ElectricMotorcycleForum.com
Tech => Home Brew => Topic started by: jack63 on January 21, 2011, 09:16:24 AM
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Hi. I'm new to this forum and new to this whole e-bike world. I've been thinking about doing a conversion for a while. Have poked around here and elsewhere on the web. The more I see and learn the more I want to do it. For now I'm just looking for some help with how to get started. I've ridden in past (many moons ago). Had a KZ400 and used it to commute to college and loved it. Now I commute to my job. What I'd like is bike with a range of 40 miles to be safe (My commute is 25 miles and I can recharge at work.) I would like to take expressways if needed so a top speed of 65-70 for 30 minutes would be ideal.
Two questions:
1- Is this doable for roughly $1000 if I were to spend $400-500 on a donor bike? I am dreaming? I know some motors go for over a grand by themselves.
2- Do I start with a donor bike to see what kind of space I have to work with or do I start with components? Any suggestions on donor bikes? I like the classic look - Rebel, Vulcan etc.
Thanks for your help.
Jack
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Well I just visited evalbum.com - awesome conversion projects from Porches to mountain bikes. I think I can answer my first question - $1000 is about 1/2 what I need especially if I spend $500 on a donor bike. I also think I need to drop the highway speed requirement. I might get a max speed of 65 mph but not sustained.
Not giving up just re-evaluating budget and learning more...
Cheers!
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Welcome to the forum.
There's a quote used a lot in Australia "tell 'im he's dreamin'"
Yes, as you've worked out, you're dreaming. Even 2000 dollars is going to be tough for the batteries alone. Prices seem to be around one dollar per watt hour. My bike has 4000 watt hours. You will also need a charger (600), battery management system and controller (500-2000). Then there's lots of other odds and sods to go with it. Custom made sprokets, dc-dc converter, mounts, wiring, connectors, contactors, mounts (both motor and battery). Oh, and I forgot to add, a motor...
It's been said that the cheapest way to buy all the parts you need these days is to buy a complete electric bike and break it apart for your conversion. Of course the end result is going to be not as good as the electric bike you've just bought...
Then if you're only gooing to spend 500 for the donor bike that means that you're pouring a great deal of money into a very old second hand bike. You'll be looking at hundreds to make an old bike safe and enjoyable to ride and in the end you're going to end up with an old bike. It will have old bike wheels and so you will have a limited choice of tyres. The suspension will be poor quality by modern standards even after you've rechromed and rebuilt the forks and replaced the rear shock/s. (Another 1000 dollars) As well the brakes will need rebuilding or replacing depending on their state (100-500 dollars).
Old bikes don't generally have fairings so you're also going to have rather unsightly mounts and odd shaped batteries on show.
In Australia you'd need an engineer's certificate saying it's safe to get it registered.
I just bought a complete one. I've probably explained in the above why I decided to do that.
I think the days of conversions are drawing to a close (not completely, but for all practical purposes. People will always mix and match engines and frames)
I estimated that it would cost me around 22000 dollars to build the bike I wanted or 14000 dollars to buy it ready made.
Cheers Jason =:)
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Jason - thanks for your input.
I started a little spreadsheet with components and costs - I'm beginning to get a little sticker shock. Maybe I should go back and look at buying new.
I just checked the Zero website. The S is listed for $10,000 USD. Top speed 67 mph (105 km/h), range Up to 50 miles (80 km). evalbum.com has a couple of Kawasakis with top speeds at about what I'm looking and similar range for around $4,000 including the donor bikes.
The $14,000 you mentioned must be one hell of a bike!
Will continue my homework. Thanks again.
Jack
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you will get what you pay for (though some expertise does make the dollars go a lot furthur), my build was around $2000 NZD, AGM SLA batteries, ME0708 motor with alltrax controller, cos I went lead acid theres no need for BMS, and a 48V power supply (50 from ebay) is enough to chare em.
However, theres no way you would get enough capacity from cheaper lead acid for the figures you have given.
Do you have any engineering (or the inclination and equipment to learn), electronics or mechanical, that could help and save money with your project? If not, I think you may want to take Jasons suggestion and just buy one. If so, you can likely end up with a very satisfying build which cost less than a premade one.
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Speed costs money, how fast do you want to go?
You can buy a sad old motorcycle. Rip out and sell the engine, exhaust etc and recover some money and end up with rusty old steel frame for free or close to it.
