Why do so few brands offer 52V (volt) batteries?

[Ken M]

It is very unlikely that the US ebike companies will be using 60V pack.

It was on Juiced FAQ section:

The Most Powerful E-Bike Batteries

Every Juiced Bike comes equipped with a massive 52V battery, one of the most powerful batteries currently available in the electric bike market. The extra battery power translates into a much faster, smoother, and longer e-bike riding range.

www.juicedbikes.com

Quote from Juiced FAQ page:
"Can we use even higher pack voltages?
Not likely. The 52V battery pack when fully charged is 58.8V. This is just under the 60 Volt limit at which point the electronics system will be classified as “High Voltage” and there will be a much stricter set of regulations needed to certify the e-bike."

Does anyone have a direct reference to the UL specification for products that is definitive on 60VDC being the limit for low voltage classification? I found tables indicating that up to 120VDC was still considered low voltage because there is little risk of air arcing.

I have read multiple opinions on this but I would like to review the actual regulations that are applicable to ebikes.

 

[Deleted member 4210]

Some of what you suggest is right on. I have to disagree with your point about acceleration and maintaining 28mph speeds. I've owned a 48Volt 750 w rear hub motor and have tested a 52V 19.2 Ah Juiced Bike. The mid drive 36 V outperformed the Juiced Bike in terms of range and held its own in terms of speed 28mph on flats. The mid drive easily pedaled unassisted on flats maintaining speeds of 15 to 16 MPH without much effort. Whereas the Juiced Bike was too heavy to pedal unassisted. Also, 36 V 16.8 Ah is plenty for Brose 1.3 motor that can be tuned to accommodate range or speed. I really think the Juiced Bike 52 V 19.2 Ah battery is needed to propel a heavy bike. Forget about pedalling unassisted. The high end brands got it right. The mid drive combines the power of the rider with the motor which is silent on the Brose that allows the rider to propel the bike with or without assistance. And it's street legal. Juiced Bike is not.

Whatever. Motor designers, and I've spoken with a number of them in coming up with custom builds for over 60 clients, we know you are wrong just from a physics standpoint. Unfortunately, Your point about weight really blows your credibility, as wind resistance above 20 mph is an exponentially increasing force, and weight of even an additional 10 to 20 lbs is minuscule to affecting speed or power needed versus the forces you encounter from wind resistance. Any professional cyclist knows that to be true in spades which is why they are constantly training in wind tunnels to perfect their aerodynamics.

 

[Kam1936]

Whatever. Motor designers, and I've spoken with a number of them in coming up with custom builds for over 60 clients, we know you are wrong just from a physics standpoint. Unfortunately, Your point about weight really blows your credibility, as wind resistance above 20 mph is an exponentially increasing force, and weight of even an additional 10 to 20 lbs is minuscule to affecting speed or power needed versus the forces you encounter from wind resistance. Any professional cyclist knows that to be true in spades which is why they are constantly training in wind tunnels to perfect their aerodynamics.

Right whatever. My friend's Juiced Bike weighs 80 + with no load. Try pedalling that unassisted. The guy standing next to his Juiced Bike is a friend. I was able to test ride it. We also rode from SCV to SFV. Much of the time I was pedaling unassisted but he had to use assist 1 or ECO to keep my pace. He complained loudly "try pedaling this thing unassisted it ain't happening." I don't know about what the professional or experts say, I'm just going on our ride experience. The Juiced Bike is HAF. That's undeniable. Juiced Bike VS Turbo Vado 5.0 side by side. 5 racks vs 2 1/2 racks. No comparison. You get what you pay for!

 

[Deleted member 4210]

Some of what you suggest is right on. I have to disagree with your point about acceleration and maintaining 28mph speeds. I've owned a 48Volt 750 w rear hub motor and have tested a 52V 19.2 Ah Juiced Bike. The mid drive 36 V outperformed the Juiced Bike in terms of range and held its own in terms of speed 28mph on flats. The mid drive easily pedaled unassisted on flats maintaining speeds of 15 to 16 MPH without much effort. Whereas the Juiced Bike was too heavy to pedal unassisted. Also, 36 V 16.8 Ah is plenty for Brose 1.3 motor that can be tuned to accommodate range or speed. I really think the Juiced Bike 52 V 19.2 Ah battery is needed to propel a heavy bike. Forget about pedalling unassisted. The high end brands got it right. The mid drive combines the power of the rider with the motor which is silent on the Brose that allows the rider to propel the bike with or without assistance. And it's street legal. Juiced Bike is not.

