recumpence
1 GW
liveforphysics said:
Ahh, yes, spin it up and gear it down. That is where the performance is.
Matt
Bofeili Crankshaft Drive
- Thread starter Matthijs
- Start date
Ahh, yes, spin it up and gear it down. That is where the performance is.
Matt
That's one reason (among several) why I didn't go directly thru the cranks on CrazyBike2's orignal powerchair drivetrain (although I didn't understand it very well at the time, and barely do now). 
Instead it has both pedals and motor merging at a jackshaft to go to the rear wheel via the bike drivetrain (atlhgouh I could definitely have done better in choosing gearing ratios for it, and hopefully will in it's replacement).
Instead it has both pedals and motor merging at a jackshaft to go to the rear wheel via the bike drivetrain (atlhgouh I could definitely have done better in choosing gearing ratios for it, and hopefully will in it's replacement).
bofeili bicycle owner's manual & motor spec sheet downloaded from bofeili.com
[youtube]kG3Drv2ocGE[/youtube]
[youtube]kG3Drv2ocGE[/youtube]
The newest models of this type of drive are wound to a Kv that uses 36V. It's a 50% step up from the early 24V units, but not as good as 48V (like the Bafang BBS02).
That being said, they have a small following in Europe, with the amps being limited to meet local laws. if you are limited on the power you can use, running it through the bikes gears helps trmendously because when you are on a steep uphill, you can downshift to a lower bicycle speed in order to keep the motors RPM's up nearer to its best motor-RPM's.
The stock planet gears are steel, and reported to be audible, some of these pics show a motor with black plastic gears swapped-in. The core of the stator is aluminum, and it is bolted to the center of the aluminum planet-gear mounting-plate, and then the edge of that plate is connected to the aluminum motor-case, so...the heat-path is better than the average geared motor, but it is still not "good".
Is it geared? yes, but there is only one layer of gear reduction (Some gear-motors have two side-by-side gear reductions, but that is not common). Here are some surgical pics from a German E-bike forum:
http://www.pedelecforum.de/forum/showthread.php?24858-Getriebeumbau-am-Bofeilimotor
That being said, they have a small following in Europe, with the amps being limited to meet local laws. if you are limited on the power you can use, running it through the bikes gears helps trmendously because when you are on a steep uphill, you can downshift to a lower bicycle speed in order to keep the motors RPM's up nearer to its best motor-RPM's.
The stock planet gears are steel, and reported to be audible, some of these pics show a motor with black plastic gears swapped-in. The core of the stator is aluminum, and it is bolted to the center of the aluminum planet-gear mounting-plate, and then the edge of that plate is connected to the aluminum motor-case, so...the heat-path is better than the average geared motor, but it is still not "good".
Is it geared? yes, but there is only one layer of gear reduction (Some gear-motors have two side-by-side gear reductions, but that is not common). Here are some surgical pics from a German E-bike forum:
http://www.pedelecforum.de/forum/showthread.php?24858-Getriebeumbau-am-Bofeilimotor
cycleops612
10 kW
re http://www.dca.com.au/bofeili-gx26-26-e-bike-crank-drive-24-speed/
I have one after much research, and i shout its merits from the rooftops.
24 gears - hello - that says it all if you think on the fundamentals of the physics involved here.
Its a 22kg alloy mtb w/ quality disks, gears & shocks, beautiful frame, NO OVERHEATING MOTOR (the housing is the frame, fab heatsink),
You may scoff, but for many unfit newebies, an ebike buy is a bit scary. With this, you ~never ever HAVE to pedal if you dont want to (no BO at work).
it also means you can load the bike with bulky slung bags of groceries etc., to the point where you cant pedal if you want to, and get home just fine. I never need the car. Its a bike you can use as a ute. I have carried a double bed frame and ends 2km (I love council cleanup seagulling on it)
12ah panasonic battery
lets just say, there are power options, best not discussed here
They seem honorable folk, not ebay smart arses who avoid you after the sale.
I say seem, as i opted to just sort things myself, so only a few dealings, all good.
many here have dazzled me with science and in same breath talk about way inferior bike costing $3500. Gimmie a break. This thing humps with elegance for $1500 last i heard.
personally i like the 3 speed options on the display. I use it like a semi auto gearbox. set it to sufficient, and have squirt in reserve at the touch of a button w/o a gear change.
possible downsides:
forget a kit, buy complete bike. the housing means a custom frame, tho in every respect, a quality standard MTB
I am hazy about cadence & still on it - the right gear ratio so i can effectively help when it struggles. In lo lo lo, you cant pedal fast enough for effect.
but yes, it seems the gearing can be right for pedaling OR motor, but not both. Still working on that.
NB
I have 3 mid drive ebikes, a new petrol MTB bike never used, and about 15 bikes, so clearly i am quite mad and should be ignored.
I have one after much research, and i shout its merits from the rooftops.
24 gears - hello - that says it all if you think on the fundamentals of the physics involved here.
