Chinese Electric Scooter Log

[diff_lock]

Am I expecting too much from my motor? Any idea what controller this is?

My only experience with hub motors is this scooter I have. The torque to the wheel seems low at ultra low speeds and I can hold the scooter back. At certain wheel positions or after some stall time the torque seems to disappear.

I suspect possible controller limitations/ built in cut offs. Manual says 60A controller limit and 48v 1500w 800rpm motor. 16.5kv calculated 10" scooter rim.
No idea what controller this is. 63v caps, 18 FET STP75NF75, .011ohm RDS, 70A cont.

18/6 = 3 FETs per phase? .004ohms total?

I have a power meter en route so this will give me a better understanding of the battery current draw.

First order of bidness is to get a lithium pack into this thing but still not sure where to look. Ping seems the easy way to go.

 

[diff_lock]

Lost power when starting on an incline.
-Controller now makes a tick / click noise when throttle is twisted.
-On board led blinking, possibly error code (4 pulses).
-Motor cogs heavily when phase wires connected to controller, spins freely once disconnected.
-No visual indication of charring in controller

Most likely a blown fet.

Looking for a new controller, I have Throttle Tamer on the way although now it might be useless.

 

[granolaboy]

what kind of scooter is that?

 

[diff_lock]

what kind of scooter is that?

Xufeng Xufeng XGY

Pre butchering:

 

[diff_lock]

Measured a short between one of the phases and battery negative. These are the low side FETS right?
Removed a FET from the group and luckily it was the blown FET. No more short in the system and FET was measured to be shorted between drain and source.
I didn't smell any hint of anything burnt in the controller so it might be that there was some nasty voltage spike. Poor controller matching to motor or over all poor controller design.

Is it risky to run a single half of a phase with a missing FET? Would the only issue be higher thermal dissipation for the two FETS?

Actually the phase still reads a lower resistance than the other phases so I won't even bother running it. Need 3-6 replacement FETs that might not work. Next step would be to source 18 FETs. Cost is not worth it, a new programable controller makes more sense.

I will remove one FET from each of the other low side phases to replace this phase's FETS making an 18 FET controller into a 15 FET.

 

[diff_lock]

Removing the single failed FET was enough to get the controller working again. There was no need to re arrange the FETs. This is now a 17 FET controller.

I have ordered an Infineon 18 FET from EM3EV but until that arrives this will have to do.

The current controller has a very strong initial output to the motor, even if you request minimum speed, there is a huge amount of torque being produced from standstill. The motor kicks way harder than is required.

The controller casing is too heavy for an e-bike and the reliability too low for an electric scooter. Repackaging this controller into a lighter case might make it suitable for an e-bike even with the missing FET.

 

[diff_lock]

Took the motor apart to remove rust and possibly shorten the cable.
Much less copper than I was expecting, I won't be expecting much from this motor.
There are exposed conductors in the motor and some rubbing between parts filling the inside of the motor with lots of fine aluminum dust.
Phase wire seems to be 8AWG (over 3mm diameter), but very stiff and low conductor count.
Looks a bit like the mxus3000.

 

[317537]

Possibly the result of all that solder on those shunts, if three are required and you sunk 48v with over current into the stator caused LVC and a spike from the motor came back and ouch. That kind of controller and those fets work for 36v and I see a lot of failures on 48v systems with regen enabled too.

Pull a shunt. The short one. or remove the solder on the other shunts and scrape them clean with a sharp knife until the torque is back to normal.



http://pdf1.alldatasheet.com/datasheet-pdf/view/23979/STMICROELECTRONICS/P75NF.html

 

[317537]

The initial torque, is the shunts im sure of it, but Im not sure what I am seeing on the shunts, solder, clipper marks and scratches, this has been altered in too many ways to understand. One if not two of those shunts may not be even part of the original part. I think you can fix the controller properly as well and make it a spare while youre at it. It wont last long like this with a missing fet as well.

The newer controllers, and general basic system with lithium BMS and such the likely hood of these things happening now are becoming less. We dont even need LVC programmed into our controllers and my batts dont even cut out for LVC they just limit current until no back spike could harm the fets.

 

[317537]

And are they 50v caps with a 48v sla system? If so, awesome. How you do that?

 

[diff_lock]

And are they 50v caps with a 48v sla system? If so, awesome. How you do that?

The three larger caps are 63v.

I have replaced the one shorted FET with the same part number although the material and engravings are a bit different (much sharper clearer on the new FET). The phase resistance when measured from ground is 10k ohm for the first two phases but the blown phase still shows a bit less at 8k ohm.

I have taken this controller apart so many times already I don't feel like desoldering a shunt, I might trim or cut a shunt in hopes of a more reliable controller.

 

[diff_lock]

Sitrep:

 

[1JohnFoster]

I like it! The lower CG increases the whee! factor because you feel faster the closer you are to the ground. Getting down is a much cheaper way to go wheee! than the tedious motor, controller and battery upgrades that people on this forum do. Also looks like you're speeding into a sort of glowing teleportation portal, is that being generated by your vehicle?

