Brushless Geared hubmotors: BIG list & details

[Knuckles]

Don't suppose that $39 shipping is to Sydney?

ha ha. Shipping from China to AU is actually the cheapest!

[voicecoils]

(more to come...)

[andys]

Doug at EV tech engineered and designed the geared hub motor over a period of many years. Too bad he didn't patent it, as now the manufacturers have sold his design to others who put their names on them. I have his hub on the rear of a bike and it is an 8 pound torque monster. One thing not mentioned much about these motors, is that they are very efficient. Quite a bit more so the the Crystalite ones. I can go 35 miles on a 48 volt 15AH Lifepo4 at an average speed of 20 MPH on a 20 inch bike.

http://www.texaselectricbikes.com/catal ... p-163.html

[voicecoils]

Doug at EV tech engineered and designed the geared hub motor over a period of many years.

Thanks for the history, AndyS. Was Doug actually the first to make them happen? I don't know how much good a patent would do in China. I've listed his motor towards the top of the thread.

[docnjoj]

Solarbbq2003 has P2b which is brushless! The P2a is a great geared motor but has brushes. About 400 Aus $ delivered! Check the website for updates! Bretts a prince to deal with!
otherDoc

Thanks Docnjoj, I've added details of his motor above. Do you have one?

Yeah! I ran it into the ground over about 1800 miles on my big trike! Great little motor, but brushed! I only do old tech!
otherDoc

[The7]

Yeah! I ran it into the ground over about 1800 miles on my big trike! Great little motor, but brushed! I only do old tech!
otherDoc

How often do you need to renew the brushes?

[voicecoils]

Solarbbq2003 has P2b which is brushless! The P2a is a great geared motor but has brushes. About 400 Aus $ delivered! Check the website for updates! Bretts a prince to deal with!
otherDoc

Thanks Docnjoj, I've added details of his motor above. Do you have one?

Yeah! I ran it into the ground over about 1800 miles on my big trike! Great little motor, but brushed! I only do old tech!
otherDoc

Just to clarify, you "ran it into the ground", so you've killed it? This is the P2a (brushed and geared) your talking about, yeah?

[andys]

Doug told me not only did he come up with the geared hub design, but he has upgraded it several times. the last changes he made was to have them built to take a standard mountain bike disc rotor as direct bolt on, and a larger diameter axle for more strength and to allow for bigger gauge wires. The ones he is selling are also built with US made bearings, and not the Chinese ones. He is supplying a CNC machined torque arm with each motor now as well.

I just ordered another one.

[shinyballs]

Is the axle of the Bafang motor hollow? What's the weight limit for the rear can it carry?

[docnjoj]

P2A brushed
Yeah! The axle spun and finally had to be rethreaded! Then the steel drive gear broke its bearings. Finally it spun 1 too many times (using CL torque arm they suck) and I retired it! May have to rebuild it, but the brushes are still fine! Its fairly quiet! Its agreat little motor but cant get them any more from Brett!
otherDoc

[Iron Yeti]

I thought I would bump this thread as I have become interested in brushless geared hub motors. I live in a very hilly area and I am thinking my money would better be invested in a geared hub motor.

My understanding is that geared hub motors might be a little bit louder and their gears might need replacing but they are more efficient than non-geared brushless hub motors.

I was planning on going with Crystalyte 408 which is rated at 500W. So would a 250W geared hub motor almost match the performance of a 408 in speed while dominating it in torque?

Recommendations?

[docnjoj]

Yeah well 250 watts is "nominal"! I routinely ran 36 volts at 20-25 amps thru my P2A! I believe we all run higher amps than we think! My motor had to haul 300 lbs of trike and human! I dont have a Cycleanalyst but I use a volt and ampmeter. I think smaller geared motors are the way to go (brushed or brushless) If they can run quiet gears, they rule!
otherDoc

[Iron Yeti]

I've been reading about the BMC Puma geared hub motor but I can't find any information or a website where I can check out the price. Help?

[pwbset]

I can't find any information or a website where I can check out the price. Help?

http://www.texaselectricbikes.com/catalog/brushless-geared-motor-p-163.html

[Iron Yeti]

I wish all these other geared hub motors weren't rear wheel. Regardless, I really want that BMC. I think I might be able to scrape up the extra funds for it, or change my battery configuration since they are more efficient.

Edit: Has anyone bought just the motor from them? What controllers are compatible with it?

[voicecoils]

I wish all these other geared hub motors weren't rear wheel. Regardless, I really want that BMC. I think I might be able to scrape up the extra funds for it, or change my battery configuration since they are more efficient.

Edit: Has anyone bought just the motor from them? What controllers are compatible with it?

