Endless Sphere

For 15-20C applications, pouch cells are the right format. 18650s can't support such high discharge rates.

Maybe ask this person:
viewtopic.php?f=9&t=108401

Do you still have any?

Good idea, but... Everything I've read online seems to imply that desat protection is for SiC and IGBT devices only. According to the datasheet for the IRF100p218, the maximum current, even for 10 microseconds, is less than 900 amps. 1800 if you have 2 in parallel. The short circuit current of my e...

No hardware over current It was with the old ones, but with the new current sensors, that's not much of an issue anymore. I have the overcurrent detect pin routed to an interrupt pin on the Teensy, and the overcurrent detection interrupt will have higher priority than everything, including the FOC ...

This is really cool. How does it do up hills? Do your arms get tired?

Yeah it was originally in the normal ebike section, but it got moved here since it's just advertising.

Small batteries in water bottles plus hiding the motor with camera angles can make a conversion look quite clean

Looks good! I really like the black printed battery and controller boxes. I need to print some for my bike. What material did you use? And which orientation did you print them? How do they handle the cold?

.... Was thinking of 25H for my small block size setup with a left side direct drive. Using 25 on the primary side of the old GNG and you can pack a bunch of teeth on a small size sprocket with it allowing much higher reduction ratios. Nice and compact also. How far apart did your sprocket and roto...

Thanks for sharing the link. Most definite, a great way to go on large spiders and sprockets. Heavier Brake rotors cut to share sprocket mount hardware would be trick. Higher kv motors need much larger sprockets than what can be commonly found in kart chain options. What chain are you running. I'm ...

My take on fitting a disc brake and sprocket on the left side:

viewtopic.php?f=28&t=110034#p1611856

Nice parts, I really like the brake/sprocket adapter. Is regen or braking possible on the castle controller? Thanks! Your bike was another inspiration for this project. Unfortunately the castle controller does not have regen. I'm thinking of getting a VESC for the torque throttle and regen capabili...

I wasn't aware that laser could do shapes so intricate and accurate. I thought you'd need to do extensive machining after. What was the cost to get it done? Did you weigh it? I almost think that stacked construction could be adapted to a belt setup running outside the caliper. Yep laser cutting wor...

So no extensive machining required? Did you offset the brake caliper? No I didn't do any machining. I just deburred the parts by hand with a deburring tool and a file. The brake disc is offset by 1/4", so yes I had to offset the brake caliper. I also moved to a 200mm rotor for spoke clearance ...

That looks much cleaner than I've previously seen laser cut, fantastic. Did you have to machine down the hub at all? I lightly deburred the backside of the parts since the laser does leave a bit of a burr on aluminum (steel cuts much cleaner). Otherwise I didn't do any machining. I was a bit worrie...

Grantmac wrote: ↑

Jan 16 2021 9:56pm

Did you make the rear sprocket and mount?

Yes it was all laser cut from 1/8" aluminum.

Inspired by FZBob's RC Mid Drive with Single Stage Reduction , I wanted a similar lightweight setup for the roads with a little more power. By running the chain all the way to the rear wheel, I can get similar motor torque and gearing to FZBob in his middle gears while still being able to pedal alon...

Hi Thud and Arlo1! Cool dirtbike Arlo1. How much does it weigh?

A few weeks ago, I bout a 100+ SPIM08HP from them. Never buying from them again. https://drive.google.com/drive/folders/1E7bgGbxKzkBvIHm7e5A7g1guDpsVqqsP?usp=sharing I'm going to buy the 70 pack of SPIM08HP when it comes back in stock. For $2/cell as long as most of the cells are still around 0.8mo...

Where did you get the printed parts from? That looks pretty bad. I have a printer myself, but I've thought about using online services for some bigger parts that I want, but that quality does not inspire confidence.

There are losses associated with rpm. Hysteresis losses and eddy current losses in the stator (and also the rotor to a lesser extent) increase proportionally to rpm and rpm^2 respectively. So more rpm means more heat, which means you can't just increase rpm forever because you're limited by "ab...

Your motor can't really sustain 9kW, but I also doubt it will take 9kW to maintain 75 km/h, so your range will probably be higher than your estimate. For a 12,5A per cell peak discharge rate, you can go with a much higher capacity 21700 cell such as the 40T which will also help give you much more ra...

33.3V is the nominal voltage for a 9S li-ion battery (3.7*9=33.3), so your BMS will work for your batteries For the 6S battery on an 8S BMS, some BMS will work and some won't. Usually, you'll want the BMS to be advertised as "6-8S" or something like that to make sure it will work for the c...

First, that RC transmitter outputs a RC PWM signal while those motor controllers need 0-5V analog signals. You could use something like the product below to convert the signals, but even still, I'm not sure those controllers will reverse the way you want them to. https://www.amazon.com/NOYITO-Multif...

https://www.modlabupenn.org/2014/07/11/anticogging/ The link above might help answer the question. It's hard to integrate that torque plot over the full rotation, but it does look to be pretty close to zero. The paper linked on that page also identifies cogging torque as having "no DC componen...