Its a 22kg alloy mtb w/ quality disks, gears & shocks, beautiful frame, NO OVERHEATING MOTOR (the housing is the frame, fab heatsink),
You may scoff, but for many unfit newebies, an ebike buy is a bit scary. With this, you ~never ever HAVE to pedal if you dont want to (no BO at work).
it also means you can load the bike with bulky slung bags of groceries etc., to the point where you cant pedal if you want to, and get home just fine. I never need the car. Its a bike you can use as a ute. I have carried a double bed frame and ends 2km (I love council cleanup seagulling on it)
12ah panasonic battery
lets just say, there are power options, best not discussed here
They seem honorable folk, not ebay smart arses who avoid you after the sale.
I say seem, as i opted to just sort things myself, so only a few dealings, all good.
many here have dazzled me with science and in same breath talk about way inferior bike costing $3500. Gimmie a break. This thing humps with elegance for $1500 last i heard.
personally i like the 3 speed options on the display. I use it like a semi auto gearbox. set it to sufficient, and have squirt in reserve at the touch of a button w/o a gear change.
possible downsides:
forget a kit, buy complete bike. the housing means a custom frame, tho in every respect, a quality standard MTB
I am hazy about cadence & still on it - the right gear ratio so i can effectively help when it struggles. In lo lo lo, you cant pedal fast enough for effect.
but yes, it seems the gearing can be right for pedaling OR motor, but not both. Still working on that.
NB
I have 3 mid drive ebikes, a new petrol MTB bike never used, and about 15 bikes, so clearly i am quite mad and should be ignored.
Many apologies for the necro-bump on this thread, but I am wondering if there is a way to tell (maybe from the disassembled photos) whether the motor is wired in a delta vs. a wye configuration? In my belt-drive / IGH conversion, I may have over-geared the bike... 72T beltring up front, 30T in the rear with a 5-speed Sturmey-Archer IGH. In top gear with less than fully-charged battery on level ground, the motor seems to "bog"... it'll slowly lose speed unless I pedal to help it, like it's below optimum RPM from the start, and gets WORSE the slower it gets?
I am wondering, if the motor is wired in delta, could I re-wire into a wye configuration to decrease speed and increase torque? Perhaps also while converting to a 48V vs. a 36V controller to regain SOME of the speed? Drop speed in half with re-wiring, then increase by 4/3 with voltage conversion = 66.6% of original RPM (with corresponding increase in torque), right? Maybe then I could get the motor to sustain in top gear.
Alternatively, I could go to a 64T beltring... 64/72 = ~88.8% of original RPM.
Just making sure I've got this right, conceptually... Volts = Speed (RPM) and Amps = Torque. I think I have the gearing I need for the "speed" just trying to figure out the best way to increase torque so that top gear doesn't bog. Maybe keep motor, gearing, voltage all the same and get a different controller capable of more amps at 36v?
Thanks in advance for any thoughts or advice to share!
I am wondering, if the motor is wired in delta, could I re-wire into a wye configuration to decrease speed and increase torque? Perhaps also while converting to a 48V vs. a 36V controller to regain SOME of the speed? Drop speed in half with re-wiring, then increase by 4/3 with voltage conversion = 66.6% of original RPM (with corresponding increase in torque), right? Maybe then I could get the motor to sustain in top gear.
Alternatively, I could go to a 64T beltring... 64/72 = ~88.8% of original RPM.
Just making sure I've got this right, conceptually... Volts = Speed (RPM) and Amps = Torque. I think I have the gearing I need for the "speed" just trying to figure out the best way to increase torque so that top gear doesn't bog. Maybe keep motor, gearing, voltage all the same and get a different controller capable of more amps at 36v?
Thanks in advance for any thoughts or advice to share!
Volvofan said:
If there are four internal winding connections, it is Wye; three of them will go to phase wires and have single ends of windings connected, while the fourth will have all three windings connected but no phase wire coming off of that.
If there are three connections of paired windings to phase wires, and no fourth connection with no phase wire, it is delta.
I don't recall which way the speed/torque goes in delta vs wye, but you can disconnect the paired windings, take one end of each and tie them together, and put phase wires on the now-separate three winding ends.
You may have to experiment with which end of the windings to tie together and which to connect to phase wires (so they are all in the same "direction"); I don't remember the way to tell without that.
I don't see any pics in any of the still-working links that show any of the actual motor internals; you'd need to be able to see the motor windings and wiring (possibly both sides) to tell which way it's wired.
So opening one up is probably the only way to find out. :/
So opening one up is probably the only way to find out. :/
Strange; those don't show up for me except in your post.
Anyway, I see four of those "cloth tubes" typically used to insulate the motor winding connections. This means it is possible (though not certain) that it is already wired in Wye. (Delta would only have three)
But...one of the sets of wires that goes into one of those four is red, and that means it could just be the 5v for the hall sensors, and nothing to do with the windings. If so, there's probably another one that holds all the black ground wires for the sensors, too, likely right next to or under the red one.
Most of the time these interconnects are all on the same side of the motor, but they could have the y-point (all three phases tie point) on the other side where we can't see it.
Anyway, I see four of those "cloth tubes" typically used to insulate the motor winding connections. This means it is possible (though not certain) that it is already wired in Wye. (Delta would only have three)
But...one of the sets of wires that goes into one of those four is red, and that means it could just be the 5v for the hall sensors, and nothing to do with the windings. If so, there's probably another one that holds all the black ground wires for the sensors, too, likely right next to or under the red one.
Most of the time these interconnects are all on the same side of the motor, but they could have the y-point (all three phases tie point) on the other side where we can't see it.