The Bafang PMGR (brushless geared) comes in a front hub. That's what I've ordered, and plan to run it at 72v ~30a

[Iron Yeti]

I wish all these other geared hub motors weren't rear wheel. Regardless, I really want that BMC. I think I might be able to scrape up the extra funds for it, or change my battery configuration since they are more efficient.

Edit: Has anyone bought just the motor from them? What controllers are compatible with it?

The Bafang PMGR (brushless geared) comes in a front hub. That's what I've ordered, and plan to run it at 72v ~30a

I actually meant I wish they weren't all front hub.

[voicecoils]

I actually meant I wish they weren't all front hub.

Ahh, got it.

There is a Bafang PMGR rear I think too, you should ask Keywin. See attached. The BMC looks quite nice, has been better tested, but is more costly.

[Iron Yeti]

Where might I contact him?

[voicecoils]

Where might I contact him?

"Keywin Ge" ecrazyman@gmail.com and ask for a quote on what you want and where you're located.

He's on eBay but not everything is listed. I've ordered but not received or tested, so proceed with caution. Knuckles has had good experiences it seeems.

[Mark_A_W]

I actually meant I wish they weren't all front hub.

Ahh, got it.

There is a Bafang PMGR rear I think too, you should ask Keywin. See attached. The BMC looks quite nice, has been better tested, but is more costly.

That's 172mm wide - it aint gunna fit in a 135mm dropout.

[andys]

e-crazyman told me last week his controllers are not fully compatible with the geared hub motors. I asked about the BMC one, and he told me he didn't have a controller that would work right with it.

[andys]

Doug at EV Tech still has some front wheel versions of the BMC geared hub, but doesn't recommend them unless you have a very strong fork and run a beefy torque arm.

[voicecoils]

Thanks for your response andys. I'll edit the BMC post to say that front OR rear can be had. sounds like the fronts are limited in supply.

do you know if the Puma and BMC are identical products? I'd like to keep this thread rolling, with good info

[Knuckles]

It is about time that I clarify some technical issues concerning the Bafang PMGR motor.
...
The ring gear in the hub appears strong and made of steel.

...
The rotor gear (sun gear) looks fairly robust as well (also made of steel).

...
(Edit 6/30/08) The planetary gear set (3 nylon planet gears) does not stay stationary during freewheel. It rotates along with the ring gear during freewheel.
Applying throttle causes the gear set to cease rotating within the motor as torque is applied to the wheel. The gear-set-freewheel-assembly is anchored to the axle by a key pin.

...
Above is the freewheel with the gears removed. The gear-set-freewheel-assembly can spin freely in one direction around the freewheel bearing.
The planet gears spin and translate (the gears move their location during freewheel and are staionary under applied rotor torque) all within the body of the motor.
The planet gears also have sealed bearings. The planet gears are held in place by those little clips.

...
Golly! What's wrong with this gear (actually it kinda looks like a sun god now ... 1960's hippie style)?

This is what happens to the gear if the torque exceeds the yield strength of the nylon gears.
See explanation of why it failed here ... viewtopic.php?f=2&t=4282&p=73746#p73578
Clearly the nylon gears are a very WEAK LINK in this motor design.

But I am not ready to throw the baby out with the bath water quite just yet!

So I plan on fabricating stronger planetary gears at my local gear fabricator shop (we have them here in NY).

Some other interesting tidbits ...
1) There is definitely a freewheel! The rotor only spins when applying torque. The planet gears are either spinng against or rotating with the ring gear.
The wheel freewheel spins with very little " resistance in the forward direction.
2) The motor will NOT run in reverse (it only freewheels in one direction).
3) Shorting the three phase wires completely brakes the motor in reverse direction only.
4) This is a VERY POWERFUL MOTOR! It has no problems at 72V and 30-amps.

The nylon gears will turn to "peanut butter" if you brake the wheel and accelerate the throttle at the same time. E BRAKES ARE ESSENTIAL!

SOLUTION: Simply add one steel gear (or maybe an alloy gear) to the planetary gear set. This is exactly what Keywin and I are planning to do.

BTW ... I am buying plenty of replacement nylon gears too (for sale of course) to all the good planetary folks just in case replacements are needed.
But I just can't wait to get my new MEGA SUPER GEARS fabricated and installed so I can SHRED UP the road with this tiny yet powerful motor!

On a final note ... Just so that we are all on the same page ... My Grubee black motor on my chopper ...
(see ... viewtopic.php?f=6&t=4160#p62316)
... is still more powerful (faster) than the Bafang (same V and amps) regardless of the Bafang gear material.
But the Bafang PMGR is infinitely superior at slower speed with UNSTOPPABLE torque output.

cheers
Knuckles

PS I will have the rear Bafang motor soon ... and put to rest once and for all ... the issue of whether this motor will fit into a rear bicycle drop-out.

Just came in.