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

[Asher]

I was looking at the list of bikes here with Bafang Ultra, and was surprised at how many were still 48V.

2020 -Top 10 Ebikes With The Bafang G510 Ultra

There is a reason some of the top bikes are using this motor, pure power 160 NM equal 118 foot lbs. of torque, the Bosch is a very good motor but at only 75nm of torque that is only 55 foot pounds of torque, and really it's designed for the European market not the North American market. If you...

electricbikereview.com

You figure especially for a performance ebike, it would be more common. What is the barrier to using 52V? Or does it significantly reduce vehicle lifespan/durability? Requires in-house battery skill because generic 52v parts aren't available from third parties?

 

[indianajo]

Electric-bikes.com cancelled my order for a MAC 12t 48v hub motor because he found out we have hills in southern Indiana. He said I would burn it up with a 48 v battery. He offered to sell me a 36 v battery. I didn't want another battery. He accused me of running a pedicab service, since my gross weight with groceries/ag supplies is 330 lb sometimes. He suggested I buy a crystal direct drive hub instead. Why don't I just buy a boat anchor and drag it along? they are cheaper. I ride unpowered 90% of the time, the motor is for 25 mph headwind days, which are more & more common.
TJ has quoted MAC as saying their hub motor is good for 500 W continuous for ~15 minutes, then they burn up. So isn't 52 v better? The place I bought my 48 v 1200 W hub motor quit selling them. He sometimes has 36 v 1000 W hub motors. So why? Think maybe warrenty returns has something to do with it? Won't 52 v shove more current through a motor than 48, and burn it up even quicker?
I get by using my hub motor at 1200 W 48 v because our uphills are short, 100', interspersed by down hills. The center of the e-bike market is California, where uphills of 15 miles are common & popular excursions. The parks are up at the top of the ridge, Look at the LA map. So obviously we all need to buy mid-drives, that cost more than hub motors, with a higher profit margin, and (most of them) drag like a boat anchor when ridden unpowered. Or direct drive motors, and never turn the power off. There is no such thing as wind (inside the bike shop).
There was one hub motor manufacturer, a swiss wheel chair motor manufacturer, that advertised a geared hub motor with cooling fins. When san diego ebike advertised one, I had no extra money. When I had $2100 to spare (not cheap), none of the three "US distributors" would answer my email asking to buy a kit.

 

[ElevenAD]

I was looking at the list of bikes here with Bafang Ultra, and was surprised at how many were still 48V.

2020 -Top 10 Ebikes With The Bafang G510 Ultra

There is a reason some of the top bikes are using this motor, pure power 160 NM equal 118 foot lbs. of torque, the Bosch is a very good motor but at only 75nm of torque that is only 55 foot pounds of torque, and really it's designed for the European market not the North American market. If you...

electricbikereview.com

You figure especially for a performance ebike, it would be more common. What is the barrier to using 52V? Or does it significantly reduce vehicle lifespan/durability? Requires in-house battery skill because generic 52v parts aren't available from third parties?

of the bikes on that list several have 52v packs, The frey has 2x 48v 14ah batteries,The Excess,the Biktrix,the Luna,the flx Blade and The Watt wagon all come with or offer 52v battery packs so its not super uncommon these days

 

[indianajo]

Hill Eater uses 36V battery for their bike.

This really didn't make sense to me.
Basically, by making it 36V, they're pushing the batteries harder by draining more electricity at higher rate to achieve the same W rating of 48V bikes.
Wouldn't it be harder on the cells?

Yes it would be harder on the cells. Not massively as long as the battery has a amp rating higher than 24. Note power delivered, rubber to the road, is much less than power consumed by the motor. I've measured my 1200 w hub motor, dragging me bike & groceries up a hill at 4 mph, at about 450 W. The other 750 W comes out as heat in the windings. Ratio of watt delivery to watt consumption is probably better when motor is pulling me horizontally at more like 8 mph, usually reading about 50 W on the display. Evidence, the motor doesn't heat up much in the second case.

 

[Deleted member 4210]

The primary advantage is 52 volts allows you to maintain and reach the higher speeds when you get up over 25 mph. Yes, they can also have more capacity, and range is another reason, but the form factor changes for the casing, and the Ebike designer runs into challenges with space on the downtube where it's commonly a frame integrated battery, and an inside the frame controller.

So cost does go up both on the changes for a less commonly specified 52 volts battery itself versus much more common 48 volts, and also it's affecting cost or at the very minimum limiting the design choices on the frame. 48 volts is plenty sufficient for most use cases including staying at speeds over 20 mph with geared hub drive motors. juiced likes to exceed those parameters and give people an ebike with some extra 'punch' where it can also allow a rider to get to speeds of 31 mph much more easily than can be done with 48 volts.

