I am currently running a 7 speed freewheel on my Leaf motor but I usually leave it on the 22T cog so I can pedal if the motor needs a little help on a steep incline.
Leaf / leafmotor / leafbike high efficiency 1500w motor
- Thread starter neptronix
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Thanks...glad I chose the freewheel version of the Leaf
.One thing that concerns me about the Leaf 1500w motor is that while it is able to run cool and efficient at 2000w (with the appropriate sized wheel) I don't think the average shark battery pack from EM3EV will be cool and efficient if used with such a combination.
For example, Samsung 35E cells are rated at 8 amps max continuous current. Since the largest shark pack from EM3EV holds 70 cells for 14S 5P that puts the pack's maximum continuous current of 40 amps (re: 5 x 8 amps = 40 amps) and yet going 40 mph with the typical bike from this thread will pull more than that thus pushing the BMS into its burst mode of 55 amps maximum.
Even the EM3EV Triangle battery pack at 14S 6P looks inadequate for the average bike build in this thread:
EM3ev 52V (14S6P) Hard-Case Triangle Ebike Battery Pack With Bag | EM3ev
EM3ev 50V (AKA 52V, 14S6P) Small Triangle Ebike Battery Pack, uses top quality official Samsung and LG Chem cells safety features not to be found elsewhere.em3ev.com
View attachment 356792
So if a person wants to push 40 mph with the chassis commonly found in this thread the battery should likewise be much bigger in order to match the efficiency of the motor. Pushing small batteries to max continuous power draw is hard on battery efficiency as well battery life.
Best to choose a bigger battery in order match discharge efficiency with motor efficiency. What is the point of having a motor with 90% efficiency at speed if the battery is simultaneously poorly efficient. In some cases (e.g. chassis limiting battery size) perhaps it is better to have a motor with less efficiency but with higher torque per amp when using certain small batteries.
For any ebike build, you need to match the motor, battery, and controller to the application.
The battery has two separate components that can be limiting factors...the cells and the BMS. Although the Leaf motor will do it without over heating if you run Statorade, there are better choices for a motor if you want to cruise at higher speeds...QS205, Cromotor, and the Crystalyte H55100 would be the motors I would recommend. The Crystalyte has a 55mm stator.
EM3ev is very conservative with their recommendations but if you follow them, your battery will last a looong time...they recommend ~50% of the max capability of the cells for "burst" current. I have a 14s6p battery from them that is over seven years old and still going strong. I also have a 14s4p battery from EM3ev with 25R cells and I pull ~60A every time I start from a standstill but pulling that much continuously like you would need to do if going over 40 mph, is not a good idea. The 25R cells are rated for 20A continuous by the manufacturer so with a 4p pack, they can provide 80A continuously...but just because it can do it, that doesn't mean it is a good idea. The limiting factor with most batteries is the BMS and not the cells.
Most ebike motors will start to decrease the torque per amp when you go over ~40A battery current and by ~60A, it is really noticable. The Grin Tech Motor Simulator does not account for saturation...I found it experimentally. Saturation is not an ON/OFF switch, it occurs gradually at first and increases as you increase the amperage...until you are just pouring more heat into the motor as opposed to getting more torque.
In my experience, most ebike components can handle 40A and if you stay below that threshold, you'll never have a problem. But as you go over about 40A, everything needs to be resized, replaced or at least evaluated to see if it can handle the amperage.
ebike4healthandfitness
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New Member Glad I found this place
Hello Endless-Sphere new member here and considering building a fairly high end e bike. I've built a Gas motorized bike before years ago. It was with what's called a shift kit (basically the mid drive version of a gas bike) and a fairly common motorized bicycle motor. Once I worked through the...
endless-sphere.com
"That leafbike 1.5kw motor can be pushed to 40mph almost continuously, add ferrofluid and it might sustain 50mph."
Also remember Leaf also sells the 35mm motor as a 2000w when used with a 60v controller.
