ElectricMotorcycleForum.com
Makes And Models => Energica => Topic started by: tunafish_phd on August 26, 2022, 10:04:50 PM
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I know there's another active post about this currently, but I didn't want this to get buried on the 3rd page of a thread for future folks. I'll keep the main part of this updated as I gain more info.
Hello all!
I finally got my 40t rear in, installed it, and have done some initial testing.
'23 Ribelle RS - Testing a 15/40 sprocket setup
(If you don't actually care about data, or my opinions, skip to the <=====> mark for the TL;DR:)
My initial thoughts: Yep. Its a lot slower off the line, basically took the bike from "I'm in danger" to "man, I'm barely beating liter bikes now"
More thoughtful thoughts:
My speedometer now PERFECTLY matches GPS - WIN
My Odometer now PERFECTLY matches GPS - WIN
I can hit 125 MPH per GPS speed now - WIN
I did not have to change my chain during this, there was enough adjustability in the rear that it wasn't an issue. - WIN
I REALLY REALLY REALLY wish there was a full torque spec manual floating around somewhere. - NEUTRAL
Efficiency took a very harsh negative dive. More thoughts on that one below. - BIG LOSS
(if you dgaf about why I think I got the efficiency loss, skip to the <----->)
Lets talk about that efficiency loss. Grab some coffee and strap in.
With ICE we're very used to discussing efficiency coming from lower RPMs or "the less the motor turns, the more efficient it should be". I think thats true for ICE engines and I think its completely wrong for EV's. Electric motors are torque machines, their draw relates directly to much torque they are supplying as opposed to how fast they are spinning. In a vacuum, keeping an electric motor spinning at 6k rpm isn't much if anymore draw than keeping it spinning at 6 rpm, the big issue we run into is resistances. Wind, rolling, friction, etc. So for us to keep speed on the highway, we're not just keeping the motor running, we're overcoming wind resistance, rolling resistance and friction. In the 44t setup, we have gearing assisting us in overcoming those resistances. By reducing the gear ratio, that extra torque has to come from somewhere, and in our case, the only place to make that up is going to be directly from the motor itself. So whereas with the 44t setup, it might take 10-12 (number from memory of flipping through screens on the highway) torque to "keep speed" its now drawing 15-17 (based on evidence from a single ride) using the 40t setup.
By changing my gear ratio, I have effectively increased the amount of torque the motor itself needs to supply to overcome the same resistances and achieve the same speeds. Basically, since I lost some gearing advantage, that has to be made up somewhere, in this case it seems to be motor battery draw.
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By the numbers (Speeds are all GPS speeds, wh/mi are average observed during riding. Keep in mind I have a lot more data for the 44t at this point):
70mph - 44t: 190 wh/mi average. 40t: 250 wh/mi average
50mph - 44t: 120 wh/mli average. 40t: 170 wh/mi average
By %/distance - 20 mile loop 85% City, 5% 70mph freeway, 10% 50mph highway
44t - 8-10% battery removed at end of loop (this is the average over the last few weeks)
40t - 19% battery used (single data point)
Conclusion about the 40t:
I'm really torn here.
I like the win's I got for Speedo, Odo.
The efficiency hit is pretty harsh.
I REALLY liked feeling like I was going to die every time I grabbed a handful of throttle with the 44t sprocket. Now its merely exciting. Its not "slow" it still beats liter bikes, but only just barely now.
I don't really care about the 125MPH limit so much. Every now and then its fun to hit, but I don't make a lot of trips to Mexico these days.
Next steps:
I think I'm going to stick with the 40t for a week or so, just to get some more data, but as of right now, I'm leaning towards going back to the 44t
I'm interested in trying a 16t in the front, but I'm pretty sure this will be VERY similar to going to a 41t in the rear (.017 difference in gear ratio and I don't have to buy the tool)
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TL;DR:
40T fixed speedometer and odometer issues. Can actually do 125 per GPS now. Bike less fast off the line or out of a dig. Bike is WAY less efficient.
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Damn, totally sucks about the energy loss. Thanks for sharing your findings!
Wanted to do the same, but losing efficiency sucks. Wish we could just have an option to correct the speedo somehow.
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I don't understand all this fuss about the speedometer. I never have time to look at it while passing everyone 8)
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Good info...cannot get away from the dynamics of street riding...for steady state operation say highway speed the difference SB nill, no?
