CRF #2 - 250R - LGX P41A 20s1p - EM200

[amberwolf]

BTW, this is one of the strapping clips I was talking about; they call them buckles.


Metal Buckles for Poly Strapping - 1/2

The page also shows tools for doing the work. and they have a guide

Uline Strapping Guide

Choose the best Strapping for your application. Read our guide to learn about types and materials, strapping tools and other helpful hints.

www.uline.com

They're available cheaper elsewhere, but I will say that in my many years working in retail unpacking things, there are some of these clips that come all bent up with loose straps, and I can bend them by hand (with a screwdriver for leverage), and some of them that I can't bend at all and have very tight straps. The better oens are usually darker grey in color, rather than shiny metallic, and they look in shape like these, rather than the cheap ones I see on amazon, etc., lke these
but they do have a useful picture of how the straps go thru it


They also make crappy plastic ones that look like a square "ring" with two "bones" loosely attached to it; these are not sufficient for something liek the forces needed on a battery compression rig.


I have a number of kinds of straps and clips I've saved from packing crates and pallets over the years, for use in projects at home. I even carry a few on whatever I'm riding at the time to strap things down to it if they wont' fit in the cargo areas built into my ride.

 

[j bjork]

Interesting to really calculate this, when I have done it on prismatics I have used 10mm alu endplates and just put as much pressure on it as I could with a clamp. How are you going to measure?

 

[bananu7]

How are you going to measure?

My initial idea was to set the tightening torque for the 4 bolts in the corners, but that comes out to like 1Nm or less... Turns out threaded bolts are pretty powerful. Not sure what advantages bands or straps would have over that approach.

 

[bananu7]

Going to earn the 'doin' science' reactions:



From 10.1007/s00158-023-03662-1.

Seems that between 30 and 60kPa would yield good results indeed.

 

[bananu7]

I don't know how I missed this post... VFR400 20kw Build

I'm now pretty sure that my ideas about v-clamps were overengineered. I'm going to simply use 10x4mm stainless steel bars, punch holes in the electrodes and bolt to the 4mm epoxy carrier directly. For the busbars, I'll get a section of 10x5mm copper bar and also screw everything together.

For the compression sides, the options I'm currently considering, but I don't think it will matter very much in the end anyway, are, in the order of most likely to least likely.

- 8mm epoxy fiberglass board (can be CNC'd to shape)
- 6mm aluminium sheet (can be laser cut to shape)
- 12-15mm plywood (I can cut it reasonably easily myself and is more pleasant to work with)
- 3D printed ribbed PLA board (unlikely as I don't have a printer big enough)
- flat composite laminate (DIY)
- composite laminate in a ribbed form (DIY)
- custom forged carbon ribbed form

That post also has a brilliant idea to enclose the bolts in PVC pipe - which I'm shamelessly going to steal. This should prevent chaffing if any of the cells come in contact with the clamping bolts. For the bolt diameter, it really seems that going past M5 is largely pointless, except perhaps for shear/bending loads - but I don't think the battery will see a lot of those. The idea is for the cells to be mostly held in place with the compression force, and the outer compression plates to extend around them in such a way there's no contact with the enclosure walls. If the whole structure rests in the outer shell evenly, the bolts should only ever see tension loads from the cells, which is what we want and comparatively tiny for what an M5 bolt can carry.

 

[jkrienert]

...That post also has a brilliant idea to enclose the bolts in PVC pipe ...

I'd suggest an alternative tube or pipe material since PVC's structural integrity is shortened in thermally cycled environments <0*C - >60*C, and is also highly toxic if inhaled in the worst case scenario, a battery fire. Maybe there are some alternative materials, like HDPE or LPDE tube, especially if you're working with M5 diam.

 

[bananu7]

I'd suggest an alternative tube or pipe material since PVC's structural integrity is shortened in thermally cycled environments <0*C - >60*C, and is also highly toxic if inhaled in the worst case scenario, a battery fire. Maybe there are some alternative materials, like HDPE or LPDE tube, especially if you're working with M5 diam.

Yeah, good point, I could use PE, PA or maybe even Teflon. I didn't really think much when I said PVC, but you're right it should be something durable.

Also perhaps a reason against plywood, then.

 

[bananu7]

Not much progress on the battery as I was away for most of the week - I've been working on:

* Getting the suspension linkage serviced - bearings went in fine, but I'm missing two key washers. I machined a set today but made them too thin and there was too much slop in the bearing. I think they need to be around 1.8mm thick, maybe even 2mm. I could just order them but they're like $10/washer.



