Levo SL Gen 1 32lb levo sl

[Eddy Current]

Men even 1kg heavier is a good weight ... with battery on!

 

[csj]

The Hubs he's used are decent and I'd happliy use those.
but 28 Dt Aerolite spokes, Alu nipples and a 30mm wide ~300g carbon 29er rim is a pretty terrible choice for anything but light (or XC race) use by a very light rider.

Hubs may be fine but the 54t driver is questionable, even for a "half power" motor. They are 24 spoke wheels, too. Even worse.

This is a competition bike where the race is only on the scale. A dropper without the control is moronic, would be better with a fixed post. Also, I suspect the single speed comment was not serious, but I would think that a lighter drivetrain is justified if you are going to use the weakest DT pawls. Drop the gear count to lower the possible torque on the hub.

One thing no one is mentioning is the battery. It is unwise to operate the bike full time on a 160 Wh battery because the cells are not intended for the resultant load they will see. All eMTBs use high power density cells because they can't afford not to. While these cells are rated for as much as 3C discharge, their cycle life is compromised when they are regularly used above ½ C (or 2 hour discharge time). Their only reason for existence is sacrificed when they are operated as though they are high current cells.

The booster batteries on SL's are 13s1p packs using 18650 cells which can provide at most 10A of peak current. To reach rated cycle life, they should be limited to under 1.7A of average current, or about 85 Watts of average draw from the pack. That's about one third of the SL's already anemic peak power output. Consistently exceeding that will result in early life failures of the packs. They will not fail catastrophically but they aren't suitable as primary batteries. It would be cool if Spec would offer a similar booster with 2170 cells. Not only would that be 230 Wh but would largely mitigate this issue.

Now, Francis could limit power to address this problem but in another stroke a genius he chose to remove the motor control from the bars, claiming that reprogramming would allow access to full power while preserving eco mode operation. When something bad happens, it's usually not the result of a single bad decision but a series of them. There's definitely a series of bad decisions here.

 

[jcmonty]

Hubs may be fine but the 54t driver is questionable, even for a "half power" motor. They are 24 spoke wheels, too. Even worse.

This is a competition bike where the race is only on the scale. A dropper without the control is moronic, would be better with a fixed post. Also, I suspect the single speed comment was not serious, but I would think that a lighter drivetrain is justified if you are going to use the weakest DT pawls. Drop the gear count to lower the possible torque on the hub.

One thing no one is mentioning is the battery. It is unwise to operate the bike full time on a 160 Wh battery because the cells are not intended for the resultant load they will see. All eMTBs use high power density cells because they can't afford not to. While these cells are rated for as much as 3C discharge, their cycle life is compromised when they are regularly used above ½ C (or 2 hour discharge time). Their only reason for existence is sacrificed when they are operated as though they are high current cells.

The booster batteries on SL's are 13s1p packs using 18650 cells which can provide at most 10A of peak current. To reach rated cycle life, they should be limited to under 1.7A of average current, or about 85 Watts of average draw from the pack. That's about one third of the SL's already anemic peak power output. Consistently exceeding that will result in early life failures of the packs. They will not fail catastrophically but they aren't suitable as primary batteries. It would be cool if Spec would offer a similar booster with 2170 cells. Not only would that be 230 Wh but would largely mitigate this issue.

Now, Francis could limit power to address this problem but in another stroke a genius he chose to remove the motor control from the bars, claiming that reprogramming would allow access to full power while preserving eco mode operation. When something bad happens, it's usually not the result of a single bad decision but a series of them. There's definitely a series of bad decisions here.

That begs the question whether or not when running the extender with the main pack still attached are you running both packs in parallel? The way I understand is that the BMS will run the main pack flat and then move to the extender, which would then be the same result of the too- high discharge rate for the longevity of the extender.

Maybe the design parameter was assuming that most folks wouldn’t actually run the extender that often and for that long of time in normal use. Hmm

 

[csj]

That begs the question whether or not when running the extender with the main pack still attached are you running both packs in parallel? The way I understand is that the BMS will run the main pack flat and then move to the extender, which would then be the same result of the too- high discharge rate for the longevity of the extender.

Maybe the design parameter was assuming that most folks wouldn’t actually run the extender that often and for that long of time in normal use. Hmm

It is unlikely that the two batteries would balance if they were at different states of charge. The most straightforward use would be one pack or the other but not both at the same time.

I think you are right that the assumption is that occasional use is fine. The cells can handle the load, just with reduced cycle life. This use, though, is not only full time but likely full charge and deep discharge on each ride. Really bad for battery life.

