Is 36v a Euro mandate?

[MLB]

Is there a law limiting Ebikes to 36v in Europe?
While there's no overwhelming reason to prefer 48v it does seem to provide a performance boost in most applications. Certainly did in my cordless E lawn mower going from 36-48v.
Given the competitive nature of this biz it just seems surprising that Bosch and others stay with 36v when the cheaper, more powerful options are all using 48v. At least in the US.
Would seem to be a simple switch even if they are limited to 36v in Europe. ?
Maybe our market is still too small to worry about making alternatives a priority?
What's really surprising is no one ever mentions it when discussing bike performance differences.
I don't really "care". Perfectly happy with my 36v Bosch as compared to 48v Easy Motion and current 36v Falco that can be changed to 48v with a battery change. Just curious.

PS - Easy Motion changed the Big Bud Pro from 36v in 2015 to 48v in 2016. Did they change their whole line? It's Spanish I believe.

 

[Cameron Newland]

There's no law limiting ebikes to 36V in Europe. There would be some significant costs, though, in upgrading a system used by millions to a wholly-incompatible system. You'd have to continue producing replacement parts for 36V systems while selling brand new 48V systems. There isn't any need for 48V mid-drives because 36V mid-drives are perfectly capable of assisting riders to 28MPH. When you consider that the EU laws on ebikes limit assist to 25kph/15.5mph, there's even less of a case for moving to 48V, as 24V would handle 25kph assist just fine.

The ideal voltage for an electric bike system is 36V. Some may say that determination is subjective or up for debate, but when you consider the extreme inefficiency of aerodynamic drag from cycling above 25 or 30MPH, it becomes clear that the value-add of an ebike is really all about getting you up to 20 or 25MPH and no further, and any acceleration above that speed is a big waste of energy. 48V systems are better for bikes that cruise at 30MPH, however, that comes with a big loss in aerodynamic efficiency at top speed, and consequently reduces range.

 

[Clydesdale_Stallion]

There's no law limiting ebikes to 36V in Europe. There would be some significant costs, though, in upgrading a system used by millions to a wholly-incompatible system. You'd have to continue producing replacement parts for 36V systems while selling brand new 48V systems. There isn't any need for 48V mid-drives because 36V mid-drives are perfectly capable of assisting riders to 28MPH. When you consider that the EU laws on ebikes limit assist to 25kph/15.5mph, there's even less of a case for moving to 48V, as 24V would handle 25kph assist just fine.

The ideal voltage for an electric bike system is 36V. Some may say that determination is subjective or up for debate, but when you consider the extreme inefficiency of aerodynamic drag from cycling above 25 or 30MPH, it becomes clear that the value-add of an ebike is really all about getting you up to 20 or 25MPH and no further, and any acceleration above that speed is a big waste of energy. 48V systems are better for bikes that cruise at 30MPH, however, that comes with a big loss in aerodynamic efficiency at top speed, and consequently reduces range.

There is a case for 48V even at low speeds. With higher voltages you can use less amps to reach the same desired power level. Less amps are desirable because it involves less heat and therefore can have higher efficiency. Higher voltages can also allow a battery to contain more energy (watt hours) using the same number of cells yielding more range.

 

[Cameron Newland]

There is a case for 48V even at low speeds. With higher voltages you can use less amps to reach the same desired power level. Less amps are desirable because it involves less heat and therefore can have higher efficiency. Higher voltages can also allow a battery to contain more energy (watt hours) using the same number of cells yielding more range.

There is no case for 48V at low speeds because 36V@15A (540W) provides all the power one could need on an electric bicycle, and 15A is easily carried by regular-gauge (~18AWG) wires without losing much energy in the form of heat. Higher voltage batteries do not contain more energy (watt-hours) using the same number of cells. They provide the exact same amount of energy, but the higher voltage systems offer lower range for two reasons:

1) less amp-hours
2) more aerodynamic drag (assuming higher top speed with higher voltage system)

Ebike range varies directly with the battery's amp-hours, not watt-hours. Why? Because higher voltage and/or more watts means higher top speed, and consequently lower efficiency/more aerodynamic drag. Lower voltage and/or less watts means lower top speed, greater range, and less aerodynamic drag.

