Normal and or carried-on to the 96v model. It is frustrating & a WASTE of battery. When you know there is still 40% more battery left. And the wheel won't let you ride it.

[Mrd777]

2 minutes ago, PriestHood said:

I haven't tried the other modes. I only (always) set my wheels to Hard/Player modes. Will have to try the other modes to see what it does and report back. In any case... the wheel does Revert back to Beginner Mode at Random.(But, I only notice this when I re-connect the app)

Yi says will get back to me when he asks technician about my wheels behavior.

If this is normal, I may not upgrade. I am really looking forward to the 96v version. So. This better not be Normal and or carried-on to the 96v model. It is frustrating & a WASTE of battery. When you know there is still 40% more battery left. And the wheel won't let you ride it.

Hey, I'm curious what you know about the 96 volt model? Do you know when, or have any additional information?

[PriestHood]

1 hour ago, Mrd777 said:

Do you know when, or have any additional information?

Only that, it is currently in testing. Been about 5 months now. But, you know these things take time. Remember... Gotways mSuper v3 didn't come out till about a whole year. Also, Kingsong & Gotway know about the 96v GT16.

2018 is going to be an Expensive year for ALL of us.

[PriestHood]

Here is an Update to my Battery dilemma. No more misunderstandings. Yi Made a graph of controller behaviour when battery drops to 40% and lower.

[Scatcat]

22 hours ago, PriestHood said:

I haven't tried the other modes. I only (always) set my wheels to Hard/Player modes. Will have to try the other modes to see what it does and report back. In any case... the wheel does Revert back to Beginner Mode at Random.(But, I only notice this when I re-connect the app)

Yi says will get back to me when he asks technician about my wheels behavior.

If this is normal, I may not upgrade. I am really looking forward to the 96v version. So. This better not be Normal and or carried-on to the 96v model. It is frustrating & a WASTE of battery. When you know there is still 40% more battery left. And the wheel won't let you ride it.

It reverts to walking mode when the app connects. If you're actually riding, you can feel it happening just as the connection is made. It seems to be a problem in the app, that doesn't read the mode before it initiates.

It seems the 1030Wh version is a bit more stable over the percentage span when it comes to max-speed. But still, I haven't had any strange behaviour down to 45% or so. But I do get tilt-back if I try to push it above 80% of max power at any charge level.

[PriestHood]

3 hours ago, Scatcat said:

But I do get tilt-back if I try to push it above 80% of max power at any charge level.

I get FULL tilt-back at 40%. It doesn't need to be a Sudden / Full tilt-back. Most of us are on the street. This is not safe. It should be gradual. Not full/Complete. Not to complain. I love this motor over the other wheels. Just don't like the algorithm. Wish they let me use more of that 40% battery. Even if I can go slow. At least down to 20%. But, once 40% is reached. The wheel does a Full Tilt-back. What a waste of battery! Or, maybe it needs to be that way. So I can be alive to tell the story. Safety First.

[Iero83]

I think there is a problem with your mother board. It shouldn't behave like this. With my GT 16 I empty the battery almost every day and have only a full tilt back when the battery is empty. Before that I get the continuous beeps then the all flashing leds.

I posted this on the french forum to show that speed can be quite high even with a low percentage of battery left. Around 2hour trip and 47km distance.

[Scatcat]

On 2017-08-07 at 3:15 AM, PriestHood said:

I get FULL tilt-back at 40%. It doesn't need to be a Sudden / Full tilt-back. Most of us are on the street. This is not safe. It should be gradual. Not full/Complete. Not to complain. I love this motor over the other wheels. Just don't like the algorithm. Wish they let me use more of that 40% battery. Even if I can go slow. At least down to 20%. But, once 40% is reached. The wheel does a Full Tilt-back. What a waste of battery! Or, maybe it needs to be that way. So I can be alive to tell the story. Safety First.

OK, I've taken mine down to <20%.

I got 80%-power warnings more and more frequently as the battery went below ~50%, but then I pushed on quite hard, so that is kind of natural. I did not get any tilt-back until I came down to 20-25% power, and then only when ignoring the beeps.

The wheel was fully rideable down to maybe 15% or so. I had to take it easy for the last mile or so, but got home alright.

The difference between this control-board and the old one is rather drastic. The old one had close to no safety features at all, while this one warns me if I reach 80% and does the tilt-back if I push even harder. The beeps are twice as loud as on the original board.

It seems a bit more power-hungry than the old setup. I don't know if that is caused by the motor or the board, probably a combination. I think the smoothness of the new motor and board (I feel like I'm floating), means I'm using more power without noticing. I do seem to trigger the speed-alarms a lot more often...

All in all it's both a gratifying, and a bit annoying experience. The general silence of the old board, without constant power-warnings etcetera was pretty nice in its way – but also somewhat scary, knowing that only my own discipline kept me from face-planting.