Here is a good video to get yourself up to speed in the basics of understanding how voltage affects speed. This applies to hub drive motors.

Micah is a degreed mechanical engineer (as I am) so he has a firm grasp on the fundamentals and can explain it well.

When you get into mid drives like Bosch or Brose or Yamaha, due to their design choices on the type of motor they are using, the gear ratios, the higher speeds they are choosing to run their motors at, and the limitations of how much torque they are willing to transmit through the crank, and then chain, back to the cassette, it's not prudent to go from 36 volts to a higher voltage to try to get higher speed. They are really constrained in what they can do with the mid drive, and how much total wattage and current they can apply to an already super high rpm motor, without making significant other compromises in terms of stress on the internal motor gears, heat build up, and durability.
With a hub drive I can overvolt that motor very easily as explained in Micahs video above. I can also optimize current flow, and have 750 watts to work with any way I chose. The same cannot be done with a brand name mid drive (Bosch, brose, Yamaha) which typically is only running 250 watts, with occasional peaks allowed of 500 watts, and doing so only at 36 volts, without risking substantial damage to that motor or its internal gearing. These guys are already running near the top of their build envelope, and putting much more than 80 nm of torque will simply rip the heck out of any chain drive or wear it out in no time.

Bafang has a completely different gearing set up for their mid drives than the big name guys, running their motors at lower RPMs, but also lower internal gear ratios, so they are not as efficient but their design allows them to use as high as 60 volts, and they are taking their motors as high as 1600 watts. Well again, that motor design rips drive trains to shreds even when you attempt to use a beefier chain , as the cassettes are limited in their thickness and strength, unless you convince those high volume guys like Shimano, Sunrace, etc to completely redesign their cassettes. They arent likely to do that anytime soon. I point this out about bafang, bc you aren't going to get much better acceleration out of a bafang unless you want to constantly be repairing your drive train.
The industry is already about 30 to 40 to 1, number of hub drive ebikes sold vs mid drives, in the US and Europe , and not including China usage since they are selling tens of millions more ebikes inside their own country with 95% of them hub drive so that would not be a fair comparison.

Over time you will see considerably more development and use of hub drives, as they start building more efficient hub drives, start going the direction of tesla with hub motors at each wheel, and they are much simpler to build, to repair, and far more durable than any mid drive design will ever be.

The hub drive industry has taken the very least path of resistance, not really needing much technology development since those motors have been around for eons and are dirt cheap and built in much higher volumes and for many more applications outside of ebikes. We will start seeing a LOT more advancements in hub drives in the next few years, while mid drives will top out due to their high cost to manufacture, very high complexity, low build volume, and far too much unnecessary expense for entire frame redesigns.

 

[Kam1936]

Here is a good video to get yourself up to speed in the basics of understanding how voltage affects speed. This applies to hub drive motors.

Micah is a degreed mechanical engineer (as I am) so he has a firm grasp on the fundamentals and can explain it well.

When you get into mid drives like Bosch or Brose or Yamaha, due to their design choices on the type of motor they are using, the gear ratios, the higher speeds they are choosing to run their motors at, and the limitations of how much torque they are willing to transmit through the crank, and then chain, back to the cassette, it's not prudent to go from 36 volts to a higher voltage to try to get higher speed. They are really constrained in what they can do with the mid drive, and how much total wattage and current they can apply to an already super high rpm motor, without making significant other compromises in terms of stress on the internal motor gears, heat build up, and durability.
With a hub drive I can overvolt that motor very easily as explained in Micahs video above. I can also optimize current flow, and have 750 watts to work with any way I chose. The same cannot be done with a brand name mid drive (Bosch, brose, Yamaha) which typically is only running 250 watts, with occasional peaks allowed of 500 watts, and doing so only at 36 volts, without risking substantial damage to that motor or its internal gearing. These guys are already running near the top of their build envelope, and putting much more than 80 nm of torque will simply rip the heck out of any chain drive or wear it out in no time.