The only way that a 48V system could offer the same range as a 36V system with an equivalent-energy (watt-hours) battery would be if the 48V system's controller was programmed to draw 25% less current from the battery so as to theoretically match the power output (in watts) of the 36V system, however, this would have one minor downside, which is that torque would be lower on the 48V system because it's drawing less current in order to produce equal power.

 

[MLB]

Why would you look at assumed higher speeds when the bikes in question are clearly all speed regulated?

 

[George S.]

“Whoever thinks that the ebike community is going to be satisfied with 250W, 500W or even 1000W ebike laws is dreaming. As long as the sun keeps rising, there’s going to be guys out there who will push the limits until they inadvertently find out what those limits are. By the same token we would like to help raise the standard of DIY ebikes across the world and see those limits pushed further. I want to see how nutso these guys can get.”

This is from the CEO of Stealth (Bomber). I assume this is why 36v batteries are disappearing from the catalogs of DIY vendors, like Luna. It means that Luna can't sell into the 36v replacement market very well, which could be a missed opportunity.

The ebike industry will have to settle whether there is a bright line somewhere, a power limit that absolutely defines an ebike. Which is not to say that you can't build something with a higher wattage, it just won't be an ebike.

I would rather buy 36 volt batteries, but good luck with that, DIY.

 

[MLB]

The Swiss Stromer ST2 uses 48v batteries.

Interesting. With Easy Motion going to some as well it sounds like it may just have been the "standard" and now that 48v is becoming more common they are getting on board too.
I find no need for the extra power, but "more power" drives american marketing and consumer trends like very little else. (maybe "sexier"?)

 

[harryS]

The number of cells in my batteries goes from a 40 count for 36 volts to 52 count for 48 volts. Sure, there's a power advantage from those 12 extra cells. You can waste it bombing along at 25 mph, or conserve it for more range at near bike speeds.

Costs more though. In the competitive Euro market or the even more frugal Asian market, I would expect a preference for 36 volts. Probably more of an economic truism than a mandate.

 

[Cameron Newland]

Why would you look at assumed higher speeds when the bikes in question are clearly all speed regulated?

I assume higher speeds because there is no reason to go to 48V except to attain higher speeds. If your bike is limited to 25kph (15.5mph) or 32kph (20mph), then all you'll need is a 36V/250W (nominal) motor. 36V/350W (nominal) Bosch systems are quite capable of 28MPH (45kph) cruising.

 

[MLB]

I assume higher speeds because there is no reason to go to 48V except to attain higher speeds. If your bike is limited to 25kph (15.5mph) or 32kph (20mph), then all you'll need is a 36V/250W (nominal) motor. 36V/350W (nominal) Bosch systems are quite capable of 28MPH (45kph) cruising.

As noted above, running higher voltage and lower amps keeps a motor cooler. My 500w Falco motor (36v) shuts down via thermal switch at less than 10 miles of mild assist. They suggest going to 48v and less amp through the controller. There are reasons other than going faster.

 

[EddieJ]

My KTM e-Race P was 48v.

 

[Cameron Newland]

As noted above, running higher voltage and lower amps keeps a motor cooler. My 500w Falco motor (36v) shuts down via thermal switch at less than 10 miles of mild assist. They suggest going to 48v and less amp through the controller. There are reasons other than going faster.

It sounds like we're in complete agreement. The Falco is shutting down because it needs 48V to go faster without overheating, just as I proposed earlier.

Would the Falco overheat if you only go 20MPH on flat ground @36V?

More importantly, any motor that overheats on mild assist at 36V is not a true 36V motor no matter what the manufacturer tells you. If it only works reliably at 48V, it's a 48V motor. If Falco knows it overheats at 36V on mild assist, they should limit the continuous current to a reliable level.

 

[tomjasz]

I would rather buy 36 volt batteries, but good luck with that, DIY.

