ElectricMotorcycleForum.com
Tech => Tech Help => Topic started by: DeadZomb1e on July 22, 2009, 03:05:34 AM
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I'm trying to build a electric motorcycle from scratch at home. I have the necessary skills to accomplish said tasks. I just have a few questions. Thanks.
Was wondering what motor is able to get a 300lb bike moving along at about 75mph and what motors are better then others?
Can I just change the front sprocket coming off of the motor to make the bike go faster?
How do I get the bike to take off pretty fast and stay going pretty fast with said motor?
Also, how do you figure out how many batteries your really going to need, I know its something like
how many horsepower it takes to do said speed times 746 (which is supposed to equal 1hp) then you have to figure out how many watt hours your battery pack has?
Why does the amps on a controller really matter?
I was also wondering about this battery, what it might be capable of (72V / 10Ah w/VMS, 2 Terminal) and could I only run one of them and get decent mileage?
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have a play round with the file here http://electricmotorcycleforum.com/boards/index.php?topic=315.0 (http://electricmotorcycleforum.com/boards/index.php?topic=315.0)
75mph is pretty quick, so youll need a good motor, frodus is probably the expert on that.
yes you can change the sprocket size, most people change the rear rather than the fron though (finer adjustment), but top speed is at the expense of acceleration.
amps generally directly relates to the torque output of the motor, so higher the better (provided the motor can handle it)
theres no link for the battery you posted, there are other very important factors when considering batteries, such as discharge current.
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theres no link for the battery you posted, there are other very important factors when considering batteries, such as discharge current.
K heres the link for the battery, and thanks for the help on the other stuff. I want to have a good mileage range as well as be able to go 75 or better.
(Battery Link)
http://www.lifebatt.com/retail_sheet.asp (http://www.lifebatt.com/retail_sheet.asp) click on High Performance link at top of page.
Also here is what I am ultimately trying to get too. (Watch The Video)
http://jozzbikes.co.uk/PHEV/electric_motorbikes/conversions.php (http://jozzbikes.co.uk/PHEV/electric_motorbikes/conversions.php)
Also here is the motor I was thinking about.
http://www.cloudelectric.com/product_p/mo-es-15-6.htm (http://www.cloudelectric.com/product_p/mo-es-15-6.htm)
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actually attended a seminar with a lifebatt rep the other week, the batteries have a discharge rating of 10C continuous so 100A continuous, or 7.2KW, this is well suited to the motor power given in the link, though the batteries will struggle under acceleration when the continuous rating of the motor is exceeded, 15C is max discharge of the lifebatt i think.
10hp continuous would be borderline for 80mph, though with extra cooling etc you may be able to run the motor up to 15hp or even 20hp, which would easily do 80mph. Again though im no expert on this type of motor.
Batteries, to get the 40hp max out of the motor, is 30ish kw, or 416A, with lifebatts you would need at least a 30ahr pack, 40 would be ideal. Frodus sells some cheaper alternatives to the lifebatts at evcomponents.com 40ahr pack @72v would cost around 1k USD, and easily fit in to a bike. I have a mate who looking at a similar project, though with a smaller motor.
watched that video, and its a pretty sweet build!
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Batteries, to get the 40hp max out of the motor, is 30ish kw, or 416A, with lifebatts you would need at least a 30ahr pack, 40 would be ideal. Frodus sells some cheaper alternatives to the lifebatts at evcomponents.com 40ahr pack @72v would cost around 1k USD, and easily fit in to a bike.
Yeah I was wondering what miles I would get out of that 40ahr pack that Frodus sells saying that I am going 70mph most of the time and how much would I get if i was going 55 most of the time?
Watched that video, and its a pretty sweet build!
Yeah, this bike made me want an electric motorcycle even more, because like most people I was thinking that an electric bike was slow, but I have seen some really fast home built electric motorcycles.
If I used the 40hp of the motor that would just be accelerating correct? I also wonder if it will accelerate quickly or not as I haven't really found a donor bike yet. Any ideas on what I should be looking for as far as a donor bike with that set up mentioned to go 75+ mph?
The link with that excel thing you wanted me to look at is broken can you send it to me any other way?