Buy an old golf cart, pull out the motor, controller and second hand batteries. Sell off the unused bits and end up with most of what you need for not much.
Put the lot in with the batteries sticking out where they will. Stick weld it all together with some scrap iron.
Presto! You've got a bike that will probably do 35 mph for 10 miles. Such a deep cycle on the batteries will destroy them in short order (they were old anyway) and then you can cut all the brackets off, put new ones on for the new batteries you've bought and instal them.
Then you'll have an old bike that will do 35 mph for 12 miles.
Then you realise that even with new batteries you can't go as far as you need, the bike weighs a tonne and is so badly balanced that you can barely ride it and stopping is frightening.
Then you remove the batteries and cut the brackets off again and fabricate new ones for lithiums. You should be able to sell off the lead and lead charger you don't need anymore at a small loss to someone else on this list who thinks lead will work.
Then you buy a BMS, controller, charger and motor to suit the lithiums and discover that the brakes aren't up to the new speed you can get out of it. So you pull them apart and find that you can't get spares for the old brakes. So you buy newer things that don't fit properly and spend a bomb getting adaptors made to mate them on. Finally it's together and it looks dreadful, so you buy fairings, fabricate mounts, cut holes in them and get them sprayed.
If you read the blogs of people doing that (building cheap electrics) you see that story repeated again and again.
Here's a typical story: http://blog.evfr.net/?paged=14 (http://blog.evfr.net/?paged=14)
It starts in August 2007 and ends with the death of the constructor while out testing the bike (still incomplete) almost exactly 3 years later. Along the way are two old motorcycles, four battery packs (two never fitted to the bike), I think four motor mounts, two controllers, two motors, assorted chargers to suit the various battery packs, fork rebuilds, replacement fairing parts, resprays and repairs and seemingly endless hassles with registration insurance and title. I don't know how much time he put into it but if you value your time at more than 10 dollars an hour (I do...) then there's got to be 10000 dollars right there.
He clearly had fun, met a lot of people, learnt a lot. However at the end of the day he still didn't have a finished motorcycle he could ride.
If you like making stuff, go ahead, make stuff. Just don't imagine that you're going to do it for 1000 dollars and end up with something that you can ride with safety and enjoy.
Me, if I couldn't buy a ready made one I would buy a bran new top shelf motorcycle as a donor. I think a new Hayabusa would be good, they have a large heavy engine and probably the lowest drag of any mass produced motorcycle on earth. Their engines are popular with kit car builders so I could probably sell it easily. I'd put in about a 20-30 hp motor (Dual Agni 95R probably). A zilla or similar controller. And as many A123 batteries as I could jam in there to get the maximum discharge as close as I can get to 1C for better battery life.
Thank goodness I don't have to do that. Not that I have 40k kicking around looking for something to do anyway.
=:)
PS 14000 is the price of a Zero DS here in Australia. The government adds about 4000 in tax. There are no other makes available, Zero S or DS are my only choices for ready made. (unless I buy someone's homebuilt monstrosity)
PPS, the Zero won't do what you said you wanted, 30 minutes at 70 mph. By definition you're going to have to have enough batteries to limit the discharge to 2C. 70 mph is going to draw about 6 kW from something as slippery as a 'busa if you lie flat on the tank. Say 8 kW if you sit upright. So you will need at least 4 kWh of *usable* battery.
Lead shouldn't be discharged more than 50% (even "deep cycle" batteries). So you will need 8 kWh of lead. Lithium shouldn't be used more than 80%, so you'd need about 5 kWh of lithium.
You'd get about 7 Wh out of each small A123 battery. They're a bit less than 100g each, but say 100g with connectors. That's about 720 cells or 72 kg or 3600 dollars and you'd get about 1-2000 cycles out of them. So 1.80-3.60 dollars per cycle.
With lead you'd need 8 kWh. I'd go for the genesis 26 ah battery. They're about 175 dollars each and have about 300 wh. So you'd need 26 of them at 10 kg each that's 260 kg and $4550 and you'll get about 500 cycles out of them. So that's about 9 dollars per cycle. Of course with that much weight, your rolling resistance will go up, so you'd probably need to add about 10% to those figures.
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BTW, Bogan's bike is a lovely conversion and pretty to look at. (I loved KR-1s). But it does 50 km/h. In case that doesn't mean much to you, that's 30 mph.
