KZ440 road legal cafe racer

I've now made a start on CADing up the frame and the battery to design the traction pack housing, then get the FEA done on the design for the local regs. I wasn't sure how how the box would be built but the ends are coming up way more complex than I anticipated, and making the pack fit in the existing frame is proving challenging (tho not impossible). I had to push outside of the design envelope to use these Lipos, and the ends are way too complex to fold or weld up from sheet so will likely need to be milled. Watch this space.

...officially on the struggle bus

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Composites are a surprisingly simple way to make one off, complex, shapes...
Would love to use CFRP or similar, but my concern is the difficulty involved in modelling and analysing composites where the box mounts up to the frame. FEA on multilayer CFRP is really difficult to get right.
 
Valid points. XXRP isn't isotropic in any aspect, and the manufacturing process' for one offs aren't analysable. So what you do is design for 150% and test to 120%. It' surprisingly easy to do.
 
Valid points. XXRP isn't isotropic in any aspect, and the manufacturing process' for one offs aren't analysable. So what you do is design for 150% and test to 120%. It' surprisingly easy to do.
Thanks PK, I'll have a play around with that too and see if I can get some acceptable results. I may have however stumbled on a way to make this from sheet metal with some internal bracing at the front hardpoints though. I'm goin to experiment with welding up some folded 4mm Al or 2mm SS sheet and see how that comes together as it may be faster than going the CFRP rout. It'll largely depend on how good/bad my welding ends up on the test pieces :D

This is the concept so far for the shell. I'm open to feedback on the idea:

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half shell (the tab at the bottom was for locating a bracket on a 3d print test piece - that wont be in the final):

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Front view of the full shell:


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Rear view of the shell
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Some more progress on the battery box designs this week with the CAD almost wrapped up now. I'll try making this housing from 3mm aluminium sheet, with milled sides and milled rear face plate. The rear face is just too complex to make from sheet and I want to simplify the analysis and manufacturing so will price up a milled piece as the first option before contemplating a CFRP version. The majority of it will be bolted together, but the front will need a bit of basic welding.

Using 5052 H32 sheet for the main body sections; 6061 for the milled sides and rear.

The 20G frontal and 10G rear loading was handled satisfactorily without the side covers so I'm optimistic that the design will broadly meet the VSB14 requirements. I'll post the FEA results once they've been finished up.

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Some more progress on the battery box designs this week with the CAD almost wrapped up now. I'll try making this housing from 3mm aluminium sheet, with milled sides and milled rear face plate. The rear face is just too complex to make from sheet and I want to simplify the analysis and manufacturing so will price up a milled piece as the first option before contemplating a CFRP version. The majority of it will be bolted together, but the front will need a bit of basic welding.

Using 5052 H32 sheet for the main body sections; 6061 for the milled sides and rear.

The 20G frontal and 10G rear loading was handled satisfactorily without the side covers so I'm optimistic that the design will broadly meet the VSB14 requirements. I'll post the FEA results once they've been finished up.

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Kawasak-e... Dammit, I like your pun better than mine.
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If I ever have to redo my tank/cover, would it be okay if I steal your idea?
 
The FEA results came out excellent on this design with a fairly good FoS across the board. The mounts and housing show that they can easily withstand a 20G frontal loading (with a 28kg battery load) so that should somewhat offset some of the welding weak points.

The 0.2 appears to be a singularity on an external corner on the perimeter of a nut so it can be discounted.

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Hi Friends, its been a while since my last post.

Lots of things going on that have taken some focus off the project. I did however get all of the FEA completed for the battery housing and sent the files off to the mill. I got an email back from them yesterday confirming that the parts had been made and shipped... they sent a "proof of life" (below) photo which was amazing to see!

I've spent a fair few late nights over the last few months putting the engineering report together for the certification as this should make the process a bit more straight forward. All of the load cases have now been done and the box + mounts are standing up to the crash test simulations. The SF looks acceptable for all critical locations, and the stress on the bolts is well within yield for class 12.9 bolts.

All of the hard parts should now be done so its downhill from here!

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I'll get some more pics up when I pick these bits up and start to test fit.

Some FEA highlights:
20G Frontal Impact

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15G Side Impact
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10G Rollover

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That looks really nice. We need an "oooh, shiny" like icon with lots of sparkly animation on it. ;)

I'd love to make parts that nice on my builds...but my ride probably wouldn't be there when I came back out from shopping. :(
 
haha, I support the addition of an "ooh shiny" icon!

I'm hoping this thing wont be too much of a target... though I'll be sure to have some good insurance on it!
 
That looks really well designed (nice work), and excellently manifested by the shop.
Seems like you have a Dutch Draft horse in the making here. Really cool.

Also, the in-progress loom looks like quite an adventure...
Are you planning to route (parts of) it in any special protective materials?

EDIT: I mentioned that particular horse breed since it is regarded as one of the sturdiest and toughest, without sacrificing a welcoming temperament :)
 
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That looks really well designed (nice work), and excellently manifested by the shop.
Seems like you have a Dutch Draft horse in the making here. Really cool.

Also, the in-progress loom looks like quite an adventure...
Are you planning to route (parts of) it in any special protective materials?

