wr250f conversion

[j bjork]

I find the elec motor a bit brutal on slippery rocks. Im temped to try an E-clutch setup too.

Doug

Indeed, but I dont think it is a motor but a controller problem. On the ktm I dont really have that problem. Sure it is a less powerful motor and controller, and therefor not as sensitive. But the throttle is so much more controllable, under half throttle or so you can really creep in to it. But over that it gives everything it got immediately. (Not everything, it is a difference between half and full throttle) The line between would probably be too sharp if it was double the power, but I have still not been able to get as aggressive response with another controller.
I havnt felt the need for a clutch on that bike.

I might be interested in your dash too if it has throttle adjustment possibilities

 

[dougf]

I thought about trying to make traction control possible...My wr has a speed pickup on the front wheel and I can get the rear wheel rpm from the speed output wire. The front wheel only pulses something like 2 times a rev though so I would probably need to upgrade that sensor. Having an adjustable amount of wheel spin would be great but its probably banned in racing. I also dont know how well the throttle input could catch wheel spin before it ramps up out of control.

I suppose I could maybe just have the traction control automatically change the electric gears as speed changes. that way when crawling over rocks at less then 10kph, limit motor to 10kph, but as the front wheel sensor gets close to 10kph, move into the middle E-gear. I suppose all this is just extra inputs and outputs, no reason not to make the hardware for it even if it doesnt work out.

Doug

 

[liveforphysics]

Hill climbing and and wet rock climbing with well tuned traction control on an EV is awesome. I used to think my wrist was fast enough, but it's pure magic to have TCS.

 

[j bjork]

Do you mean you will control the fardriver over the tx rx ports, and not use the throttle or brake inputs at all?
It seems like something has to be done, fardriver:s throttle control seems horrible :?

 

[dougf]

Do you mean you will control the fardriver over the tx rx ports, and not use the throttle or brake inputs at all?
It seems like something has to be done, fardriver:s throttle control seems horrible :?

I dont believe you can do throttle and brake input over the rs485. Looking into what i can do. Im not sure about your throttle situation. Mine definitely surges a bit during constant speed and is a bit stuttery taking off. I put some of that down to my throttle which produced similar effects on the APT when i swapped it from the hall throttle. If you get time, maybe put some tape on the throttle assembly, mark out 0, 1/4, 1/2 and full throttle positions and measure the voltage you get (can use fardriver app) to check that your throttle actually puts out a linear signal. Some variable pots are non linear. My 5v out also has some noise, around 200mV p-p if i remember correctly. If your throttle is non linear ill have a think about a way to rectify it.

Doug

 

[j bjork]

Thanks, I updated my thread with measurements and thoughts.

 

[dougf]

An update on my progress of reading data straight from the controller. For those who want to do this too, hopefully this will get you going,

When initially turned on the drive will try and init the bluetooth modem. If its not plugged in it will continually try. Not a bit deal but make sure your code will handle it.

To start the data streaming back send these bytes,

{0xAA, 0x13, 0xEC, 0x07, 0x01, 0xF1, 0xA2, 0x5D, 0xF0, 0xF0, 0xF0, 0xF0, 0xF0, 0xF0, 0xF0, 0xF0}

A stream will start, but about once a second you will need to send this,

{0xAA, 0x13, 0xEC, 0x07, 0x01, 0xF1, 0xA2, 0x5D}

to keep it going.

The data coming back has a leading sync byte of 0xAA, followed by an ID packet going from 0x00 to 0x17 (24 fields). The rest of the packets seem to be data. Each packet is 16 bytes long, so 14 data Bytes.

Ive been a bit lazy because its cold in the shed but I dragged the bike into the kitchen and did some testing 8) . So far I have decoded throttle %, riding gear (low mid high), brake on, regen active, voltage, SOC, Throttle ADC reading (12bit ADC) and MOS temp. Couldnt find current, hard to tell by free spinning the wheel in the air, might be a job for the dyno. Im guessing watts is calculated, not transmitted. I also havent looked at writing data at all yet. Will look at it later. It would be nice to be able to change at least some of the basic settings from the dash.



If you just want it for SOC then it should be really easy to do with something like an arduino and a dual 7 seg display module.

Will update as I work more out.

