Has anybody un-displayed and un-PASed a mid drive?

[Chalo]

The community bike shop where I work just took a donation of a Yuba Spicy Curry e-bike cargo bike with a Currie mid drive. Both the Currie battery and the button panel are very tired, and not replaceable with original equipment (because it seems most manufacturers of closed parts ecosystems are fly by night hustlers at heart).

Having recently de-sophisticated a couple of e-bikes by applying dual mode "dumb" controllers that are fitted only with a throttle and an on-off switch, I was thinking maybe this is something I could do with this otherwise bummer of a project. Mainly, I can't figure out why it wouldn't work to find the motor phase leads wherever they are buried, and address them directly just like I would a hub motor.

Has anybody done it? Has anybody figured out a good reason not to do it?

 

[gromike]

Isn't that a Bosch motor on that ebike? I've read of people putting an external controller on a mid-drive motor, so it might be doable.

 

[amberwolf]

Unless they use some wierd motor in there, it should work fine.

If it's sensored, with typical 120spaced hall sensors, pretty much any dumb controller would work.

Sensorless, you d' just need a sensorless dumb controller (or the dual mode type).

If it's a really small motor running a really high rpm and a huge geardown, you might needa controller capble of a high erpm.

cscattered around the froum here, there have been a number of bbsxx and other middrives gutted of their electronics and converted to things like the phaserunner, vesc, etc., to give functionality or power or whatever that the orgiinal systms didnt' ahve.

 

[stancecoke]

@Tomblarom offers sets to fit a BAFANG middrive into Bosch bikes:

Shop

In unserem Shop finden Sie alle Produkte aus der INNOTRACE Familie. Seien Sie ein Teil davon und genießen Sie das unvergleichliche Fahrvergnügen.

www.ebikerepair.eu

 

[Chalo]

@Tomblarom offers sets to fit a BAFANG middrive into Bosch bikes:

Shop

In unserem Shop finden Sie alle Produkte aus der INNOTRACE Familie. Seien Sie ein Teil davon und genießen Sie das unvergleichliche Fahrvergnügen.

www.ebikerepair.eu

Now that's a good idea! But it's not a good idea for this particular bike. To redeem this bike and get it back in service at a reasonable money and labor cost, I must try to keep the hard parts that still work right and aren't rapidly disintegrating into microplastics.

I'm going to try it. The worst that could happen is the bike ends up about the same amount of screwed up as it is already.

EDIT:
I think a better adapter for Bosch, Steps, and even Bafang shovel-bottomed bike frames would be one that mounts a regular threaded bottom bracket shell that can be retrofitted with Bafang BBSxx, Cyclone, or just ordinary pedal cranks. Y'know, to grant those bikes a divorce from their abusive partner.

 

[fechter]

As far as I know, most of the Bosch mid drives don't have a freewheel between the motor and the pedals. If the motor runs, it will drive the pedals, so throttle only could be a safety issue.

 

[JackFlorey]

I think a better adapter for Bosch, Steps, and even Bafang shovel-bottomed bike frames would be one that mounts a regular threaded bottom bracket shell that can be retrofitted with Bafang BBSxx, Cyclone, or just ordinary pedal cranks. Y'know, to grant those bikes a divorce from their abusive partner.

I would pay big $$ for something like that. Well, not big $$ but I'd pay.

 

[Chalo]

As far as I know, most of the Bosch mid drives don't have a freewheel between the motor and the pedals. If the motor runs, it will drive the pedals, so throttle only could be a safety issue.

This one isn't a Bosch, but a Currie. I will assess whether it has a dependable overrunning clutch, thanks for reminding me.

 

[PaulD]

EDIT:
I think a better adapter for Bosch, Steps, and even Bafang shovel-bottomed bike frames would be one that mounts a regular threaded bottom bracket shell that can be retrofitted with Bafang BBSxx, Cyclone, or just ordinary pedal cranks. Y'know, to grant those bikes a divorce from their abusive partner.

I built one for a Shimano EP8/E8000. I can't find a picture, but here is the CAD. If you have the dimensions for the Currie drive, i'd consider making a few. It's just some laser cut 4130 plates with a BB shell welded in.

 

[stancecoke]

This one isn't a Bosch, but a Currie

just took a donation of a Yuba Spicy Curry e-bike cargo bike

The Yuba Spicy Curry uses a Bosch drivetrain?! I never heard about a Currie motor....

 

[Chalo]

The Yuba Spicy Curry uses a Bosch drivetrain?! I never heard about a Currie motor....

