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Dear Forum members
The marvel of seeing a man pedalling slowly while being taken at a relatively fast pace is startling. And I want to DiY this effect!
at $44,000...I did not feel like buying it. firstly because I can't afford it. So I decided to build something that could eventually reach 50mph on a strengthened frame.
I would very much like to be able to attach some sort of pedelec sensor to my curtis 1412 300amp controller. I get the feeling that some sort of slip resistant switch may be needed to activate a throttle that, upon rotating would begin to accelerate. is there no simple 5k dimmer switch that can be rotated on a spring to begin moving? or would this cascade with physical treehugging :lol:
What do you think I should add to my current completed electric bicycle (with 5k throttle) to allow it to be operated by pedals alone? The problem here is that I have a 5k throttle problem.... no hall effect sensors....
The only way I can think of doing it is to attach some sort of magnet that detects the rpms and engages the motor as a result by work of automaton. This would induce the motor to move a certain limited ammount before stopping...I sense some programming is coming with a processor ICMP5.
here is a video of the eROCKIT as a reminder
http://www.youtube.com/watch?v=Zmwd1aup68Q
What do you guys think?
The marvel of seeing a man pedalling slowly while being taken at a relatively fast pace is startling. And I want to DiY this effect!
at $44,000...I did not feel like buying it. firstly because I can't afford it. So I decided to build something that could eventually reach 50mph on a strengthened frame.
I would very much like to be able to attach some sort of pedelec sensor to my curtis 1412 300amp controller. I get the feeling that some sort of slip resistant switch may be needed to activate a throttle that, upon rotating would begin to accelerate. is there no simple 5k dimmer switch that can be rotated on a spring to begin moving? or would this cascade with physical treehugging :lol:
What do you think I should add to my current completed electric bicycle (with 5k throttle) to allow it to be operated by pedals alone? The problem here is that I have a 5k throttle problem.... no hall effect sensors....
The only way I can think of doing it is to attach some sort of magnet that detects the rpms and engages the motor as a result by work of automaton. This would induce the motor to move a certain limited ammount before stopping...I sense some programming is coming with a processor ICMP5.
here is a video of the eROCKIT as a reminder
http://www.youtube.com/watch?v=Zmwd1aup68Q
What do you guys think?
Malcolm
10 kW
The simplest way to mimic this effect is to use a Bionx hub motor, which has strain gauges built into the motor. These sense how much torque you're applying through the pedals and adjust the power to the motor accordingly. Unfortunately it's a low-power system (350W max I think) so you're not going to get to 50 mph.
Here are some more threads on the subject:
http://endless-sphere.com/forums/search.php?keywords=torque+sensor&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search
Here are some more threads on the subject:
http://endless-sphere.com/forums/search.php?keywords=torque+sensor&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search
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I currently have a 7hp ETEK motor setup on a mountain bike with bioshock forks and a strengthening fork at the back (interesting concept.)This setup has reached 51mph on Lead acid batteries that supplied 150amps of power (instead of 300a) no pedalling was required. currently I am doing this by throttle.
I intend on upgrading to LiPO 50c discharge batteries soon... as I see this is becoming my only option pretty fast. I've been doing the math and figure these packs would be a good option.
The pedal.... is the bit that's bizarre.... I really would like this method to work in the simplest form ... maybe through a large gear cog placed on the motor chain, when chainwheel moves, it turns the throttle a little bit....you would have to pedal pretty fast to get the throttle pressed all the way...interesting concept.... surely there's got to be some sort of RPM calculator that can send a signal to a servo that I can attach to a 5k pot...so let's say 10rpm = 10% throttle, 20rpm = 40% throttle, 30pm = 100% throttle.
I intend on upgrading to LiPO 50c discharge batteries soon... as I see this is becoming my only option pretty fast. I've been doing the math and figure these packs would be a good option.