And it's got wood, that's good too. But looks like you've reduced the ability of the front wheel to turn a bit. Is this a temporary set up, or permanent part of the evolution? Are you going to add a fairing?

 

[diff_lock]

I like it! The lower CG increases the whee! factor because you feel faster the closer you are to the ground. Getting down is a much cheaper way to go wheee! than the tedious motor, controller and battery upgrades that people on this forum do. Also looks like you're speeding into a sort of glowing teleportation portal, is that being generated by your vehicle?

And it's got wood, that's good too. But looks like you've reduced the ability of the front wheel to turn a bit. Is this a temporary set up, or permanent part of the evolution? Are you going to add a fairing?

Yeah it feels faster already without any other modifications. Leaning is lots of fun as is the position.

Portal in front is just the LED headlight reflecting off the ground.

Front tire does make contact at steering lock but for even very slow maneuvers this has not been an issue, only when walking the bike and trying to do three point turns in small areas.

Wood was temporary but it seems to be stiffer than the actual scooter frame. I am not sure what to replace it with since it works so well and costs so little. I have used a polyurethane based varnish on the wood, which says something about how long I plan to have it on there.

I tried and failed at a coroplast front faring, mostly for weather protection. Still have not come up with a proper solution for an effective front fairing. Need to make some coroplast mud guards / fenders too.

 

[diff_lock]

 

[1JohnFoster]

Wood was temporary but it seems to be stiffer than the actual scooter frame. I am not sure what to replace it with since it works so well and costs so little.

Amen. Wood can be much lighter, stronger and stiffer than the steel technology used in manufacturing scooters. You could decrease your turning radius just by replacing the 2x4 booms with narrower wood. Or getting fancier you could replace the booms with a wooden platform shape that arches up under your knees and doesn't go beside the wheel. But that would interfere if you eventually want pedals on the front end.

The lower you are, the less far you fall. Your machine has the Ruckus/ AmberWolf/ street person sort of cool. Since "resilience" is now in, maybe "self sufficiency" will come back eventually, and people will once again appreciate the beauty of materials such as scrap wood, plastic wrap as twine, plastic baskets and drill & bolt construction.

I tried and failed at a coroplast front faring, mostly for weather protection.

Fairings are very tricky. You can draw out something that looks really good, but you can't get in and out of it, or it hits the handle bars if you hinge it. Or your toes or heels are just a couple centimeters longer with a different pair of shoes. But if you continue the gonzo approach and just rapidly make a bunch of full size disposable cardboard & packing tape fairings you'll figure things out a lot faster.

Those are very bright lights, I guess you want people to see you. Others have mounted lights up on poles. Are those little white blobs 12V regulators or just terminal blocks?

Do you live in the back of a bike shop inside an abandoned mini-mall ?

 

[diff_lock]

Those are very bright lights, I guess you want people to see you. Others have mounted lights up on poles. Are those little white blobs 12V regulators or just terminal blocks?

Do you live in the back of a bike shop inside an abandoned mini-mall ?

The scooter has its own 12V regulator and 12V system (horn, signals, and lights). Just household terminal blocks.

Most if not all housing /residential communities here have dedicated bicycle rooms for warm storage, and sometimes they have power.

Once I get the lithium system working the 1.8kWh battery will be so light and small that I will just carry it in for charging at home or other destinations.

Plastic wrap is magical for cable management and we will see if it does anything against moisture, I use greased connectors too.

 

[skate-or-die]

Oh man that scooter looks crazy scary haha

 

[1JohnFoster]

Once I get the lithium system working the 1.8kWh battery will be so light and small that I will just carry it in for charging at home or other destinations.

Diff_lock, any progress on your scooter? This is my favorite project on ES. Have you used it for commuting?
Is it cold yet?
Lithium batteries yet?

 

[diff_lock]

Battery: EM3EV 14S 13P, Samsung 29E, (52V ~38Ah), ~1.8kWh, 8-9kg, 600-700 usd per kWh

Controller: EM3EV Infineon 18 FET 4110 at 88A battery current limit with a battery to phase ratio of ~1.5.

Charger: Grin Technologies Cycle Satiator. ~10kmph charge speed (360W)

Scooter energy usage: 25-35 Wh/km

Commute: 18km soon to be 15km at 25kmph avg. I charge for less than 2hrs in the morning to 70% with the Satiator. I charge again for less than 2hrs and commute back home. 30% DOD (70%-40%)

Range: I have done 42km trips at 20kmph averages by charging up to 80% and discharging down to 30%. With the same DOD I have done about 30km of hard riding (speed limited to 45kmph by law).

Top speed (voltage limited): 66kmph.

Regen: No.

Only a normal cycle computer is used and in combination with the Satiator I am able to monitor consumption.