There's a Bosch version waiting for service in the other bike shop where I work. But the one that was donated to the community bike shop is definitely Currie 100%, with some weird proprietary shovel for a BB.

Currie control buttons turn into chewed gum after some time.

 

[neptronix]

Has anybody done it? Has anybody figured out a good reason not to do it?

You know what's funny? there's tons of people who used to hook up bafang mid drives to external controllers to pump them up.

If the motor internally has 5 hall wires and 3 phase wires, any controller that can support a geared hub motor should be able to drive most double reduction mid drives.

A VESC based controller will drive anything under the sun. 30kRPM? no problem. Sensorless? not bad! Halls and phase wired wrong? no problem. You throw a motor at it, and it works.

The only issue with a VESC is that you need one with a sealed case and some contact against the bike's frame for cooling. You need to overspec the hell out of them, or bolt on heatsinks, because they don't have a lot of thermal mass.

They're not super cheap, but they're nice to have on hand for the rare hard to drive motors ( some mid drives, dual reduction geared hubs )

 

[stancecoke]

You throw a motor at it, and it works.

Any cheap Brainpower controller has a self learning function and can drive the motor sensorless. Of course only in block commutation, but with a geared motor you will have some noise anyway.
I've driven a Shengyi middrive with several controllers on my test bench, sensored and sensorless. I never had one, that failed.
Of course, if you want to have a working speed limit for legal concerns, the controller has to limit the motors rpm by an external wheel speed sensor.

regards
stancecoke

 

[neptronix]

Interesting, i haven't heard of these before at all.
Are they fully programmable and capable of high-ish eRPM? ( IE, wouldn't be a stuttery mess on a MAC )

 

[Chalo]

You know what's funny? there's tons of people who used to hook up bafang mid drives to external controllers to pump them up.

I've seen that, but only in combination with Eggrider interfaces and other things that are the opposite of what I would like to do. So I haven't known what voodoo is going on in there.

If the motor internally has 5 hall wires and 3 phase wires, any controller that can support a geared hub motor should be able to drive most double reduction mid drives.

That's my hope. I've been using very cheap dual mode 36/48V 18A controllers (so as to maximize the batteries that will work) with those cruddy off-white "2.8mm" and "6.3mm" connectors. I'm trying to configure the converted bikes such that any replacement part we keep stocked can be used as a drop-in replacement without having to reconcile plugs. So far, my reconciliation overhead is down to putting charge and discharge plugs on the batteries, a male plug housing on the throttle, a JST-RCY pair for the on-off switch and controller enable wire, and whatever the salvaged motor needs (often only a breakout cable for its 9 pin plug).

A VESC based controller will drive anything under the sun. 30kRPM? no problem. Sensorless? not bad! Halls and phase wired wrong? no problem. You throw a motor at it, and it works.

They're not super cheap, but they're nice to have on hand for the rare hard to drive motors ( some mid drives, dual reduction geared hubs )

I reckon that's an egg I'll have to crack sooner or later. Seems like a very good tool for solving slightly different problems than what I'm rasslin with at the moment.

 

[stancecoke]

Interesting, i haven't heard of these before at all.

?! There are quite often discussions about that controllers here in the forum, just search for XLD or Brainpower.

XLD Brainpower motor controller XunLiDa

Hello I need some help regarding XLD Brainpower motor controller XunLiDa. I have two wersions of it: Model: KSLA19 no LCD Model: KSLU37 with LCD The one with LCD is installed on e-bike with Bionx (internal controller removed) motor. It works OK, just the regen braking is not there. When the...

endless-sphere.com

Are they fully programmable and capable of high-ish eRPM?

They are programmable by the display, but there is confusion quite often, as there seem to be different firmware versions, that behave different. I never checked the max rpm, but of course it depends on the gear ratio of the middrive. That probably is not much higher than that of a geared hub motor, as the chainring normally turns slower than the wheel.

Perhaps @Chalo can figure out the number of pole pairs and the mechanical gear ratio of his "Currie" motor.

regards
stancecoke

 

[neptronix]

I think they just use the eggrider because it's a nice display that's similar/better than stock.
Otherwise it's just 5 halls and 3 phase wires.. same as driving a hub motor.. except the electrical RPM is more like a geared motor... other than that.. you should be able to use whatever controller.

I standardize all my connectors to this..
Phase connections: hobbyking 4mm bullets.. but you can use smaller, 3mm or less.
Hall connections: JST PH 2.0... because this is what comes on VESCs typically and i'm a VESC fanboy now. You can buy these in large quantities.

with JST PH 2.0, you can buy a 'kit' of connectors with different pins for $20 and this kit should be useable for every single connector on the controller. You can even get them pre-crimped.



