ST1300 Electric Drive Conversion

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Oct 16, 2013
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155
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Marlborough, MA, USA
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2006 ST1300
I'm at the very early stages of thinking of a project. I love my ST1300 as it is, and will keep it that way. That said, I am really interested in having an electric motorcycle, and am also interested in the project of making one. My thoughts were to find another ST1300 (ideally one that needs a new engine!), and use that as the rolling chassis for my electric conversion. I know that the electric conversion would not have the same range as an ICE powered ST1300, and that is perfectly fine with me. I don't really need it to be a long range touring bike. I just really like the whole machine and would benefit from the Honda build quality, as well as enjoy the aesthetics of another ST1300 chassis in the garage. That said, I don't have to stick with an ST1300, and could move to something else more suitable if it looked right.

The ST1300 is my goal though and will do some more research to see if that's an appropriate target, or if I should change my sights to something else.

If you have, or know of someone who has, already converted an ST1300 to electric power, I'm interested in pointers to their project. I've seen a variety of projects on the net, converting a variety of motorcycles. I even found one guy who started to convert his ST1100, http://st1100ev.blogspot.com/ which is great. It's a good start, but the project hasn't been updated in a while.

At this early stage, I am working on figuring out:

  • how many Watts the electric motor should be able to provide continuously to move me and the bike (bike - engine and associated parts + electric motor + batteries + motor controller + extras + rider (165lbs))
  • what physical size and weight that motor would be, where it will fit, and how it will mount
  • determining the volume available to hold the batteries, which will in part determine total battery capacity, which will determine overall range
  • choosing a battery chemistry, either Lithium Ion or Lithium Polymer (I have extensive experience with both)

There are more issues to enumerate, but for the purposes of getting started, that's my list.

As I said, this project is in the early stage. I've just started thinking about it, but I can't quite get it out of my mind. So it's something I want to learn more about and see if it's something I will pursue. I know that I can purchase a production built electric motorcycle from Zero Motorcycles and Brammo. Those are some great products, and they are good possibilities. However, I'm also interested in making one, so I want to see if I can do that too.

If you have any input/feedback/suggestions/help/data/whereabouts of a rolling chassis, whatever, please share.

Thank you!
Joel
 

Mellow

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I think once you remove the engine you've removed the most reliable part of the ST... but, you at least know the frame will support some good weight.

Haven't seen anyone do this w/ST1300 so it would be cool to watch the progress, good luck.
 
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I know that the electric conversion would not have the same range as an ICE powered ST1300
I've read a few project builds.....probably get less than 20 miles on a charge.....there was a VFR project in Washington or Oregon a couple years ago.....you could google that.....someone on here electrified his mountain bike.....you could contact him, and lastly there's a racing class for electric mcs....that's where the best technology would be found....but major manufacturers stick big bucks into them......good luck and keep us posted.....(BTW, the weight is the killer, hp to weight ratio is everything, and the ST is not known for being light)
 
OP
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2006 ST1300
There are lots of unknowns to work out. I haven't seen what the ST looks like with the engine removed, and don't know exactly where the drive shaft resides. It might be problematic to directly couple the electric motor to the existing drive shaft, but might not, depending on the space available for the motor can. Using a belt drive to centrally locate the motor, might be ok, if the pulleys I'd need to use would have a diameter that would fit into the existing location without fouling anything.

I am slightly concerned about the force that the motor would induce onto the motorcycle frame when it undergoes acceleration. I have to think about the force diagram carefully, but at first blush, it seems that the electric motor mounted with the shaft inline with the drive shaft would induce a bike roll opposite the motor shaft direction of rotation. If it were mounted with the motor shaft perpendicular to the frame, then I think it would induce a pitch axis movement instead. It might not be a high enough magnitude of torque to worry about, but it's something on my mind.

The goldenmotor site looks interesting. I see they offer 10kW drives. I see that the engine in the ST has about 117HP (87kW) on tap if I'm reading the information correctly. I have performed other electric conversions on very large electric helicopter models, and found that equating ICE HP to motor HP or Watts is not 1:1. A smaller output electric motor could provide significantly more power at the drive shaft than the equivalent rated ICE. Though I don't know how that will translate to a motorcycle. I'm certain that 87kW is more than I'd need from an electric motor, but I don't know if the requirements are truly only 10kW. That seems low. I have more research to do to see what I need to target. I wouldn't be surprised though if I could thoroughly power the ST1300 on 50kW.

If anyone knows what the engine weighs, that would be helpful.

I see that GoldenMotor has a dealer in Manchester, NH. They are not too far up the road. Perhaps I'll end up going over there to talk with them...

If a better/more suitable frame makes better sense, I'll look at that too.

At any rate, thanks for the feedback, and I'm looking forward to more.