 

[Rob Rides EMTB]

It is unwise to operate the bike full time on a 160 Wh battery because the cells are not intended for the resultant load they will see.

Do you have any source / citation?

Specialized allow a choice when using the 160Wh range extender to be discharged first, before the internal battery.

The Levo SL is a 48v system and discharge rate is lower than full fat Levo.

9:43 here. Confirmed 7 amps max.

 

[jcmonty]

Do you have any source / citation?

Specialized allow a choice when using the 160Wh range extender to be discharged first, before the internal battery.

The Levo SL is a 48v system and discharge rate is lower than full fat Levo.

9:43 here. Confirmed 7 amps max.

It’s a 3.3ah battery . If 0.5c continuous is the spec - that’s ~1.7a. Multiply by 48v gets your 85watts continuous.

c rating is related to the battery type, and without looking, I would wonder what the continuous output and max c rating is measured against in terms of time.

 

[csj]

Do you have any source / citation?

Specialized allow a choice when using the 160Wh range extender to be discharged first, before the internal battery.

The Levo SL is a 48v system and discharge rate is lower than full fat Levo.

9:43 here. Confirmed 7 amps max.

7A is not surprising for the pack.

I doubt there's any e-bike source for cycle degradation, it is a limitation of current battery chemistry.

Here is a link to a Panasonic 20700 data sheet. Not the same as the cells used but a variant. Look at the last chart. http://www.batteryspace.com/prod-specs/10873 specs .pdf

The chart shows much more rapid degradation at higher discharge than lower. Both of the rates show rapid degeneration.

Here's the Sanyo GA https://www.orbtronic.com/content/Datasheet-specs-Sanyo-Panasonic-NCR18650GA-3500mah.pdf

Look at the last graph. Only one discharge rate is shown and it is quite high (6A). Degradation is bad. The GA is fairly representative of what Spec may use. It has been the standard for a while.

The GA cell at high discharge rates degrades from 3.5 Ah to under 3 Ah in only 100 cycles and to about 2.6 Ah in 200. There are plenty of 3 Ah and 2.5 Ah cells that won't degrade like this, so the entire reason for using the high capacity cell is lost if usage results in a rapid loss of capacity. You might notice degradation slows and is briefly level at 300 cycles, but capacity is only 60% by then. No one here would accept that.

Samsung doesn't show graphs in their data sheets, but their cycle life is similar.

Tesla has invested a great deal into managing this issue since they use these cells and have to warranty battery cycle life. Cycle life is at the forefront of battery development and it is well understood that you don't use high energy cells in high current applications and expect longevity. That's exactly what is going on with this bike.

Power tools don't use these kinds of cells, they use high power cells exactly for this reason. While a cell like in the charts is suitable for a booster pack, it's not the right choice in such small quantities as a primary battery.

Frankly, I think this does a real disservice to the potential buyer. Francis has been told of this problem, there was an MTBR thread on it, but he doesn't concern himself with it. He'll likely be given all the replacement packs he wants anyway, if he rides this bike enough for it to matter, so this serves to set unrealistic expectations of what a bike should weigh and what it can do. Not a fan.

 

[RCDallas]

7A is not surprising for the pack.

I doubt there's any e-bike source for cycle degradation, it is a limitation of current battery chemistry.

Here is a link to a Panasonic 20700 data sheet. Not the same as the cells used but a variant. Look at the last chart. http://www.batteryspace.com/prod-specs/10873 specs .pdf

The chart shows much more rapid degradation at higher discharge than lower. Both of the rates show rapid degeneration.

Here's the Sanyo GA https://www.orbtronic.com/content/Datasheet-specs-Sanyo-Panasonic-NCR18650GA-3500mah.pdf

Look at the last graph. Only one discharge rate is shown and it is quite high (6A). Degradation is bad. The GA is fairly representative of what Spec may use. It has been the standard for a while.

The GA cell at high discharge rates degrades from 3.5 Ah to under 3 Ah in only 100 cycles and to about 2.6 Ah in 200. There are plenty of 3 Ah and 2.5 Ah cells that won't degrade like this, so the entire reason for using the high capacity cell is lost if usage results in a rapid loss of capacity. You might notice degradation slows and is briefly level at 300 cycles, but capacity is only 60% by then. No one here would accept that.

Samsung doesn't show graphs in their data sheets, but their cycle life is similar.

Tesla has invested a great deal into managing this issue since they use these cells and have to warranty battery cycle life. Cycle life is at the forefront of battery development and it is well understood that you don't use high energy cells in high current applications and expect longevity. That's exactly what is going on with this bike.

