Most efficient 1-2Kw motor ?
- Thread starter jmygann
- Start date
mwkeefer
1 MW
Brushless, 3 Phase and Wye terminated...
Either geared hub (intended for 20mph at pack lvc) or reduction system and then efficiency between 89-93% roughly could be expected.
You will find motors like the Astro 3210 are most efficient at around 17/18A and reterminated to wye... then reduction will consume a bit (small factor) and so will final transmission...
Also, I have found tuning the controller to provide about 2-3x the most efficient current still results in the motor settling into that efficiency window when cruising at intended (geared for) speed... it pulls much more current for starting and accelleration but that gives you the torque you need to reach those higher speeds quickly.
I believe one of the guys on here has an Astro reduction setup with a 60A limit but when running on a 12S pack and average cruising at 20mph using the throttle for "Pulse and Go" style riding... his best average was 18wh per mile. I can tell you 18wh per mile is freaking respectible if not down right awesome... and this setup was geared for 45 or 50mph top speed if I can recall correctly so it wasn't even cruising in the "efficient" zone of the motor since the controller required PWM control for throttling to 20mph.
jym - do you have weight of riders + cargo + bike as it stands now... I could do a few calculations to figure the torque requried and also the max hp/wattage to maintain the 20mph specified... also how quickly do you want to reach 20mph, are you trying to accellerate like a winnebago or a GSXR 750 up to your max 20mph speed?
About the 18wh a mile... if you had a 12S2P pack weighing 7.2lbs and providing 444wh of power, you could travel about 24.66 miles before using the 10AH capacity you were carrying.
My best personal is on a geared hub motor with a 15S pack and 69A limit (nominal 12A) and top speed of about 28mph... I can acheive 32wh per mile without pedaling at all... by comparison the same bike (20") with a DD 9x7 9C hub requires between 44 and 55wh per mile without pedaling on the same controller with lower peak currents (since a direct drive hub can pull max current uphill or under full throttle for too long and the phase wires are too small) of 50A.
Sorry... I missed the chain/belt bit... If you need more than a single stage of reduction I would use belt for primary (I think belts properly tensioned can be 98% efficient or 2% loss)... if you can use a single reduction stage (what size are your wheels to be, 20", 24", 26"?) then a chain is easier to implement and with a 20mph cap... a single left side style drive on a freewheel would be ideal... that's a large #219 style sprocket on the disc side of a normal bike rear wheel... linked to where the disc brake would go with a Freewheel to keep pedaling independent of the motor (no drag when pedal assisting) and a motor like an astro mounted either below and behind the bottom bracket (where the cranks are) with a chain linking directly to the rear sprocket. If this is suspension bike, that introduces other issues... chain growth and such.
-Mike
Either geared hub (intended for 20mph at pack lvc) or reduction system and then efficiency between 89-93% roughly could be expected.
You will find motors like the Astro 3210 are most efficient at around 17/18A and reterminated to wye... then reduction will consume a bit (small factor) and so will final transmission...
Also, I have found tuning the controller to provide about 2-3x the most efficient current still results in the motor settling into that efficiency window when cruising at intended (geared for) speed... it pulls much more current for starting and accelleration but that gives you the torque you need to reach those higher speeds quickly.
I believe one of the guys on here has an Astro reduction setup with a 60A limit but when running on a 12S pack and average cruising at 20mph using the throttle for "Pulse and Go" style riding... his best average was 18wh per mile. I can tell you 18wh per mile is freaking respectible if not down right awesome... and this setup was geared for 45 or 50mph top speed if I can recall correctly so it wasn't even cruising in the "efficient" zone of the motor since the controller required PWM control for throttling to 20mph.
jym - do you have weight of riders + cargo + bike as it stands now... I could do a few calculations to figure the torque requried and also the max hp/wattage to maintain the 20mph specified... also how quickly do you want to reach 20mph, are you trying to accellerate like a winnebago or a GSXR 750 up to your max 20mph speed?