You want to go 70. 2 1/3 times faster. You need to cube power as you increase speed. So that's (2 1/3)^3. You will be drawing more than 12 times more power at 70 than he does at 30.
You can't do 12 times more power for 1/2 the dollars.
12 times the power is going to cost you very close to 12 times as much. Which would be 24000 NZD.
It won't be quite that bad but you get the idea.
=:)
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for another 500nzd I could almost certainly get it to 100kmhr (60mph), but this would be quite hard on the batteries, which is why I make the generalisation, that lead acid technology is really only good for round town speeds.
I disagree with gasdive's suggestion that an old bike won't cut it, theres heaps of old bike out there (like my kr1) that are rolling frames going cheap, you will probably need to rebuild the brakes but thats just a few seals and some fluid, maybe you'll need a wheel bearing or two, but it's still far cheaper than a newer model. lithium iron phosphates are coming down in price, and up in availability, you could likely get a good pack for 2k, plus motor for 500, controller for 500, bms/charger another 500, plus 500 bike, is 4k (NZD) ballpark, round up to 5k for contingencies, and you could get a very nice bike, provided you are able to do the assembly and bulk of the fabrication yourself.
Just budget it out for the whole build, we'll tell ya if you're missing something major, then you'll know pretty much what you're in for :D
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Thanks for all the input. It's great hearing the opposing views.
If I dropped the expressway requirement and stuck to back roads my commute would be about 20 miles (32 km), stop and go, max. speed about 45 mph (72 km/h). Roughly 40 minutes drive time. That's one way. I can recharge at work.
Could I do this with 6 12v lead acid batteries? (The max number of lead acid batteries I've seen on conversions is 6 12v.)
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Could I do this with 6 12v lead acid batteries? (The max number of lead acid batteries I've seen on conversions is 6 12v.)
All you've specified there is the voltage. About 78 volts.
Well 78 volts will get you to 45 mph very easily. How long you can stay there depends on how many Ah the batteries are. If you use the Genesis 26 Ah batteries that's about 1 kWh of usable energy. It seems to be a shorter trip now you're on the back roads. To make the maths easier, we'll say that the distance is the same. The 70 mph for 30 minutes was a distance of 35 miles. We estimated that you would use about 4 kWh at that speed. If you halve the speed the drag will drop to roughly 1/4. So since the energy used is force times distance, and the distance is the same while the force is 1/4 then clearly the energy needed is 1/4. So with 6 genesis batteries, 35 mph riding, no stopping or starting, no hills, and (most importantly) no headwind, then yes, you can make it on 6 genesis 26 Ah batteries.
Why do I say "most importantly" when I talk about headwind? If you're driving a car that can do 120 mph at 60 mph then it's only using 1/8 of it's maximum power. If you hit a 35 mph head wind then the drag goes up about 2.5 times. The total energy for your trip (due to wind drag) goes up 2.5 times, but in a car, there is so much other drag and energy loss that you will barely notice. Yes the drag goes up 2.5 times but the drag is probably less than half the energy use in that car. So your experience in cars tells you that you don't need to change your driving plans based on the weather report. Who checks to see the wind direction before they set off on a trip?
Compare that with a motorcycle running into a 35 mph headwind at 35 mph. Now wind drag is almost the whole energy budget. There are no pumping losses, no transmission drag, no airconditioning, no cooling system, no fan, no alternator and very little rolling resistance. Energy is almost all spent on moving the air around.
The bike is seeing an apparent wind of 70 mph. Drag goes up in a square relationship to speed, so drag is 4 times higher than it was in still air. Again energy used is force times distance, distance is the same, force needs to be 4 times higher to overcome drag that's four times higher... So you're back to using the same energy as you would have needed to cover that distance at 70 mph in still air. 4kWh! If you only have 6 genesis 26 Ah batteries you'll use your normal depth of discharge in the first quarter of the trip, then all the emergency depth of discharge in the second quarter and by the time you get half way to work the bike will stop.
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Last post I talked about headwind and what that meant to an electric motorcycle. (btw, the 4 kWh estimate was for a very very slippery motorcycle, real world would probably be about 8 kWh on a naked bike)
I mentioned "no stopping" and "no hills".
So how much energy goes into both of those?