* Getting the swingarm ready - I decided to use the #3 swingarm that came with the bike. I've glued up the chain hole with epoxy putty, I'll transfer the steel axle plates from the good one, remove the stuck slider bolt and it should be good to go.



* The steel plates were removed because the Kawasaki wheel is wider, and with the stock spacer it didn't fit the swingarm. I'll put the plates back on but will machine a new set of spacers instead. That alone should help fix the rear disc alignment problem.
* I have received a new rear brake from Aliexpress, but unfortunately they send me a wrong one - for KTM. I have the old brake carrier though so I can test fitment while i wait for the new part.

 

[bananu7]

I made one 20mm-tall spacer:



With the steel plates added back, it was actually a perfect, snug fit. I was initially concerned about 2mm misalignment, but I can move the wheel by far more by misaligning the axle by like 1mm, so I don't think it matters, especially with offroad tyres.

The caliper mount now clears the disc... barely. But barely is perfectly adequate, as the caliper itself should have more wiggle room. Still waiting for the new one to get here, hopefully for Honda this time.



With that solved, I could get it sort-of-together. Not going to lie, it was quite a moment to see it resemble a motorcycle again. Unfortunately I've realized I'm missing two swingarm washers (the ones that sit on the outside of the swingarm). I had one spare, but will have to remake another one myself, fortunately that's an easy job. Man, the lathe is really proving to be an useful purchase!



Getting the swingarm in allowed me to check the chainline with the new motor mount:



This looks much better. I set the stand to a resting static sag of the bike, and ran a piece of wire (no chain yet in my possesion) to check. With a fresh, super thick slider, the wire rests on it, but nothing crazy, despite the smaller sprockets (14-52 @ 428) right now, so it seems that 10mm higher was a good call. However, I want to do another revision of the mount to change two things:

1) pull the motor back - I think I will dare to try 5mm. I have about 10mm of clearance, but the gearbox part of the motor might go into my newly sealed epoxy cover if I go that far. 5mm would put the sprocket about on par with the stock engine.

2) rotate the motor around the sprocket axis so that it's less tilted back. This will move some of its mass down and crucially utilize the space low in the frame, while leaving more for the battery.

I plan to order two sets of those mounts and replace the ones in #1 as well, so that would allow the battery in #1 to finally rest properly, as right now it's jammed between the motor and the frame.

I really wish I had a 3D scanner for this, it'd make it so much simpler, but it's still a good exercise to do it by hand.

I hope to have the final CAD files for the mounts on the weekends so that I can order them early next week. Unfortunately the one place I found that sold CNC-cut fiberglass pulled their offers so I have nowhere to order the battery insides right now. I plan to call them and ask if it might come back.

 

[bananu7]

It's been a month with no update, as I was busy with other things that took priority - such as preparing for a rally this week by getting proper tyres on my KTM:


With the #2 CRF, I mostly worked on the mechanicals still. I printed the new mount, 5mm backwards and rotated and it seems to fit. So i got to modifying the engine with precision equipment:



And after a while I had this:



I will machine some washers of exact thicknesses to make everything lay flat, then I'll just need the two big spacers that go in the middle and I can assemble the rear wheel and swingarm.

 

[bananu7]

I'm slowly but surely chipping away at the battery design. It's much, much easier to fix stuff with mouse clicks than a file...



I've realized the pack is about as wide as the BMS is long, which gives me a great opportunity to mount it, provided i can route cables in a reasonable way. I think the side panel cutouts should hold (I know it's a bit thin on the sides, it's WIP and I'll likely make them slightly larger). The sides will be in either 6 or 8mm plate, which should be really strong.

I also already have the copper and steel for the bars and inter-electrode washers, just need to cut everything to size and drill.

 

[bananu7]

I have assembled the front wheel with a new tyre and tube, so both wheels are ready. I still didn't get my laser cut motor mounts, hopefully next week, so in the meantime the work on the battery continues; I'm also thinking about doing the suspension as that will be necessary to put it on wheels.

 

[bananu7]

Finally...

It took way longer than it should have. Eventually i contacted my first supplier, cancelled my ordered and made another one. With those i can start working on the set of 6 spacers for the motor that will put it in the frame, which in turn will allow me to put the bike on wheels. It's a bit tricky since I still haven't done the suspension... In the front I'll just change the oil, in the back I'll give it out for proper service, but that will take about two weeks. The upside is I can also give out my spare shock for CRF #1.

 

[John555]

I'm slowly but surely chipping away at the battery design. It's much, much easier to fix stuff with mouse clicks than a file...

