Having done the mockup for the wheels and mounted the brake rotors and made a mockup for the rear sprocket adapter the next step is mounting the motor.
Since the frame is designed to fit a hub motor and we’re going to use mid-drive motors we need to figure out a good way to mount the motor on the frame. I’ve considered quite a few different positions for the motor but they all have drawbacks. I decided the best solution is to make a motor mount right in front of the rear wheel, making the shortest possible chain line while still keeping the motor as close to the pivot as possible as to limit the unsprung mass momentum of the bike. The tricky part is that this is where the rear shock sits.. So I started by mounting the 200mm shock I’ve got and made the bike sit in the fully extended position on the bench. I then removed the shock, cut the lower shock mounts off and did some measuring.. The CAD turned out like this.
There is going to be a bracket on the left side of the motor too but as of now I’m not sure wether to simply make a motor/shock bracket or to make a new custom endcap for the motor. The right bracket prototype is being printed right now and I’ll use that to check more clearances and get a better feel for the solution. In the CAD I’ve moved the shock all the way to the right to limit the forces on the M8 bolt that holds the shock but where it’s going to go is not yet decided. The upper mount might screw right into the frame or I’ll make it a part of the seat.
I’m going to try to make this modification without welding anything to the frame so it’ll be easier to reproduce if anyone else wants to build a similar ”bike”.
Winter is coming and last winter me and the kid agreed on needing fatbikes to ride on the snow..
Of course they’d need powerful motors enough to propel them through the snow and not bog down even when hitting deeper pockets of powder. At first I planned on building my own frames, but as summer came and went and I didn’t have time to get going I decided to get a test frame to start building on to see if our planned setup would pan out..
So, this is what I got:
It’s a chinese clone of a ”Stealth bomber” type frame, made entirely from 2mm steel, making it both heavy (20+kg) and sturdy. We’ve got 20″ fatbike wheels on there and personally I think it looks sick. 🙂
The rear suspension I just stole from another bike we’ve previously built and gutted, and the front suspension is a 190mm travel air-sprung fork made 100% from chinesium, but it still seems of rather OK quality.
To get enough power to have fun on these we’re going to use LightningRods BigBlock motors, good for somewhere in the vincinity of 14kW. We’re going to build a couple of hefty 72v battery packs with at least 30Ah capacity and using either ASI BAC2000 or BAC4000 motor controllers to translate the battery DC current to pure joy on the rear wheel.
And yeah, there probably won’t be any reason to put pedals on a bike like this, so we won’t. Footpegs’ll have to do. Since this frame is originally built for hub motors and we’re not using that there are modifications to be made. We’re probably going to fit the motor right where the rear suspension sits right now and move the suspension upwards. A single stage 219 chain reduction will translate the power from the motor shaft to the rear hub. Then we’re building motorcycle style seats to go on the bikes too, some kind of twist throttle, hydraulic brakes, probably have to make my own studded wheels, lights (since it’s mostly dark in the winter) and possibly a kickstand..
Well, that’s the plan. We’ll see how it works out and if we get to ride it this winter. As it sits now the frame, wheels and suspension is in place. I’ve got the motors and controllers but no batteries or other electronics needed. Next week I should get the chain and prockets to be able to start manufacturing adapters to mount stuff where it’s not intended to go and I’ll post updates whenever I get around to it.
First I’ll need to do some modifications to the CNC plasmacutter though to be able to precision cut the parts I need for this project, so that’s next..
So, early this summer season I did something really stupid. I replaced the brake pads on my ebike and took it out for a test.. Riding 50m on the street outside our house being a little bit too tired. The bike was in second gear, I thought it was in third so when I pushed the throttle it wheelied.. a little too much.. Tired as I was I slammed the brakes.. both of them.. so when the front wheel hit the ground it was locked sending me over the bars. Never let go so when the neighbor found me in the ditch I had scratches on the outsides of my hands, my elbow was bleeding badly and I had hit my head pretty bad which knocked me out for a bit. Since I was just going to test the brakes I was not wearing a helmet.. :/
When I regained consciousness I was pretty out of it and after talking to my brother a bit asking the same question over and over he sent me off to the ER. A few stitches, a couple of shots and a complete brain scan later I got to go home with orders to REST.. which of course I did not.
My daughter turned 15 this summer and she got an electric moped for her birthday. Since the bike can fit two batteries I of course had to build one from cells I’ve reclaimed from old scrap ebike batteries..
These are Samsung 30T 3000mAh 21700 cells, good for 35A a piece.
Since the moped and charger says 60V I built this 16s10p pack which would fit the battery compartment in the moped easily.. but then I checked the voltage of the charger and realized it’s a 17s system.. :/ So, I had to put an extra 10s cell on top of the pack making the fit pretty tight, but it still works.
I’ve made the pack in such a way that there’s a SuperSoco connector connected to the 60A BMS and I’ve got 2 XT90 connectors that bypasses the BMS so that I can use the same pack on my future LightningRods BB builds..
The problem is that the SuperSoco uses a serial connection to talk to the battery to display the correct charge state and such which makes this pack show 5% charge even when fully charged.. I’ve ordered a connector that should solve that problem, still waiting to test it.