Hey George! I don't know if you are comfortable with soldering, but there's a new kit about to be introduced. 10s3p with GA cells the 3p are already welded and the 10s is accomplished without over heating the cells. Pricing and more to come over the next week. NOT my project nor do I have any $$ invested. I do have a sample pack and I find 10s3p GA cells are about perfect for my BBS01. I expect to get near 20 miles and the active wife will get twice that for mileage. Very stealthy at that size as well.

 

[George S.]

Hey George! I don't know if you are comfortable with soldering, but there's a new kit about to be introduced. 10s3p with GA cells the 3p are already welded and the 10s is accomplished without over heating the cells. Pricing and more to come over the next week. NOT my project nor do I have any $$ invested. I do have a sample pack and I find 10s3p GA cells are about perfect for my BBS01. I expect to get near 20 miles and the active wife will get twice that for mileage. Very stealthy at that size as well.

Thanks. I like the idea of pre-welded cells a lot. I (Link Removed - No Longer Exists)for an early spring project if I could run down some information. I have the Luna Mini pack with the 30Q cells. It's a great size and 3+ lbs, but the 52 volt isn't ideal. I can carry two small packs easily, separately, and get range if I need it.

The GA cells may end up being something that a lot of people use. I really expect the RC guys to get out of LiPo because the cost of real cells is now low enough and there is a better power to weight ratio. I like the basic LiPo chargers which provide a lot more information, and work with standard lith cells. If Hobby King started pushing this stuff, I don't know what would happen.

I hope you can post anything you find out. I would probably buy one if the price is decent. I feel like I want some options where I put sub-packs into a useable pack and maybe I do my own work on the chargers and BMS.

 

[tomjasz]

I hope you can post anything you find out. I would probably buy one if the price is decent. I feel like I want some options where I put sub-packs into a useable pack and maybe I do my own work on the chargers and BMS.

George,

I will, the announcement is about a week out and the video is done. If you email me I can share a picture that I ask not be shared until the story breaks. [email protected] I'm looking forward to the discussion. It isn't the perfect solution but a viable one.

 

[MLB]

It sounds like we're in complete agreement. The Falco is shutting down because it needs 48V to go faster without overheating, just as I proposed earlier.

Would the Falco overheat if you only go 20MPH on flat ground @36V?

More importantly, any motor that overheats on mild assist at 36V is not a true 36V motor no matter what the manufacturer tells you. If it only works reliably at 48V, it's a 48V motor. If Falco knows it overheats at 36V on mild assist, they should limit the continuous current to a reliable level.

I don't speak in riddles, so no, we're not in agreement.
The Falco IS overheating BELOW 20mph on flat ground at 36v. And I'm pretty sure they know what their motor IS.

 

[Cameron Newland]

I don't speak in riddles, so no, we're not in agreement.
The Falco IS overheating BELOW 20mph on flat ground at 36v. And I'm pretty sure they know what their motor IS.

Interesting. If a motor overheats during the course of normal operation at 36V, is it truly a 36V motor?

 

[AlanFalck]

I've acquired a 48v Battery for my 36V Easy Motion lite, I modified the plug and tested it, yes a 48v Batt on a 36v Bike and found no difference. The controller converts the DC to AC anyway, so the motor would not see any change.
I've made a short video if you are interested in this project

(and no, I'm not concerned about warranty or compliance).

 

[MLB]

I've ridden 2 bikes in both 36v and 48v and there was a

I've acquired a 48v Battery for my 36V Easy Motion lite, I modified the plug and tested it, yes a 48v Batt on a 36v Bike and found no difference. The controller converts the DC to AC anyway, so the motor would not see any change.
I've made a short video if you are interested in this project

(and no, I'm not concerned about warranty or compliance)


I've ridden 2 different bikes in both 36v and 48v and there was a definite and easy to notice difference in performance. If you felt no difference then I'd think something in the system not recognizing or taking advantage of the extra voltage.

 

[AlanFalck]

Hi my initial comparison was not very scientific so I'll do some better testing once I have installed my new BMS and charger I'm building for the 48v pack. I do recall a you tube speed hack adding in an extra pack to the 36v system boosting performance significantly so I'll do some more testing.