Bafang has a completely different gearing set up for their mid drives than the big name guys, running their motors at lower RPMs, but also lower internal gear ratios, so they are not as efficient but their design allows them to use as high as 60 volts, and they are taking their motors as high as 1600 watts. Well again, that motor design rips drive trains to shreds even when you attempt to use a beefier chain , as the cassettes are limited in their thickness and strength, unless you convince those high volume guys like Shimano, Sunrace, etc to completely redesign their cassettes. They arent likely to do that anytime soon. I point this out about bafang, bc you aren't going to get much better acceleration out of a bafang unless you want to constantly be repairing your drive train.
The industry is already about 30 to 40 to 1, number of hub drive ebikes sold vs mid drives, in the US and Europe , and not including China usage since they are selling tens of millions more ebikes inside their own country with 95% of them hub drive so that would not be a fair comparison.

Over time you will see considerably more development and use of hub drives, as they start building more efficient hub drives, start going the direction of tesla with hub motors at each wheel, and they are much simpler to build, to repair, and far more durable than any mid drive design will ever be.

The hub drive industry has taken the very least path of resistance, not really needing much technology development since those motors have been around for eons and are dirt cheap and built in much higher volumes and for many more applications outside of ebikes. We will start seeing a LOT more advancements in hub drives in the next few years, while mid drives will top out due to their high cost to manufacture, very high complexity, low build volume, and far too much unnecessary expense for entire frame redesigns.

Experience speaks volumes. Like I said I rode the bike with the rear hub torque + cadence sensor. I wasn't impressed. 52V 19.2 Ah 750 w with over 1000 w peak. I felt like I was on a tank, rather than a bike. Maybe it's the way those bikes are designed. The bike just felt cheap in comparison to my Vado. I'm no expert engineer. I prefer the feel and stability of the complete package of the mid drive Brose over the rear hub Juiced Bike. In terms of my own limited experience with the Juiced Bike I rode, I wouldn't want to own one. I prefer the mid drive any and everyday.

 

[Asher]

You're also comparing a $2k ebike to a $5k? one. The Juiced CCS felt like a heavy beach cruiser to me sans assist, perfectly fine for riding at 10-15 mph. Junking the suspension for a rigid form and using better tires helped. Juiced could definitely use a refresh though.

 

[trainman]

My personal feeling on this is, if you keep pushing for more power and speed you are setting yourself up for legislation to require drivers licenses and insurance as your ebike is reaching motorcycle status. I realize off roading is a different story, but if you want to keep your ebike classified as a bicycle then you will have to stay within bicycle regulations. Having legislators change the laws is slow to happen and in may states the laws have been upgraded for ebikes, regulations today are slow to go through the system.

 

[AHicks]

It's not always about speed. For many, it's often about the GRUNT available at low speeds - under 15 mph for instance. The squirt quickly across the busy street/intersection and no sweat hill climbing kind of performance....

 

[fooferdoggie]

It's not always about speed. For many, it's often about the GRUNT available at low speeds - under 15 mph for instance. The squirt quickly across the busy street/intersection and no sweat hill climbing kind of performance....

I get that on my Bosch and using gears.

 

[Kam1936]

You're also comparing a $2k ebike to a $5k? one. The Juiced CCS felt like a heavy beach cruiser to me sans assist, perfectly fine for riding at 10-15 mph. Junking the suspension for a rigid form and using better tires helped. Juiced could definitely use a refresh though.

Wasn't trying to compare, I was just disputing the 52 V battery findings. Another thing I noticed was the 52 V battery depleted much faster going up steep hills ( Up Sierra Highway from the old rd). The mid drive I could pedal in ECO at a lower gear whereas the Juiced Bike, it was necessary to get up the hill in highest mode. Probably due to the heavy weight of the bike and the motor being in the rear. I didn't notice any acceleration advantage Juiced Bike had over the Turbo Vado's mid drive. Other than his bike was also equipped with a throttle. I don't know if it's possible to integrate that power 52V 19.2 750 w with Vado's system and the way it was designed. I feel plenty of power with 36 V 16.8 Ah accompanied with the Brose motor. I like to ride my bike like a regular bike and only use assistance when needed. When I do use assistance ECO is fine. I seldom use Sport or Turbo. At an average rate of speed of 14 mph assisted/unassisted 100 mile range is attainable with moderate hills. I'm more concerned about range than high speeds.

 

[Asher]

if you keep pushing for more power and speed you are setting yourself up for legislation to require drivers licenses and insurance as your ebike is reaching motorcycle status.

Speed, agreed, power, not really. It's dumb to sell an ebike as 28 mph when it goes 10 mph on hills. The solution is more power. It's speed that kills, not really power, especially if ebike weights are capped (as I think they should be and often are), at around ~45 kg/100 lbs.

