Recent content by nsasch

Yes, I'm hiding a project, but that's because there's nothing to share yet. My spec is 65-70mph on 6% grade, reliability, and 200 mile range. I've finished basic calculations, assuming a decent drag coefficient for side-by-side seating of 2 people, and it seems possible. I'm waiting for good...

This topic excited me when I first saw it. I've been meaning to start a thread on dual motor drives, but I had no question and no profound statement or new data. I still don't know what this thread is about, but.... dual motor drives! So, for a time far in the future where time and money is no...

Is this really true? I'd worry about dying cells. If one cell's Ri goes way up due to an unpredicted problem, it could be discharged to 0V while the cells around it are fine. Upon charging, it will blow up. Just by the physical nature of parallel connections, it would be difficult to disconnect...

Current flowing to a dead cell would be a very bad thing though, resulting in fire. Am I missing something? If a cell has problems, and it gets drained very low, lower than the neighboring cells, it's voltage could reach 1V, for example. While charging a bunch of cells to 4.2V, while the cells...

That thread was helpful, thank you. I think this is a common problem with all Lithium chemistries, but if you combine cells in parallel to get your capacity, and _then_ place them in series for the voltage, you can charge to 4.2V on sets of cells with a simple charger like the Mastech or any...

I second that. Most LiPo cells can charge at 1 or 2C, but I have yet to find a charger that can supply that sort of current for high voltage packs (24-48V). I would switch to LiPo in a second, if I could find a charger that can charge 2kW-h in an hour. Long trip? Put your batteries in a...

Those clamps really make things easy, even if they're not so easy to manufacture. I like this build. At this rate, it should be finished very soon. By the way, is the angle between the "foot" of the mount, and the rest, adjustable? Right now the motor mount stands straight up from the part...

It's rare to see more than 2C out of LiFePo4, besides A123, even among the high-priced American-made batteries. We can all just wait for EEStor's super-capacitor to come out. That will solve all of our problems. :lol:

If you want to keep your rear wheel, you only have a few options. You can use a mid-drive setup like the Cyclone motor with double freewheel, you can have the motor drive the cranks (more difficult on a trike, with the boom way out front), you can modify your hub to have a left-hand sprocket to...

Ypedal: You might want to either buy a unicycle for practice, or look into using one of your hub motors, with no torque arm, to keep the bike upright when on one wheel.

Well, yes. 500-750W happen to be right in the range of peak efficiency, if this graph is correct. But just short of 500W (100-200) and efficiency drops off very quickly. If you're running low on power, for example, it's almost better to go at 500W than 100W to get where you're going, since...

Miles, I don't know how I missed that program after all my googling and forum reading. Very helpful. Although these graphs are estimates, I think it's safe to say these R/C motors lose efficiency quickly when outputting low power (<750W). For cruising speed, around 40km/h (25mph), I would only...

So, we see RC motors used for high-power, but there's also a good application for low-power, long-range. If it can handle 2000W for half an hour or an hour, it can definitely handle 500-1000W for a day. Matt's recumbent gets excellent range, and 14Wh/mile IIRC, but I don't think that's the max...

The PowerTap hub was wonderful when testing my Cyclone setup. (PowerTap Watts) / (Watt's Up Watts) * 100% = system efficiency (excluding rolling resistance). It's also great for optimizing gearing. The new PowerTap hubs also have ANT+ Sport signals for use with other devices. You can buy chips...

I normally read all of your posts, but only the Catrike 700 posts do I always respond to. So, you've convinced me that you can make a useful motorized Catrike 700. I love the speed of the 700, but using it on roads at high speed is difficult due to very low ground clearance. Speed bumps are...