I took this path w/my builds because i got tired of sourcing all kinds of weird connectors and i want interchangeable parts, so i just standardize everything across my fleet now.

 

[Chalo]

It's cool to get a look at the specifics of the integrations that all of us DIYers have to work out for ourselves.

My goal-- and I'm not sure it's even plausible-- is to strip down, cheap down, simplify, and standardize a basic e-bike kit to the point it can be maintained by someone who has already failed at most of life's challenges (or someone who's suffering technological and cultural whiplash from having been relocated across the world).

A working e-bike is a great hand up for a struggling person, but more than that, gaining even a very basic understanding of the tech not only allows him or her to be more self-reliant, but also may become a step towards unlocking other technical things that bring career opportunities or cost of living benefits.

 

[neptronix]

I like your attitude about this matter.
My local communist bike shop just takes these bikes in and puts them on the floor to sell.. as is..
..majority of these bikes seems like they have a controller or display problem.

Not rocket science to fix and give to a person who could use it.. but that shop is all bike guys and no electronics guys..

 

[AdR]

I now use a spintend 75V/250A vesc at half the price of my original phaserunner. I too am now a vesc fanboi. lol
Only negatives so far is the larger foot print/non water proofness of the vesc. Broke the budget splurging on the $6 heatsink. hahaha

 

[JackFlorey]

Not rocket science to fix and give to a person who could use it.. but that shop is all bike guys and no electronics guys..

I've fixed a fair number of ebikes for other people and sometimes it IS rocket science, and I end up tracing it to a bad balancer inside the pack (after an hour of testing and disassembly) that I can't fix anyway because the BMS IC is not marked.

But about half of them just had dumb mistakes / failures like a broken pin in a connector or a brake sensor that's always on - and those can be fixed with 15 minutes of work. Unfortunately people with the skill to detect/do something like that can make a lot more money elsewhere.

 

[A-DamW]

I reckon that's an egg I'll have to crack sooner or later. Seems like a very good tool for solving slightly different problems than what I'm rasslin with at the moment.

Just for a smidge of clarity, you WILL need a computer(usb/BT interface) or phone(BT interface) with vesc-tool installed to set up the controller initially,
Once configured, you do not need a display.

I run my setups with just a throttle.

Some vesc controllers do have integrated on/off switches, for those that don't, a bms switch, or mechanical switch could suffice.

If you want some specific details, I am available for information overload.

 

[Chalo]

Well, I got around to de-Currieing the Spicy Curry, and it was not too bad. I had to pull both cranks and an elaborate chainring/double chainguard assembly with spacer washers on both sides. Then two screws to remove a beauty cover, three bolts to detach the motor unit, a lil bit of tonsil surgery to drag all the cords out of the frame, and then I was able to open it up and see what was going on inside.

I recognized battery power and motor phases right away.


Just a bit more poking around and I identified the Hall sensor wires.

Then I ruthlessly deleted all the other stuff. I left the torque sensor and thermistor cables dangling because they weren't in the way. With no controller inside to suffer from (or cause) electrical noise, I took the chokes, plug, and ring terminals off of the phase and Hall wires and spliced them to a 9 pin Higo extension cable that I chopped the female end off of. It was long enough to feed rearward through the frame conduit and a few inches out the other end. For the cable to leave the motor unit, I drilled a hole through a potted terminal block on the top (the gray plastic thing in the first picture), which is sheltered up inside the frame mount.

The motor unit ran very smoothly on my test controller, so I reassembled everything but with an empty skull.

I'm still sorting out a good battery, so it hasn't hit the road yet. I'll be back soon with photos of the external controller installation and cockpit.

 

[marvin78]

Unfortunately people with the skill to detect/do something like that can make a lot more money elsewhere.

Nah, the unfortunate thing isn't that people can earn more money with those skills when applied in a pure commercial setting, the unfortunate thing is that to many people feel 'making more money' is more important as doing something which gives you feeling off purpose.

Ofc, being able to do both at the same time is even better, but if not possible I feel more people should really rethink what makes them happy in the end.

 

[neptronix]

I now use a spintend 75V/250A vesc at half the price of my original phaserunner. I too am now a vesc fanboi. lol
Only negatives so far is the larger foot print/non water proofness of the vesc. Broke the budget splurging on the $6 heatsink. hahaha

This is a huge problem with VESCs that makes me only recommend them for high power builds... for anything below that, i like the phaserunner for it's waterproofness, simple programming interface, and refinement.

Have yet to see another VESC maker do better than a half assed job on packaging :/