To do:
-find winter tires that fit
-new rear shocks
-new front fork
-Replace bullet connectors with Anderson connectors
-Finish EVA foam seat (lumbar support)
-aero mods

 

[1JohnFoster]

Scooter energy usage: 25-35 Wh/km

Not great especially considering your more aero position.
Dragging drum brakes? Are you keeping tire pressure low because your springs are too stiff and your tires have bad traction at higher pressure?

Top speed (voltage limited): 66kmph.
How safe does that feel in traffic?
Does it feel safe at 25kph? Do cars see you down there?

-find winter tires that fit -new rear shocks -new front fork
My problem with Chineese scooters was the "shocks" have springs way too stiff but underdamped. The suspension joints, telescopes and headsets get loose and everything flops around.
I never looked for studded tires for scooter.

 

[diff_lock]

Scooter energy usage: 25-35 Wh/km

Not great especially considering your more aero position.
Dragging drum brakes? Are you keeping tire pressure low because your springs are too stiff and your tires have bad traction at higher pressure?

Top speed (voltage limited): 66kmph.
How safe does that feel in traffic?
Does it feel safe at 25kph? Do cars see you down there?

-find winter tires that fit -new rear shocks -new front fork
My problem with Chineese scooters was the "shocks" have springs way too stiff but underdamped. The suspension joints, telescopes and headsets get loose and everything flops around.
I never looked for studded tires for scooter.

How did you guess about the crappy tires? The first day I filled them to a proper pressure I low sided. I have not checked their current pressure but it could be they are a bit low, but not low enough for comfort.

Wheels seem to spin freely. I can sometimes hear a bit of dragging but I cannot feel any deceleration from that.

I do not drive fast usually, I have my speed limit switch set to 35kmph for when I am on multi use paths where moped use is allowed and 45kmph when I am in traffic. I am much happier at lower speeds with this crappy scooter. I am already used to cruising at 35kmph and that feels fine on the scooter. It stops really well in the dry, have avoided a few rabbits / pedestrians but my speed was not above 35kmph (personal limit for safety and energy consumption). Finnish drivers are pretty used to sharing the road with slow scooters, and the fact that they are actually interested in wtf I am riding seems to slow them down around me even if I am not in the same lane. Visibility is not an issue at all, I have people yelling compliments from 10s of meters away, and yielding way earlier than if I were in a car or bicycle. Biggest issue are cyclists and pedestrians who cannot hear me, my solution is to install a bicycle bell ASAP, it could have come in handy many times. I usually just yield to everyone anyway, try not to get in people's way.

I have new rear shocks on the way that should actually be shocks rather than just springs. I do not know what to do about the front end as it is really crap and front ends are not cheap since they have braking components and stuff. I might look into transplanting a whole other scooter front end but that won't be cheap and would require outsourcing fabrication.

I actually got some really nice winter tires but they are too fat. I was hopping they would just fit, but it wasn't the case.

 

[1JohnFoster]

I have people yelling compliments from 10s of meters away, and yielding way earlier than if I were in a car or bicycle.

That's so cool!

Biggest issue are cyclists and pedestrians who cannot hear me, my solution is to install a bicycle bell ASAP

I don't like to "ding" people out of the way, it makes you "appear out of nowhere" and scares people. I just drag a foot on the ground so they hear and turn around. I've thought of having a jingle bell that I can deploy to make a noise that steadily grows. I wonder if people on the shared foot/bike path find your contraption more or less fearsome looking than the original scooter monstrosity.

... I do not know what to do about the front end as it is really crap and front ends are not cheap since they have braking components and stuff.

Did you look replacing the whole thing with 20" bike suspension forks with V or disc brakes and 20" bike tires? Most of these are really crappy, but better than scooter stuff. At least you would have a good choice of tires. Some new forks come with really long head tubes, or you could cut down the scooter head tube.

Too bad about the tires not fitting. By "winter" do you mean knobby, studded, or better ice grip rubber compound?
How far do you roll if you cut the power at 35km? What size are the tires?
If you want to stay really cheap, maybe you could cut grooves. The rubber on scooter tires is typically way thicker than you need. You would be more suceptible to flats, just like a bike. But it would be incredibly difficult to cut grooves. I admit I've never tried! I can picture myself spending days making jigs then end up cutting through the tire. I have added sheet metal screws to tires before studs became available. It's really hard to get just the right length of screw, and they wear down very fast, I don't recommend it.

 

[diff_lock]

soft and fiber/grit filled tire compound, snow tread, and tungsten carbide studs:

I just found a shop with scooter front end off cuts for like 50 bucks, but I would need to find someone to weld onto my frame.

Very interesting concept with the bicycle front end, I wonder if the bearing sizes match. But heavy duty front bicycle shocks will cost much more than a whole scooter front end (literally front with everything, whole front half of a scooter).

Current tires are 3.00" x 10". I will probably roll a few 100m coasting from 35kmph.

I might try that jingle / cow bell idea. Better than that beeping they have for electric vehicles at pikes peak. My indicators do beep but it is not loud enough. Even on my bicycle I usually skid a tire on some gravel rather than ding a bell.