 

[ElevenAD]

Experience speaks volumes. Like I said I rode the bike with the rear hub torque + cadence sensor. I wasn't impressed. 52V 19.2 Ah 750 w with over 1000 w peak. I felt like I was on a tank, rather than a bike. Maybe it's the way those bikes are designed. The bike just felt cheap in comparison to my Vado. I'm no expert engineer. I prefer the feel and stability of the complete package of the mid drive Brose over the rear hub Juiced Bike. In terms of my own limited experience with the Juiced Bike I rode, I wouldn't want to own one. I prefer the mid drive any and everyday.

what level PAS were you using on the Juiced vs the Vado? what was the top speed you reached on the the Juiced vs the Vado?
were you running the Juiced in Sport or Race mode?

 

[AHicks]

I get that on my Bosch and using gears.

I get it with a MAC 12t geared rear hub and 35a controller, without having to constantly mess with gears. Different strokes......there's no wrong answer or "better" setup here. Get what you like and go ride/have fun!

 

[fooferdoggie]

I get it with a MAC 12t geared rear hub and 35a controller, without having to constantly mess with gears. Different strokes......there's no wrong answer or "better" setup here. Get what you like and go ride/have fun!

messing with gears keeps my cadence up so I get exercise and it gives me a longer range with battery and my legs and less stress on the motor. I ride a bike to ride it I got tired of using a electric scooter.

 

[AHicks]

messing with gears keeps my cadence up so I get exercise and it gives me a longer range with battery and my legs and less stress on the motor. I ride a bike to ride it I got tired of using a electric scooter.

And I ride with a different purpose in mind, never stress my 1000w+ motor, and get an easy 35 mile range. So is one of us wrong, or maybe we both enjoy riding for our own/different reasons.... Is there really a need for an "us vs. them" or "me/my bike is better than yours" mentality here?

 

[tomjasz]

52 V battery depleted much faster going up steep hills (

That makes absolutely no sense. Some other factor is affecting the 52V battery. Lower output cells and the BMS can affect performance. One needs to discuss which cells and what the BMS limits are. You need to compare apples to apples. Same cells, same BMS, and then monitor output.

 

[AHicks]

Timpo, there's WAY more to that argument than you are alluding to. It's NOT just about acceleration of revolving weight, though your point regarding sprung vs. unsprung weight is legitimate. For starters, when it comes to a direct drive motor, the larger the diameter of the hub, the more torque is available from the motor. A simple lesson in leverage. There's more, but that fact alone blows your theory.

If it were that easy, everyone would be doing it!

 

[antboy]

I'm not talking about unsprung weight. I'm talking about rotating mass (I don't know the proper term)
In fact, I don't think the theory of unsprung / sprung mass applies to the hub motor if it's attached on to the hard tail like Juiced.

I think you missed the point. I think he was talking about how heavy it felt unassisted. The hub motor will only act as a dead weight if it's unassisted.
When you said "the larger diameter of the hub, there's more torque available" yeah I agree, this is exactly why BionX D500 looks like a gigantic disc. However, this was not his point.

If my theory is wrong, you are more than welcome to address it. I don't pretend to be an engineer, as I mentioned on the post above.

Is it the same between a DD hub and geared hub?

It's my impression that part of the reason direct drives have so much resistance is because when unpowered, the whole motor rotates, but with geared hubs in general only the case rotates, thanks to the the clutch?

 

[AHicks]

I'm not talking about unsprung weight. I'm talking about rotating mass (I don't know the proper term)
In fact, I don't think the theory of unsprung / sprung mass applies to the hub motor if it's attached on to the hard tail like Juiced.

I think you missed the point. I think he was talking about how heavy it felt unassisted. The hub motor will only act as a dead weight if it's unassisted.
When you said "the larger diameter of the hub, there's more torque available" yeah I agree, this is exactly why BionX D500 looks like a gigantic disc. However, this was not his point.

If my theory is wrong, you are more than welcome to address it. I don't pretend to be an engineer, as I mentioned on the post above.

I'm lost apparently.

 

[tomjasz]

Is it the same between a DD hub and geared hub?

It's my impression that part of the reason direct drives have so much resistance is because when unpowered, the whole motor rotates, but with geared hubs in general only the case rotates, thanks to the the clutch?

DD is a rather large mass of magnet, fairly powerful too, surrounding the entire diameter. A Gear Drive uses a much smaller stator and rotor using gears for mechanical advantage. IME far less drag in a GD! Newer and smaller GD motors are even smaller with even less drag.