EDIT: Although neptronix did state the following also ---> New Member Glad I found this place
"40mph needs 2000w to sustain the speed on the leafbike 1.5kw if you are in a tucked position, a few hundred watts more otherwise. it will be at around 85% efficiency at that point. Will tolerate that for about 5-10 miles continuous before overheating if you add no additional cooling tricks ( hubsinks, ferrofluid, or drill holes into it )"
I reckon 5 to 10 miles at 40 mph is pretty good. In the world of ebikes (where the "long range" is much much shorter than in the gasoline world) that would qualify as almost continuously I believe.
In the link below EM3EV states "We would recommend the cells be ran at roughly 50% of their max continuous ratings. Of course they can provide the full discharge, but there can be voltage sag and reduced capacity if this is done."
EM3ev 72V (20S10P) Rectangle Ebike Battery Pack (24.5AH-29.5AH) | EM3ev
EM3ev 72V (20s10p) Rectangle Ebike Battery Pack uses top quality official Samsung and LG Chem cells and safety features that will not be found elsewhere.
em3ev.com
For a 35E cell that means 4 amps per cell.
It's not the motor I am concerned about, it's the battery.
For example, lets say our target is 40 mph with 2000 motor watts and this is achieved at 85% efficiency (as stated by neptronix in the second link I provided). This means the controller needs 2353 watts (re: 2353 x .85 = 2000.05 watts) from the battery. And remember the battery itself will not be 100% efficient at delivering these 2353 watts to the controller. Yeah definitely a person wouldn't want Samsung 35E, Panasonic PF or Panasonic GA cells in a the EM3EV Jumbo shark 14S5P pack for this purpose. Unfortunately the Samsung 35E and Panasonic GA are also the highest capacity cells.
That leaves the high discharge/low energy density cells (Samsung 25R, Molicel 28A and LG HG2) as the only remaining choices. The Samsung 25R is actually very good at discharging high amps efficiently though it is the lowest capaciy cell sold by EM3EV. I don't know much about the LG HG2 and the Molicel 28A other than they have high maximum continous discharge of 20A and 35A respectively.
But if your BMS is limited to 40 amps continuous these cells don't help for continuous operation of the goal. They may not even help a person momentarily hit 40 mph (via 55 amp burst mode of BMS) on flat ground with no headwind for various reasons including non ideal tire diameter and motor winding selection. Then there is also efficiency loss occuring at the level of the BMS to think about when the BMS is operating in this "burst mode".
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If you have 35E cells in your battery and you have the EM3ev smart BMS, you can safely pull 8A per "p" string but your battery just won't last nearly as long as it would if you pulled 4A per "p". If you have a 14s5p battery with 35E cells, the run below shows you can only get about 35 mph with 40A assuming you are sitting upright.New Member Glad I found this place
Hello Endless-Sphere new member here and considering building a fairly high end e bike. I've built a Gas motorized bike before years ago. It was with what's called a shift kit (basically the mid drive version of a gas bike) and a fairly common motorized bicycle motor. Once I worked through the...
"That leafbike 1.5kw motor can be pushed to 40mph almost continuously, add ferrofluid and it might sustain 50mph."
Also remember Leaf also sells the 35mm motor as a 2000w when used with a 60v controller.
EDIT: Although neptronix did state the following also ---> New Member Glad I found this place
"40mph needs 2000w to sustain the speed on the leafbike 1.5kw if you are in a tucked position, a few hundred watts more otherwise. it will be at around 85% efficiency at that point. Will tolerate that for about 5-10 miles continuous before overheating if you add no additional cooling tricks ( hubsinks, ferrofluid, or drill holes into it )"
I reckon 5 to 10 miles at 40 mph is pretty good. In the world of ebikes (where the "long range" is much much shorter than in the gasoline world) that would qualify as almost continuously I believe...........
The 2000w Leaf motor that is 135-137mm OLD is the exact same motor as the 1500w Leaf motor, they just say 2000w because at 60v you will pull about the same amperage as running it at 48v and 1500w. It is the amperage that does the heating and not the watts or voltage.
The EM3ev Smart BMS is rated for "40A continuous plus". 40A with a 52v battery will get you 35 mph with the 4T Leaf motor and I included the Crystalyte 3548 motor to get a good estimate on the temperature for the Leaf...obviously you will need to run Statorade to keep the temperature acceptable if you are running a 26" wheel...I used 686mm because that is the OD of a Maxxis Hookworm 26x2.5" tire:
So you basically have two choices if you want to ride at speeds above 35 mph:
A. Get a new and/or an additional battery. For the "additional battery", you could wire another identical battery in parallel to double the amperage available but that has its own unique challenges.
