Making the puzzle fit

Started yesterdays work with welding the new controller mount. I decided that it was better to use the existing mounting holes in the motor than to build something around the motor, especially since fitting the battery packs and all leaves very little space around the motor. So I made a bracket that mounts on top of the motor. To fit the M12x1.5 screws I had to mill the heads down on them to be low profile enough to not protrude from the mounting holes.

This mounts rigidly to the motor and with the threaded M6 holes for the controller to mount to everything is snugly and firmly in place.

One advantage to mounting the controller like this is that I can shorten the phase cables quite a lot leading to less losses.. even though the cables are thick enough to withstand all the current the evant should need in the future – less is still more in this case.

Time for the next piece of the puzzle. Since I don’t have all the parameters for the plasma cutter perfectly dialed in yet there is quite some slag buildup on the parts, requiring some grinding and sanding to get them ready for welding..

This is where the battery box is going to sit that’ll house one of the two battery packs in the evant..

.. and this is what it’ll look like from behind. Quite awesome if you ask me.. Still everything needs primer and paint so the warning symbol won’t be as visible, but I’ll try to remedy that somehow..

And this is how the battery sits inside the machine..

I want the pack to sit as far forward as possible to make sure it gets as little abuse as possible from the wheel and whatever debris that might throw at it. I’m going to make a side plate for the battery compartent to protect it further..

The second battery pack is going to go the other way in the machine, sitting as far forward as possible in front of the motor.

Something like that. I’ll add padding to the cover to push the packs firmly in place and to cushion it somewhat – even though the batteries themselves should be able to withstand quite some abuse.. (hopefully)

The only problem now is that the packs actually won’t fit under the “hood” – which is also the mount for the seat, so..

Getting the grinder out and squaring up the problematic part. I just love working with steel, it’s such a forgiving material. If something’s wrong, just cut it up, make a new part and weld it all together, and it’s strong as ever! Add some paint and it looks like new..

So with that modification the battery fits in the machine. Now it’s just a matter of making the pieces I need to cover all holes I’ve made and welding it all together.. After that I need to take care of the electrical wiring, adding the 12V DC-DC converter and installing the BMS displays (whenever I get those from China).. So, quite a lot more to do but the hardest part is done I guess..

So far it’s been a super easy and super fun project.. Let’s just hope it works when all is complete.


Fitting the battery pack in the evant

So, when everything was installed and fitted I realised there was only 200mm where the batteries needed to go, and the batteries are 230mm wide.. Hmm.. Well..

I started with removing the controller and the controller bracket but still the batteries won’t fit side by side.. So I tried a few placements and some could fit the battery pack but parts of it would interfere with the rear wheels when turning, other placements wouldn’t fit at all until I found one that fit..

To make sure everything fits height-wise I put the seat mount back on the machine. There was some interference so I had to chop it up a bit..

Cutting and grinding discs on the angle grinder has a way of setting things on fire.. mostly me, but today all that caught fire was my gloves.. =)

Some steel removed from the inner side of the seat mount and now it all fits with margin to spare!

Since I got rid of the mount for the controller and since I need some brackets for the batteries I rigged the plasma cutter to cut some steel.

After a bit of fiddling due to the steel sheet bending (I need a THC) it finally made a puzzle!

Tomorrows task will be cleaning these up and welding them to something that looks kind of like this..

After that the batteries should fit and the controller should be rigidly mounted to the top of the motor.. If that happens all that’s left is to build the final version of the throttle, remove all spare wires from the wiring harness and route everything to the dash.. Oh, yes, I need to mount the DC-DC converter to get 12V from my 110V battery too, and wire in a main switch.. Well..


First test run of the evant

And there it is:

It’s finally moving, powered by the electric motor!

I connected two of my emergency get-back-home ebike batteries of 48V 4Ah with a maximum current output of ~15A. That’s way to little to drive the QS-motor that’s in the Evant but still it runs. Don’t want to run it for too long though since I haven’t calibrated the valve for forward/backward motion and have to keep the P-brake engaged for the machine not to roll off the lift it’s on – which makes for quite some resistance in the hydraulic system.

