Now really - how to extend mileage?

[#47 (formerly 9 of 30)]

I have read that 5k rpm is the peak power band for the Empulse R. But also that is the most efficient rpm to run the bike at. So it is not like an ICE where the idea is to lower the rpm to save fuel? When the 120 +/- mile range at 19 mph was given, what rpm was used? There is no way to go 19 mph at 5k rpm.

I am trying to take an extended ride to the mountains of San Diego County this Friday ( furlough day at work). I have two charging stations planned into the trip but I want to try and get the best range. The first twenty miles is all freeway. Then I hit the first charging station for an hour. Then about 23 miles to the top of Palomar Mountain. Total elevation change of 4,200 feet, but all slower driving. Then back down the "east grade" and down to Santa Ysabel (famous Dudley's Bread and Julian Pie store) and the last charging point. About 33 miles, but about half is downhill - see if I can put some juice back into the battery.
From there I should make it home (about 46 miles). I will have my personal charger in my bag just in case.

[ttxgpfan]

No, not like a gas motor at all.  5k is what you are looking for.  Sport mode has the higher regen, right?

[Shinysideup]

For the same load, electric motors draw much more current at low rpm's; so much so that the Empulse's controller map has to cut back on the power below 4500 rpm to prevent wheelies. Therefore cranking on at low rpm's will impact your range quite a bit... like you wouldn't want to hill climb at 2K. You can actually hear the motor working harder at these lower rpm's. Whereas at 5K in second gear up a long hill, she sings a happy little howl.

While the Empulse won't do 19 mph at 5K, that isn't an issue, for the 19 mph figure is, in the fed mileage test, an average speed in a city environment. Actually one of the mods I'm thinking about would be to increase the rear sprocket size to achieve 5K at lower speeds, since I use the bike in a city every day all day long, and make 6th gear more useful in the speed range I most use (below 85 mph).

IIRC, peak efficiency for both Normal and Sport modes is at 5K, but peak power is at 7K and 6K respectively.

The topography of your trip brings up a question that's been floating in the back of my mind since I've been riding the R:

In long downhills, will I recover more, less,  or the same juice in Sport mode or Normal mode?

My experience of Sport regen is that it's aggressive enough that it will stop the bike on all but the steepest hills. (Down San Francisco's famously steep hills of 20+% grade, it limits speed to about 15 mph). So it may be easier to be in Normal mode for a long period, rather than Sport and having to modulate the amount of regen with the throttle continulously. I suspect, but don't know, that the total amount of energy reclaimed would be pretty close.

More technical minds than mine might know the answer to this no-so-burning question: Protomech? BrammoBrian?

Be sure to give us a trip report... sounds fun!

[protomech]

Gut feeling is that you probably want moderate, consistent regen rather than spiky bursts of regen. The Zero will likewise regen at different rates based upon sport or eco mode; but for us, it's flipped so that eco has stronger regeneration.

Of course, anything lost to friction is 100% lost.. so if light regen is not enough, then strong regen will almost certainly be a win.

Keep in mind the 121 mile range EPA UDDS test is an overall average of 19 mph, but that includes long idle periods to model combustion engine losses. The actual moving average is closer to 30-35 mph, which should be around 4k RPM in 1st gear.

The #1 best thing you can do to extend range is to slow down. Avoiding the freeway will help. Drafting cars or 18 wheelers can also reduce power requirements, if you don't mind hitting suddenly-visible potholes, other foreign object debris in the road, or testing yourself to see if you really can out-panic-brake a car.

The #2 best thing you can do is improve aerodynamics of the bike or riding position. Avoid loose and flapping clothing for sure. A crouched tuck and a windshield can help - total improvement between riding posture and windshield is probably on the order of 10% IME. Not huge, but it helps.

You can probably do some field analysis using the Empulse datalogger. The Zero bikes don't have a lot that's useful.

[#47 (formerly 9 of 30)]

Thanks guys.
So 5k it is - as much as possible. For sure on the grade up the mountain.
I will try tucking down on the freeway.
6 - 7% grade on the east grade. I will check the battery level before and after the drive down. I am curious too.

David

[7racer]

don't forget to reset the trip computer when you set off!  I'm curious to see what you get.

[flar]

If you can stop and power cycle the bike between stretches then the bike will start a new log file so you can then see how each leg differs in terms of power consumption using the log viewer.  Or, if you can remember the mileage then we now know how to correlate the readings with the odometer so that can be used to break up the analysis as well...