Now I feel a lot safer, but also feel the alarms kick in too quickly. I get the beeps even if the >80% power push is just momentary. Like going up a ramp from my basement door to the pavement. The climb is just 8-10 feet long but the elevation is somewhere in the range from 70-80%. Of course that means I will push beyond the 80% warning, but the beep comes just as the climb is already over – luckily without any tendency to tilt-back.

Wouldn't that be fun, getting a tilt-back in a 80% climb? I'd probably look like a clown in the circus, waving my arms to retain my balance and then going down again. 

[Blackmagicman]

 

Hello to the EUC members all around the world.

I am an euc enthusiast from Kassel / Germany an I have a Rockwheel GT 16 since may this year. I got it from Rockwheel Store and first I was very satisfied with it´s Performance, agility, power and everything. Than I had a cut off issue. The wheel throws me off whith a bad wobble. This happens only one time but my trust in the wheel got lost. But since that one issue the wheel didn´t make any problems until monday. I can not use the Rockwheel any more because of a very bad wobble every time I try to step on. It is not possible to start a ride. Even if I give a little bit pressure on the front of the pedals with my hands it starts that bad vibration. It feels like it is moving very fast forward and backward with a high frequency. It is always in playing mode, the only mode I normaly use. It is often in walking mode but not always, so that sometimes it is possible to start a ride an the wheel than behaves absolutly normal during the whole tour. I did a little video that shows the problem.

Rockwheel GT 16 hard wobble.WMV

[US69]

1 minute ago, Blackmagicman said:

 

Hello to the EUC members all around the world.

I am an euc enthusiast from Kassel / Germany an I have a Rockwheel GT 16 since may this year. I got it from Rockwheel Store and first I was very satisfied with it´s Performance, agility, power and everything. Than I had a cut off issue. The wheel throws me off whith a bad wobble. This happens only one time but my trust in the wheel got lost. But since that one issue the wheel didn´t make any problems until monday. I can not use the Rockwheel any more because of a very bad wobble every time I try to step on. It is not possible to start a ride. Even if I give a little bit pressure on the front of the pedals with my hands it starts that bad vibration. It feels like it is moving very fast forward and backward with a high frequency. It is always in playing mode, the only mode I normaly use. It is often in walking mode but not always, so that sometimes it is possible to start a ride an the wheel than behaves absolutly normal during the whole tour. I did a little video that shows the problem.

Rockwheel GT 16 hard wobble.WMV

Did you contact the seller? Yi Chen from Rockwheel Store is normally quite helpfull!

We have some stories here, where he even helped people that did not buy directly from him!

[Blackmagicman]

Just now, KingSong69 said:

Did you contact the seller? Yi Chen from Rockwheel Store is normally quite helpfull!

We have some stories here, where he even helped people that did not buy directly from him!

Sure Mr. Yi chen is a good one and I am very satisfied with the delivery and erverything around. Of course I wrote him a mail with the problem but it is not possible to drag a video  to the mail at ali express. So I have the hope that he can look at the video here in this forum.

[Chriull]

9 minutes ago, Blackmagicman said:

Sure Mr. Yi chen is a good one and I am very satisfied with the delivery and erverything around. Of course I wrote him a mail with the problem but it is not possible to drag a video  to the mail at ali express. So I have the hope that he can look at the video here in this forum.

You tried it with a link to some video platform/cloud service after uploading it there? Then it should be quite possible to include this link in an mail!

maybe you just are restricted to some servers/services since this concerns china?

[Gimlet]

Have you checked that the wheel nuts are tight on the axle? It's quite common for them to come loose on various makes and models of euc.

[Chriull]

2 minutes ago, Gimlet said:

Have you checked that the wheel nuts are tight on the axle? It's quite common for them to come loose on various makes and models of euc.

@Blackmagicman- you did some visual inspections of the interior? Sounds like a good idea.

Loose axle nuts should be even noticeable without opening the wheel?

Maybe the motherboard or some connectors came loose? Or the hall sensor cables got melted and have some kind of short circuit... Don't know if a GT16 also could have some cable melting issues?

[MaxLinux]

2 minutes ago, Chriull said:

Loose axle nuts should be even noticeable without opening the wheel?

Watching that video, I doubt axle nuts are causing this!

[Chriull]

1 minute ago, MaxLinux said:

Watching that video, I doubt axle nuts are causing this!

Could be true - but maybe loose axle nuts could introduce some "backlash/free travel" which causes the wheel to start this wild wobble/resonating? I never experienced this, but it's an easy check for @Blackmagicman - also the interior inspection, if he wants to open the wheel.

So @Blackmagicman has something to do while waiting for help from Rockwheel... and if he gets a motherboard for replacement he already knows how to open the wheel ...