Endless Sphere

Powervelocity Controllers use Sinusoidal Commutation, not FOC (Field Oriented Control). The Sabvoton that I have is FOC as are the PhaseRunners. There's a world of difference in the way they generate sinewaves and in the feature sets they offer. https://www.motioncontroltips.com/faq-whats-the-differ...

Justin has measured saturation on a number of motors, there's an old thread on the subject. http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=14494 It's hard to saturate a motor instantly due to the inductance of the winding, unless you have infinite voltage to drive it with. Justin found it ...

Sometimes we want to use a Topeak trunk with some regular saddlebags. The trunk has some small fold-out saddlebags but they aren't very large or heavy duty. Unfortunately the trunk sits too low and the saddlebags need more room to clip to the bars. So I whipped up a variation of my earlier design to...

I saw the announcement about the bridge. Very interesting.

I recall reading about Eric of Lunacycle riding across the Golden Gate bridge at night during a big storm. Quite the adventure.

Working with closed systems is so frustrating. Hence one reason most folks on ES use DIY or modified setups. I think undercharging the battery to make it last longer is silly. Use it. After several years of use replace it. Hobbling an already marginal system is not worthwhile, in my opinion. The onl...

OK no time now, will parse later see if specific answers are there to see if my understanding is better. You have to model your actual data to get specific useful predictions. Generalizations don't get you there, even if they are all correct for some situations. Well when choosing and sourcing the ...

PETG is a good choice. I haven't tried TPU yet, have heard it can really bond to the PEI and create problems. PETG bonds pretty well to PEI as well, damaged one build plate that way.

You have to model your actual data to get specific useful predictions. Generalizations don't get you there, even if they are all correct for some situations. You need enough voltage to: 1) overcome back EMF for the speed you are going and have enough voltage left to both: 2) overcome resistive losse...

It's not like I want to climb that hill at 25km/hr. So, if back EMF limitting the current isn't the issue reducing torque, there has to be something else on my bike reducing the current at lower battery voltage. If I read all comments correctly, there is no electrical limitation that explains such ...

At very low speeds battery voltage is not much of a problem because back EMF is very low so full torque can be generated. As speed rises the ability to generate the same torque falls off due to back EMF.

What they told you isn't wrong, it is just part of the whole picture.

This thread started with an observation about reduced torque due to battery sag. Clearly that is an example of this. There are many ways to think about these electromechanical systems. Some of them lend themselves to understanding more than others. The back EMF of the motor fights the battery voltag...

Lots of good info here, but the motors are the same (as was mentioned). So referring to one as a 36V motor and the other as a 72V motor is confusing. Might be better to edit it and call it the 36V system vs the 72V system. And you can get more performance out of the same motor with a 72V system... T...

The simplest solution is to avoid using the end of the battery capacity where sag becomes a factor. Increase the capacity of the battery by paralleling additional cells. They can be tied in so the BMS, charging, etc remains the same.

I checked, he plans to use them so that didn't help. I may have some other 6S that I should dispose of, not sure. They may not be a good fit for you, 25V full charge works for 25/50/75/100V but skips over some other desirable voltages. I also have a 14S balancing charger that I haven't used in awhil...

Great.

I gave some lipos to a friend, he isn't using them, perhaps I should see if he still wants them. Mostly 6S5AH Turnigy. What are you looking at using?

I see 2 possible options to always get the maximam possible torque. 1. Use a boost converter so that the motor always get's 40V. This has the disadvantage that the current drawn from the battery will increase. If we consider The 40V * 8A example, that's 320W Assume the converter efficency is 90%, t...

Voltage sag means higher amps required just to get the same power. Keep the voltage higher, get your power at lower amps, less stress, more efficient less waste as heat Raising battery voltage lowers battery current for the same power. However motor voltage/current don't change for same power. Cont...

Voltage sag means higher amps required just to get the same power. Keep the voltage higher, get your power at lower amps, less stress, more efficient less waste as heat Raising battery voltage lowers battery current for the same power. However motor voltage/current don't change for same power. Cont...

Welcome to ES. Yes torque often changes with battery voltage, not directly but due to consequences. It is Normal. Torque is (directly proportional to) motor current. Max motor current is from (battery voltage minus back EMF) divided by system resistance. Back EMF is proportional to speed (and motor ...

RadCity.jpg A great looking commuting machine. Clearly some people want to argue rather than add real value to this thread or to ES. There is no requirement that we prove anything. This is not a debate. The experience of maintenance and reliability of different drive system types are well covered e...

I just tested the throttle onset and it does have a little more deadband than some, but not all that much. We could adjust the position of the paddle on the half-twist and change the feel that way to some degree. A more programmable controller would really open things up for adjustment. Traditional ...

It should have a significant dead travel, that's standard. I believe the point is that your motor springs into action only when you really want it to, not because you accidentally moved the throttle a little when you were wrestling the handlebars etc. Perhaps, however I've not seen a super-wide low...

I recall a thread years ago where a guy wanted to climb hills faster. He bought an Optibike for 15K or so and knew he had the best there was. Then he went on a ride with some other folks and was totally blown away by a DIY direct drive hubmotor bike that didn't even have a pedal chain. Putting some ...

The clear is nice. I wonder why they dropped it. The black seemed better than the stainless steel for my Diamondback. Each build is different.

The one I bought is black, stainless was also available. My older ones are dark tinted clear.