[#47 (formerly 9 of 30)]

If you can stop and power cycle the bike between stretches then the bike will start a new log file so you can then see how each leg differs in terms of power consumption using the log viewer.  Or, if you can remember the mileage then we now know how to correlate the readings with the odometer so that can be used to break up the analysis as well...

Will do.
How hard is it to look at the files in the logger? I know there was a discussion about it.

David

[implovator]

So I was switching through the dash display today and I stopped on the PWR display. OMG, it's so awesome. It displays the current power output (or input) in kW. When you're in regen it displays a "+" in front of it. Now it's not instantaneous, either because it doesn't update regularly or it is taking an average every couple of seconds. However, I think you can totally use it as a way to gauge your current output.

I used it a little but today to test a theory that 5k isn't the optimum RPM for cruising. I don't have anything definitive, but I do think I saw a drop while cruising at 51 mph when I shifted up and dropped my RPMs to somewhere around 4.3k.

Anyhow, I'm not saying that I think the optimum RPM for sustained low speed is below 5k yet, but I am saying that you can likely use the PWR reading as a way of getting quicker feedback than running an experiment and pulling the logs later.

[FreepZ]

Will do.
How hard is it to look at the files in the logger? I know there was a discussion about it.

The log files on my bike are on an Apple formatted USB stick, which needs an Apple computer to read it. Other people say they've been able to read their USB sticks with a PC.

Once you get the logs, reading them is super easy. Just use flar's Enspector (which I've modified). You can get it here:
https://bitbucket.org/freepz/enspector/downloads

Note that the Enspector uses a settings file that determine what graphs can be displayed. The default file only has a few settings in there (Odometer, and motor temp, I think). I've recently found the speed and RPM in the data, so I will upload a new settings file to show that some time tonight.

If you don't want to wait, you can manually update the graph by using these values:
Name: Speed
Offset: 0
Length: 2
Scale: 0.1

[BrammoBrian]

So I was switching through the dash display today and I stopped on the PWR display. OMG, it's so awesome. It displays the current power output (or input) in kW. When you're in regen it displays a "+" in front of it. Now it's not instantaneous, either because it doesn't update regularly or it is taking an average every couple of seconds. However, I think you can totally use it as a way to gauge your current output.

I used it a little but today to test a theory that 5k isn't the optimum RPM for cruising. I don't have anything definitive, but I do think I saw a drop while cruising at 51 mph when I shifted up and dropped my RPMs to somewhere around 4.3k.

Anyhow, I'm not saying that I think the optimum RPM for sustained low speed is below 5k yet, but I am saying that you can likely use the PWR reading as a way of getting quicker feedback than running an experiment and pulling the logs later.

Just a quick note to say that the 5k rpm is really just a general guideline based on the efficiency of the motor.  It doesn't necessarily mean that this is the most efficient rpm for a the entire system for a given set of environment variables.  Riding to maximize range is different then riding to maximize pleasure/performance.  I had an extensive conversation with one of our test riders, Wayne Buck, who has more miles on an electric motorcycle than probably anyone in the world.  He specializes in milking range from these vehicles and enjoys doing it - he even got over 60 miles from an Enertia Classic and has done many, many Empulse rides at 70-100 miles.  He describes himself as a "steady state" rider - i.e. he does not make abrupt throttle position changes and anticipates speed changes well in advance to minimize energy consumption.  His tactic is to use the range estimator to "coach" his throttle input, but you could also use the power display to the same result.  He mentioned that he felt my blanket recommendation for 5k rpm is misleading for those trying to maximize range as it may turn out that for a certain rider and environment it is more beneficial to keep the rpm lower than 5k.  I will try to get him to participate here and provide his "tips" for riding far. Here's a pic of Wayne with the Empulse.  As you can see, he's not a petite jockey for the bike, so you can trust that his ability to get great range is due to technique!   

[FreepZ]

A note about the Power meter on the Dash. I find it to be quite impossible to read. It changes state rather quickly and fluctuates wildly (anywhere from 3 kW to 6 kW every update), but the LCD can't keep up with the change. As a result, the numbers blur together, and I cannot tell what the actual power is.

A solution for that would be to slow down the refresh rate so that the numbers change less often.