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Steady state riding at highway speeds my energy draw went up be almost 50%!
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Steady state riding at highway speeds my energy draw went up be almost 50%!
:o
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Thank you for sharing this (for me) totally unexpected outcome!
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by show of hands who here believes that the data collection in this thread might, just might, be flawed
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by show of hands who here believes that the data collection in this thread might, just might, be flawed
Hard to say either way without more data points.
I've had two Suzukis previously and they both underread by about 10%, can't say it ever bothered me. For electric bikes, I'd just want the guessometer to mean an accurate distance - meaning 100 miles to mean a hundred miles and not 10% less at 90 miles.
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by show of hands who here believes that the data collection in this thread might, just might, be flawed
Which part? I just reported exactly my experience. I'd like to know how you'd like me to collect more data to help prove what I've learned.
Edit: Prove maybe too strong a word.. Verify is probably a better way to put that?
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I'm sorry to ask (since I don't have a bunch of time to look/think about this in greater detail), but my first question that doesn't seem clear to me: stated efficiency is significantly lost at highway speeds, but it wasn't clear, so, is the highway speed efficiency comparison same speedo speeds from 44t to 40t, or same gps speeds? (ie. are we talking 65mph by both speedo's, or 65mph by gps, and yes I understand 40t speedo=gps speed now, since same speedo speeds from 44t wouldn't be actually same speeds)
Also, realized when you mentioned odometer now reads accurately, it just occurred to me (sorry, maybe I'm slow here :P) but this would have implications for warranty if odometer read 10% higher than actual (as in, you exceed your warranty miles sooner). Just stating as this seems sketchy, like if a manufacturer was allowed 10% higher speedo/odo, wouldn't it be in their best interest to always make sure it's at the max instead of accurate? Just asking to see if I'm wrong here.
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My understanding is the odo reads correctly while the speedo reads incorrectly. The bike knows the real speed, it just displays a different one on the dash for some reason.
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Which part? I just reported exactly my experience. I'd like to know how you'd like me to collect more data to help prove what I've learned.
Edit: Prove maybe too strong a word.. Verify is probably a better way to put that?
We're going to need more data, but there's a chance that, when you changed the gearing, you also interfered with the range calculations algorithm. If the speedo is based on motor RPM and now that's all out of whack with reality, there's a good chance this threw a wrench at Wh/mi and SoC algorithms. I'd be interested to see if the SoC gets miscalculated. Really I'd like to watch the voltage and log that but most people aren't able to access such data.
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Hmm. That would be interesting. You're right, technically I think changing the gearing would interfere with the WH/Mi calculation. Thats why I also included my SOC for a known distance.
Let me talk through my interpretation of what you said about the wh/mi calculation..
Lets assume the motor has no knowledge of actual mileage, because I believe it does not. If I change the gearing, the electronics should have no way of knowing that the distance in a "mile" has changed. Now that we've corrected for mileage/speed by changing sprocket sizes, it would make sense that it takes more energy to go an actual mile because you're physically traveling further "per mile" according to the computer.
I'll go drive a larger, cruise control centric loop this evening and repeat it tomorrow evening with the different sprocket to see where I wind up with with SOC. That should at least get at the total electrons consumed while staying in as controlled an environment as possible. Will also note down any data I can find flipping through the menu's.
Will report back with findings. In the mean time. If you or anyone else has any other data points you'd like me to collect, let me know!
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The odometer on my Ribelle is not perfect but it is close. My trip odometer for today's commute shows. 61.6 miles. My GPS shows 60.4 miles. But of course my speedometer is 10% off like everyone else's. Just a data point for this discussion.
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Really I'd like to watch the voltage and log that but most people aren't able to access such data.
Hans Capelle wrote the excellent OBD app (emapp for iOS, there's an android version too) that gets the voltages from the OBD connector over BLE. That app could be used to log the battery/current/soc/speed values to produce helpful graphs? I don't know if the Android app logs the data, AFAIK the iOS app just shows it... This would take a lot of the guesswork out of the equation.
