Double check my numbers, anyone?

[FreepZ]

I don't really want to self promote, but here goes anyway.

I've been inspired by Brammofan (and others) to write a blog about owning and operating an Empulse. It's a bit premature, since I don't own one at the moment, but the plan is to start the blog with some preparation steps that I'm going through in anticipation of owning the bike. (E.g. I'm sure I'll have a posting that describes the installation of a J1772 charging station in my garage.)

My most recent posting is related to planning a route and estimating power usage. I would be grateful if some folks from this forum could take a second look over the posting and let me know if I made any obvious errors.

Here's the link:
http://freepz.wordpress.com/2012/03/23/planning-the-route/

[protomech]

Wow, a 75 mile commute? Is that something that you do every day? : o

One thing I would love to see, from Brammo or Zero, is aero fairings for highway riding. I could probably make it on the ZF9 down to mom's house, 80 miles away on state highways at 55 mph with less aero drag. No way in the current configuration.

And for all we know, Brammo may have done some substantial aero work on the Empulse to reduce its drag at highway speeds. That would be a huge benefit for high speed riding.. but it would also probably dictate some rather extreme departures from the concept design.

One suggestion I would make is to change "Power requirements" to "Energy requirements" .. or "capacity used" if you'd rather.

A big question for me is what the actual shipping battery configuration for the Empulse 10.0 will be - and this has a big impact on what your trip plans will be, since you're right at the edge of what's possible.

The easy options for Brammo are 9.3 kWh (88v 105ah, using 3x 35ah), 9.8 kWh (88v 110ah, using 2x 55ah), and 10.7 kWh (88v 120ah, using 2x60ah, 3x40ah, 4x30ah, etc). Of course, they could probably get a custom cell size made with a big enough order.. but I think they're going to pitch the Empulse as a bit of a specialty item.

I think your best bet will be the No Highway route for now. This should be a bit safer, since you can run with traffic flow instead of running well under it. I would definitely start conservative and progress from there. Your math looks fine - at least as a placeholder until you get your bike and you can see how your riding style and riding posture actually work out. Ordering the Empulse with clipons vs the higher handlebars could make a significant difference in highway energy consumption.

Because charging is so slow, even with the Empulse 3kw charger, if you can make the trip in one leg at a slower speed it will definitely be faster than a higher speed route that requires an hour of charging in a break. Of course, two hours on a bike you may be ready for a short stop in the middle anyhow : P

Your numbers look good, I just really would caution you against a) pushing your range on the freeway and b) pushing your safety by running below traffic speeds. You might ask Nathan Abbott how well b) works out.. (actually it seems to work out okay, he made a trip back that way recently to meet the girl that hit him, they're friends of a type now : P)

[protomech]

Also, we don't know what inlets the Empulse will feature - it will certainly have a J1772 inlet, but it may also have a C20 inlet as on the Enertia. In that case you should be able to get a very cheap ($30) cable that would plug in just fine at the UCF location.

If the Empulse just has a J1772 port, then Brammo will likely supply you with a J1772 to NEMA 5-15 cable for 110v charging included with the bike. You could make a pigtail adapter to plug into a NEMA 6-20 socket yourself.

I suspect Brammo will go the former route (two inlets) rather than supply you with a J1772 cable, since the J1772 plugs are still quite expensive.

In either case, I don't think you would need to bring a portable charging station with you, a standard cable or a small adapter and your stock cable should be fine.

[EmpulseRider]

Welcome to the club Freepz! You may be able to get Brammo to send you some free schwag since you're blogging about Brammo products. They sent out Brammo hats a while back. Worth a try at least.

[FreepZ]

@protomech:

Thanks for the suggested changes.

I would expect the Empulse to have a C20 inlet, but would I be able to plug 240 V in there and get faster charging, or would it be limited to 120 V slow charging? At UCF they have 20 A, 120 V and 240 V sockets (NEMA 5-20 and 6-20), so if the only purpose of an adapter would be to convert the plug, I wouldn't need that (unless the Empulse only had J1772).