Well the stopping is easy to estimate. The kinetic energy of the bike is converted directly into heat when you stop. So all the energy it took to get you up to speed is wasted. In units used for most of the world, kg, m/s and joules the formula is Energy equals half mass times velocity squared. (classically)
So say with lead batteries the bike weighs 300 kg laden (you're sitting on it too and you need to be accelerated). Lets work it out (very roughly and ignoring relatavistic effects).
So it's half 300 times 35 mph expressed in m/s which is near as makes no difference to 15 m/s times 15 m/s divided by two.
300 X 15 X 15 / 2 = 33750 joules
If you divide by 3600 you get watt hours. It comes out to be about 9 watt hours for each time you stop.
You can stop about 25 times for a quarter of your available energy budget. (harking back to the 6 genesis lead batteries)
if you're going twice as fast (70 mph) then the energy will be four times as much. About 36 watt hours.
Stop 7 times and that's a quarter of your energy budget. (roughly)
Only you know how many stops and starts there are on the journey.
Now consider hills. To make the maths easy I'm going to assume that all the energy is wasted, that is to say you have to control your speed and you can't just ride up and down the hills at a constant speed just by using the throttle.
Again we will use a classical formula and assume that the earth is flat to make the maths easier. The answer will be close to reality.
In that case the energy that you put in to go up the hill is given by the mass times gravity times the height that you go up (or down). If you do the calculation in kg, m and seconds the answer comes out in jouels again.
300 x 10 x ? (what height is there on the trip to work?). We don't know.... So lets rearrange this to find out what height we can go up using only 1/4 of the energy budget.
250 watt hours is 900 000 joules.
900 000 / 300 /10 gives the height in meters. That's 300 metres.
Not bad really, 300 metres is about 1000 feet (give or take). A significant hill. Or two 500 foot hills. Or four 250 foot hills.
Again, only you know how hilly your trip to work really is.
Of course this (and all my other calculations) assume 100% efficiency and zero rolling resistance.
In reality the motor is about 85%, the controller is about 95% and when you discharge a battery fast it puts out less energy than its rated amount. For instance a Genesis discharged in one hour only produces 21.7 Ah rather than it's rated 26 Ah. 83% of it's rated capacity. Discharged in half an hour it only produces 19.5 Ah, 75% of it's rated capacity.
All those inefficencies multipy together. 0.85 x 0.95 x 0.83 and you get (roughly) 2/3 of the rated capacity.
So in the real world, the range will be 2/3 of what I've calculated. The battery capacity used up by climbing a 1000 foot hill will be half as much *again* as what I've calculated. The number of stops you can get away with will be only two thirds. That's if you select enough batteries that you can run for an hour. If you can only run for half an hour then it will be even *worse*.
=:)
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Thanks for all the input. It's great hearing the opposing views.
If I dropped the expressway requirement and stuck to back roads my commute would be about 20 miles (32 km), stop and go, max. speed about 45 mph (72 km/h). Roughly 40 minutes drive time. That's one way. I can recharge at work.
Could I do this with 6 12v lead acid batteries? (The max number of lead acid batteries I've seen on conversions is 6 12v.)
I think that's a big ask for lead acids, probably possible to get the speed and range with a slippery well maintained (low rolling friction bike) but not easy to fit all the batteries in there. There are probably a few 72V systems out there, see what sorta figures they are getting, and what they need to do it.
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I should have been clear. I've got opinions and I've got physics.
Opinions from me are things like me saying it's pointless to start with an old bike and then do a very expensive conversion on it. I know that's not a common opinion in the EV conversion world. Most people start with something that the ICE world considers rubbish or scrap and then fix that up. To me that seems a waste of money because the end result is a very expensive old bike. I don't like old things as much as new things. I don't think I'm alone. Most people value new vehicles more than old ones. Some people value old things more than new things. That's why there is a vintage and veteran vehicle movement. There's no right and wrong. Both opinions are valid.
Then there's physics. No amount of wishful thinking, hoping or clever design will change the amount of energy needed to disturb a certain amount of air by a certain amount. There's a known amount of energy that can be extracted from a battery. These are things that are right and wrong. If the calculations show it's not possible to get the amount of energy out of the battery that you need to do what you want, then it's not possible. You need to either store more energy or change what you want to do. SWIGZ bike is an example of both. He stored more energy and added a KERS so he didn't lose the energy every time he slowed down.
=:)
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Yes air drag is a constant, but without knowing what the constant is, it's pointless to say you can't change it.