About the 18wh a mile... if you had a 12S2P pack weighing 7.2lbs and providing 444wh of power, you could travel about 24.66 miles before using the 10AH capacity you were carrying.
My best personal is on a geared hub motor with a 15S pack and 69A limit (nominal 12A) and top speed of about 28mph... I can acheive 32wh per mile without pedaling at all... by comparison the same bike (20") with a DD 9x7 9C hub requires between 44 and 55wh per mile without pedaling on the same controller with lower peak currents (since a direct drive hub can pull max current uphill or under full throttle for too long and the phase wires are too small) of 50A.
Sorry... I missed the chain/belt bit... If you need more than a single stage of reduction I would use belt for primary (I think belts properly tensioned can be 98% efficient or 2% loss)... if you can use a single reduction stage (what size are your wheels to be, 20", 24", 26"?) then a chain is easier to implement and with a 20mph cap... a single left side style drive on a freewheel would be ideal... that's a large #219 style sprocket on the disc side of a normal bike rear wheel... linked to where the disc brake would go with a Freewheel to keep pedaling independent of the motor (no drag when pedal assisting) and a motor like an astro mounted either below and behind the bottom bracket (where the cranks are) with a chain linking directly to the rear sprocket. If this is suspension bike, that introduces other issues... chain growth and such.
-Mike
liveforphysics
100 TW
If you want the most efficient, only axial flux ironless motors will do.
The CISRO hubmotor is 99% efficient if you want a hubmotor.
The launch point motor is 98%(if I remember right).
They aren't cheap though, but they are sized correctly for E-bike/ LEV applications, and would be the most efficient out there.
The CISRO hubmotor is 99% efficient if you want a hubmotor.
The launch point motor is 98%(if I remember right).
They aren't cheap though, but they are sized correctly for E-bike/ LEV applications, and would be the most efficient out there.
olaf-lampe
10 kW
How about Perm motor or Lynch/Agni? They beat the Etek in efficiency, but pricing is also a lot higher...
Olaf
Olaf
John in CR
100 TW
I thought the RC guys bragged that their little motors were 90%+ efficient. Then you can get more power than you're asking for significantly less than an Etek.
Malcolm
10 kW
"New Lithium/Graphite brushes can last for decades"
Wow. I gotta get me some of them.
They've clearly made vast improvements over the first Etek. My first set of brushes only lasted 1000 miles
Wow. I gotta get me some of them.
They've clearly made vast improvements over the first Etek. My first set of brushes only lasted 1000 miles
liveforphysics
100 TW
It means it's axial flux. This is a great thing, and just like all the others.
That site is a bunch of snake-oil crooks trying to sucker people, or it's just run by honest idiots.
Take the snake-oil middle-man away and buy from Mars if you want one of those.
You shouldn't make a thread asking for the most efficient though if you actually want the most perfectly average cheapo solution.
That site is a bunch of snake-oil crooks trying to sucker people, or it's just run by honest idiots.
Take the snake-oil middle-man away and buy from Mars if you want one of those.
You shouldn't make a thread asking for the most efficient though if you actually want the most perfectly average cheapo solution.
AussieJester
1 TW
If you want a brushless mars PM enoob he has a supplier of new (old stock) mars brushless motors
for ~$US250
KiM
for ~$US250
KiM
Tiberius
10 kW
jmygann said:
That's one of the problems. It isn't a fixed number for a given motor. It depends on the rpm and the power, so you really have to have a specific application and working conditions in mind before asking.
As examples:
A given motor tends to get more efficient the faster you spin it, but obviously there is a limit beyond which you get other problems.
A given motor at a given rpm gets less efficient as you put more power through it. So you can get very high efficiencies by running motors at less that their ratings. For instance Astroflight (one of the RC motor manufacturers who are good at publishing data) can show 94% efficiency on some of their motors, but this falls to 90% at higher power.
Nick
robert.smu
100 µW
- Joined
- Mar 29, 2010
- Messages
- 7
Maybe someone know, what is the speed(rpm) of astro 3210 8t motor, when it has best efficiency?
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