brushed vs brushless

[mnplus1556]

what are the advantages/disadvantages? is one more efficient?

also, what are the best kind of batteries now adays and from what site?


thanks guys

 

[neptronix]

Haha...
One is more efficient than the other... sometimes... other times not :lol:

Batteries? depends on your needs and what you're trying to do. That's as vague of a question too. It's like asking which car is best.

What kind of range are you looking for? what kind of speed? do you have hills? will you be hauling stuff?

 

[Farfle]

It sure depends on a loooot of variables... how big, how heavy, how fast and how much you are looking to spend.

For example, Ebike sized stuff? Brushless is a near no-brainer, but for car and motorcycle sized stuff, brushed can be a good setup for cheap horsepower. it all depends on what you are planning to do. As far as efficiency goes, it also depends on the motor design, brushed motors like the Lemco and Agni can be more efficient than most poorly designed chinese brushless motors, on the flip size, the most efficient motor in the world IIRC is brushless (Csiro).

The same applies for batteries, how much for how long and at what cost?

for ebike sized stuff, ping makes a good low-C rate pack that are pretty reliable and have a great cycle life. Headways are slightly better discharge wise, but can get bulky in a hurry, they also have a decent cycle life. Cell-man at EM3EV.com makes an excellent A123 26650 pack that is awesome for high-cycle life, high-discharge and ok energy density, but big packs can be a little costly (Worth it, as is the rest of the stuff he sells). Turnigy packs are an awesome bang-for-your-buck battery, lots of discharge capability, super modular and very lightweight. Cycle life can be in the mid hundreds if treated right but they will explode and burn your house/workplace/apt down if you mistreat them.

 

[Farfle]

nep beat me to it, we need more info man.

 

[spinningmagnets]

Brushed controllers are sometimes cheaper than brushless. Whatever voltage a brushed motor is designed for, they seem to work well enough using about 12V more, however...when you start using 24V or 36V more than the brushes were designed for, they die fast. You will become an expert in changing brushes and breaking them in.

BrushLESS motors can use a wide range of voltages. Hub motors that are sold as 36V kits, have been run on everything up to 100V. As long as you keep an eye on the heat (mostly affected by amps rather than volts), high volts are OK. The controllers are somewhat more expensive.

Each has their strengths and weaknesses, but...don't automatically laugh at brushes...Luke used a brushed Agni to apply E-motorcycle power to a race E-bike.

As a general rule, brushless can be a little more efficient.

 

[amberwolf]

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=37326&hilit=brushed+vs+brushless
http://www.endless-sphere.com/forums/search.php?keywords=brushed+brushless&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
etc etc

 

[dogman dan]

In general, the current state of the art is a brushless motor, often a hubmotor, and some kind of lithium battery.

Brushed is cheaper, and can still be a good choice when the rides will be short enough for less efficeincy of a brushed to not matter. But usually it does matter, and so more and more, you don't see brushed except on toys. Brushed will make about 20% more of the battery into heat.

A pretty typical setup for a longer commute, up to 20 miles range, is a 36v brushless hubmotor, 20 amps 36v controller, and a 36v 20 ah battery. That gets you into a long enough range to actually do without a car at all for many. In general, once you get out of school in the USA, your job is never going to be 5 miles from home. So you need some range, and a battery safe enough to charge at work to make it happen.

 

[mnplus1556]

Thanks for all the replies. And i was looking into buying a magic pie hub motor. I would run it at 48 v for about 1000 watts. Would u guys suggest going with magic pie? I just want to go like 20-25 mph. I wanna be able to pedal with the motor too. And as for the battery, i would like to be able to go about 20 miles. From looking online, id prob need bout 15 ah right? So would i be able to get a pack for under 400? I was looking at this site: bmsbattery.com. anyone ever buy from there before? They seem to have good prices...

 

[mnplus1556]

Oh and no, i live in the suburbs of Chicago so no big hills

 

[Drunkskunk]

A Magic Pie is a heavier motor than you need for what you want. Nothing wrong with it, but a cheaper 9C/MXUS/GM 901/Clone/Ect motor will do 25mph+ at 48 volts on flat ground.

As for the battery, don't cheap out on it. A good battery is far more important to an ebike than a good motor. Sure, that sounds counter intuitive, but a bike will only be as good as the battery that powers it.

