Real Life Range?

[FreepZ]

Something that I found very appealing with the Empulse was the 100 mile range. Looking at the details of the Zero S's claimed range (114 miles for city riding, but only 63 miles on the highway), and reading protomech's post, I'm beginning to wonder if I will be able get the range that I need for the Empulse to make sense for me.

At 75 mph, a 10.0 kwh bike will probably drain its pack in about 40 minutes / 50 miles.

My plan is to be able to drive from Orlando to Melbourne (FL) on a single charge. The shortest route, which also has much of the way going under 60 mph, is just under 80 miles. Here's the speed /distance breakdown:

25 miles at 40-45 mph (City driving)
25 miles at 50-60 mph (State Road driving)
30 miles at 70-75 mph (Highway driving)

Being Florida, it's pretty much all flat, so no need to worry about climbing any hills.

I have a bad feeling that I would only be able to make that trip if I was being very conservative with speed. I.e. 45 in the city, 55 on state roads and 65 on the highways.

According to Google Maps, the fastest way would be 75 miles of highway and 10 miles of city speeds. I'm pretty sure that there's no way the Empulse could do that.

Sadly, as was pointed out by emotofreak:

Also, as far as I know, Zero is the ONLY electric motorcycle company, in all of history, to have ACTUALLY performed, and reported, the MIC's City (UDDS), and Highway (70mph and 55mph) range numbers.

Once again, Brammo has no data with which to compare...

So until we get real life data, who knows what the actual numbers are going to be?

[protomech]

Here are numbers that I'm using for my own calculations:

45 mph = 110 wh/mile
55 mph = 130 wh/mile
65 mph = 160 wh/mile
70 mph = 180 wh/mile

These are hand-wavey numbers to be sure. They're based loosely on Zero's range numbers and commute logs from one of the forum members here. So just understand that they could be off by 10-15%. In particular, the Empulse may be more (or less) aerodynamic than the Zero, and the controller may be more (or less) efficient.

25 miles (45 mph) * 110 wh/mi = 2.75 kwh
25 miles (55 mph) * 130 wh/mi = 3.25 kwh
30 miles (65 mph) * 160 wh/mi = 4.80 kwh

So around 10.8 kwh total needed for the trip (135 wh/mi average). Ding, you ran out of battery¹.

Options:

* ride a slightly longer, slightly slower route. If you do 25 miles @ 45 mph, you can do around 60 more at 50 mph. 45 mph the whole way is around 90 miles.
* break midway for about an hour to charge, stretch legs, read a book. 1 hour of charging should be around 1 kwh or 6-10 miles.
* decrease the bike's drag through the air. partial streamlining perhaps.
* take another mode of transportation.
* steal the Empulse RR. 12.5 kwh should get you there just fine : )

¹The key number is the pack's nominal (actual) capacity. Zero has traditionally sold their bikes on a maximum capacity rating (about 15% higher than nominal), though since 2011 they have also listed the nominal capacity rating. Brammo's specifications for the Enertia are nominal; I am assuming the Enertia Plus and Empulse capacity ratings are also nominal. If I'm wrong then I'm overestimating the amount you can draw from the pack by around 15%.

 

[FreepZ]

Thanks for doing the math, protomech.

It's looking pretty bad for my hopes of being able to make that trip in one go. I could do the entire trip at under 45 mph by skipping the highway, but it wouldn't be nearly as much fun, it would take a good deal longer and any problem could end up with me stranded. Taking a break on the way isn't really an option as I don't have any place to stop, and I really don't want to have to wait around for an hour.

Of course I'll have exactly the same issues with any other vehicle that is advertised to have a range of 100 miles (e.g. the Nissan Leaf). For goodness sake, I may have to buy a Tesla Model S to get an all electric vehicle that fulfills my range requirements, and that's a heck of a lot more expensive than an Empulse.

I suppose that I can hold out on hope until a real Empulse can be tested, but I guess that I should be prepared to be disappointed.

[Shinysideup]

Another option, in theory only at this point, is to carry extra electrons, either side cases, top case, and/or trailer.

Touring ICE bikes often add extra gas tanks, so why not batteries? Of course the details will have to be worked out, but that's to be expected for a product that isn't in production

This is likely not a cheap option, but less expensive than a Tesla!

[protomech]

Of course I'll have exactly the same issues with any other vehicle that is advertised to have a range of 100 miles (e.g. the Nissan Leaf). For goodness sake, I may have to buy a Tesla Model S to get an all electric vehicle that fulfills my range requirements, and that's a heck of a lot more expensive than an Empulse.

I suppose that I can hold out on hope until a real Empulse can be tested, but I guess that I should be prepared to be disappointed.

Absolutely, you'll want to wait to see what the real world range is. I'm doing a LOT of guessing here.

I suspect the Leaf could barely make the trip - its battery is 2.4x as large as the Empulse 10 and it probably uses around 2x the energy for the trip. The Coda EV sedan has a much larger battery - 36 kwh - and they claim 100 miles highway range. $45k is a much more expensive than the Leaf, but a good bit cheaper than the Model S which should have the same size pack.

Our experience with gas vehicles is that we hear YMMV and think "yeah, sure". I used to drive a mustang rated at 19 city, 27 highway. Driving carefully, I got around 24 mpg city, 30 mpg highway @ 70 mph (no AC). Speed wasn't a huge factor in energy consumption - in fact, fuel consumption got *better* at a constant moderate highway speed than in stop and go city driving. But on an EV bike, 70 mph uses almost 3x as much as energy per mile as EPA UDDS city driving cycle - no surprise then that the UDDS is listed as the keynote range figures.