And yes, there are 36 volt batteries being used to acheive speeds of 28 mph, but that is primarily on mid drives where those motors are and can be spun at much higher RPMs than hub drives (since they are not attached to the rim) and efficiency can be leveraged through the drive train better,since the motor is transferring its power through the cassette,instead of directly to the wheel like the hub can do. A juiced hub drive ebike though at 52 volts and also with 750 watt motor will make it considerably easier for the rider to accelerate a heck of a lot faster and reach 28 or even 30 mph, versus ANY ebike with a mid drive motor on the market right now that is only operating at 36volts.

You'll likely see more 52 volt options on some existing brands some time this year, as the competition keeps growing. Some may do it in combination with a lot more amphours to allow a rider reach closer to the century Mark on range, rather than necessarily adding it for speed.

 

[pushkar]

From an Ebike vendor perspective, the reality is older cases are designed for 13s packs (48v) first. Most cases are typically retrofitted with a 14s (52v) pack but that needs non ideal welding / layout. They also fit fewer cells due to this design constraint. Typically a case designed for 13s will offer a little more Wh than when it’s used for 14s (not by much but you get the idea).

if a redesign is available (as is the case with the newer offerings like ours), the frames or bike is built with the redesigned pack dimensions in mind. The 14s packs are a little more expensive, but they allow for a good layout without sacrificing the number of cells that can be fit in.

there are of course other reasons (BMS availability, motor controller limitations etc) but this basics design issue is a very interesting factor IMO.

 

[Ken M]

One of the reasons I don't like tube integrated batteries is that it typically limits the peak voltage. I do believe there is some technical merit to 52V and even 60V batteries providing somewhat better overall efficiency. With the EU limiting speeds to 32kph on most ebikes sold there it makes no sense for the industry to give much thought to batteries over 48V, or even 36V given the market share advantage Europe has.

I think as more US commuters experience the benefits of higher voltage and higher wattage ebikes maybe the market share will grow and there will be more turnkey 52V or higher models. I don't think there is any merit to voltages higher than 60V because most geared and direct drive motors will assist above 30mph at those voltages and that enough for effective transportation on an ebike.

 

[Stefan Mikes]

With the EU limiting speeds to 32kph on most ebikes sold there it makes no sense for the industry to give much thought to batteries over 48V, or even 36V given the market share advantage Europe has.

1. The European law limits the "Class 1" e-bikes to 25 km/h (15.5 mph)
2. The European law limits the battery voltage to 48 V.

Given the market share of Europe, the point (2) seems to answer the question of the OP.

 

[Asher]

Thank you for the answers, especially Mike and Pushkar.

@Stefan Mikes, the low EU speed limit + the high speed justification makes sense for why 48V is more common. But I've never seen a 48V limit in EU law, despite just looking for it. Do you have a link?

I had just figured that given multiple years of 52V enthusiast bikes being available, it would have become more prevalent, and dominant among high speed, Bafang Ultra level bikes. Evidently 52V packs still aren't quite the commodity I thought they'd be by now.

Eg, Reention in-tube eel/rhino/dragon batteries don't really allow for 52v unless you leave a lot of empty space. http://www.reention.com/product/2

 

[AHicks]

2 things I can think of. First I think, is that 48v is working pretty good, and second, the 52v concept hasn't been around long enough to become more popular. I think it will be given more time.

And back to my pet peeve, again. Comments that lump gear driven and direct drive rear hubs together, which can be incredibly misleading to the uninitiated. Like "mid drives where those motors are and can be spun at much higher RPMs than hub drives" which is total baloney. While that might be true regarding direct drives, gear driven rear hubs have motors that are able to turn every bit as fast as any mid drive.

 

[Asher]

the 52v concept hasn't been around long enough to become more popular.

It's been around since at least 2015. Ebike development cycle is 2-3 years, less for most components. eg https://endless-sphere.com/forums/viewtopic.php?t=74991

Insofar as time is a factor, it's because the big brands are euro mid-drives powering slower bikes and don't need it, and the small brands don't have the money/volume to do it in-house, unless it's a core appeal of the brand, like Juiced/Luna. Looks like the high power/speed market is now taking off though, with s-pedelecs in Europe and Class 3s in the US.

 

[Stefan Mikes]

But I've never seen a 48V limit in EU law, despite just looking for it. Do you have a link?