EDIT: I suppose I should explain how to get voltage from 2 bytes. basically the controller is returning a 16bit number as 2 bytes, an upper and lower byte. If the voltage is at 95.5V the packet will look like this;

0xAA(sync), 0x01(ID), 0x03(upper byte), 0xBB(lower byte), (more data......)

so the 2 bytes together are 0x03BB. Convert that to decimal and its 955. Divide by 100. If your new to programming your data processing should look something like this;

voltage = ((upper byte << 8 ) + lower byte)/100
or;
voltage = (256 * upper byte + lower byte) /100

Doug

 

[DogDipstick]

How much money does all this cost?

Nice craftsmanship.
I'm curious about the machined plastic used for the battery box ?

The white plastic is PVC foam board. Used in sign making. It machines really easily, doesnt change shape like hdpe and is incredibly light.

I would use poly-carbonate. Much stronger, fire rated, and does not give off deadly fumes when burned. Can take one hell of an impact. Single component glue ( no purpleprimer) for a reliable bond. Helicoils can be tapped into them and then they can place thousands of pounds of preload on the fasteners to keep part together.

Machines bettr.

Reasons why its used in industry. You never see a "pvc " machine guard. Or at least. I haven't.

Ever see PVC used in a structural application?

A serious question.

 

[PaPaSteve]

How much money does all this cost?
I would use poly-carbonate. Much stronger, fire rated, and does not give off deadly fumes when burned. Can take one hell of an impact. Single component glue ( no purpleprimer) for a reliable bond. Helicoils can be tapped into them and then they can place thousands of pounds of preload on the fasteners to keep part together.

Machines bettr.

Reasons why its used in industry. You never see a "pvc " machine guard. Or at least. I haven't.

Ever see PVC used in a structural application?

A serious question.

Lithium fumes are quite toxic on their own.
Fumes from PVC or polycarbonate ?
One may be a bit more poisonous but neither should be inhaled.

The battery part being machined is just a place holder for assembly and has very little structural duty.
If light weight is important ...
polycarbonate = 1.2 g/cc
expanded PVC = 0.7 g/cc

For me ... at this point, it's just interesting to see what others are doing.

 

[Eastwood]

20220524_194641.jpg

Looks great with the super Moto setup!

 

[dougf]

I used the PVC foamboard because I had it and It isnt meant to do any serious structual stuff aside from holding the cells in a pattern. Its also very light. The original plan was to put the assembled pack into an aluminium box but I had designed too much precision into it as far as fitting it into the bike so I just glassed it. While I would deem it "strong enough" for the type of riding I do (bit of a pansy) I definitly wouldnt make it this way again.

There shouldnt be gasses coming out of the battery.

Looks great with the super Moto setup!

Thanks mate, I will probably keep these new black rims for dirt and relace the old OEM hubs to a pair of 17" rims for the true supermoto setup. This bike ended up on the heavy end of dirtbikes so I will probably angle it more towards road-trail or dual sport duties. For true dirtbike I think Id use the smaller 138 motor and make the battery about half as big.

Regards

Doug

 

[Eastwood]

Thanks mate, I will probably keep these new black rims for dirt and relace the old OEM hubs to a pair of 17" rims for the true supermoto setup. This bike ended up on the heavy end of dirtbikes so I will probably angle it more towards road-trail or dual sport duties. For true dirtbike I think Id use the smaller 138 motor and make the battery about half as big.

Regards

Doug

Yeah I can understand trying to keep the weight down I’m in the same predicament. Actually from reading your thread and others it was one of the reasonings I went with the QS 138 to try to keep my current build weight down. Have you been able to test the range with your battery off-road? I’m sure that QS 180 is a monster off-road 8)

So your battery is 24s17p Molicel p42a.. what’s the total weight of your battery? I’m considering a very similar size battery. Curious of what your weight came out to be. Trying to find that balance between Range and keeping the bike light.

Yeah that would be awesome to have two wheel sets for your bike!

 

[dougf]

Yeah I have, I got about 95km of gravel road riding and used about 68Ah. I ended up getting towed back the last 3kms because I had set my low voltage cutoff a bit high and only discharged to about 2.8v per cell. When I get into single track stuff, further. Probably around 110km if I take it easy. On the Hwy at 80kph, about 80km and at 100kph, about 50km.