Joel
 

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Joel, if you're on Facebook check this out: https://www.facebook.com/media/set/?set=a.1077532625567.2014065.1443783414&type=1&l=b9bb03652f

I spoke to the guy who built this bike, which is based on a VFR800 frame. His interesting approach has something to do with his job, as he uses batteries from his employer's computer system's UPS which must be replaced every so often even though they aren't necessarily bad. I started to write an article about the project but found no paying publishers who were interested, so I worked on other projects to put a roof over my family's head. Maybe the FB pix will help you think through your challenges?
 

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I think once you remove the engine you've removed the most reliable part of the ST...
Not to mention that you'll also have removed a key part of the frame, since the engine is a stressed member. The entire lower part of the fairing requires the tip-over bars for support, so you'd have to manufacture someplace to bolt those on or the whole thing's going to be awfully floppy.

Chain- or belt-driven bikes are usually better candidates for electric conversion because the they're a lot less lossy than the whole shaft and final drive mechanism and don't weigh anywhere near as much.

Although if you do go ahead with this, it would be awfully cool to have a couple of batteries (even empty ones) sticking out of the fairing where the valve covers would have been. :)

--Mark
 
OP
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Good points about the stress on the frame without the engine (though I'd certainly fabricate a support as necessary), and also that the chain or belt drive is a mechanically easier arrangement to work with. I still remain excited about all of this, though, perhaps this will swing me to another chassis decision altogether. Though if it's not going to be my beloved ST1300 design, I hope I can still post about it here to share with my ST1300 family. :)

More homework to do!

Joel
 
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If a better/more suitable frame makes better sense, I'll look at that too.
You might wanna try to locate a blown up motorcross or enduro bike.....light strong frame, chain drive....in my mind simpler logistics.....and do the motard thing to it.......keep us posted......sounds like fun........ff
 
OP
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No doubt that a smaller bike will have better performance, will cost less to convert, and will have easier conversion logistics. I will have to look seriously at some other frame alternatives to see what might make sense. I chose the ST1300 as my target because I simply love the bike and would be thrilled to own a second, as an electric. Though, the practicality of this conversion may not be so good, and that may inspire me to choose a more suitable subject. This is all good. This is what the project is all about.

I'll do some more reading and looking, and see if any particular motorcycle frame inspires me. Part of what I liked about the project was that I am so thrilled with the ST, that I'd want a second. There are other motorcycles that look appealing to me, but the one I wanted to own was the ST1300. So that's what I got. I don't have a short list of bikes that I'd also like to own, that would fill my list of potential conversion subjects. But, that in and of itself is a fun thing to do, so I'll keep my eyes out to see what else appeals to me, so I'll have some options.

I ran the numbers tonight to figure out what the battery situation looks like in terms of number, volume, weight, cost, and expected range. I'm going to do some more fact checking to validate some assumptions I made. But even the most liberal assumptions don't bode well for a good conversion with the ST1300.

At the very low end of the power spectrum, if I powered the bike with a 20kW motor and really need to draw 20kW/hrs cruising around for that hour, I'd need 228 x 6s 5000mAH Lithium Polymer batteries to power this system for one continuous hour of operation. (I can provide the math later, but let's leave it out for a moment). That would be almost 300lbs worth of battery, and would cost $17,000 without getting any special quantity discount. The volume is large, and though I didn't calculate it, the volumetric scanner in my eyes tell me that it wouldn't fit well on the bike. These individual batteries are about the size of a brick. If I assumed that the 20kW would let me drive at 45mph for an hour, that's a 45 mile range. If it actually takes only 10kW to drive at 45mph for an hour, then it either doubles my range to 90 miles, or I can use half the batteries, save the weight and save the expense. But even that, a 10kW Lithium Polymer array, is pricey at $8500.

It's not that spending $8500 on Lithium Polymer batteries is out of the question. But, that's still only a 10kW array, so the range is really short, but I don't know exactly what it would be. There are too many unknowns at the moment. It could be 20 miles, it could be 45. It's too hard to say just yet.

So the obvious problem is that the ST1300 chassis is a beast of a machine, and given that, requires such a large motor in the first place. So if I chose a smaller/lighter frame, as some of you have suggested, it lets me use smaller batteries, a smaller motor, keep the cost down, make it easier to fit, and extend the range of the whole system! :)

Well, more thinking to do..

Joel
 
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Very very interesting project. The size of the ST should give you quite some space to put in a decent battery pack. I am working in the EV arena, as sales manager.

