Search found 304 matches

by thepronghorn
Feb 25 2021 6:00pm
Forum: Electric Aircraft
Topic: Battery pack selection for self-launching glider
Replies: 7
Views: 167

Re: Battery pack selection for self-launching glider

For 15-20C applications, pouch cells are the right format. 18650s can't support such high discharge rates.
by thepronghorn
Feb 24 2021 3:44pm
Forum: General Discussion
Topic: freerchobby.cc opinions
Replies: 2
Views: 75

Re: freerchobby.cc opinions

Maybe ask this person:
viewtopic.php?f=9&t=108401
by thepronghorn
Feb 07 2021 5:27pm
Forum: Motor Technology
Topic: Another attempt at building a motor controller
Replies: 92
Views: 2194

Re: Another attempt at building a motor controller

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...
by thepronghorn
Feb 06 2021 9:18pm
Forum: Motor Technology
Topic: Another attempt at building a motor controller
Replies: 92
Views: 2194

Re: Another attempt at building a motor controller

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 ...
by thepronghorn
Jan 30 2021 9:44pm
Forum: Stand-up E-scooters and E-skateboards
Topic: Broomstick Number Two
Replies: 23
Views: 726

Re: Broomstick Number Two

This is really cool. How does it do up hills? Do your arms get tired?
by thepronghorn
Jan 27 2021 2:22am
Forum: Items for Sale - New
Topic: Holstedtr's PedalUma Ad Thread
Replies: 12
Views: 510

Re: Stealthy Mid-drives that Do not look electric

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 :wink:
by thepronghorn
Jan 26 2021 1:50pm
Forum: EBike Build Threads
Topic: My attempt at lightweight, torque based EMTB
Replies: 38
Views: 3756

Re: My attempt at lightweight, torque based EMTB

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?
by thepronghorn
Jan 20 2021 5:03pm
Forum: EBike Non-hub Motor Drives
Topic: Trek Fuel - Small block left drive first build
Replies: 23
Views: 1075

Re: Trek Fuel - Small block left drive first build

.... 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...
by thepronghorn
Jan 20 2021 3:30pm
Forum: EBike Non-hub Motor Drives
Topic: Trek Fuel - Small block left drive first build
Replies: 23
Views: 1075

Re: Trek Fuel - Small block left drive first build

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 ...
by thepronghorn
Jan 19 2021 2:47pm
Forum: EBike Non-hub Motor Drives
Topic: Trek Fuel - Small block left drive first build
Replies: 23
Views: 1075

Re: Trek Fuel - Small block left drive first build

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

viewtopic.php?f=28&t=110034#p1611856
by thepronghorn
Jan 18 2021 3:33pm
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Re: Single stage RC left hand drive

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...
by thepronghorn
Jan 17 2021 5:27pm
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Re: Single stage RC left hand drive

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...
by thepronghorn
Jan 17 2021 2:43pm
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Re: Single stage RC left hand drive

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 ...
by thepronghorn
Jan 17 2021 1:53am
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Re: Single stage RC left hand drive

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...
by thepronghorn
Jan 16 2021 10:43pm
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Re: Single stage RC left hand drive

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.
by thepronghorn
Jan 16 2021 4:37pm
Forum: EBike Non-hub Motor Drives
Topic: Single stage RC left hand drive
Replies: 12
Views: 524

Single stage RC left hand drive

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...
by thepronghorn
Jan 16 2021 3:44pm
Forum: General Discussion
Topic: Electric 450 CRF conversion.
Replies: 13
Views: 670

Re: Electric 450 CRF conversion.

Hi Thud and Arlo1! Cool dirtbike Arlo1. How much does it weigh?
by thepronghorn
Jan 13 2021 1:59pm
Forum: Vendor Relations Corner
Topic: Battery Clearing House
Replies: 12
Views: 1159

Re: Battery Clearing House

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...
by thepronghorn
Jan 09 2021 3:35am
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 54
Views: 4111

Re: EKartGo Project

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.
by thepronghorn
Jan 09 2021 12:28am
Forum: Motor Technology
Topic: Extracting maximum power from a BLDC
Replies: 2
Views: 498

Re: Extracting maximum power from a BLDC

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...
by thepronghorn
Dec 19 2020 3:24am
Forum: Large EV General Discussion
Topic: Electric Quad ATV
Replies: 3
Views: 663

Re: Electric Quad ATV

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...
by thepronghorn
Dec 16 2020 5:12pm
Forum: Electric Watercraft
Topic: Solar Party Hut Pontoon
Replies: 1
Views: 371

Re: Solar Party Hut Pontoon

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...
by thepronghorn
Dec 08 2020 6:35am
Forum: EBike General Discussion
Topic: Radio Remote Control BLDC controller
Replies: 2
Views: 445

Re: Radio Remote Control BLDC controller

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...
by thepronghorn
Dec 07 2020 4:07pm
Forum: Motor Technology
Topic: what is cogging torque?
Replies: 72
Views: 5441

Re: what is cogging torque?

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...