Power tools don't use these kinds of cells, they use high power cells exactly for this reason. While a cell like in the charts is suitable for a booster pack, it's not the right choice in such small quantities as a primary battery.

Frankly, I think this does a real disservice to the potential buyer. Francis has been told of this problem, there was an MTBR thread on it, but he doesn't concern himself with it. He'll likely be given all the replacement packs he wants anyway, if he rides this bike enough for it to matter, so this serves to set unrealistic expectations of what a bike should weigh and what it can do. Not a fan.

The max current of the SL is 7A but looking at all the rides posted the riders are getting about 1.5-2hrs use out of an extender battery which would translate to and average discharge rate of .5 -.67C which is less of a compromise. I agree that the lifespan of the smaller battery will be reduced compared to a higher capacity battery and I wouldn't do it just to save weight but the slightly shortened lifespan of using just the extender battery should be acceptable considering the convenience of being able to fly with two of theses batteries in your carry-on. Can't do that with any other eMTB battery out there.

 

[csj]

The max current of the SL is 7A but looking at all the rides posted the riders are getting about 1.5-2hrs use out of an extender battery which would translate to and average discharge rate of .5 -.67C which is less of a compromise. I agree that the lifespan of the smaller battery will be reduced compared to a higher capacity battery and I wouldn't do it just to save weight but the slightly shortened lifespan of using just the extender battery should be acceptable considering the convenience of being able to fly with two of theses batteries in your carry-on. Can't do that with any other eMTB battery out there.

I agree, if a rider gets that kind of ride length out of an extender then cycle life should be fine, but that would imply that riders are only averaging 80-100 watts which is pretty low. It's another argument, of course, but when have you crippled an eMTB sufficiently that assist is no longer justified?

As a practical matter, though, Francis in the video explicitly claimed that full power would be usable and that removing the ability to ensure low power usage (through the handlebar control) was a virtue. He's really not giving any consideration to limiting power draw and I know for unrelated reasons that he ignores that any such cycle life issue even exists.

Also, 160 Wh batteries are not acceptable in carry-ons everywhere. Definitely a factor if that works in your case. In the US, you can ship 300 Wh batteries without much trouble provided you use ground (and label properly). I'd rather exploit that personally, though I'm not aware of any option to other than full custom.

 

[jcmonty]

The max current of the SL is 7A but looking at all the rides posted the riders are getting about 1.5-2hrs use out of an extender battery which would translate to and average discharge rate of .5 -.67C which is less of a compromise. I agree that the lifespan of the smaller battery will be reduced compared to a higher capacity battery and I wouldn't do it just to save weight but the slightly shortened lifespan of using just the extender battery should be acceptable considering the convenience of being able to fly with two of theses batteries in your carry-on. Can't do that with any other eMTB battery out there.

You bring up a good point on the ride length, but in reality, the "Pedaling time" or when the motor is active will be less than that full amount. So the average wattage and by extension, the average discharge when in use will be higher. Of course, that will vary with terrain.

Side note: There is a cool third party app called "Elevate" that integrates with Strava on the desktop. One of the parameters that you can check out is "pedaling time". I back out my average wattage (from bike) this way since when I am not pedaling, the motor output is nil.

 

[Fivetones]

I think comparing a £350 battery to a £60k car/battery is a little unfair. Expectations of battery life and degradation are much much higher for a car. I think degradation vs. convenience is the compromise most are willing to take for an ebike battery.

 

[csj]

I think comparing a £350 battery to a £60k car/battery is a little unfair. Expectations of battery life and degradation are much much higher for a car. I think degradation vs. convenience is the compromise most are willing to take for an ebike battery.

Sure, but who made that comparison? It's hard to say who is willing to accept such a compromise when few even realize it exists. If your 160 Wh battery offers only 110 Wh after a year of use, will you just accept that you agreed to that up front or will you seek warranty replacement? I bet most will do the latter. I know Francis will.

Also, I'll note the Francis suggested that using this bike would entail carrying a couple of extra batteries in a pack. First, you think he's planning on 2 hours per battery? Second, why bother removing the internal battery in the first place then?

 

[csj]

So with reporting battery to travel/fly. If your battery is down to 30% power can you claim it’s capacity to fly? Or is a drained battery as unstable as a max charged battery?

The capacity relates to the total lithium content of the battery, so no. That would be nice.

 

[CjP]

Looking up online, most airlines allow up to two spare batteries between 100 to 160w to be carried in carry on luggage.

 

[OldGoatMTB]

Some of the things he has done to get it under 32lbs are not really practical, but some are not too expensive (lighter tubeless tyres) and make sense

Crazy losing the main battery and the dropper switch. Crazy expensive, too!