So.. since I didn’t rest enough after the head injury it kind of never got better. I’ve now been diagnosed with ’fatigue’, when the brain kind of gets overloaded way too easily. This can happen after a serious head trauma I’ve been told, so I need to let the brain rest A LOT for some time to come. This totally sucks. I have not been able to ride my bike this summer as my brain has not been able to keep up with offroad riding..
In order to be able to get some 2-wheel action me and my wife got one of these each.. not as quick or agile as the Swoop, but it’s super cozy and quite fun to glide around on!
So, it’s been quite a boring summer due to me not wearing a helmet and having a bit of bad luck.. So, if you’re reading this – take it from me.. wearing a helmet when riding is a super good idea, like EVERY time!
Keep safe – have fun. I’ll soon have more fun projects to share!
After running the evant for two charges the controller died. It starts, I can connect to it using the USB dongle but as soon as I give throttle input I get an overcurrent error.
Measuring the phases it turns out that one phase is shorted to B-, typical mosfet failure. QSmotor, that I bought the motor and controller from, was reluctant to send me a new controller even though they state there’s a 1year and 3 month warranty period. Somehow they say I damaged the controller but it’s virtually impossible to damage the controller in this way except when assembling it. In the end they offered for me to send the controller back to be repaired, or pay half the price for a new controller.. I chose to send it back, which it turned out was not a viable option at all.. so..
The problem with buying a new controller at half price is that Shanghai is shut down due to Covid and the factory is closed.. so QS couldn’t really tell me when I could get a new controller, so the Evant project halted..
Until..
I’ve already started planning my next project. It’s going to be a couple of awesome dirtbike replacements.. powerful LightningRod bigblock motors and matching ASI BAC controllers. More on this later. The thing is, I’ve already bought and got the motors and controllers. So.. I started out connecting my 50A VESC to the QSmotor, just to try it out, and sure – it runs. Wierd that the 800A APT96800 controller got damaged from pushing the same amount of power that a 50A VESC can handle.. well well..
For my build I’m going to use the ASI BAC4000 controller. It can handle 400+ phase amps but is limited to 72V max nominal voltage on the batteries. Since I’ve already built the 48V packs that’s going to be utilized in future projects as well, I’m running the Evant on two 48V packs in parallell yielding 60Ah and 2,9kWh. After discussing the matter with mr HV on the HV discord I connected the BAC4000 to the QSmotor and made connectors to precharge and connect the two packs in parallell.
One problem with this setup is that the QS motor uses an encoder to keep track of the rotor position while the ASI BAC only supports hall sensors.
But it turns out the BAC4000 actually handles the motor better in sensorless mode than the APT96800 did using the encoder. 😀
With the APT the motor sometimes stalled, loosing sync, requiring me to turn the machine off and on again for it to regain sync. The BAC4000 hasn’t lost sync once during the hours of use I’ve put it through.
Well, now that the machine runs again it’s time to finish the project. Until now I’ve been driving the Evant with an android tablet in one hand keeping track of the battery status..
The ANT BMS is super with it’s bluetooth connection and app showing all the data you need, but it’s a bit cumbersome driving around holding a tablet all the time.
I got a display that connects to the BMS in the battery..
Printed a sealed backside and TPU gaskets for it..
And viola, the last piece of the conversion is in place! The display shows the voltage of the battery, the temperature of all four temp sensors in the pack, the highest and lowest cell voltages and the current draw. Since the display connects to one BMS in one of the two batteries the actual current going to the controller is actually double what the display shows though. But now I can keep track of the battery status while driving the machine with two hands!
Today I’ve been moving heavy wet snow from our lawn just to test the Evant out. Turns out I can drive it for a little more than 50 minutes on a full charge..
.. and then it’s time for charging. I got two of these Eltek Flatpack 1500 from a friend and they’re able to push a little more than 30A each into the packs.
Unfortunately one of them had a problem with the voltage regulation and died after charging one pack but with these chargers I can charge one set of batteries in approx 45 minutes. This means that with 2 sets of batteries I should be able to run the machine back to back assuming the motor or controller doesn’t overheat.
So now the build is more or less complete.
I’ve got a few panels to remount that I need to repair first but the machine is definitely ready for use again.
Testing the limits of the battery I ran out of juice in the middle of the driveway..
So I had to get the charger and charge it for 10 minutes to be able to drive it back into the garage. =)
When stuff goes sideways like this it truly helps having good people to turn to. The Evant is running again thanks to the awesome help from Captain Codswallop and mr HV on the HV discord. They helped me tune the BAC4000 for my setup and have been super helpful in making the right decisions and making a wireloom that fits my needs. If you want to build a high power ebike or just make any kind of electric conversion I really recommend joining the High Voltage Light Electric Vehicles discord server.
Also, check out the HV channel on youtube: https://www.youtube.com/c/HighVoltageKits
Well, that’s that. I’ll post further updates if the controller or motor fails, but for now this project is more or less finished! Hope you’ve found it interesting!
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.
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..
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.
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..
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..