Thanks man you are doing an awesome job answering my questions as i'm new to the whole electric motorcycle thing.
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Jozzer is one of my good friends! He helped a ton on the TTXGP entry that I helped with. I'm sure either he or I can help with anything you need. I can help you get in touch and source an Agni motor.... and I've got a great controller at Synkromotive that would be great for a high performance bike. The headway cells we sell at EVComponents are good cells, and they're fairly cheap for the peak current you can get out of them (10C and if setup right, 15C peak for short bursts).
PM me and I'll get you more information on our offering..... I can help you decide on what kind of pack you need.
That motor might be 40Hp peak, but not at 72V. I have the same type of motor, only its from Advanced DC. Its a great motor, but expect more like 25hp at 72V. 40 Hp requires over 100V.
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Jozzer is one of my good friends!
Hahaha, i should have known he wud be!
Easiest if i just email you the spreadsheet, send me an email if you want to keep yours private. Spreadsheet should give you an idea of ranges with different pack sizes, though it hasnt been compared with actual results yet.
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Jozzer is one of my good friends!
Hahaha, i should have known he wud be!
:) What can I say, I'm a networker....lol
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How easy is it to come up with 100v though on a electric motorcycle? That doesn't sound to easy. I checked out Agni motors website and they didn't have anyway of ordering anything on it. Are their motors good for electric sport bikes?
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100V at 40Ah is 4000wh, 32 cells in series, 4 in parallel for a total of 128cells of headway or 32 cells of 40ah thundersky or sky energy cells.
Thundersky would cost: $1408 and give about 160A continuous.
Headway would cost: $2176 and give you 400A continuous and be easier to fit into the frame.
BMS not included in that price.
email me
travis@evcomponents.com to discuss battery requirements.
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Headway would cost: $2176 and give you 400A continuous and be easier to fit into the frame.
This seems like the best way to go but definitely way high of a price, that pushes my budget completely over the edge but is do-able. Is there a different way I can go to where I could still get 400A? I might not even need the 40hp of the engine to obtain 75+mph. All this is hard for my brain to except from all the math and equations needed lol.
BMS not included in that price.
You'll have to remind me what BMS is again.
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BMS = battery management system, you NEED one if you're using lifepo4... we sell that too.
as far as 400A, you might not ever see that coming out of the batteries. We had mine to 65mph and it was using less than 100A on the battery side, and the motor side was ~150A....
current is torque/acceleration
volts is speed
as long as your voltage is there, and you can supple a decent amount of current (to get the horsepower), you'll be fine. I used some shitty batteries (36Ah of lead at 72V) and got to 65.... the voltage sagged a ton so I never got to 75mph.
have you played with the excel from Lennon Roger's website?
http://lennonrodgers.googlepages.com/emoto_step1 (http://lennonrodgers.googlepages.com/emoto_step1)
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I can't find a good free program to open .xls formats. I don't have excel on my computer so. Ok, so it is possible at least to get 75+ out of it but I would need really good batteries. So I will probably start out with some crappier batteries then switch to something better later on.
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go download openoffice, its free and essentially the same thing as office.... it'l open it.
if you have crappy bats, you won't get much above 65 or so.... but yeah, you can upgrade.
Maybe go lead acid first, and get it running.... then upgrade bats after prices drop and you've saved extra cash for them.
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Ok thanks. Downloading it now. Yeah I think going crappy batteries at first to get it running would be the best idea. Seeings though where I live 55mph is the top speed on most of the roads. I just wanted to be able to hit the highway if I wanted too but I can go for that later on.
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K, got another question. How many amp controller am I going to need? I'm guessing around 450 amp or better.
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go as high as you can.... but realize a 450A kelly does not perform as well as a 450A alltrax. Curtis is good as well....
what kind are you thinking?
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go as high as you can.... but realize a 450A kelly does not perform as well as a 450A alltrax. Curtis is good as well....
what kind are you thinking?
Alltrax... definitely Alltrax. Then there was that 650 amp you said on that one website. I could never get a hold of them to see how much they were running.
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its a 700A controller
you can't get a hold of them?
PM me and I'll get you more information....