The twist trottle is quite unusable in the Evant so I’ve made a quick hack for a system to control the RPM of the motor:

It’s just a 10k potentiometer and a switch. The plan is to set the RPM with the potentiometer and use the switch as an on/off switch to turn the motor off whenever it doesn’t need to run. That way I won’t need to adjust the RPM of the motor to turn it off, which I’ll want to do every time I’m standing still and not working with the machine.

Just made a quick and dirty connection to try it out and it works just as expected. So the next step is to make some kind of enclosure for it, put a better cable on it and a proper connector.


Mounting the motor and controller on the evant

So, when test fitting the motor I realised the bottom side of the motor isn’t flat so it needed a spacer to sit flat on the motor mount.

Fortunately, now that I own a CNC plasmacutter, making a spacer like this is just a couple of minutes of work.

This fits perfectly on the motor. Welded the spacer to the motor mount and used the plasma to cut the inner hole out of the mount as well, and after some paint..

.. it was time to mount the motor in the Evant again.

I decided it was way to much work trying to mount and unmount the motor when bolted with the M12 bolts from underneath so I welded the holes I had drilled and drilled and tapped holes for M8 bolts instead. This way I can remove the motor without the hassle of fighting with the hydraulic pump all the time making life much easier for me! 4x M8 should be strong enough to hold the motor in place easy.

With the new, shorter belt the position of the motor is perfect. I can adjust tension in both ways and get a properly tensioned belt. So, with this confirmed it was time to mount the controller.

On goes the controller mount using M6 screws.

And on goes the controller. The wires between the motor and controller are way too long and I’ll shorten them once I’ve test run the motor.

When measuring I’ve got about 20mm too little space to fit my batteries, so that’ll have to be remedied somehow.

The next step is to figure the wiring out. Most of those aren’t going anywhere on my machine so I’ll disconnect them from the connector and make a new wiring harness with only the leads I need. All I really need is the mains switch, the speed input and the hall sensor and thermistor input signal wires.

So, hopefully I’ll be able to spin the motor up tomorrow. I’ll just have to make a wiring harness to get 96V into the controller.. and a better throttle..


Finishing the battery pack for the Evant

When all the copper plates were welded to the cells and all the BMS wires were added..

.. it was time to finish the battery build. I printed the box and the TPU divider and put the cell pack in it’s place.

I’ve bought a couple of ANT 300A BMSes to protect the packs and they come with screw terminals mounted.. so I pressed the same type of terminal on the negative leads of the pack..

After that it was just a matter of adding the BMS.

.. connecting all the wires ..

.. and pushing the positive and negative power feeds through the TPU grommet..

To finish the packs I soldered EC5 connectors to the power leads and printed a “connector” to house the 3 connectors to make it easier to connect the battery pack to the Evant and impossible to connect the wrong leads shorting a battery pack out..

So.. now I’ve got one complete battery pack of 26s10p which gives me a 96V pattery with 30A capacity yielding a whopping 2,9kWh. This is what I’m going to use for testing. I’ve got enough cells to make one more complete setup so that I can charge one pack while using the other. Hopefully I’ll be able to run the machine for at least half an hour on each pack.. Doing the math :
Avant original motor power: 10kW
Estimated mean power output: 33%
Estimated mean power output: 3.3kW

That should give me almost 55 minutes of run time on my pack, but to have some margin let’s say 45 minutes. Charging the pack at 30A (1C) would take more or less an hour to charge the pack fully, so it might be possible to get back to back running.. otherwise I can build one more pack to have two packs charging while I’m running the third. That should give me continous driving with pretty good margins but it’d cost me approx $700 to build.. We’ll see how it works, only testing will tell..


Plasma cutting parts for the E-vant

So, at first I finished building the CNC plasma by adding all the electronics and controllers..

I printed a box for the controller and raspberry pi, added all the cables, a relay for the plasma trigger and closed it all off.

I had to do some work with Klipper to get it to work for the plasma cutter. It’s designed for driving 3D printers and making a config that works the way I wanted to was a bit tricky, but as I suspected it was totally possible.

So, after configuring Klipper and writing a custom POST processor for Fusion 360 it was finally time for the first cut..

I placed the CNC plasma on 4040 profiles to get it off the floor, filled a frying pan with water and put a sheet of 1.5mm stainless on the pan.. and off we go!

It actually worked surprisingly well!