The pedal.... is the bit that's bizarre.... I really would like this method to work in the simplest form ... maybe through a large gear cog placed on the motor chain, when chainwheel moves, it turns the throttle a little bit....you would have to pedal pretty fast to get the throttle pressed all the way...interesting concept.... surely there's got to be some sort of RPM calculator that can send a signal to a servo that I can attach to a 5k pot...so let's say 10rpm = 10% throttle, 20rpm = 40% throttle, 30pm = 100% throttle.
Malcolm said:
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One way you could do it is a single hall sensor on the frame, and a bunch of magnets around the granny ring. As each passes the sensor it sends a pulse.
Use an op-amp to integrate that pulse into a voltage level. Another op-amp to scale that voltage level as needed for input into a voltage-to-resistance converter.
The V-R converter is easily done like this:
http://www.maxim-ic.com/app-notes/index.mvp/id/3284
Just use the p/n for the 5K version. It's output is used instead of your handlebar throttle.
If you want both of them to work, then use your handlebar throttle as an input to another op-amp to let you scale it's input to that circuit, and feed it into the V-R converter in parallel with the first one, both with series resistors to prevent feedback of one into the other.
If you're not handy with electronics, it'll take you a bit of time to find all the pre-made circuit diagrams for the pieces of this around the web, but it's all already there. There are links in Ypedal's recent thread about learning electronics that have some of it, perhaps all.
The magnets on the granny ring/sensor on frame can be replaced with a rolller on top of the pedal chain, too, but it doesn't work very well with the motor power running thru that chain, too.
Use an op-amp to integrate that pulse into a voltage level. Another op-amp to scale that voltage level as needed for input into a voltage-to-resistance converter.
The V-R converter is easily done like this:
http://www.maxim-ic.com/app-notes/index.mvp/id/3284
Just use the p/n for the 5K version. It's output is used instead of your handlebar throttle.
If you want both of them to work, then use your handlebar throttle as an input to another op-amp to let you scale it's input to that circuit, and feed it into the V-R converter in parallel with the first one, both with series resistors to prevent feedback of one into the other.
If you're not handy with electronics, it'll take you a bit of time to find all the pre-made circuit diagrams for the pieces of this around the web, but it's all already there. There are links in Ypedal's recent thread about learning electronics that have some of it, perhaps all.
The magnets on the granny ring/sensor on frame can be replaced with a rolller on top of the pedal chain, too, but it doesn't work very well with the motor power running thru that chain, too.
AussieJester
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novembersierra28 said:
It will, just hope your near home when it does
KiM
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AussieJester
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novembersierra28 said:
BMS can do two functions (that i know of anywayz) 1) it will balance indivdual cells, this is extremely important with lithium chemistry, over charging is bad, very bad. 2) the BMS can also stop the controller from drawing too much current, if the batteries are for example rated at 2c and you want to pull 300amps from them your going to destroy the batteries in 5 minutes... If i were you i would seriously reconsider Lipos (lithium Polymer) Using a GGoodrum BMS (see my sig for link) you can have a high discharge pack very cheaply that is easy to charge and keep balanced and large degree lighter than any other battery chem currently available...
Best of luck...
KiM
p.s still think your freewheel will bust the pawls are what break in the cheap freewheels, they have half the number of the White Industries ENO...hope im wrong though
liveforphysics
100 TW
Buy 8 of these packs:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8586
Configure the packs 4P 2S so it makes a 20Ah 44.4v nominal voltage pack capable of 500amp continuous discharge, and weighing 14.7lbs.
It's $400 in LiPo, and about $100 in shipping.
A BMS is not for bikes pulling 300amps.
Since you're an ultra battery newbee, you need to read the whole thread in the battery section on using LiPo, and if you follow the golden rules, it will turn out fine.
Picking up a pair of the new 400w turnigy 6S chargers would work out great for a charge and balance solution.
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=11340
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8586
Configure the packs 4P 2S so it makes a 20Ah 44.4v nominal voltage pack capable of 500amp continuous discharge, and weighing 14.7lbs.
