My1018 brushless alternative?

[HrKlev]

Im looking at making a diy torque sensor, low power (5-700w peak), light weight mid drive. I currently have a tsdz2 which I like very much, except the ground clearance. I do have a MY1018 brushed motor laying around here, a BB torque with a freewheel on the way, and a CA v3. Trying to make a lightweight system I will also use a small battery as possible for what I need, and I am a little sceptical about how efficient the brushed MY1018 motor is. Last time I used it I only had a cadence based system, so its not a direct comparison, but it used almost twice the energy as the tsdz2 on the same routes. The MY1018 ticks all the other boxes with size, gearing and power. I have tried finding a comparable brushless motor, but cant seem to find anything. They are either way too big (cyclone, etc), or small without reduction gears (RC motors), and thus way too high rpm. Are there any brushless motors in the 500-1000w area with planetary gears that would be suitable for a mid drive build?

[amberwolf]

I do have a MY1018 brushed motor laying around here,

Which kind is it? There are several types, some with gears, some with mounts welded to the casing, different types of casing, etc. Depends on which kind it is as to what could be used to replace it.

I am a little sceptical about how efficient the brushed MY1018 motor is.

Brushed motors are less efficient than brushless, but not necessarily by all that much. The main thing is relative to your particular usage and setup, whetehr the motor is wound for the speed you want out of it under the load you are putting on it. That's true of either motor type.

So you would want to first decide the speed you want out of the motor, under it's load. Typically something like 80% of it's unloaded RPM is going to be it's max loaded RPM. If you need to use it at high loads at a lower speed, you'd want to gear the system to work at those speeds, or have shiftable gears that are setup for the speed range(s) you need.

Are there any brushless motors in the 500-1000w area with planetary gears that would be suitable for a mid drive build?

FWIW, geared hubmotors, which output in the RPM ranges your cranks would see, have been used for this. So have DD hubmotors...but the geared hubs have the option of remachining some parts to turn them into *axle drive* units instead of *housing drive* units, making htem a little easier to use in a middrive in a frame, wihtout putting a cover around the housing so you don't have stuff (or you) rub or catch on it. Crossbreak did it here to at least one motor, and there's other similar threads.
viewtopic.php?f=28&t=45245

[HrKlev]

Which kind is it? There are several types, some with gears, some with mounts welded to the casing, different types of casing, etc. Depends on which kind it is as to what could be used to replace it.

Sorry, I forgot there was several types of this motor. It is a 36V 450w motor with internal reducer gears. It is listed as 450rpm on electric scooter parts, sp I would think that is unloaded. https://electricscooterparts.com/hookup ... X2500B.pdf

Brushed motors are less efficient than brushless, but not necessarily by all that much. The main thing is relative to your particular usage and setup, whetehr the motor is wound for the speed you want out of it under the load you are putting on it. That's true of either motor type.

So you would want to first decide the speed you want out of the motor, under it's load. Typically something like 80% of it's unloaded RPM is going to be it's max loaded RPM. If you need to use it at high loads at a lower speed, you'd want to gear the system to work at those speeds, or have shiftable gears that are setup for the speed range(s) you need.

Hm, maybe I should give it another go. Its free after all. The motor is going on a bike that is used for quite tecnical single trails, so the rpm will vary a lot. 120rpm cadence for short bursts, but most of the riding will be a lot lower, probably closer to 70-80rpm cadence most of the time. So my plan was to use the 14t freewheel that is already on it, and a 42t chainring. That would give me the 120rpm max cadence I want.

FWIW, geared hubmotors, which output in the RPM ranges your cranks would see, have been used for this. So have DD hubmotors...but the geared hubs have the option of remachining some parts to turn them into *axle drive* units instead of *housing drive* units, making htem a little easier to use in a middrive in a frame, wihtout putting a cover around the housing so you don't have stuff (or you) rub or catch on it. Crossbreak did it here to at least one motor, and there's other similar threads.
viewtopic.php?f=28&t=45245

Thanks a lot for that info! I remember reading about it some guys using huge hub motors as mid drives, so I dont know why I didnt think about small hub motors could be an alternative I will do some reading!

[gogo]

The My2018 has heat limitations and will waste lots of electrons once its getting thermally stressed.

[HrKlev]

Decided to give the my1018 a go. Cyc torque sensor, freewheel, a chopped up cyclone chainring as an adapter from whatever bcd the freewheel is to 104 bcd chainrings. And some other things I found in the parts bin. Will wire it up with the Cycle Analyst tomorrow and do some testing. If it is decent I will clean it up some more and maybe finally make the casing for the battery

[HrKlev]

Did a test run today to compare the efficiency with the tsdz2 I had installed before. It was empty 7 km from home, even if I tried to be economical the last 50% of the ride. Definately a lot thirstier, unfortunately.

So compared to the tsdz2:

Pro's:
-Ground clearance
-Less resistance when battery is empty
-Chainline

Cons
-Not as efficient
-NOISE!! Slightly embarrasing passing people out in the forest on something that sounds like an electric chainsaw
-Couldnt find a way to tune out the snap I get in the driveline when to motor starts with the CA. At least not with still having the response needed for single trail riding

I think the tsdz2 goes back on for now, and I'll live with the ground clearance. At least until I get my hands on a small hub motor and coverts it to axle drive or something else. At least now I have a spare setup for when the tsdz2 breaks. It was a fun project after all

[andrea_104kg]

Congratulations on experimenting, it has always intrigued me. The noise depends on both the chain and the straight teeth of the motor reducer. I know they have built a version with helical teeth but it is not easy to find. As for the power how is it compared to the tsdz2?

[HrKlev]

Thanks! Most of the noise was definately the gear reduction growling. I have a cyclone 3kw (running only 600w@35v) on my fatbike now until I receive some other oarts, and its whisper quiet compared to this. Maybe its something wrong with the my1018. I tried to find the one with vertical gears when I bought mine, but no success unfortunately.

I didnt test full power, I just set max 500w input power like my tsdz2 and adjusted the torque setup until they felt about the same. Normally I use about 2-300w assistance on the trails. The my1018 ran out of power long before the tsdz2, so a lot more of that power went to heating, unfortunately. It did seem like I had to use higher assistance level compared to the tsdz2 to keep the same speed on the fireroads in between. Didnt do any accurate testing, though, the noise kind of made me lose some interest :p

[geofft]

Thanks! Most of the noise was definately the gear reduction growling. I have a cyclone 3kw (running only 600w@35v) on my fatbike now until I receive some other oarts, and its whisper quiet compared to this. Maybe its something wrong with the my1018. I tried to find the one with vertical gears when I bought mine, but no success unfortunately.

I didnt test full power, I just set max 500w input power like my tsdz2 and adjusted the torque setup until they felt about the same. Normally I use about 2-300w assistance on the trails. The my1018 ran out of power long before the tsdz2, so a lot more of that power went to heating, unfortunately. It did seem like I had to use higher assistance level compared to the tsdz2 to keep the same speed on the fireroads in between. Didnt do any accurate testing, though, the noise kind of made me lose some interest :p

I'm fairly sure the MY1018 motor has straight cut reduction gears and are noisy beasts. Check out the XYD-16 version of this motor, this looks identical to the MY1018 but is fitted with helical reduction gears. From what I remember from playing around with these motors a few years back the helical version is much quieter.

[HrKlev]

Yeah, that was the one I was searching for, but didnt find any places to buy from which seemed like a serious site. Anyway, I have ordered a Bafang g311 and a baserunner, that I will be mounting as a mid drive. Seems like Grin is quite busy atm, so just need to be a little patient....