Can't help you too much on the technical side, but maybe some pointers on the concept :
1. To drive a car at highway speeds, you only need about 30kW average. Of course to accelerate you need more. Most of the early compact EVs have about 30-60kW motors. 20-30kW for a bike should be more than sufficient in my opinion.
2. An electric motor has great torque at low RPM, but in order to reach highway speeds, you typically need to have some kind of transmission. Typically, EV's have a transmission with one fixed drive ratio. Since this is very difficult to design and build, I recommend you to select an electric motor that has a similar RPM range as the ST1300 engine, and just use the 5-speed gearbox. It's easier to do, and it will give you monster acceleration. You may never need to use Gear 1 & 2. My company actually converted a BMW 3-series, put in a 200hp electric motor with 6000rpm rated speed. We just hooked it up to the 5-sp manual gearbox. You can probably get electric motors with a slightly higher speed range, say 8000-9000 rpm, 20-30kW should give you fantastic performance this way :)


Good luck and do keep us posted !
 
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I was lucky enough to test drive a Lito Sora, and I was amazed at the research they had put in that thing to make it what it was. It was very compact and somewhat heavy for the size, but very nimble and it felt light and so smooth. I'd buy one right now if I had 45 grands. To achieve that, they had to design the bike from scratch and I think only the wheels and front fork were standard aftermarket. The frame was pretty complex and as different from a conventional motorcycle frame as say, a car frame. And I am not exaggerating. So the big problem I see with a retrofit into a conventional bike is that you would not be able to make it as compact and probably not as balanced because the shape of the frame would already be defined beforehand and would not fit the shape of the motor and batteries. Did I mention lots of batteries?

I'd start by finding the right components and custom build a frame around it. And probably even then it would be pretty expensive, and you would end up with an oversized electric scooter.
 
OP
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Marlborough, MA, USA
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2006 ST1300
I've been running some calculations to see where things stand. I've had to make a few basic assumptions to get started, and I think I have some numbers that put me in the right ball-park. Here's what I've worked out so far:

I am projecting that the ICE and ICE related accessories weigh approximately 200 pounds. If I use a 10kW/hr array of LiPo batteries, I can make such a battery at approximately 200 pounds. If I go for LiIon or another LiXX chemistry, it's closer to 260lbs. The LiPo array will require 1.7 cubic feet, and the LiIon would require 2.4 cubic feet.

I picked a target of 10kW/h array as a starting point. If I go too small, the range will be limited. If I go too big, the volume gets high and the weight and power requirements go up and that impacts range, too. There are diminishing returns and a real knee in the curve. I have not exhausted all options yet. I've only begun to draw the curves. There's an optimal battery size somewhere, but I haven't calculated it yet. Still, from what I can tell, 10kW/hr would be a good starting size for this bike given its weight.

Since I weigh 165lbs, the bike without the motor (660 - 200), plus batteries (200 lbs), plus motor (30 - 100 pounds) and miscellaneous related to the motor electronics, gives me an approximate driving weight (me + bike) at 850 to 925lbs, depending on the motor choice. Lets go with 900 pounds for now.

For my target, I decided that accelerating to 65MPH in 6s to 8s would be ideal. Given that, I calculated how much power in watts is required to accelerate 900 pounds to 65MPH. Ignoring mechanical inefficiency and wind resistance, just to keep it simple enough for me to calculate easily, I learned that it will take approximately 57kW peak to accelerate to 65MPH in 6s, and 43kW peak to accelerate to 65MPH in 8s. Before I ran any numbers, I was looking at the 10kW motors from Golden Motor to get started, which peak out at 20kW. That motor, would require 17 seconds to accelerate the bike to 65MPH. That's kinda slow.

I didn't calculate the power required to achieve steady state operation once at a given speed, but, based on data I have seen, I expect it to be in the 8 to 12kW range if I keep the bike at 35-45mph.

Let's say the bike consumes 10kW/hr on average. The battery array is good for 80% of its rated capacity, so we get 8kW/hr out of 10kW/hr.

Assuming I get 8kW/hr from the battery, and the bike draws 10kW/hr, I'd get a little over 45 minutes of run time in my speed range. If that held up, I'd get 30 miles per charge at 40mph.

The LiPo array has a street price of close to $7K before any quantity discount. The LiIon array would cost a little less, and is easier to charge. LiIon is a better choice in that regard for a project like this, but there's a weight and volume penalty.

The motor + controller will cost on the order of $3500 to $7000 depending on what motor I would choose.

I can see that making the E-ST1300 is technically feasible, but it will get very expensive very quickly.

I haven't thrown in the towel yet. I have been fascinated by running the equations to see what was possible. Certainly, building a lighter bike will be cheaper, and will have better performance. The "only" problem is finding a suitable bike that I'd really like to ride when this is all finished. Otherwise, it's an expensive intellectual and physical exercise. I'd really like to tear down a bike and build one as an electric, but I'm not so sure the ST1300 will be a good starting point for that simply give its weight.

That's all for now..

Joel
 
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