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Okay - went out on a longer ride, using cruise control to stay at speed limits via GPS whenever possible, in Urban mode, using "moderate" acceleration
loop is mostly 50-60 MPH with maybe 4 miles of "city" driving
51 miles using GPS using 44t sprocket
Started at 98% SOC, finished at 51% - 47% SOC used
Will re-run same loop this evening just to validate those numbers. Then I'll switch sprockets and do it twice again to see what the SOC impacts are. After I'm done I'll update the main post.
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Okay - went out on a longer ride....
Kudos for establishing sprocket change is not a good idea to correct speedo given the noticeable performance loss.
To explain efficiency loss there's likely other variables at play particularly w/ respect to EMCE motor versus the classic PMAC on older bikes, dunno.
To make the "steady-state" data capture easy, why not pick (3) gps speeds like 40mph, 60mph and 80mph which always represents motor mid range regardless of sprocket selected.
Rule is flat road, no pot holes and avoid undulations, activate cruise control for only 2-3 second intervals and do so w/ video capturing bike display setup for trending, the WattHour/Mile value will speak to what is really happening.
These short runs can be done with little space and always negate wind by making 2-runs opposite direction.
Not challenging original results because it factors realistic conditions and many unknowns so consider this test case suggestion pure waste of time.
The speedo source is the quadrature signaling from motor encoder we cannot mess w/ that because it also serves as velocity feedback to drive...we are stuck w/ the 10% error which is easier to mentally manage versus an error of odd value all because of EU compliance w/ ISO standards.
One could say Energica is quite savvy to purposely pick 10% just move the decimal point over one and subtract.
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Speedo deviation is 12-13% on my Ribelle RS and also on my old EsseEsse9, depending on tyre make and wear. Odometer on my Ribelle deviates 3%, that's more than on my EsseEsse9, which was within 1% accurate.
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I just picked the bike up with the new 41T rear sprocket and rode back today, almost 100% interstate at 70-73 MPH. Before I discuss the results, let me start by saying it’s based off a single ride and using semi-educated guesses, with no attempt to be scientific and control for variables like wind speed and direction. However, it’s clear to me that there has been a positive effect on my efficiency at highway speeds. I usually get 55 miles of range for sure 100%->0%, 60 miles if I’m lucky, and 65 if I’m sweating bullets with range anxiety and winds are favorable. Today I rode 55 miles from Alameda to Vacaville and still had 19% SoC left, which I don’t believe has ever happened before on my northbound I-80 trips.
The Wh/mi reader made it look like my efficiency was worse than usual until I remembered that the bike thinks a mile is 6.8% shorter than it really is, causing the efficiency to read high. I’ll have to mentally subtract about 10 Wh/mi in the future. The speedometer is significantly more accurate. When I wanted to go 73 MPH, I used to set it to an indicated 81-82 MPH, and now it’s 76. I’d be even happier if it were balls-on accurate, but we can’t have everything in this world.
I only noticed a slight change to acceleration off the line, it’s still absurdly quick. And when I’m already going 20+ MPH I can’t tell any difference at all. I would suspect it would be even quicker when accelerating to pass someone at highway speeds but I don’t do that very often so I wouldn’t be the best judge.
All in all, I’m very happy with the change and would recommend it to anyone who does a lot of highway riding, even if I can’t be 100% sure that efficiency has actually improved yet.
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A few more rides, and it seems like there is still a positive effect on efficiency, but it’s still too early to tell. It was also extremely windy for one of those rides, making my guesswork even less scientific.
I spoke too soon on the acceleration. I tried giving it the beans from a full stop and it was nowhere near the same level of acceleration. It actually felt like the traction control was kicking in, maybe due to receiving unexpected values. I’ll dial it down to 1 and see if that makes a difference.
Still enjoying the benefits to my speedo’s accuracy.
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So what kind of range are you guys getting with the stock set up? Is it more than 100 miles?
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Well mine is the 13.4 kWh, so nowhere near that. More like 55 miles, 60 on a good day. Now I’m getting about 65, and the gearing change seems to have bumped it a little more but I can’t confirm that yet until I take another ride into the Bay Area. I also noticed that Hans’s app seems to no longer require an ODB dongle for iOS so I’ll try that to give me better data too.
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So what kind of range are you guys getting with the stock set up? Is it more than 100 miles?
if I ran it to 0 I'd be getting right around 100 miles riding on cruise control at 70 on the dash in a tuck.
"Comfortable" range around 90 miles.