It is in the Polish Road Code, which is based on the EU law. That part is related to "normal bicycles", which may be electrically assisted. That limitation is not pertaining to S-Pedelecs, that are classified as L1e-B mopeds.

 

[Asher]

It is in the Polish Road Code, which is based on the EU law. That part is related to "normal bicycles", which may be electrically assisted. That limitation is not pertaining to S-Pedelecs, that are classified as L1e-B mopeds.

Ah apparently this regulation kicks in for 50-1000V. Is that what you're referring to?

[Technically a 48V is >50v when fully charged]

Directive - 2014/35 - EN - Low Voltage Directive - EUR-Lex

eur-lex.europa.eu

 

[Stefan Mikes]

Ah apparently this regulation kicks in for 50-1000V. Is that what you're referring to?

[Technically a 48V is >50v when fully charged]

Directive - 2014/35 - EN - Low Voltage Directive - EUR-Lex

eur-lex.europa.eu

Do you want me to translate that section of the Road Code?...
I do repeat. S-Pedelecs have no voltage limit. Only the Electrically Power Assisted Cycles are limited by speed, power and voltage in Poland. No big brand offers more than 48V batteries in Europe.

 

[Asher]

Do you want me to translate that section of the Road Code?...
I do repeat. S-Pedelecs have no voltage limit. Only the Electrically Power Assisted Cycles are limited by speed, power and voltage in Poland. No big brand offers more than 48V batteries in Europe.

You said Europe, now you're saying Poland. Is it EU or not?

 

[Stefan Mikes]

You said Europe, now you're saying Poland. Is it EU or not?

Poland is a full member of the EU. Polish lawmakers don't invent such rules themselves but follow the EU law.

 

[steve marino]

I could be wrong, it's just a hunch, but I suspect that a 52V battery w/ a 750 watt motor at half throttle is more efficient, and runs cooler, than a 26V battery w/ a 375 watt motor at full throttle. Of course, the smaller battery and motor weigh less, but on an eBike, once it gets rolling weight is not critical, only from a stand still. So it depends on what you want to do w/ the bike.

 

[tomjasz]

The primary advantage is 52 volts allows you to maintain and reach the higher speeds when you get up over 25

Marginal difference with a BBSHD. A bit more with a DD and GD, in my experience. I have 14s3p and 2 7p 52V. PF, 22P, and 29E cells.

Bafang factory has always disliked the BBS series running 52V. The capacitors were 60v they and some resellers suggest 54.6v for motor longevity.
They actually messed with the firmware and limited the series to give an error message when running a 52v. A real nightmare for a month or two.

 

[tomjasz]

I could be wrong, it's just a hunch, but I suspect that a 52V battery w/ a 750 watt motor at half throttle is more efficient, and runs cooler, than a 26V battery w/ a 375 watt motor at full throttle. Of course, the smaller battery and motor weigh less, but on an eBike, once it gets rolling weight is not critical, only from a stand still. So it depends on what you want to do w/ the bike.

Sorry you can’t extrapolate without knowing what the motor demand is ,the BMS spec, and battery out put.

 

[Kam1936]

The primary advantage is 52 volts allows you to maintain and reach the higher speeds when you get up over 25 mph. Yes, they can also have more capacity, and range is another reason, but the form factor changes for the casing, and the Ebike designer runs into challenges with space on the downtube where it's commonly a frame integrated battery, and an inside the frame controller.

So cost does go up both on the changes for a less commonly specified 52 volts battery itself versus much more common 48 volts, and also it's affecting cost or at the very minimum limiting the design choices on the frame. 48 volts is plenty sufficient for most use cases including staying at speeds over 20 mph with geared hub drive motors. juiced likes to exceed those parameters and give people an ebike with some extra 'punch' where it can also allow a rider to get to speeds of 31 mph much more easily than can be done with 48 volts.

And yes, there are 36 volt batteries being used to acheive speeds of 28 mph, but that is primarily on mid drives where those motors are and can be spun at much higher RPMs than hub drives (since they are not attached to the rim) and efficiency can be leveraged through the drive train better,since the motor is transferring its power through the cassette,instead of directly to the wheel like the hub can do. A juiced hub drive ebike though at 52 volts and also with 750 watt motor will make it considerably easier for the rider to accelerate a heck of a lot faster and reach 28 or even 30 mph, versus ANY ebike with a mid drive motor on the market right now that is only operating at 36volts.

You'll likely see more 52 volt options on some existing brands some time this year, as the competition keeps growing. Some may do it in combination with a lot more amphours to allow a rider reach closer to the century Mark on range, rather than necessarily adding it for speed.

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.