Yes, Molicel P42A in 24s17p. Total weight including wires was around 33kg.

For a dual sport bike I'm pretty happy with the range and weight. For a dirtbike/mx bike I think Id go the watercooled 138, half the battery capacity (might be tricky, molicels would be struggling for power density at that point so It might need to be pouches) and make the battery pack modular and swappable.
By my back of the napkin calcs I could probably lose 3kg worth of headlight/taillight etc, 15kg of battery and about 8kg of motor bringing the bike weight to about 114kg. For MX I would also lose the bash plate, bark busters and flex bars probably saving another few kgs.

I'm not too put off by weight, I do a lot of off road riding with a Tiger 800 which tops the scales at 253kg without luggage :lol: . Would love to build an electric adv bike but I think the charging infrastructure is lacking here a bit in WA.

Doug

 

[dougf]

For anyone curious this is the wear on my motor shaft after about 20hrs or about 500kms.



Looks pretty good considering the sprocket fits pretty poorly. I do have it doubled up with a second sprocket to increase the contact area though.

Doug

 

[j bjork]

What sprockets are you using?

I think tomorrow is dyno Sunday

 

[dougf]

Just some Generic sprockets i found from a local store,



A bit tricky to find 520, most pit bikes are 428.

Ha, nah my dyno is currently buried against the wall. I did re-run autolearn with no chain, doesnt feel any different, although rated rpm went up to 2840ish from 2700. I also tried out both linear and eco throttle maps. I hate eco, so much i pulled over to change it. Linear, i also didnt like too much. Its definitely less surgy in linear but i dislike how much i need to turn the throttle. Im guessing the best feeling throttle is something like linear when below about 15kph, then something more like sport as you get faster. I should be able to program throttle maps in the dash im building, can use speed as a modifier. Im also optermistic that variable regen might be possible simply by writing new values over the rs485. You can modify values in flash without forcing a save and reboot. The drive may still trip out or stumble when it happens, i havent tested it. Im already dodgy enough without riding down the road with a laptop taped to the tank .

Doug

 

[speedy1984]

I found linear mode and 224 value is the best throttle setting i have used.

 

[j bjork]

It seems like the rated rpm changes with the battery voltage, but I cant say for sure.

Yes, eco is just horrible.. I dont see the use of these ECO coeff 1-8 either, anything other than 8 and the bike hardly moves :?
It would be nice if they were useful to tame sport throttle a little.

Im pretty happy to stay in linear and 224 for now, it still ramps faster than I can get grip in the dirt.
I tried lower throttle rate and sport, didnt like it at all. Aggressive with a delay
Sport and 224 is way too aggressive for me

What 428 sprockets have you found?
I think the smallest I found was 14 tooth, now I have custom.
Would be nice if there was something over the shelf available.

It sure is interesting to hear what you come up with on that dash.
When trying to program the sevcon I drove with the computer in a backpack and logging, but no real time reading values then.

 

[speedy1984]

I follow the thread because of that 180 beastI'd use that in a road bike where the weight at least from the riding point of view is less of an issue.Would be great to put one in a Rs125 or little KTM Duke ect, it's definitely made me look for another chassis lol.Even though I've only around 3hrs testing on my little 138v3 build it was the right choice for simple Enduro/tight fast trail bike build.Hoping my build is around the 100-105kg mark when it's all finished.Feels very light and flickable when moving and definitely lighter than any 450 I've ever ridden that's for sure.

 

[dougf]

It seems like the rated rpm changes with the battery voltage, but I cant say for sure.

Yes, eco is just horrible.. I dont see the use of these ECO coeff 1-8 either, anything other than 8 and the bike hardly moves :?
It would be nice if they were useful to tame sport throttle a little.

Im pretty happy to stay in linear and 224 for now, it still ramps faster than I can get grip in the dirt.
I tried lower throttle rate and sport, didnt like it at all. Aggressive with a delay
Sport and 224 is way too aggressive for me

What 428 sprockets have you found?
I think the smallest I found was 14 tooth, now I have custom.
Would be nice if there was something over the shelf available.

It sure is interesting to hear what you come up with on that dash.
When trying to program the sevcon I drove with the computer in a backpack and logging, but no real time reading values then.

428 and 520 qre both available, ill try and get some model numbers. I got an 11t 428 at home.