You can search for people's expeirance with BMS battery here. Many unhappy customers for various reasons. It would very much Not be my recomendation.

And yep, 48V 15Ah battery would be just about right for a reliable 20 mile range, especialy with Chicago style headwinds

 

[spinningmagnets]

Whether you get the Magic-Pie or something from cell_man, get the controller, motor, and throttle from the same supplier, so the plugs will all match.

If your planned commute is pretty flat, consider the MAC geared-hub from cell_man using 36V. http://em3ev.com/store/index.php?route=product/product&path=36&product_id=55

The 8T motor will provide 25-MPH top speed on a 26-inch wheel at 36V, the 10T is slower, the 7T is faster.

 

[Farfle]

+1 for a cell man kit. Excellent quality stuff that's open for mod-ability later.

 

[neptronix]

Any of the mid sized hub motors can do 25mph pretty well.

I'd recommend a MAC motor though because i know that your climate gets rainy, snowy, etc. MAC/BMC motors are more resilient in situations like that.

It can also take more power later on.

 

[iperov]

brushed vs brushless
muscle power win !

 

[Farfle]

brushed vs brushless
muscle power win !

TBH, human horsepower output is kinda lame... a 6 lb 250w geared hubby the size of two fists can kick the crap out of 99% of the worlds population. And for the other 1%, an 11lb motor the size of a pie dish can easily destroy any pro cyclist. There is a chart showing sustainable power over a given time for an average joe, and a "first class athlete". Its a little pathetic. Sadly, I think machines got muscle power beat on this one.

 

[Drunkskunk]

Muscle is so much less efficent that an ebike that we sould be embarased as humans for wasting so much energy just walking.

Consider it takes around 40 watts of energy to grow, harvest, transport, store, process, deliver, and cook just 1 watt worth of food. Then your body is only able to absorb around 80% of the energy from the food we eat. And our bodies are only around 25% efficent, so for every 1 watt of work we do, it took something close to 200 watts of coal, oil, and/or nukes to produce it.

contrast that to an ebike. The power grid is around 50% efficent, your charger is around 90% efficent, and a hub motor is around 80% efficent. So for every 1 watt of work done by an ebike, we needed 2.78 watts of coal, oil, and/or nukes.

I have no idea where it is now, but I had found a study that showed driving a small car at (something like) 30mph was more efficent and less enviromentaly damaging than walking the same distance.

 

[iperov]

so I recommend you grow more fat on your legs and ride with motor

 

[dogman dan]

On the other hand, if you eat enough "Chicago food", you could stand to burn calories at a rate of 50-100w for an hour a day. Might not lose that much weight, but you'll keep your heart in better shape.

Any decent direct drive hubmotor kit will work fine, or a more powerful gearmotor like a mac or bmc. You can pedal along with the motor on either kind, direct drive or gearmotor. Select a speed, and hold the throttle there, then pedal up about 1-2 mph more speed to extend your range without blowing out your guts pedaling.

48v 15 ah or 36v 20 ah battery. Budget $600-700 for a really good battery. Either one will have about 750 watthours, yet still be small and light enough to carry ok. Rage will be 20-30 miles depending on speed. To get 30 miles, you'd have to ride pretty slow, 15-16 mph. But you'll have 20 miles at 25 mph for sure.

 

[iperov]

Muscle is so much less efficent that an ebike

I think white(fast) muscles is really low efficiency
but RED(slow) muscles work on oxygen and fat, consumed from whole body, and can be activated by riding e-bike only, because very important never enable white muscles and provide "lazy pedaling" all time, so we can improve e-bike efficiency by lazy pedaling on ~30kmh

sry bad englihs )

 

[mnplus1556]

Hey u guys, all this efficiency stuff is actually very interesting. I love tht kinda stuff. I remember a few years back i cam across like an essay pdf file, i think it was on this forum, that compared the ebike to regular pedal. Like which was more efficient and consumed more resources and stuff like tht. It covered like everything that it took for both. Anybody know what im talking about or know where i could find this?

 

[wesnewell]

This kit with 15ah of 12s rc lipo will get you a top speed of ~28mph, and a range of 20 miles at 25mph or 30 miles at 20mph.
http://www.ebay.com/itm/48V1000W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/380576606219
15ah of 20C 12s lipo, rated for up to 300A, will cost you ~$250. A 12s charger and PSU will be another $100.
Or you could get a 15ah lifepo4 for a little more.