I used the same cells in my design

ATV Adly QS138 90H V3 + Votol EM200/2

Hi. Base for my build is ATV Adly SuperSonic 50 https://www.1000ps.com/en-gb/model/6158/adly-supersonic-50/2016 The previous owner hasn't used it for the last few years, so there will be a lot of work to refresh some key elements It is factory fitted with 50 cc engine, but frame is identical to...

endless-sphere.com

A 3x10 aluminum flat bar was used as a clamp

 

[bananu7]

I used the same cells in my design

ATV Adly QS138 90H V3 + Votol EM200/2

Hi. Base for my build is ATV Adly SuperSonic 50 https://www.1000ps.com/en-gb/model/6158/adly-supersonic-50/2016 The previous owner hasn't used it for the last few years, so there will be a lot of work to refresh some key elements It is factory fitted with 50 cc engine, but frame is identical to...

endless-sphere.com

A 3x10 aluminum flat bar was used as a clamp

OMG you're right, I even looked at your thread back in winter and completely forgot since thanks for linking it, I'll reread it again, but it seems that I have the right/similar ideas.



I have a small update, I made the precise washers to align the plates. I measure it at the bolts under tension to minimize the effect of individual plate misalignment; that will be corrected with spacers when it's all together, but they should sit parallel on the motor. The spacing is just a smidge under 55mm, I machined a 54.8mm spacer with 10mm ID and it fits quite alright, so I now need a 17mm ID one for the other end, as well as 4 small side spacers which I'll measure for with everything on the bike. The #2 bike has a different wheel which means possibly different chain alignment, so I want to have it all together to measure.

 

[bananu7]

Couldn't resist it. I machined the second inner spacer and put it on wheels:



Benefit A: now it's something i can roll around instead of bunch of parts just laying around.
Benefit B: huge motivation boost to keep working on it

New motor mount makes the motor collide with a swingarm, restricting movement to the left. I think it can go far enough to the left to allow for proper chainline, but i have to measure it all precisely to be absolutely sure. Worst case I can take a bit of meat from the motor.

 

[bananu7]

Did the service of the front brake today. Pump is going to trash. It had a broken bolt stuck inside that I failed to extract, but really every single part of it needed replacement. It's easier to just source a completely new one.

The caliper on the other hand looks pretty decent. I unstuck both pistons with compressed air, replaced the pins and rubber covers and gave it a good clean. Almost like new, except it's missing one flat spring, but I guess I'll have to live with that. New pads ordered.



I also did more chain line checking and I have less wiggle room than I'd prefer. I noted down some provisional numbers that can work and after that it's pretty much empirical anyway. The #1 definitely could use adjusting as it's eating away the right side of the sprocket consistently... I got the chain out too and measured I need 4 fewer links, so I can order that at least.

 

[bananu7]

Did the front suspension service today. I figured it's the best occasion to learn doing it with an USD fork. I was very glad that I had the spare set laying around to keep reference of.


I did make a couple mistakes, and scratched the compression rod at the very bottom, which I hope doesn't affect the shaft seal as it sits a bit higher. That being said, I assembled one of the cartridges so far and it's definitely leaking - from the top, which means either the outside oring or the internal compression stack shaft seal. Thankfully I have two spare cartridge tops, so maybe I can just swap one in and skip replacing the seal.

All in all doing that is quite a bit easier once you understand all of the parts and how they function and what's their purpose, but I'm still angry at myself for not 3D printing a soft U key for holding the shaft...

 

[bananu7]

That being said, I assembled one of the cartridges so far and it's definitely leaking - from the top, which means either the outside oring or the internal compression stack shaft seal. Thankfully I have two spare cartridge tops, so maybe I can just swap one in and skip replacing the seal.

Yup, that did the trick. I went with the two tops that were in better shape. I decided not to touch the damping for now and leave it to the future owner to decide what to do with the suspension - at the very least it would need different springs, most likely.

Rebuilding this one makes me wonder about swapping the cartridge springs on mine, though - it definitely feels like it can be done without pulling the rods out; just slide the entire cartridge out, unscrew the top, rebuild the cartridge (optionally altering base valve a bit), then refill to 42mm and live with the extra couple ml of oil in the fork. Those springs are so freaking expensive for what they are, but all i've heard about changing them is that it's worth it...

Either way, the bike was back on two wheels only temporarily, as I've taken the shock out, took the spring out, and i need to take both for service. In the meantime, it's really high time to start working on battery sizing and enclosure, as I've been procrastinating on this way too long. I still need a couple of motor spacers but it's going to be a quick job, and ideally i'll fit them with the new chain which should get here tomorrow.