I think gasdive, you are unfamiliar with the world of DIY/customs, we see a project like this not as an expensive old bike but a hand-built custom bike, which is why many custom EV owner/builders are happy with what they have done. There hasn't been too much improvement in the last 25 years regarding frames, brakes, and suspension, so I don't see any advantage in using a new biker over an old oneanyway.
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It's reasonably easy to figure out the total drag on any motorcycle that's had a full road test done. Find out the maximum power on the dyno. Find out the top speed. From there the calculation is easy.
This gives you the *minimum* power/energy requirement to do what you want to do. No amount of hand waving will reduce it below that amount. Everything you do from there will increase the storage requirement, adding weight, stopping, going up and down hills. Things like KERS can reduce these other inefficiencies but a steady state roll is the minimum energy requirement.
For instance say your target speed is 110 km/h and your glider is a hayabusa. A 'busa makes near as makes no difference to 150 hp at the rear wheel and has a (non speed limited) top speed of 310 km/h. So to go 110 km/h you would need 150/(310/110)^3 hp at the rear wheel. Which is about 6.7 hp if you lie flat on the tank.
For comparison a BMW R1200GS makes about 88 hp and does 210 km/h. 88/(210/110)^3 is 12.7 hp at the same speed. I used that because I could find the figures and it's typical of a big unfaired bike. (as was popular 30 years ago) It has a few odd shaped projections as one finds on many first iteration electric conversions.
From there you can figure out what you need electrically to get that much power to the rear wheel. I worked out that you're roughly speaking going to get 2/3 of the rated battery power out the rear wheel. So for the 'Busa that's 6.7 X 0.745 X 3 / 2 = 7.5 kW
Or for the GS
12.7 X 0.745 x 3 / 2 = 14.2 kW
Then you simply multiply the time you want to be at that speed by the energy rate to get the total energy requirement.
So (harking back to previous examples) half an hour would equal 3.75 kWh for the 'Busa and 7.1 kWh for the GS conversion. That is usable energy from the batteries chosen.
That's the end of the physics. I'm willing to admit to arithmetic mistakes but the basics are indisputable.
Below is number supported opinion...
For lead you don't want to go below 50% and for lithium you don't want to go below 80%.
So lets do the comparison. Lead with an old draggy bike, Lithium for a new 'busa (I really don't know as I write this how it will come out, so I'm interested too...)
So the lead bike will need 14.2 kWh of batteries. The Genesis 26 have about 343 (rated) watt hours. So you'd need 42 of them at a bit over 420 kg and 7350 USD. (neglecting connectors) I don't think you can get away without a BMS for a battery pack like that. They would last about 500 cycles.
The Lithium bike needs 4.7 kWh. That's 670 A123 batteries. About 3350 USD and 67 kg (including connectors). (possibly up to 7000 dollars if you end up having to buy deWalt packs and rip them apart) You'll get about 2000 cycles.
So after 2000 cycles you'd have spent 3350 on Lithiums for a slippery bike, or 29 000 USD on batteries for lead in an old unfaired bike.
The difference in price would have let you buy 4 near new 'busas
http://sfbay.craigslist.org/eby/mcd/2180644321.html (http://sfbay.craigslist.org/eby/mcd/2180644321.html)
Or you can buy 2 bran new ones
http://suzukicycles.com/Product%20Lines/Cycles/Products/Hayabusa/2011/GSX1300R.aspx?category=sportbike (http://suzukicycles.com/Product%20Lines/Cycles/Products/Hayabusa/2011/GSX1300R.aspx?category=sportbike)
That's not even counting what you can sell the bran new engine for.
My *opinion* is that converting draggy old bikes to lead battery electric, while fun, is a complete waste of time and money. Which is why, despite thinking about it seriously for over a decade, I haven't done it.
=:)
PS, or for the price of the lead acid batteries *alone* you could buy two Brammo Empulse 10.0 that would do everything that's been discussed. (before rebates that is)
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do you work at brammo or something gasdive? ::) the r1200s is an adventure bike, you do realise they made sportsbikes 25 years ago as well? take my kr1 for example (only 23 years old but close enough)
KR1
55hp and 225kmhr, gives 6.4hp for 110 (looks better than the busa because the drag equation isn't perfect and that is probably crank hp), so yeh, old bikes are just as good as new ones. As you've illustrated, lead acids aren't practical or cost effective for highway speed bikes.