If I ride heads up I get about 80 miles.
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100 miles for a Ribelle RS, ? They advertise twice that WTF
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As it cools off in my area a bit, I'm getting more motivated to do a bunch of sprocket changes again.
I'm putting together a loop with minimal stops and traffic and will be running on cruise control as much as possible. For speeds, I'm leaning towards doing 2 runs. One favoring the Speedo for Cruise control, one favoring GPS speeds, Just to see how things stack up, for a total of 4 runs.
Data Points to gather on each run:
1. Odometer reading vs GPS mileage reading
2. SOC at start/end
3. Wh/mi avg reading at a known point in the loop
4. Speedo vs GPS reading at 20/40/60 MPH dash
I realize these are only single data points, but I only have so much time/patience for this at this point.
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100 miles for a Ribelle RS, ? They advertise twice that WTF
Thats why I'm so fired up to get more and more real-world data.
If I'm doing 30-50 MPH I can get 120-140 miles all day long, but real-world highways are not 50mph in the US, they're 60+.
I honestly think the claims are just..... wrong. :-\
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What mode? ECO, SPORT etc
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Sport
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My commute on my Ribelle is 95 miles (144 km) and I get there with 15% left. Commute is 95% highway at 62mph, but I do the distance @68mph according to my Garmin GPS. Slightly better, but not much. Extrapolating I get 95/85*100 = 112 miles of range.
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Reckon that's a good 50% more than my SR/F gets at the same speed, so that's nice.
Cas :)
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As it cools off in my area a bit, I'm getting more motivated to do a bunch of sprocket changes again.
I'm putting together a loop with minimal stops and traffic and will be running on cruise control as much as possible. For speeds, I'm leaning towards doing 2 runs. One favoring the Speedo for Cruise control, one favoring GPS speeds, Just to see how things stack up, for a total of 4 runs.
Data Points to gather on each run:
1. Odometer reading vs GPS mileage reading
2. SOC at start/end
3. Wh/mi avg reading at a known point in the loop
4. Speedo vs GPS reading at 20/40/60 MPH dash
I realize these are only single data points, but I only have so much time/patience for this at this point.
If you want comparable results for different gearing, you need
a fixed route, starting and stopping at the same elevation
fixed speed throughout the course
fixed temperature
no winds
AND
you need to compare how much charge you put into the bike each day- not the bike readout (lots of potential errors).
Even on a fixed route, my daily usage varies a lot.
I commute a fixed route of 83+-1km (depending on map service used to calculate the route). On normal weekdays i charge my SS9+ for just that trip. I get data from the charging box (easee smart charger) which is used solely for the bike.
The lowest consumption i have this year is 5.8kWh one day, maximum is above 10kWh. In August i went relatively consistently below 7 kWh and in May i was mostly at or just below 8 kwh- for the same trip. Wind, temperature and speed has of course everything to do with this. I use significantly less when traversing congested traffic at 20-30 km/h than the usual 80-90 on the same stretches, and wind is generally bad no matter what direction it comes from, because it adds more than it subtracts when going against or sideways vs with its direction.
Adding some data, i have run the bike down to 1% once and then 0% (not stopping) another time. Those days i charged 18.34k and 18.72 kWh, which may or may not seem reasonable considering 18.9kWh advertised capacity, and charge loss is hidden within those figures, so the battery probably stored a few percent less. Range I got was about 230 km as reported by the bike, (i have no better measurement, as i spent the last km's circling very close to home to avoid having to push the bike up hill or for hours.
If the odometer is reasonably accurate i thus got 18,72kWh / 230km = 81,4 Wh/km when emptying the battery- That is a day i was not holding back (i wanted it done) so no slow riding, but no American or German highways either- mostly twisty roads limited around 60-80km/h. Comparably my commute varies from 70 to 120wh/km (typically between 84 and 96 wh/km) - as reported by the charger.
Using the bike to get reported wh/km is meaningless because it uses a moving average of a few km/s. The bike SoC status does change a few percent (around 10% of what is used on a trip of 41.5 km) after the battery has rested for a few minutes, or when temperature changes. SoC is thus not an accurate measure of consumption.
TL:DR Single trip energy usage can be expected to vary quite a lot: 10%+ in similar conditions, and you need to measure consumption outside the bike to get good data.