It's $400 in LiPo, and about $100 in shipping.
A BMS is not for bikes pulling 300amps.
Since you're an ultra battery newbee, you need to read the whole thread in the battery section on using LiPo, and if you follow the golden rules, it will turn out fine.
Picking up a pair of the new 400w turnigy 6S chargers would work out great for a charge and balance solution.
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=11340
cell_man
100 kW
novembersierra28 said:
Sorry I think you're getting mixed up with your figures. I quoted you 934USD for an assembled 16S (52.8V nominal) 15Ah pack including BMS, 48V 5A charger and shipping to the UK if you wire transferred or an additional 3.4% if Paypal. It's 744USD for the pack with BMS and under 700USD if you don't want a BMS, 600USD in just cells. You can bypass the BMS for discharge if you like. I think Li Po is probably more suitable for your application though
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AussieJester
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Voltage sag will not be a problem if you use 30c lipos. I pull 140amp with my small 44v 15ah setup and see less than 4 volts sag. Mine are 20c 22v 5000mah packs. I strongly suggest you read the info Luke linked you to and also checkout the link for GGoodrums products they are cheap and will make building your pack very easy.
KiM
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ah....complikated.
so If I get this right, an op-amp changes the pulse into a voltage level which in turn changes through into resistance. clever..just learnt something right here.
well, I will go on Ypedal's and search.
I have been thinking up of methods that involve kinetics and magnets...this has made it simpler. the sensors won't go wrong.
so If I get this right, an op-amp changes the pulse into a voltage level which in turn changes through into resistance. clever..just learnt something right here.
well, I will go on Ypedal's and search.
I have been thinking up of methods that involve kinetics and magnets...this has made it simpler. the sensors won't go wrong.
amberwolf said:One way you could do it is a single hall sensor on the frame, and a bunch of magnets around the granny ring. As each passes the sensor it sends a pulse.
Use an op-amp to integrate that pulse into a voltage level. Another op-amp to scale that voltage level as needed for input into a voltage-to-resistance converter.
The V-R converter is easily done like this:
http://www.maxim-ic.com/app-notes/index.mvp/id/3284
Just use the p/n for the 5K version. It's output is used instead of your handlebar throttle.
If you want both of them to work, then use your handlebar throttle as an input to another op-amp to let you scale it's input to that circuit, and feed it into the V-R converter in parallel with the first one, both with series resistors to prevent feedback of one into the other.
If you're not handy with electronics, it'll take you a bit of time to find all the pre-made circuit diagrams for the pieces of this around the web, but it's all already there. There are links in Ypedal's recent thread about learning electronics that have some of it, perhaps all.
The magnets on the granny ring/sensor on frame can be replaced with a rolller on top of the pedal chain, too, but it doesn't work very well with the motor power running thru that chain, too.
AussieJester
1 TW
Why your fixated on 44v i don't know the packs come in 22v if you series 3 you have 66v 5 ah Get 12 of them in series and parallel and
you have your 66v 20ah. A Turnigy Meter from hobby King or a WattsUp meter or a cycle analyst all are used for battery monitoring.
KiM
you have your 66v 20ah. A Turnigy Meter from hobby King or a WattsUp meter or a cycle analyst all are used for battery monitoring.
KiM
His Curtis brushed controller can only go up to 48V nominal. Same as on my CrazyBike2.
Same as on my CrazyBike2.
a bit.novembersierra28 said:
There are other ways to do it, but this one would definitely work, and all the individual circuits needed are already available on the web, along with calculations for resistors/capacitors to do different things with them (kinda like the 555; it's all been done already, by so many, that info is easy to find). All that's needed is to hook the circuits up to each other and your sensor and controller, and voila! Or, at least, it's supposed to work like that. Exactily.
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AussieJester
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So use 18v lipo packs for 54 volts would be 60 hot off the charger.
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