But you could still buy the batteries (lithium iron) and all parts (inlcuding bike) for less than half the price of an Empulse 10.
and if we go to his 72kmhr requirement, that drops to around 2hp, add in some rolling drag losses and call it 3kW half an hour commute time is 1.5kwHr, round it to 4 for contingencies and DOD and you'll need a 55Ahr 72V pack. Works out to a draw of .75C so all good for most deep cycle batteries. Around 10 of the ones you listed (not sure if they are the best though) at 100kg and <2000bucks. I think I'd still go with the lithium iron cells for this application though.
another option, (and the one I've chosen) is to get a good motor, frame, controller, and some 'tester' batteries, to get it up and running at half speed, then once I have a bit more money, do a battery upgrade. The 'tester' batteries were around 1/6 the price of lithium ones when I bought. But even the 'tester' batteries are good enough for my commute.
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do you work at brammo or something gasdive?
I thought we could have different *opinions*. Aparently if I hold a different *opinion* to you I could only do that if I'm getting paid by some evil corporation?
You do some math to show that if he's prepared to go very slowly, he can build a 25 year old bike for less than 7000 dollars.
Or if he's not happy with the idea of building a 25 year old motorcycle, he can buy a bran new enertia (that does 100 km/h). He hasn't said which state in the US he lives in, but here's the prices in some states with rebates:
Oklahoma 4059
Colorado 4225
Illinos 4240
Hawaii 5597
California 5834
My *Opinion* is that 4-6000 dollars for a bran new motorcycle represents better value for money than 7000 dollars and 100 hours of your time to build a 25 year old motorcycle. The hotrod community who also build expensive old cars and the chopper community who build expensive old motorcycles have a *different opinion*. As I've said several times, they're *both valid* opinions. As I've said before, if his goal is fun building and the satisfaction of having made something himself then go ahead and build a bike. If his goal is to ride to work on an electric bike, then he's better off buying one. I haven't said, only implied, if he only has 1000 dollars to spend, then his best option is the bus.
=:)
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do you work at brammo or something gasdive?
I thought we could have different *opinions*. Apparently if I hold a different *opinion* to you I could only do that if I'm getting paid by some evil corporation?
of course we can, it was just that you put such a biased and misleading slant on the numbers for old bikes, suggests a vested interest. And you still don't understand DIY/modding, that 25 year old bike will be easily worth double what was paid in construction for it to the creator, of course that's only if it performs as you want it to; if not, it isn't worth so much, so planning is the key! There is a hell of a lot of satisfaction to be had from motorcycle customisation, those who don't are missing out, and those who do, know the more you customise, the better the result :D
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I think I do understand the culture of modifying vehicles. That's why I drew the comparison between electrics and Hot Rodding and Chopper cultures. I've got a friend who builds hotrods.
Thing is that this guy has come here expressing a desire for an electric vehicle to get to work. If someone came on to a Hot Rod forum and said "I need a car to drive to work and I have some small amount of money to spend", would the right advice for that person be to buy a 1938 Ford Coupe spray it in primer and put a temporary engine in it while they fix it up, with the idea that would get them around 'till they could afford a 454 engine, 9" diff, 350 tranny, disc brake front end, 8 coats of paint and a chop top? Would you justify that by saying that it will be worth twice as much to you at the end?
Well it might be worth twice as much to him, but it's not the right solution for someone in that position as decribed.
If he came on and said he was tossing up between a '38 ford and a '38 chev, then the advice would be *completely* different.
If his goal is "an electric motorcycle to ride to work" then my opinion is that buying one is going to be better than building one, but either option is going to cost more money than he has. I get the feeling that he only considered building because he couldn't afford to buy one. Just like building a hotrod costs more than buying a Yaris (that is far better by every objective measure), building an electric bike costs more (now that they're available for sale) than buying a ready made one (for equivalent performance). You may see that as a horribly bias opinion. That's your right.
=:)
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I take no exception to you expressing your opinion, but putting up shonky figures in a build sub-forum to convince members not to build at all kinda ticks me off. Your posts seem to be less about helping the guy, and more about convincing him to make the same choice you did, not cool.
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I don't think my figures were shonky, I showed my reasoning for each one.
Bogan said it all really: "round up to 5k for contingencies, and you could get a very nice bike, provided you are able to do the assembly and bulk of the fabrication yourself."