B. Reduce the top speed you want to achieve.
Reducing the aerodynamic drag is another approach that could help but it may require a completely different vehicle and that is why I did not include it.
Tid bit...if you use a 24" wheel and a Schwalbe Pick-Up 24x2.6" tire (631mm OD), you may be able to get away without running Statorade and still be able to run ~35 mph with 52v/40A and a 4T Leaf motor.
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On a 4T leaf motor i think you really want 60A at a minimum, that's where the fun starts.
Running any battery at close to it's maximum output will produce a lot of heat in the pack and this can reduce the pack's life significantly, you also risk overheating the battery which could cause it to explode.
Smallest battery w/1-3C cells i'd run is 23AH. That way, at a 35mph cruising speed, you're running about 2C. That's still producing some notable heat, but it's at least bordering on 'bad'.
Preferably you have a 30-40AH pack instead.
If you have a much higher power output cell pack, these statements don't apply. I used to run RC Lipo and flux weakening to achieve higher speeds because my battery pack could output 100's of amps.
Running any battery at close to it's maximum output will produce a lot of heat in the pack and this can reduce the pack's life significantly, you also risk overheating the battery which could cause it to explode.
Smallest battery w/1-3C cells i'd run is 23AH. That way, at a 35mph cruising speed, you're running about 2C. That's still producing some notable heat, but it's at least bordering on 'bad'.
Preferably you have a 30-40AH pack instead.
If you have a much higher power output cell pack, these statements don't apply. I used to run RC Lipo and flux weakening to achieve higher speeds because my battery pack could output 100's of amps.
ebike4healthandfitness
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Here are some specs on two cells from the 21700 form factor which EM3EV will eventually switch to:
The Samsung 50S (5000 mah) looks pretty impressive with that 25a max continuous discharge and 2.5 amp standard charge and 6 amp max charge (10 amps is listed for step charge).
The Molicel 42a (4200 mah) has 45a max continuous discharge with a 4.2 amp standard charge and 8.4 amp max charge.
If EM3EV offers the 70 cell 21700 Shark pack (which is larger than the 70 cell 18650 shark pack) that is obviously going to provide a big boost in discharge and charge metrics. (Samsung 50S would provide 125 continuous amps with 12.5 amp standard charge and 30 amp max charge with 50 amps for step charge. Molicel 42a would provide 225 max continuous amps with 21 amps standard charge and 42 amps max charge)
The Samsung 50S (5000 mah) looks pretty impressive with that 25a max continuous discharge and 2.5 amp standard charge and 6 amp max charge (10 amps is listed for step charge).
The Molicel 42a (4200 mah) has 45a max continuous discharge with a 4.2 amp standard charge and 8.4 amp max charge.
If EM3EV offers the 70 cell 21700 Shark pack (which is larger than the 70 cell 18650 shark pack) that is obviously going to provide a big boost in discharge and charge metrics. (Samsung 50S would provide 125 continuous amps with 12.5 amp standard charge and 30 amp max charge with 50 amps for step charge. Molicel 42a would provide 225 max continuous amps with 21 amps standard charge and 42 amps max charge)
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Yeah i have a 52v 19.5AH pack of those; 40A aka ~2C is where they start to get saggy. You're really pushing them at 2.5C.
em3ev started selling a pack with it a few months ago.
You'll find yourself wanting 50-60A power to get up to those high speeds fast. My 19.5ah battery cuts after 50A.
I wish i had more like a 25AH pack; i'm starting to push the pack at 2500w and it's starting to get notably saggy then.
Leafbike 1.5kw is best ran at 3000W-4000W peak for 35-40mph duty. And like any motor, it'll consume a lot of power at that speed, so you need big amp hours to get decent range if you plan to go that speed often.
em3ev started selling a pack with it a few months ago.
You'll find yourself wanting 50-60A power to get up to those high speeds fast. My 19.5ah battery cuts after 50A.