Without tweaking it actually cuts pretty cleanly but there is much room for improvement! So, time to put the plasma to work!

I made a shelf for the motor controller for the Evant in CAD, did a quick CAM processing increasing the feed to 2000mm/min and uploaded it to the plasma.

And of course, when I took the video the controller failed. I did some more runs and it seems the X stepper controller has a tendency to reset every now and then.. And then I realised I’m using a 60W 12V PSU.. That means I’ve got a total of 5A to run all the steppers, the controller and the pi.. which was a bit too little. After switching to a 200W PSU everything worked fine!

I made two side walls..

And of course when it’s CNC controlled there’s room for.. well.. flare. 🙂

After tweaking the feed and amps of the plasma I’ve got it to where the cut parts fall off the metal sheet. Sure, there’s room for improvement as I get quite a buildup of steel on the back of the part but a quick runover with the grinder solves that.

I just had to tack weld the parts together to see how well it fits.

It’s not as precise as the mill but MUCH faster, and cuts 3mm steel sheet in seconds!

I’m going to turn the motor 180 degrees to get the cables poking out the back and the controller shelf is going to be turned 90 degrees to mount at the left and front sides of the motor.

Something like this..

We’re getting closer to testing the Evant. Today I got the new belt which I hope will fit the new pulley and motor location.. But this weekend I’m going to focus on building the kitchen so we’ll see how far I get with the Evant. Considering the snowfall here the past week or so it’d be really good to get it running soon..


Evant – battery builds

Ok, so the snow has started pouring down outside and I really feel the need for the Evant to run.. so this week I’ve been tinkering with the battery..

Since the motor/controller has a peak consumption of 200+ amps and the cells I’m building the battery from are able to push 35A continously giving a whooping 350A for the pack – I need something better than nickel strips to carry the current in this pack.. so I got the tip from a guy on a discord server to use copper sheets..

Copper conducts current 10-15 times better than the nickel strips I’ve been using, probably more since they’re more often than not just nickel plated steel strips.

The thing with copper though is that it’s virtually impossible to weld with hobbyist equipment. That’s where RioCole showed me a method to get the copper sheet welded to the LiIon-cells using nickel plated steel strips as a conduit.

First of all I needed to cut the copper sheet to shape. It’s easy to do with a pair of scissors but I wanted better looks for my connecting copper. The design I make for the cell holders also make the poles of the cells sit recessed about 0.2mm, which requires that the copper sheet is able to bend down to weld properly.. to do that without distorting the entire sheet I need tabs that bend down which are hard to make manually..

Then I realized that my vinyl cutter should be able to at least scratch the cu sheet.. At first I had trouble with the cutter not gripping the copper sheet properly which made it twist, but after taping it down to a piece of vinyl it works flawlessly!

I started out with some test pieces..

.. and then went for a design with a cut Z-slot..

At first I thought that putting nickel strips in series would give me better current capabilities, but it was so much easier to get good welds with short pieces of nickel – so that’s what I did..

Starting to get the hang of welding the copper sheets to the cells. All connections are good and tested. The problem now is that the ANT BMS I got for this pack was too big to fit the casing I printed earlier.. so I had to redesign the battery box..

This beast is currently on the printer so an update will follow when it’s done printing and the battery is fully welded and ready for finishing..


E-vant: Remdrevsbearbetning

Så, i torsdags fick jag så äntligen remdrevet till elmotorn.. Det enda problemet var att jag fick det obearbetat då ingen vi kunde komma på att fråga ville ta sig an arbetet med att skära splines åt mig. Så, då får man helt enkelt ta och göra’t på egen hand då..

Jag började med att spänna upp remdrevet i min lilla manuella fräs för att plana av 2mm från botten..

Det gick jättedåligt, så jag gav upp den tanken rätt snart.. istället lade jag till en extra operation på CNC-jobbet och spände upp och mätte in remdrevet på CNC-maskinen..

Jag byggde CNC-fräsen för att kunna fräsa skivmaterial och aluminium. Stål hade jag aldrig en tanke på att jag skulle lyckas fräsa men det visar sig att stål nästan är mer lättfräst än alu.. men jag kör väldigt försiktigt. Här har jag en 8mm pinnfräs som tar 0.2mm ingrepp, 2mm i taget i 500mm/min hastighet.. (Note to self)

Efter att fräsen planat av toppen på remhjulet är ytan så slät att man inte kan känna några spår ens med nageln. Galet!

