GM BLT-800W bench racing

This motor is looking better the more i look at it :lol: now that i've had some sleep, i've done a bit 'o math..

24S on this motor + a 4.33:1 reduction should = ~475rpm loaded on a 24" wheel. That's about 36-37mph or 58 km/hr. Or maybe 40mph constant on a 26: wheel.

I compared the specs to the golden motor HPM-5000B, and i think the 800W motor might make some good power if we feed it enough volts!!

92v on the BLT-800 spins at 2500rpm unloaded.
48v on the HPM-5000B spins at 4021rpm unloaded.

The HPM-5000B is listed to create 13nm max torque on 48v.
The BLT-800 would produce 9.6nm at 48v, but on 92v, i would guess that it produces 11-12nm on the higher voltage.

Given that the BLT-800 would be spinning at 62% the RPM, it would theoretically produce 50-60% of the torque that the HPM-5000B would, once it is geared down to wheel speed.

But here is a mystery - why does the BLT-650 make 11.3nm torque max at 48v, but the BLT-800W makes 9.6nm? maybe they didn't push it hard enough on the dyno.
The maximum efficiency point is at 6nm for the 800w motor and 4.6nm for the 650w motor, so i am thinking that they just didn't push the 800w as hard. The 800W should handle more constant power i guess?

The unloaded RPM for the 800W is 1333 versus ~1150 for the 650W and 500W motors though, so that might be the difference. Less torque, but higher speed.

http://www.goldenmotor.com/hubmotors/BLT-650W Performance Curve.jpg

http://www.goldenmotor.com/hubmotors/BLT-800W%20Performance%20Curve.jpg

So the constant loaded torque when reduced 4.33:1 for the 800W x 48v would be 39.57n-m. ( 29 ft-lb ) at 234rpm ( 80% efficiency! )
For the 650W x 48v, that would be 45.465n-m. ( 33.5 ft-lb ) at 199rpm ( 81% efficiency! )

Let's compare this to golden motor's 9C clone ( the pro-kit motor, not the magic pie ): 18.6n-m ( 13.7ft-lb ) at at 266rpm ( 77% efficiency on 36v. Woah! that's pathetic :lol: No wonder those motors make so much heat!

29 / 13.7 = 2.11 times more constant torque from the GM BLT 800W motor than their 9C clone If i get extra torque constant from running 24S, maybe i get 2.25-2.5 times more torque..?

let's compare it to a Crystalyte HS ( per the dyno test on crystalyte.com ):

4:33 GM BLT-800 motor on 48V: 39.57NM constant at 234RPM - 80% efficiency
Crystalyte HS3540 on 48V: 26.53NM constant at 271RPM - 83.2% efficiency

Since the Crystalyte HS is running 14% faster, let's take 14% off the BLT-800's torque figure..

BLT-800W: 34nm constant, HS3540: 26.5nm constant.

By these numbers, the BLT should produce 33% more torque constant than the Crystalyte HS 3540.

So maybe the BLT-800 can perform more like a Crystalyte 53xx or 54xx? But the motor is 19LBS and only $108.. O_O

Phew, i am tired from all this bench racing.. :lol:

It could be a potentially badarse motor, just watch your no load current, you may find that when spinning fast the poor quality stator may make a ton of heat just spinning

Farfle, no load current is 1.5A on 48v. That seems pretty good for a motor of this stature, doesn't it?

I am trying to get some pics of the interior of the motor from GM Canada and li-ghtcycle as we speak.

Yeah, may not be bad as long as they aren't exaggerating.

Gobs of Mayo on a double-decker Bacon Lettuce Tomato sandwich:



4 Tbsp (Gobs) Mayo + 10 strips Bacon + 4 leafs Lettuce + 6 slices Tomato + 3 slices bread = 1100 calories or 4600 kJ of energy. Enough for about 170 minutes of cycling ..and apparently it's delicious!

Golden motor is usually not too bad about their specs.