I wish i had more like a 25AH pack; i'm starting to push the pack at 2500w and it's starting to get notably saggy then.
Leafbike 1.5kw is best ran at 3000W-4000W peak for 35-40mph duty. And like any motor, it'll consume a lot of power at that speed, so you need big amp hours to get decent range if you plan to go that speed often.
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ebike4healthandfitness
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This must have had the Samsung 50E, not the Samsung 50S. Both have 5000 mah capacity per cell but there is a big difference in max continuous discharge with the Samsung 50E at only 9.8 Amps rather than 25 Amps which the Samsung 50S has.
Samsung 50E:
Samsung 50S:
Nope, i have the 50S.
Consider that max continuous amps for any cell is simply a thermal limit ( due to energy waste ) for a single cell at room temperature that's below the threshold of it blowing up or dying.
You want to derate the hell out of those figures because oyu have all your cells crammed together with no outlet for the heat.
That and the horrible voltage sag and capacity loss you get at full blast.
Molicel P45B is a hell of a cell if you can get your hands on them.
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ebike4healthandfitness
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Yeah the Molicel 45B looks super impressive:
Bench Test Results: Molicel P45B - 50A 4500mAh 21700…an extraordinary cell!
As Battery Mooch I tested these cells in January for my Patreon supporters and have been torture testing them along with the Molicel P42A and the Samsung 40T since then. With the release of the Molicel P45B hopefully coming soon it’s finally time to post some test results. The cycle life torture...
endless-sphere.com
"In my testing the P45B was a better performer in every way over the Molicel P42A:
The P45B had almost 9% higher capacity.
The P45B had about 33% lower DC IR (at 100% charge).
The P45B’s charge rates are 4.5A standard/13.5A max (70°C cutoff) and the P42A’s are 4.2A standard/8.4A max (60°C cutoff).
The P45B had longer run times at all discharge current levels."
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ebike4healthandfitness
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What is the rating of the BMS for continuous and burst?
ebike4healthandfitness
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And I was thinking the 13.5 amps max charge for the Molicel 45B was impressive then comes this:
"It was designed with an ultra-fast 5C C-rate for fast charging."
5.0 Ah at 5C means 25 amps max charge per cell. That is almost double what the already super impressive 45B offers.
"It was designed with an ultra-fast 5C C-rate for fast charging."
5.0 Ah at 5C means 25 amps max charge per cell. That is almost double what the already super impressive 45B offers.
I have some information from the manufacturer that might be useful:
- The default axle is indeed 12 mm on the cassette side and 14 mm on the disc side. However, they can produce the motor with both sides being 14 mm at the same price.
- Leaf uses winding machines but also hand-winds some motors, which is why they offer more than just the standard 3T, 4T, and 5T speeds. The hand-wound motors have higher speeds. For example, according to Leaf, a hand-wound 4T motor is 70 rpm faster than a machine-wound one. The hand-wound motors have more copper fill, I think, making them faster and more efficient.
- Unfortunately, they do not offer different axle lengths. After many requests, they offered to check if they could find a longer axle, but typically, they produce the motor with only one axle length.
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Bengy22
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Not to turn this isn't a battery thread but the P50B is already old news, leaked spec's of the upcoming P60B:
Attachments
ebike4healthandfitness
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This 6 Ah with 45 amps max charge per cell and 90 amps discharge (at 90C cutoff).
That means a 80 cell 21700 shark pack like the one shown below could max charge at over 13,300 watts:
This assuming a person had a controller capable of providing that much regen current and the bike frame, wiring and axle was able to keep that regen flowing without breaking, melting/burning up or sending the rider over the handlebars.
Obviously another thing to think about is charging from a level 2 charger, but that would require a charger to be integrated which would increase the size. GaN (Gallium Nitride) should make it smaller, cooler and more efficient though.
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The Toecutter
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I can't find hub motors for my application powerful enough to fully use the power my 20S6P pack of Molicel P42A will be able to put out. The P60B is just ridiculous! I could still use the extra range though.
Leafbike needs to make us a motor with modern technology that can do like 3x the peak power of their current offering for the same weight. This would imply peak efficiency around 95%. And then Grin do the same for its All-Axle side motors. THN I'll b ready to mess with such a battery.