Your probably right, i seem to recall first running the autotune with a reasonably flat battery. I was thinking about it a bit, what total gear ratio are you running? I used my bike a lot with 11/52. Changed to 11/60 last week on both wheel sets and i sort of like the more mellow taller gearing. Might try 12/60. My thoughts were the taller gearing makes the bike more controllable at slow speed but still pulls good up top.

Didnt try eco coeff. In eco i would go to take off, nothing..nothing...nothing...wheelie. i still like sport and 128. I also program my throttle ref voltages to be full throttle in about 1/8th of a turn of the throttle....hate large throw throttles.

Itching to get my pcbs in to fab. Gonna have to pinch the stm32 off of another board, chip shortage has destroyed stock of those. I will keep thread updated with progress of dash.

I think id deff go double or higher in voltage for a road bike. Drop the current right down. Pretty much rules out QS motors. I want well over 100kw on a road bike 8) . Might buy a used 125sx and convert that with a 138 though. I think elec bikes would work really well in MX where trying to control slow speed traction never really happens. I will need to get my wr on a mx track at some stage for a little test.

Doug

 

[j bjork]

So you are at 4,7x-1 or 5,45-1, that explains some of the differences I think
I am at 7,1-1 or so..

Very interested in that 11 tooth 428 :thumb:

 

[dougf]

So you are at 4,7x-1 or 5,45-1, that explains some of the differences I think
I am at 7,1-1 or so..

Very interested in that 11 tooth 428 :thumb:

Yeah ok, very low geared. Id need a 78t rear to get anywhere near that low. I thought i had problems with traction :lol: . Even with 5.45 i can still pull wheelies over 80kph, gearing up might be a simple solution to tame your bike a bit? I know with big bore thumpers and 500cc 2 strokes they are usually geared pretty high probably for that reason. Only road bikes can make use of extra torque...or supermotos.

Ok, front sprocket i use currently is a MTX 327 11T #520

And you are correct, no 11T 428. Smallest i see is a 13T.
MTX 1264 13T #428.

Doug

 

[j bjork]

Yes, gear up would be interesting to try. I have also considered lowering the phase amps..
But both feels wrong somehow :wink:

The sprockets seem to follow the same numbers as JT sprockets, but they dont have smaller than 14t 1264.
13 is better, I will see if I can get one of those. They seem to mostly sell in Australia and New Zealand.
Thanks for the tip

Have you checked out jtf 1324 for a better fitting 520?
http://www.jtsprockets.com/catalogue/part/JTF1324/

Maybe there is a MTX version too :wink:

 

[PaPaSteve]

Here's a method I use to eliminate wear on a spline shaft.
Assuming the shaft and sprocket have been cleaned for assembly ...
Glue the sprocket in place with JB Weld epoxy.
Any number of other metal locking adhesives will also be viable.
To remove, the technique is to apply some moderate pressure with some form of gear puller and then start heating the sprocket.
A propane or butane torch does it.
For these kind of heat tasks I like to use a Hot-Air Rework Station.
Pressure from the puller and about 200 ~ 250F heat to the sprocket ... it pops right off.
Clean the old adhesive from the shaft, inspect the seal, install a new sprocket.
This approach has been a successful and standard operating procedure on my motorcycles for many years ...

Hot-Air Rework Station
https://www.sparkfun.com/products/19101?gclid=CjwKCAjwi8iXBhBeEiwAKbUofRsLbGEo-9G7Nz-zL_EIHHuW7wfcLKKp-mjfiTAT5EYiEjKxS08WHBoCaOIQAvD_BwE

As Always
Your Results May Vary

 

[dougf]

Yeah i could jb weld it i suppose. Ive actually drawn a custom one up but i was put off a bit by the need to setup the shaper and harden the steel afterwards. I think ill just machine a clamping hub that bolts to the sprocket. Will still need to cut keyways but it wont need hardening. A job for later on.

I wouldnt drop phase amps. This is a fast bike even with 4.7-1 gearing. Pulls 1.9 second 60fts. I would guess that at 7-1 you are seriously struggling for traction. I wouldnt be suprised if your pushing 1000nm at the rear wheel. Have you tried having low speed selectable with a switch to tame it down in slow stuff?

Probably hit some slippery rocks this weekend on mine, will see how it handles it.

Doug