Det blev många operationer och många varv då det är 5 olika diametrar på olika djup som ska fräsas i hjulet.. Efter en lång väntan var första sidan klar..

Då var det bara att spänna upp och mäta in andra sidan och köra vidare..

Jag lät fräsen göra anvisningar med 60 graders delning för att veta hur jag skulle skära splinesen när det var klart. Använde en 3mm pinnfräs men med facit i hand skulle jag gjort spåren djupare för att få en bättre anvisning att gå efter..

En 5mm spårkilsreamer fick göra jobbet för att skära splines. Detta moment hade jag aldrig testat förr men det var tämligen enkelt.. Bara i med reamern där jag gjort en anvisning, i med kalaset i pressen och..

.. några försiktiga drag senare så hade man ett spår.. Sen var det bara att lägga i en shims, köra ett varv till och upprepa 6 gånger runt hela hålet.

Och vips hade man ett remhjul med splines..

Eftersom att anvisningsspåren var lite korta så blev inte delningen helt perfekt, men efter lite bearbetning medelst fil så passade hjulet såhär bra på motorn..


Och för att se till att hjulet inte lossnar hade jag ett par C-clips som får agera låsring.

Klart över förväntat resultat, 100% lyckat faktiskt.. så om nu hjulet är för litet så kan jag enkelt bearbeta ett nytt för att kunna dreva om!

Fortsättning följer..

E-vant: batteripack och motorfäste

Så blev det äntligen helg igen med lite tid att fortsätta bygget av E-vanten.

Batteripacket som hittills enbart funnits i CAD har nu hoppat ut i verkligheten:

Inte 100% färdigt men tillräckligt klart för att testa i maskinen. Det svarta är PLA+ och det orangea är TPU, alltså typ gummipackning. Stabila som tusan och riktigt snygga med, om jag får säga det själv.

Så, första steget var ju att testa om allting kommer att rymmas i maskinen efter konverteringen, så det blev att placera komponenter..

Det ser mycket lovande ut..

Kontrollenheten som är framför motorn kommer monteras på kåpan där sätet sitter och batterilådorna har cirka 5mm tillgodo – restriktivt räknat – innan de tar i upptill.. Detta blir klockrent! Om kapaciteten blir för liten skulle det gå att bygga längre packar med fler celler men förhoppningsvis behövs inte det.

Så, nu när komponentplaceringen är “klar” börjar det vara dags att göra fästen för delarna.

Caddade upp och printade en hålmall för motorn. Sedan borrade jag 13mm hål för fästskruvarna (M12x1.5 – som jag inte har) och skar ut ett sjukt runt hål för remhjulet i mitten med plasman. Fruktansvärt smidig maskin plasmaskäraren alltså!

Med nya motorkuddar var det lite bökigare att få dit motorplåten, men med lite vilja och våld så gick det bra.

Motorn passar klockrent. Här inser jag att jag inte kommer att behöva någon distans mellan motor och motorplåt. Samtidigt inser jag att jag inte kommer att kunna dra åt motorkudden som sitter vid motorn efter att motorn är monterad.. och jag kommer inte kunna montera motorn med motorplåten på plats.. Hmmm.. Tre sekunder senare insåg jag att motorkudden är skruvad både upptill och undertill, så det är ju inget problem alls. 😀

Nästa steg blir att börja tillverka batterifästet på maskinen. Det ska bli en ram av alu eller plast, och sidor av rostfri plåt.. Det är planen, men planer är ju till för att ändras.

Remhjul till motorn är beställt men jag hittade ingen som ville göra splines åt mig – så jag har även beställt en brotsch för att skära egna splines. Det har jag aldrig gjort förut så det blir intressant. Tror att jag fuskar med fräsen för att få delningen på 60 grader rätt..
Även remmen är beställd men hade tyvärr leveranstid i mitten på februari så innan dess kommer jag inte att kunna testa maskinen.. Förhoppningen är att ha BMS:er och klara batterier och rubbet monterat när remmen kommer så att maskinen iallafall ska gå att testköra då…

Fortsättning följer.