When hunting around, i found another series of trike motors that could be pretty awesome;



http://www.uumotor.com/shop/electric-tricycle-motor/1000w-electric-tricycle-gear-motor-air-cooling

http://www.aliexpress.com/store/pro...ushless-motor-long-life/601157_304378362.html

( note, they make these up to 2200W rated )

Their torque specs seem to be based on what happens before the 5:1 reduction, or is it a 6:1 reduction? at what voltage? lol. Ok, but it's a big monster motor with a 5:1 - 6:1 reduction mounted to it, it's gotta be quite powerful compared to the hub motors we use.. here is one pic of the stator that i found:



13.45NM @ 650RPM would equal 37.391 nm @ 233rpm that the BLT produces at rated volts, and i bet these have a broader torque band.. if that's at 48v, then it could make way more power/torque at higher volts.

These are stupidly long though, 20-30cm long ( that's 8in-1ft in American units ), so they wouldn't work too well on an upright bike unless you're okay with a big motor hanging out the sides all awkward like.. i guess that's why scooter motors are better, eh? square shape and all.. the BLT is okay though, about 6 inches long, can be hidden by panniers etc

Wish i had a trike right now though

OK, now that i look at UU's page on alibaba for the 1000W motor, i see that the motor will produce 3300rpm ( before the planetary reduction ) at 48v, 60v, and 72v. You can select the different winds on their page..

http://www.aliexpress.com/item/1000W-48v-BLDC-motor-1kw-for-electric-tricycle/513561521.html
http://www.aliexpress.com/item/Tric...with-brushless-motor-long-life/304378362.html
http://www.aliexpress.com/item/1000...ectric-tricycle-and-motorcycle/526167478.html

UU 1000W gearmotor:
48v 12.5 rpm/v = 1150rpm output at 92v
60v 10 rpm/v = 920rpm output at 92v
72v 8.3 rpm/v = 754rpm output at 92v

I wonder if the 48v 1000W would tolerate being ran at twice it's rated RPM? It would be singing along at >6000rpm .. could make ~2000W continuous.

Maybe it would not be so good unless your idea is to be as unstealthy as possible.

OK, back to bench racing the BLT :lol:

Ahem..

..sorry.. could not resist

BLT looks ready for some serious liquid cooling.

Alcohol cooled BLT? I think so!

Here you go. Please keep in mind this motor was in use for a while then I believe the hall sensors failed. It was sent back and a new one sent out. This motor then sat for about 8 months before I opened it today. I was really surprised at how strong the magnets are. It took a lot of force to pull it apart. Hope what you are looking for can be seen in these pictures.

Gary

Wow, not a lot of poles on that bad boy. I bet it can spin up some more
They sure didn't optimize these for weight, did they? :lol: oh well, lots of thermal mass is a good thing when you're overvolting/overamping a motor.

So i'm going to guess that there's about 33% more stator / magnet in the 800w going off the dimensions of this 'half full' 650w.

Yeah allright, i'm anxious to get my hands on one now..

Just ordered up a 650w and a 800w.
Should have them here by late december/early january due to one of the motors being out of stock.

Still haven't tested the 2kW MAC motor sitting on my desk but honestly, these are more exciting because they don't need a 2 stage reduction, just high volts..

I'll ship you the 650 today. The 800 will be about a month. They are to heavy to go in the same box anyway, so there is no point in making you wait. The outside dimensions are identical so you can setup your mount and use either one on the same bike.

Gary

Golden Motor Canada said:

I'll ship you the 650 today. The 800 will be about a month. They are to heavy to go in the same box anyway, so there is no point in making you wait. The outside dimensions are identical so you can setup your mount and use either one on the same bike.

Gary

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Allrighty; thanks. If there are additional shipping cost from splitting the package, just hit me up via PM and i'll pay you the difference. I ordered both at the same time because your system gave me a lower shipping cost, but i don't want you losing money on me, especially since these motors are a pretty good deal anyway.

I love motor porn threads

Looks like you should machine some new end plates, no wonder their motors are always so heavy.

I'm not really worried about any extra shipping cost. I haven't really made any money at this game yet so why start now

The first one should be landing at your front door anytime now. I'm looking forward to seeing what you do with it

Gary

magudaman said:

Looks like you should machine some new end plates, no wonder their motors are always so heavy.