Or you can buy a complete factory built bike for 3500
http://electricmotorcycleforum.com/boards/index.php?topic=1582.msg4151#msg4151 (http://electricmotorcycleforum.com/boards/index.php?topic=1582.msg4151#msg4151)
=:)
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Philosophy time.
A bit about me first. As my name suggests I've got an interest in diving. Significantly I've got an interest in mixed gas diving. I took up this sport at a time when there was no training available for surface oriented mixed gas diving at all. There were no readily available decompression tables. I taught myself, which was hard as most of the available information was either classified or proprietary. Still I managed to do it and survive, even writing my own decompression tables for gas mixes that no-one else was using. Lots of people didn't survive. I heard a little later that the death rate for mixed gas diving was running at about 20% per dive. I think that was an over estimate, but it was pretty high.
Then I started to get interested in closed circuit mixed gas diving. There was only one “availableâ€
rebreather at the time. They were five years wages each, minimum order of five and only available to reputable governments. And I'm not kidding about the “reputable governments†bit. It was classified as a weapon just like the guided missiles made by the same company and every bit as hard to obtain.
So I made my own. Not only did I make my own, I was a joint founder of AARG which was a group of like minded individuals who were interested in building their own rebreathers. “So I made my own†encapsulates a 5 year journey that took me to some interesting places (including working for an underwater electric vehicle factory), cost me at least tens of thousands of dollars and at least 8000 hours of my time. Perhaps the amount of research I did was overkill but unlike an electric motorcycle, that simply stops, if a rebreather goes wrong the least dangerous thing that will happen is you will inhale a saturated solution of calcium hydroxide (like the drain cleaner, DrainO). More usually you will go to sleep and drown, or convulse and drown or surface and die of the bends.
I think my home build credentials are impeccable. I've done it, I've supported it, I've helped others do it.
So when would I build a rebreather and when would I buy one? In the days when there were none available, the choice was easy. You build or go without. Now 20 years later there are factory built ones around (most are copies of the AARG machines). Now I'd only build if I was going to build something that did things that the factory machines can't do. Cost is part of the reason. It's a lot cheaper to buy the factory kit. They buy their parts in bulk and there's little wastage. For me if I need a tube that's 300 mm long I have to buy a 6 metre pipe to get it. I spend a day of my time researching where I can buy said pipe and I have to drive to the pipe merchants and buy just one at full retail. The factory spends a day researching, gets a pallet of 50 delivered at wholesale price and makes 1000 tubes. For each rebreather part they spend a few seconds and a small part of a dollar where I spend a day and 50 dollars. If I need to put a tapered thread on the inside and outside of a fitting, I buy a tap and die. They're 600 dollars each and I use them both twice. The so each fitting costs me 300 dollars. Compare that with the factory who also spends 600 dollars each but uses them 2000 times. So each fitting costs them 30 cents. Multiply that out for the hundreds of parts involved, include all the parts that you've bought and then discovered they weren't quite right and all the special tools required and you soon discover that building yourself is the most expensive and time consuming way to do it. I see the lessons learnt from building rebreathers as directly applicable to electric bikes.
Safety is the other reason. It's not as much of a concern on an electric bike. They're far less likely to kill you than rebreathers. But it's still a concern. Yes they're slower than the ICE bikes they're based on, but there are a lot of hacks that you're going to be the one out there testing. I'd rather have the factory test riders take that risk for me. Again that's a value judgement. I've taken plenty of risks in the past but only after I'd thought them through and determined that there was no way to do what I wanted without taking those risks.
Remember that blog I linked to? I really strongly identified with that guy. He immersed himself in the electric bike world in order to complete his project. I did the same in the rebreather world (such as it was then). He built a lot and then discarded what he'd built as he learnt more. I had the same experience. He made a lot of friends along the way. So did I. In the end he died while testing. I didn't but I sure came close.
So right now if you apply the criterion that I use for rebreathers, “only build if I was going to build something that did things that the factory machines can't do†that leaves you with a lot of scope. There are only really 3 bikes on the market at the moment. The Zero dirtbike, the Zero street bike and the Brammo street bike (all three have two different versions, but they're really the same bikes). There are others coming like the Brammo 10.0 but if there's one thing I've really learnt from 'breathers it's that it's much easier to write a spec sheet than it is to deliver a product. So the list of things that current electrics can't do or can't be is long. No two seat bikes yet. No bikes with a freeway range beyond about 20 km. No bikes with a top speed over 110 km/h. No choppers, no trials bikes, no drag bikes, no faired bikes. If you're wanting to home build a bike that is or does any of those things, then hats off to you! Go forth and produce something amazing. Tell the rest of us how you did it (like I did with rebreathers). Home building now should be the realm of the incredible one off work of art.