Hot-swap packs are tricky to use for touring. First, the bike has to have a small pack to be easily handled - the Zero XU 3.0 kwh pack weighs around 50 lbs. Second, the top speed on a small pack bike is limited - XU is 55 mph. Third, at 55 mph you'll be swapping a pack every 20 miles or so.

Add-on packs run into the same limitations except that you don't have to stop to swap. Generally speaking, a fixed integrated pack is a much better design than add-on packs for any particular capacity configuration .. which doesn't help when you're already looking at the highest capacity fixed pack size.

[WanderLust]

Also consider that the range will decrease over time, I dunno how long you plan to be taking this trip and how often...
But if you don't already have a 20% buffer, it doesn't wound like a safe bet to me...

[2Slow4u]

That 20% buffer should already be built in to Brammos system integration. It would be poor engineering on their side if they actually let you discharge to a true 0% SOC. I'm pretty sure this is why the production Empulse gets 10 kWh yet the race bike can use 12kWh (true 100% discharge).

They have to plan for customers driving these things until they shut-off, then not plugging it in all winter and being able to charge it up in the spring and ride as normal. Good old designing products for the mass market.

[oobflyer]

In my experience with a 25AH (3.75 kWh) pack the range varied greatly. With "real world" riding (a mix of city/freeway riding) I could get between 25 and 30 miles/per charge. On a range-test-ride, riding at a constant 25 MPH I got 50 miles on a single charge.
With a 9 or 10 kWh pack we should be able to get 60-70 miles per charge on "real world" riding. I'm betting the 100+ mile range claims only apply to the slow, continuous riding.

[protomech]

Brammo bills the Enertia as having a 3.1 kwh capacity.

The Enertia uses 6 Valence U-Charge 12XP modules. Each module is rated at 12.8V (nominal) and 40Ah (nominal). That gives a total nominal capacity of 3.1 kwh (3.072 if the nominal ratings are precise).

Though we don't know battery details yet for the Empulse, I don't know why they would list anything other than nominal capacity.

Here's the storage procedure for the Enertia:

Preparation for Storage
1. Wash and dry your Enertia. Wax all painted surfaces (except matte surfaces).
2. Lubricate the drive chain (page 65).
3. Inflate the tires to their recommended pressures (page 60).
4. Fully charge the bike (page 39).
5. Store your Enertia in an unheated area, free of dampness, away from sunlight, with a minimum of daily temperature variation.
6. Place your Enertia on blocks to lift both tires off the floor.
7. Cover your Enertia with a porous material. Avoid using plastic or similar non-breathing materials that restrict air flow and allow heat and moisture to accumulate.
If possible, fully charge the bike at least once every (3) three months during storage.

If you discharge down to an indicated 0% charge (which likely IS 0% SOC) and then store it for the winter, you're going to be very unhappy come the spring.

Same thing if you put E85 or diesel in a standard gas car.. there's only so much the manufacturer can do to protect the customer.

***

The overall answer to the question of "real life range?" is that it's impossible to give a single fixed number that adequately covers how far you can travel on the bike.

Zero's 114 mile range on their 7.9 kwh bike is fine if you operate it exactly like the bike was tested. Brammo's "100 mile / 100 mph" ad copy can easily be misinterpreted by a consumer. "Gosh, I ride a lot slower than that, like 85 mph, and I only have a 60 mile commute.. I'll take one!"

Most would-be consumers are smart enough to know that they may not see the manufacturer mileage or range, but typically manufacturer education efforts (if any) are wholly disconnected from their advertising.

[Homer Jay]

When you guys start talking about kilowatts, I am on a completely different planet.  But, reading your discussion about real world distance made me think of a question.  I really don't know how the Integrated Electric Transmission works on the Empulse (I guess you wont need to blip the throttle on downshifts or worry about a back torque limiting clutch, or maybe you do), but in addition to increasing top speed, should it not also increase the range?   

I'd be interested to know.

Take Care.

[oobflyer]

Zero's 114 mile range on their 7.9 kwh bike is fine if you operate it exactly like the bike was tested.

I think the 114 range is based on the 9kWh version.

...in addition to increasing top speed, should it not also increase the range?

This seems quite logical - that's why auto makers changed their transmissions from three to six speeds over the years - to take advantage of the power band and make the most efficient use of fuel.

I would think that Brammo would have had the time to test the new power train with the new transmission and post some new specs....

[protomech]

Off-topic, but Coda just announced a price drop down to $40k for their 36 kwh sedan. That compares more favorably to the 24 kwh Leaf ($35k), and is a straight comparison to the 16 kwh Volt ($40k).
http://green.autoblog.com/2011/11/17/coda-announces-price-drop-starts-production-of-all-electric-s/

When you guys start talking about kilowatts, I am on a completely different planet.  But, reading your discussion about real world distance made me think of a question.  I really don't know how the Integrated Electric Transmission works on the Empulse (I guess you wont need to blip the throttle on downshifts or worry about a back torque limiting clutch, or maybe you do), but in addition to increasing top speed, should it not also increase the range?   

I'd be interested to know.

I think we're all eagerly awaiting details on the IET. Don't know if you'll need to rev-match; carelessly blipping the throttle on an unloaded electric motor (clutch disengaged) is typically a quick way to damage the motor at rpm_max, though I expect Brammo will have addressed this. Back torque should not be a problem.

The IET is likely to be less efficient at a given gear ratio than a direct drive transmission. If you can operate the motor in a more efficient regime then you may be able to make back some or all of these losses. Motor efficiency maps will be specific to a given motor, but generally electric motors are pretty efficient across their range of operation.