Low-Speed Sputtering 2KW controller/hub motor

[chuxxnorris]

Searched a bit for these specific problems but can't seem to find the same issues. Appreciate any help offered and happy to read though any resources if I've missed them.

Some background: currently in china, riding a china-clone Yamaha Vino, 60v30ah LiFePO4 and recently upped to 2000watt controller and hub motor. However, I suspect the motor is used, not new, due to varying sputtering issues - and want to get a second opinion. Also it reads "48v2000w" on the side - though it should be watts that matter, as the volts is really irrelevant labeling for the motor correct?

Problem 1:
Old 1500watt controller failed to drive the new 2000w hub motor; it was dreadfully slow, sputtering constantly - a downgrade in performance from my original 800watt motor. Shop claimed this was a controller issue, that not enough watts were being delivered to the 2000 watt motor. Is this plausible?

I also know there could sometimes controller compatibility issues between hall and phase wires - so I then upgraded to what was claimed to be a matching 2000watt controller which got me back up to speed.

Problem 2:
However throttle under 10% - when the scooter is creeping along - is still very rough, not smooth at all and sputtering. It hasn't every failed to start yet, so not sure if there are dead spots. The problem goes away if I crank throttle to 10-20% and beyond, scooter will jump to speed and runs fairly smoothly - reaches 35 mph nicely and eventually up to 45mph.

However the sputtering constantly re-occurs if i'm gentle on the throttle, trying to use it at 5 or so MPH. Makes it a bit of a concern in high-traffic, avoiding jay-walker-situations in the city; scooter is either sputtering and lurching unsmoothly and slowly, or i have to gun the throttle it takes me faster then I want.

Much appreciate any advice! I know some people with hall sensor issues have lurchiness and sputtering that increases as the speed goes up. My problem seems a bit different and is low speed focused - hope some can shed light on a solution.

 

[granolaboy]

On a previous scooter I had a hub motor with a blown hall sensor. It really grumbled and jerked when at low speed, but seemed alright at high speeds.

Your hall sensor/phase wire connections might not be correct either.

Although, neither of these theories add up with a new hub motor, and a matching controller.

I'd test the halls anyway and try out all the hall/phase combinations (all 36) and see which one runs forwards the smoothest.

 

[chuxxnorris]

On a previous scooter I had a hub motor with a blown hall sensor. It really grumbled and jerked when at low speed, but seemed alright at high speeds.

Your hall sensor/phase wire connections might not be correct either.

Although, neither of these theories add up with a new hub motor, and a matching controller.

I'd test the halls anyway and try out all the hall/phase combinations (all 36) and see which one runs forwards the smoothest.

Thanks for the advice. Do you think there would be a problem with the "48v" indicated on the 2000watt motor? I'm on a 60v set up and I know it's watt rating that should matter, but also heard that some motors do not like higher voltage.

Meanwhile I will drop the bike off to try different hall/phase combinations at the shop to see if that can resolve the problem.

 

[Skedgy Sky]

I also have a stuttering a very low speed issue, something like what you describe. The problem got more apperant as I stepped up the voltage.

I'm using a cromotor and 24fet controller - have not tried any other motors yet.

I've read somewhere else it might be hall sensors.
Fortunately I think the cromotor has two sets of hall sensors, so I can easily swap over. .. but I just haven't done it yet. I guess the problem doesn't bother me enough to make me feel like trying to fix it, but if I try the other set of hall sensors and it solves my problem then maybe it'll solve yours too. It is strange how it's bad at low speed but good at higher speeds.
I'll let you know how it goes if I get around to it.

 

[veloman]

I am having low speed stuttering on my HT3525 with 12fet 4110 cellman controller. It started happening on my last ride after doing a high speed stretch on 120% setting. My power is still set pretty low, I was pulling 1700w for maybe 15 seconds. 74v 28amps peak setting.

No issues above 9mph, but always stutters off the line now (which is dangerous for crossing intersections). I check my phase and hall connections, throttle and CA plug.

Has anyone found a resolution to this problem?

My next step is going to try another throttle just to rule that easy variable out. Then I will try another motor.

I can replace a hall sensor, but if it's a controller issue, I am a bit worried. I've since reset my speed settings to 100% max (instead of 120%).

 

[chuxxnorris]

@veloman, have you tried setting your power a bit higher? I'm not familiar with controllers but by 100%, 120%, are you saying these are controller output peak relative to the hub motor rating? Actually I've sort of found going the other direction (3KW on 2KW motor) or even higher can remove the stutter.

Still though just to clarify - some stuttering to the point where you get rough/unreliable starts seems to likely be a hall sensor issue.

For myself, stuttering is just unsmooth - but not to the point where getting moving is ever an issue, it's just sounds like "brbrbrbr" instead of the normal whine/groan noise. Perhaps these are different issues?

In fact just upping the controller power has fixed the problem for me - I just moved up to a 3kw 60-84v 100a peak (cheap, inefficient, but working) china controller. This was at the suggestion of someone else who was having rough starts, he upped to 5kw on a 2kw rated hub and removed any sputter.

Just an aside, i'm talking from china where the "rating" of these hubs is pretty rough at best, and it's pretty common to run them hot (as any failure pretty cheap to fix here).

Now throttle is fairly "smooth", has a big lunge that can pick up the front wheel a little if throttling too much at the very start - but i prefer that to the stutter.

 

[veloman]

I mean, all power cuts off for a split second. Maybe its every revolution until above 9mph. More power won't help. It does sound more like a hall sensor issue.

I rode 32 miles today on it. If I go easy off the line, it won't stutter. So not sure if it's a hall issue. Sounds almost like a phase current thing.

 

[veloman]

I mean, all power cuts off for a split second. Maybe its every revolution until above 9mph. More power won't help. It does sound more like a hall sensor issue.

I rode 32 miles today on it. If I go easy off the line, it won't stutter. So not sure if it's a hall issue. Sounds almost like a phase current thing.

I used the ebike tester on the motor and then the controller. Everything seems to be working fine. It's definitely only stuttering when under higher load at low speed.

 

[patrickza]

Did you ever resolve this? I'm having the exact same issue with my cromotor and lyen controller. Also disappears once I'm moving but does feel like slight cutouts when starting up. My review tester seems to indicate everything is normal, and unloaded the wheel will turn really slowly and smoothly.