[Shinysideup]

Another solution to make the readout more useful for those trying to maximize range: switch to  a scalar graph, 0kW at the bottom and 20kW at the top. Keeping the bars at a minimum would help tame the right wrist!

I'm not quite geekish enough to want to delve into my memory stick on a regular basis, so what I do after each ride (when I remember!) is divide the percent of SOC used (100 minus dashboard battery percentage figure) by the miles on each trip. This gives me an index figure that is easy to compare for such variables as identical trips, the type of riding environment involved, my own style employed (hyper-mile vs. aggressive fun) etc. It occurs to me that this is easy enough to do, that, if others are interested in doing so, we could post comparative figures with notes about the rides to see how we're doing as a group.

Lastly, I really look forward to hearing from and learning from Wayne Buck's experience. Hope he finds his way into our asylum!

- Bill

[#47 (formerly 9 of 30)]

I have been watching the power meter, but it does fluctuate up and down a bunch.
I will cycle the power at different points of the route.
The downhill section should not use any power - may even get back one or two percent.
I am going to document every stop - SOC, mileage of stage and RPM ( I will try to keep the RPM steady) and post here.

David

[#47 (formerly 9 of 30)]

Bike ride report:
Had a great time yesterday with friends. I left home one hour and 25 minutes before they did. The first 2.3 miles was non-freeway with the last part all freeway. Got to the North County Fair shopping center off of I-15 with 67% SOC and a total of 21 miles RPM was between 4k and 5k and speeds between 55 and 65 mph.
Elevation was 225 feet - started at 400 feet altitude. Bike took 70 minutes to charge at the Blink station. The hot chocolate ($3.15) at the Starbucks cost more than charging the bike did ($3.00). Waited a mile down the road for the two ICE bikes and one Fiat 500 Abarth to show up. The Fiat driver was my backup and stuck with me the whole ride from there on.
27.1 miles to bottom of the south grade up Palomar. SOC was 54% but elevation is now 2,700 feet. Speeds have been in the 50's keeping the RPM around 5k. Fiat driver takes my bag with L1 charger in it.
6.9 miles to top and Palomar Store. Elevation 5,260 feet.  SOC 36%. 1st gear and 5k all the way up. Hung out at the top and talked to some bicycle riders about the bike.
Down the East grade to the Lake Henshaw Resort (across from Lake Henshaw on S76) and altitude of 2,700 feet. 12.4 miles and 27% SOC. Thought I would maybe come out even with the regen, but did not. 1st and 2nd gear coming down holding at 5k.
For some reason I shifted up into higher gears and never went over 4k on up to the pass elevation of 3,400 feet and then down to Santa Ysabel. Coming down the other side the 10% SOC "Batteries Low" warning came on so of course I went up to 70 mph (I knew I only had a couple of miles to go.
Santa Ysabel elevation 2,900 feet. 12 miles from Henshaw. SOC -  6%. Three empty L2 Blink charging stations. First one would not show any amps charging on the bike screen. Also said 8.25 hours left to charge! Moved to middle charger and it said 3.25 hours to charge. Set my stopwatch, put all my gear in the Abarth and off we all went to the Santa Ysabel Casino for lunch. Then the ICE bike riders left and the Abarth driver and I hung out at the Casino. Took me about 45 minutes to lose - some money and the just talked about things. Work (we both like working there. All four of us work together), guns and casinos. I asked for the manager and got the security guy. I asked him about installing a L2 charger in the parking lot. He said they had already talked about it. I brought up the part where the person waiting for their vehicle to charge (like what I was doing) would have lots of time to spend at their Casino. He agreed. So they know that at least one person would like a charger (or 2) there.
So 3 hours and 15 minutes later I am back at the bike. 6 minutes left on bike screen. About 5 Cobra replica cars pull through the lot. Bright blue with the two white stripes down the middle. NICE!
100% SOC and I know 48 miles to go back on 78 through Ramona and back to I-15. Had some fun on the on ramp. The meters were on and I had to stop. 1st gear and just hit the throttle. The Abarth driver said I just kind of disappeared. Had a truck pull up next to me a couple of miles later and give me a thumbs up.
Got home with 32% SOC and 48 miles driven. Great little experiment. 127 miles total driven. 58.4 miles on 94% of battery in the middle section. The drive back from Santa Ysabel was in the mid 3k RPM and never less than 3rd gear (except for the ramp - he he).