cargo wrote:Which hub gear do you intend to use?. Will there be enough room for it width-wise.?
xarvox wrote:cargo wrote:Which hub gear do you intend to use?. Will there be enough room for it width-wise.?
I havent gotten that far in the progress yet. The gear is so far very optional, and will eventually have to be removed anyways (since it probably wont cope almost 3kW of power ).
Im starting to worry that im over-estimating the gearing ratio needed, so i humbly ask what the forum gurus have to say..?
care to estimate a proper ratio?
Geardown-speed calculator - created by johnrobholmes (see attachment)
xarvox wrote:ive also started looking at throttle controls and i think i will go with a pistol throttle on left side (removing the front deraillour).
I will be using servo tester to control the esc, but i got some ideas on howto make the pot controllable by wire
Fechter's Throttle Interface for RC controllers
Postby GGoodrum on Fri Jan 09, 2009 1:05 pm
I'm getting some test boards made, which I should get back early next week. Here's what it will look like
The large caps are 330uF/100V. That should be more than enough to help the controller. As Richard pointed out, some of the resistor values might need to be tweaked a bit, here and there, but hopefully by this time next week, we will have that all sorted out.
I will try mine with my Hacker-based test setup, which I'm hoping to get up and running this weekend.
some bits are still missing a final solution, i dont think its a good idea to run a "stiff" drivetrain, without any type of clutch/one way bearing.
I will spend the evening thinking about this, and if you guys know of any smart clutch/freewheel solutions, please post a link
I fried a few more of these motors but have been running the same one for the last 2 months with no issues. I have had to mod the endbelll to accept 4 fan blades. These draw air in at the endbell and pass it out the 'stator' end (where it fixes to the mount). I have not tried it again on 36 or 48V for 2 reasons. Firstly I don't want to burn any more motors and secondly 35mph is more than adequate for around town since the limit is generally 30mph or less. This modded motor does run a lot cooler - without the blades it would rise about 50C on an extended run up-hill. On a warm day that was problematic since once the bell passes 78C the motors are toasted. With the modded bell the rise is more like 40C.
Oh yeah - the 10,000mfd cap I added has sorted the start-up issues - it now pulls without glitch from a standstill but I do prefer to pedal to 3mph or so before peddaling - for obvious reasons:)
The current plan is a single stage transmission with 1:9,2 ratio (10T and 92T gocart sprockets) with chain and chain-tensioner.
xarvox wrote:Ive started a project with some fellow rc plane junkies, to create a throttle device between the speed controller and a electric bike throttle (found locally for about $30) that will limit the max amp drawn from battery and set by a pot, meaning i wont risk burning my precious drivetrain
xarvox wrote:We did some "manual adjustments" with a hammer on the frame and adjusted the rear wheel sprocket mounting, so now the wheel freely rotates and thereÂ´s clearance for the chain, but i cant get a straight angle to any possible motor-locations..
xarvox wrote:The rear wheel frame wasn't wide enough to allow such large diameter sprocket and will not allow me to easily run a chain thru/around it.
As i see it thereÂ´s only three possible solutions for this:
1: mount chain guide wheels on both sides of the chain at the rear sprocket to clear the frame
2: build a structure to allow motor mount above rear wheel.
3: scratch the rear wheel drive and steal my brothers old front wheel with disk brake mount.
The downsides are obvious..
1 will drop efficiency and make more noise.
2 will move the weight even further from the pivoting point (fully springdampened bike) making it very shock and vibration-prone.
3, all the weight at front, but on the other hand, easier cable management
But what would you suggest as solution?