The 75 mile commute has been daily for the past week, but I'm going to modify it so that I only do one leg per day. I.e. Stay one night in Orlando, and then stay the next night in Melbourne. That way, when I get the Empulse, I won't have to worry about not getting a full charge before heading back. Also, riding for 2 hours isn't easy. I'm developing a new appreciation for the folks that can ride 4-8 hours at a stretch.

If there are any accessories that would make the bike more streamlined (e.g. windshield), I'll take them! I wonder how much difference fairings would make, since the bike looks pretty smooth already. (Okay, on second look, there are a bunch of bumps around the battery compartment that might make a difference at 65 mph.)



As for taking the Highway, I'm certainly going to do some trials to see what I can get before attempting to do the full trip to Orlando. Also, since I'm only 935th in line, I expect to get a lot more data from the lucky lucky folks who got their bikes before me.

@EmpulseBuyer:

Thanks for the welcome!

I haven't done all that much. Perhaps when I have a few more posts under my belt, I'll tell Brammo about the blog. Heck, they might even find out without me telling them directly.

[protomech]

Euro countries that can do 220v and 10-15a will plug in somewhere. It won't be J1772, I imagine. Most ebike chargers will operate on 80-250v and 50-60hz, the chargers in general don't care whether the power comes from a J1772 inlet or a standard wall plug. So while I don't know for sure, I suspect the Empulse will come with a general purpose plug for a standard 110/220 socket, a localized cable for the same, and a J1772 inlet.

[Richard230]

Regarding streamlining, check out the 1990 BMW K1. My understanding is that bike had about the best streamlining of any mass-produced motorcycle made.  Too bad that few people cared for its looks and it only sold for two years.

On the other hand, the first production BMW motorcycle to be designed in a wind tunnel, was their R100RS model, which worked well at high speeds and was a long running and very popular model.

My observation of the current market is that motorcycle customers really don't like the looks of streamlined motorcycles and that is why the manufacturers are not building them.  It is a sad thing to say that many new automobiles get better fuel mileage at freeway speeds than most motorcycles do - while carrying 4 or 5 passengers, plus their luggage.

As an example, my BMW F650GS gets 70 mpg at 55 mph and only 45 mpg at 75 mph. That discrepancy is almost entirely due to its very poor drag coefficient - which is the result of market and styling compromises. 

[FreepZ]

I would think that one of the problems with a motorcycle is that big rider sitting on top of it, with all of his (or her) gear flapping in the wind. A windshield may help, except that the cross-section area with a big windshield is going to be more than just that of the rider. When I'm riding at 55 mph (or more), I can definitely feel the difference between sitting up and getting the full force of the wind on my chest, and tucking down so that the wind is mostly hitting my helmet. The problem with tucking down is that it gets very tedious after a while.

Perhaps something like this would have better streamlining, but unless I had something to hold up my head, it would get very painful very soon. This is something that is more realistic, but looks pretty gaudy to me, and somewhat impractical for daily use.

Brammo is going with the cafe racer look for the Empulse, which is devoid of anything like a fairing. However, if Brammo wants to come out with some fairings, I'll take them since I'd like to get as much mileage from the battery as possible (although the Empulse does look good without the fairings .

[Richard230]

Your second illustration is the way to go for streamlining, but it would be subject to side-winds and you wouldn't want to ride it on a windy day.

A properly designed and sized windshield can help smooth out the airflow over the rider slightly, but those are tough to design properly and will work for some riders better than others, depending upon their bulk. riding clothing and how they sit on the bike. Your best bet for getting the maximum mileage on a motorcycle is to just slow down - unfortunately.

[protomech]

Take a look at Craig Vetter's fairings:
http://www.craigvetter.com/pages/470MPG/high%20mileage%20fairing.html

I don't know what conditions he tested in to get 470 mpg, but don't get hung up on it. The 2011 FE challenge showed Mr. Vetter and his fairing average 92 mpg in a real-world ride, in 37 degree cold and rain and generally miserable conditions. Speeds were often over 70 mph. This compares to 50s stock at 70.

A 2x reduction in energy used/mile could turn 180 Wh/mile at 70 mph into 90 Wh/mile .. and 120 Wh/mile at 55 mph into 65-70 Wh/mile. In a 7.9 kWh ZF9, that'd give an 88 mile interstate range and a 113 mile state highway range.