EDIT: I mentioned that particular horse breed since it is regarded as one of the sturdiest and toughest, without sacrificing a welcoming temperament :)
Thanks! the prototyping house I use is turning out to be very capable. The cost is not too bad all things considered but I will look at tooling up with a router table when I start my next build. It’s definitely starting to add up now.

I decided to re-loom the while bike because of the mo unit and the new dash. It would have been difficult to make the original wiring work cleanly and would have ended up with lots of joins and sub looms. I’m planing to put the whole lot into heat shrink but wanted to get the housings in place first so I know where to terminate them all.
 
Random question to everyone following the build, I’ve been trying to find some high current plugs for the battery outputs. I have an SB350 Anderson plug but it’s massive, and there aren’t any good waterproof panel mount sockets for these so don’t really want to use it.

Can anyone suggest a smaller panel mount plug/socket solution that can carry up to 250A? It needs to be compatible with 00 (70mm^2) cable.
 
Well, the SB175 is UL1977 rated for 280A (table at end of post copied from Andersonpower), and IIRC it's about half the size of the SB350 (still pretty big). But the largest barrel contacts for it only go up to 1/0.

What kind of waterproofing are you after? WP the contacts from behind (wire entrance), or only protect them from in front (when not in use)? Or something else?

The 175's get used in trailers and other environmentally-exposed things, so I've seen some panelmount stuff for those that *ought* to be WP for that kind of usage (but dont' know if they really are).

Would a 3D printed part for the mount be an option? If so, the WP boot / cover / gasket can also be made by printing a mold to cast them with in silicone.





SPECIFICATIONS​

ELECTRICAL
Current Rating AmperesUL 1977CSA
• SB®5012050
• SB®120240130
• SB®175280175
MECHANICAL
Environmental Protection
• SB®50, SB®120 and SB®175IP64
Wire Size RangeAWGmm²
• SB®5016 to 61.3 to 13.3
• SB®12010 to 15.3 to 42.4
• SB®17512 to 1/03.3 to 53.5
 
Why do you want to use 70mm².
I have a QS10kW Hub motor drawing 400A during acceleration from the 21S100Ah battery, all is wired with 35mm² and does not get hot during normal drive.
If I stay in the 10kW normal motor rating, my 7kWH battery cant deliver 150A for about 30 Minutes, and only therefore I have choosen the wire size.
 
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Well, the SB175 is UL1977 rated for 280A (table at end of post copied from Andersonpower), and IIRC it's about half the size of the SB350 (still pretty big). But the largest barrel contacts for it only go up to 1/0.

What kind of waterproofing are you after? WP the contacts from behind (wire entrance), or only protect them from in front (when not in use)? Or something else?

The 175's get used in trailers and other environmentally-exposed things, so I've seen some panelmount stuff for those that *ought* to be WP for that kind of usage (but dont' know if they really are).

Would a 3D printed part for the mount be an option? If so, the WP boot / cover / gasket can also be made by printing a mold to cast them with in silicone.

...
Thanks Amberwolf. The reason I grabbed the SB360 is it was the only plug I could get to support 70mm^2 wire, which I've used through the HV system.

I'd like to put some kind of weather-proof panel mount socket/s on the top of the box so I can quickly disconnect it for maintenance. I really don't want to chance any water getting into the traction pack enclosure when I wash the bike or if it gets caught in the rain.

Incidentally I managed to track these down today and they are a very compelling size. This is the type of thing I had in mind, but was hoping to see what some others on the forum may have used:

Why do you want to use 70mm².
I have a QS10kW Hub motor drawing 400A during acceleration from the 21S100Ah battery, all is wired with 35mm² and does not get hot during normal drive.
If I stay in the 10kW normal motor rating, my 7kWH battery must deliver 150A for about 30 Minutes, and only therefore I have choosen the wire size.

Dominik, some of the references I used for wire sizing suggested 2/0 gauge (00) for anything over 200A, and most plugs rated for 250A use 70mm cable which is why I went this size. There's a lot of conflicting ratings and advice so I picked the most conservative one I could find for electric drives (I really should have just calculated it):

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The motor tops out at ~220A burst - but you're right, it wont be drawing peak current for long periods. I'm sure thinner cables would probably support this with minimal heating, but I didn't have much practical experience with high current cable performance. I thought it's a negligible cost and weight increase for the short lengths from the battery pack to the motor controller so I don't mind oversizing it to minimise any introduced heat in the battery box. Most of the runs will be packed into enclosures and run close to electronics so it won't have much opportunity for convection cooling. It was a very conservative decision, and maybe not right one, but I already have all of the cables and crimps done for it.

I'm running much thinner wires for the charger and DC converter (6AWG for charging, 10AWG for DC converter).
 
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Random question to everyone following the build, I’ve been trying to find some high current plugs for the battery outputs. I have an SB350 Anderson plug but it’s massive, and there aren’t any good waterproof panel mount sockets for these so don’t really want to use it.

Can anyone suggest a smaller panel mount plug/socket solution that can carry up to 250A? It needs to be compatible with 00 (70mm^2) cable.
Check out the RADLOK series.
 
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