If you say you want to do the equivalent of building a rebreather that is more dangerous and has less range than a factory machine then I will continue to suggest that you just buy a factory one. I'll even do it on a home brew sub section of an electric vehicle forum.
=:)
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Remember that blog I linked to? I really strongly identified with that guy. He immersed himself in the electric bike world in order to complete his project. I did the same in the rebreather world (such as it was then). He built a lot and then discarded what he'd built as he learnt more. I had the same experience. He made a lot of friends along the way. So did I. In the end he died while testing. I didn't but I sure came close.
I believe Travis Gintz (the eVFR guy) is still allive and well, and posts as Frodus on several different web forums such as Endless Sphere
http://www.endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=6092 (http://www.endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=6092)
The guy who died was Matt Dieckmann, who I believe was a friend of Travis, and many who were involved in electric motorcycle racing.
http://www.wired.com/autopia/2010/09/matt-dieckmann-killed/ (http://www.wired.com/autopia/2010/09/matt-dieckmann-killed/)
Anyways, GasDive, I agree with your point, and have been following this thread with great interest, it is good to see the differences of *opinions*
-ryan
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Sorry, I've got the two confused.
I hope I haven't upset anyone. As I said, I strongly identify with those (two) and that sort of experience and I really feel I could fit neatly into those shoes.
Cheers Jason =:)
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If you say you want to do the equivalent of building a rebreather that is more dangerous and has less range than a factory machine then I will continue to suggest that you just buy a factory one. I'll even do it on a home brew sub section of an electric vehicle forum.
See, there you go again, you've provided no evidence to show a home built bike is more dangerous than a factory one (in fact with the zero s etc still in their infancy, I wouldn't be surprised if a donor chassis would handle better), yet you say it is. People coming to the home brew will be far better off with an unbiased evaluation of their options, rather than somebody just telling them what to do.
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Chill out Bogan....
My first bike had 72V and 36Ah of SLA and a K91 motor. It cost me about $2k to build. Range was about 15 miles, it was heavy and topped out at 60mph.
Then I wanted more range.... so I went lithium and should be able to get 80-100mph and about 50 miles or so. Cost is over $8k with an AC15, Lithium, Full BMS and a DeltaQ charger and its not even done yet. Still need to build a battery box and paint the fairings and wire it all up. I expect to spend another $1-2k.
The Empulse 10.0 runs about $11k with all the federal incentives and discounts in oregon. Comparatively, the 6.0 would cost about $7900 with incentives for federal and oregon. Its so low in fact, that I actually considered parting out my project and just buying an Empulse. An Enertia would cost just over $7000.
Please don't try to argue about how you can build for less. I'm sure you can get parts for less, used and throw on an old outdated chassis that needs work/paint/parts. And I'm sure you can machine your own parts. But how much is your time worth? Sure its a fun project, but in the end, whats the bottom line? Add up all your parts cost, labor, research, etc and compare to the cost of a Brammo......try to compare apples to apples, and the manufactured bike will win. My bike will cost quite a bit in the end, and it'l be fun and a huge learning experience, but cheaper? not even close.
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Please don't try to argue about how you can build for less. I'm sure you can get parts for less, used and throw on an old outdated chassis that needs work/paint/parts. And I'm sure you can machine your own parts. But how much is your time worth? Sure its a fun project, but in the end, whats the bottom line? Add up all your parts cost, labor, research, etc and compare to the cost of a Brammo......try to compare apples to apples, and the manufactured bike will win. My bike will cost quite a bit in the end, and it'l be fun and a huge learning experience, but cheaper? not even close.
It's up to the builder to decide how much their time is worth, if their are like me and enjoy the experience and learning, it could be nothing! It's also up to the builder to find an old chassis that does what they want, ally framed bikes from around 1990 handle very well, can be cheap, and require little work if you know what you're looking for.
I think as people who have done conversions ourselves, it's more appropriate to inform people of what is required, help out with component choices, budgets etc. But it isn't appropriate to make their decision for them, that's why I took offense to what gasdive has been posting.