Also significant: that boosts an ~850W charge speed from 4.7 miles recharged per hour to 9.4 miles recharged per hour. A 3 kW charger on the Empulse would be boosted from 17 miles per hour to 33 miles per hour - and this is for 70 mph highway miles.

***

Agree that side winds could produce some very dangerous behavior. A well-designed fairing may be able to mitigate some portion of the danger from cross-winds - and a light motorcycle like the Zero will already be subject to some level of crosswind already. Here's a selection of comments from the competitors:

"I didn't really notice the head or tail winds and passing trucks, at least nothing of any concern. It seems the faster the bikes go, the more stable it is. I did notice a side wind from Prim to the base of Mountain Pass. The bike was stable, but I learned to lean into the side winds a good bit." -- Fred Hayes, 133 mpg diesel

"Passing semi-trucks usually caused a minor wiggle. I think that I have been lucky to have a stable motorcycle to start with. Very strong continuous cross wind did push me around but not something that I could not handle. Just lean into the wind and continue at speed." -- Alan Smith, 95 mpg gas ninja 250

"Unsurprisingly, the Street Fighter has the least comfort. The rider has to fight against wind at highway speed. However, it is not subject to strong cross winds at all. It rides very stable and predictable." -- Joshua Chen, unfaired 95 mpg diesel

"I was also forced to lean and counter-steer strongly to maintain my lane position during some of the strong side gusts. Passing the numerous trucks produced some movements but I was usually able to maintain my speed to complete the pass. Compared to the other bikes mine was the most affected by the winds." -- Vic Valdes, 61 mpg gas

Carol Vetter, following Vic in the car said: "It was scarey to ride behind Vic"

[2Slow4u]

My only input is we dont know what depth of discharge brammo will let us run till. So if u have a 10kwhsaw pack limited to 80% the dod then you only get 8kwh...

[FreepZ]

My only input is we dont know what depth of discharge brammo will let us run till. So if u have a 10kwhsaw pack limited to 80% the dod then you only get 8kwh...

I agree. There are a lot of unknowns with the Empulse. It may turn out that I won't be able to even make a 75 mile trip at any reasonable speed. Even thought the Empulse's tag line is "100+ miles, 100+ mph" it may be that the 100 mile range will only be available in "ideal driving conditions", which might mean 35 mph.

As much as I'm looking forward to getting an Empulse, I think that we can all agree that the bike's introduction video is a little bit misleading. The video says:
100+ miles
100+ mph
100 % electric



Very catchy, but it is very easy to understand that as 100 miles AT 100 mph, rather than 100 miles OR 100 mph. Sadly, a more clear explanation of the facts isn't nearly as exciting. I.e.

100+ miles *
100+ mph **

* when going 35 mph
** with 50 miles range

I'm making those numbers up, but you get the idea. At least the 100% electric is 100% true!

Hopefully we'll get some real data soon and we can set aside all the myths and rumors and bring to light the facts.

[protomech]

I don't know how many people will be seriously tripped up over that. 100 mph is a somewhat extreme speed for road riding - it's extreme enough that I think the range claim will be generally understood to be distinct from the top speed claim.

Let's take the Lightning bike as a more extreme example - which they're now selling for $39k. They say:

The Lightning Electric SuperBike has a usable freeway speed range of over 100 miles and a combined city and highway EPA range of over 150 miles and a top speed potential of over 218 mph.

That's a bit more detail than the Empulse video provides, but it's the same basic facts - range and top speed presented side by side. 218 is a rather extreme speed - I wouldn't consider the freeway range to have been calculated at that speed : p

Btw - they have a 12 kWh pack. 100+ miles at freeway speed, if accurate, is a good indication of the benefits of an aero fairing. I assume that's 70 mph speed, so < 120 Wh/mile. Zero S is around 180 Wh/mile at that speed.

I would expect the Enertia Plus's 80+ miles 60+ mph claim to be more easily confused, since many people will want to commonly ride the bike at 60+ mph.