 

[bananu7]

I cut the motor spacers. The front ones went straight in but I had problems getting the rear to line up. I have some unidentified clearance issues. Need to get it all out, mount the motor to plates so it's rigid and then try again to see if it lines up.



The look very similar to the ones in #1:



I also got the chain and of course I bought the wrong length again. I knew I needed 4 fewer links, but had erroneously noted that the #1 had 144 links so ordered 140... 144 was the first wrong length. I'll just cut it to size, but that's another item that just adds to the time.



I also did more mockups for battery sizing. I'm slowly accepting I will need to cut the frame a bit. Just two minor corners that I've seen others do, to give me a 20cm long rectangle. Cells are 8.6mm per cell, giving 172mm. Plates will be 5-6mm, so let's say 184mm. Leaves me with 3mm each side for enclosure thickness and 10mm of wiggle room. If you think that's plenty, you're either very experienced or not experienced at fitting batteries at all

 

[bananu7]

The motor is in! I had to re-spin the leftmost spacer because i cut it too long, shortened it too much and then had to make another one... But it's all in, torqued to spec. The clearance to the swingarm is absolutely minimal:



The washers aren't really necessary, as the spacer takes the compression force at this point, but I've added them in respect of Lamborghini mechanics.

Chainline seems really good:



This is a thick slider but it's clear how the chain goes on it at proper angle and will have plenty of clearance with the suspension compressed. I've also replaced the allen bolt seen in the lower position with the stock motor mounting bolt for street cred.

With that out of the way, the only mechanical bits left are
- rear shock, currently sitting in my trunk to be dropped off for service
- brakes waiting for parts to arrive.

So, I've started working on molds for the airbox and battery:

 

[bananu7]

I've received and mounted the front brake master. I've reused the old brake hose for now, as it seemed in okay shape. I might replace it later if I don't trust it enough. The front brake after bleeding seems to work very well - my rebuild of the caliper seems to have worked well. It still has the old pads, but considering it's also on the old disc, I am inclined to just use them if they still work well, as they have plenty of meat left and there's no point in replacing them prematurely.

I also got my new rear brake hose, which almost allowed me to test the rear brake. Unfortunately the casting doesn't have a cutout where the hose barb would go, like the OEM caliper does. It will take me probably another 15 minutes with the file to get it all the way done, as I ran out of patience around half of it.



The brake hose is otherwise really nice. It's from here: https://pl.aliexpress.com/item/1005...t_main.47.1deb1c24IzqvKX&gatewayAdapt=glo2pol


I had my reservations about those replaceable barbs initially, but they really work quite well. You can rotate the hose around and make everything fit perfectly, in contrast to my clamped hose on CRF#1 that never wants to lie the way i want it to. It also came with a 90 degree barb that's perfect for my LHRB pumps.

I want to try the rear brake ASAP to see if it works better than in CRF #1, but that might be hard to do without power, lol. Getting the battery ready is of utmost priority.

 

[bananu7]

I replaced my phone's battery and while I'm waiting for the new glass back my main camera is not operational, so you get selfie quality pics.

I have decided to reuse part of the old airbox for better fitment.


I think I still need to adjust the shape a bit to utilize the space better and make it more narrow. The weird color is because I already filled and sanded one layer. The green thick filler I used to hate is actually super useful for making a structural backbone for elements made of several pieces of foam.

 

[bananu7]

Ooookay. Did another bleed, ...

Also I've just realized I posted this in the wrong thread, lol...

Well, on the CRF#2 front, I decided to bite the bullet and ordered Pattern Coat Primer, a specialized gelcoat from Easy Composites that's designed for pattern making. I figured I'm spending so much time on those i might as well try to get the best results i can...

 

[bananu7]

Yet another iteration. While I was measuring everything again, i noticed that my carrier boards had waaaay to large spacing. I want to compress the cells, not spread them apart. This means that the more practical location for the BMS now becomes in the front. The frame is curved so as long as I literally cut the corners i can fit it much more lengthwise front-to-back.

I also replaced flexible cabling with rigid busbars. I ordered a torch and want to try a stab at heating and bending the copper stock to shape. If I can get this right, it should be much better to get wired than the cables. I'll only use flexible connectors for the very last part, where the bars meet the terminals. To that effect, I bought 74mm flexible copper braids, that should be perfect for this scenario. I only need enough give to put the screws on and tighten them.