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Yeah possibly. There's gotta be some extra metal to shave off here. I wonder if the 800W motor also has this excess material in it... we'll see.

Golden Motor Canada said:

The first one should be landing at your front door anytime now. I'm looking forward to seeing what you do with it

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I should have it today or tomorrow. Anxious to get it apart and see how thick the laminations are. My fingers are really crossed here that it's the motor i calculated that it could be

to get 750W to stay Fed. Legal "bicycle" ..... can't that be done with the controller and voltage ??

like this motor ...

http://www.goldenmotor.ca/products/48-Volt-5KW-BLDC-Motor.html

jmygann said:

to get 750W to stay Fed. Legal "bicycle" ..... can't that be done with the controller and voltage ??

like this motor ...

http://www.goldenmotor.ca/products/48-Volt-5KW-BLDC-Motor.html

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Sure... run the 650W motor at 750W ( bump the voltage up a few hairs ) and have yourself a good fun legal eagle time :lol:

A 5kW motor running at 750W would be a pretty epic waste of money though.. 22lbs of motor and you'd only be using approximately 1/10th of what it can produce.. almost worthy of a ban from the forum :lol:

I got the used/dead 650W motor in today.



I have bad news, and i have bad news, which one do you want first? :lol:

Motor laminations were are a lofty 0.5mm each so high RPM operation is not going to be very good. Maybe it can do 1500rpm at ~80% efficiency? still kinda sad.

The sprocket at the end is 14mm internally and fits a #41 chain.

The axle/magnet assembly was not balanced and had some minor wobble in it. Maybe this is fine at ~1000rpm, but not the 2000rpm i was counting on. I don't see how this could have been disbalanced after it was constructed.

The end caps were a little over 1 pound each, the axle/magnet assembly is about 4.5 pounds. The motor mounts were about half a pound collectively, and the case/stator assy. was 10-11lbs.

Construction is not all that great, but i guess you get what you pay for for $100! There was a neo magnet that was a different color than the others. All the neo magnets were scratched up, but this could be due to the motor being taken apart 3-5 different times. After cleaning out the magnet/iron dust from the stator slots, i was able to get the motor running without replacing the halls ( the hall epoxy wouldn't melt anyway with 1500w of heating gun attacking it. )

On the upside, on 36v the no-load was 1.09 amps. I didn't catch the rotational speed, but i'm thinking it was about ~700rpm. We tried the 'cardboard box' test :lol: to see if i could get the motor to slow down, pushing thick cardboard and wood at the sprocket at WOT, and couldn't the motor to slow down from the no-load speed. Nope. Tore right through everything i handed it :lol: this motor has some torque for sure.

The whole thing came in at about 18lbs. More than expected.

Just one more disclaimer before you check out the pics: This is a used motor that was considered dead that came into Golden Motor Canada, has been opened at least 3 times now. It doesn't represent a brand new product!









































Anyway, i am not suddenly too excited about the BLT-800. 0.5mm laminations = death to all super high RPM adventures.
However this motor will move a trike, and dissipate a bunch of heat ( due to all the extra steel ) when said trike is hauling a bunch of stuff up a hill, and heck, could be easily turned into some kind of cost-effective bench mounted power tool or other industrial application ( just look at the case - surely they use the same casing for industrial heavy machinery motors ). But it isn't for me.

I know the 800W will be more powerful but if a >20lb motor ( estimated ) isn't gonna spin up some and make 1500w continuous for me, then i can't say i'm super interested, as i could pull that off with a crystalyte hub or magic pie.

neptronix said:

Motor laminations were are a lofty 0.5mm each so high RPM operation is not going to be very good. Maybe it can do 1500rpm at ~80% efficiency? still kinda sad.

.

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I would spin it up and take some mesurements. I bet magnets comming off will be an issue before eddy currents are!

Arlo1 said:

I would spin it up and take some mesurements. I bet magnets comming off will be an issue before eddy currents are!

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You're right Arlo; i shouldn't give up so easily. I guess i'll test out the no-load on various voltages tomorrow.