AMZ technologies had back in 2014 a geared hub motor of 7 lbs that could do 50+ horsepower peak. Used in the world's fastest-accelerating EV, but not for sale to the public.
That said, there's always middrives and all of their accompanying issues and headaches, I suppose...
Leafbike needs to make us a motor with modern technology that can do like 3x the peak power of their current offering for the same weight. This would imply peak efficiency around 95%. And then Grin do the same for its All-Axle side motors. THN I'll b ready to mess with such a battery.
AMZ technologies had back in 2014 a geared hub motor of 7 lbs that could do 50+ horsepower peak. Used in the world's fastest-accelerating EV, but not for sale to the public.
That said, there's always middrives and all of their accompanying issues and headaches, I suppose...
ebike4healthandfitness
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Acceleration in 2016 (Yes, these were 50 hp per wheel):
Acceleration in 2023:
According to the video below this 2023 motor is IPM (28,000 rpm). Here is a shot of the reduction which is a stepped planetary gear:
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yantra yatra
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For my next bike I’m looking at either a torque sensing Bafang M635 torque sensing BBSHD or a Leaf 1500w.
Can anyone advise how expensive and time consuming, complicated to set up the Leaf will end up with
- regen braking
- a controller capable of 4-5kw bursts
- dual battery setup potentially (eg 2 x 48v or 52v batteries run in parallel for double amps of nominal rating l, plus regen on dual batteries if they are paired correctly)
I think there were some other factors I was going to consider but can’t remember now. I’m leaning towards the Leaf for ease and simplicity with drivetrains, but am not sure if efficiency will be all right with a fair bit of serious hill climbing.
The other option to wait for is the Proton mid drive from CYC capable of 3kw+, But it will be expensive and a long wait
Can anyone advise how expensive and time consuming, complicated to set up the Leaf will end up with
- regen braking
- a controller capable of 4-5kw bursts
- dual battery setup potentially (eg 2 x 48v or 52v batteries run in parallel for double amps of nominal rating l, plus regen on dual batteries if they are paired correctly)
I think there were some other factors I was going to consider but can’t remember now. I’m leaning towards the Leaf for ease and simplicity with drivetrains, but am not sure if efficiency will be all right with a fair bit of serious hill climbing.
The other option to wait for is the Proton mid drive from CYC capable of 3kw+, But it will be expensive and a long wait
I’d like to see the M635 build. I don’t see many folks using it yet, so it would be nice to see an example and hear the real world experience. Thanks for checking!
Bengy22
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Well technically they are not out yet. It was leaked in a annual report you can read here published back in March. Estimated completion of R&D in 2024. Those figures should be taken with a grain of salt but I would bet if they are off its not by far considering where I found that photo was published before the 50B figures were out. But the 60 in the same suggests 6ah and the "P" nomination is for their high discharge cells. Probably will be another year or two before mass market release though. P50B's has had samples out since the beginning of the year (at least) and still hasn't hit mass market, most guesses seem to be EOY. Also worth noting is the crazy XA3 cells they are working on. 4ah and 90c discharge and a 40c charge (seems to be a 10s peak though). https://media.taiwancement.com/web_tcc/en/report/annual/2023 Annual.pdf
Also >5ah 21700's have been a thing for a bit now. First one that comes to mind is the LG m58, 5.8ah which has been out 2 years now. And then what ever cell Vapcell rewraps for their F60 6ah. Although those cells are not rated for high amps, and to really get more capacity out of them vs your typical 5ah cell they need to be ran at really low amps (<5). What could really be interesting though is from my understanding if you build a high discharge cell like the P60B you are sacrificing capacity in the design. So the question is if Molicel works on a high capacity cell (which they designate with "M") what would the capacity be? Possibly 7ah, maybe even 8ah?!?
ebike4healthandfitness
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That has to be the worst reason ever to suggest an ebike part.
ebike4healthandfitness
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How steep and long are the climbs? How much do you weigh?
Not really. The choices are so random that there is not clear use case, and just a random wish list. You’re welcome to go the twenty questions route. (I didn't suggest any ebike parts. I only expressed my preference to see an M635 build).
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