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-   -   Project E-Mini Bike, Using an Outrunner (https://www.rc-monster.com/forum/showthread.php?t=22765)

Metallover 08.06.2009 12:22 AM

Project E-Mini Bike, Using an Outrunner
 
Well, I'm already head deep in this project. I got it a couple days ago and since the stock battery was dead, I decided to go right at it with the brushless stuff. Should be faster then the stock 150w brushed motor. Using the stock gearing for now; It's probably overgeared though. It's a 250kv HXT outrunner made for 36v, running on 24v sla with a supersimple controller. Might do a 9s lipo in the far future.:intello:

I got the bike for $30 plus $8 gas. In the honda I got 32mpg, pretty good for the thing. It's got a 2.2 i4 iirc. Average is about 28-29.

The first major problem came up (besides the shotty pinion boring and filling up the damn rear tire) and it's the throttle. I have a servo tester here and it really sucks to use. I want to use the twist throttle that's already on the bike. It has 3 wires and I really want to replace the pot on the servo tester with the thumb throttle. Let me know how I can do it, please.:whip:

It looks sweet with the body on, I'll get some body on pics when I'm done.

chassis after stripping
http://i345.photobucket.com/albums/p...1/S7301952.jpg

motor and mount
http://i345.photobucket.com/albums/p...1/S7301960.jpg

servo tester
http://i345.photobucket.com/albums/p...1/S7301962.jpg

http://i345.photobucket.com/albums/p...1/S7301961.jpg

want to hook up this throttle,, Guessing green is ground, yellow is signal, and red is +
http://i345.photobucket.com/albums/p...1/S7301963.jpg

BL_RV0 08.06.2009 12:57 AM

Awesome! That's the same bike I'm doing the gas conversion on!!

J57ltr 08.06.2009 12:59 AM

Break out your meter and measure the wires on the pot installed on the servo tester. The outside pins should read about 5K. The middle is the wiper, it moves along from highest to lowest. so if you are on one of the outer pins the resistance will rise (or fall) as you turn the pot. The leads on the throttle will be the same if they both are the same resistance then you'll be OK. basically you will have to just remove the pot and replace it with the throttle control. Although since most ESC's have to be in a neutral position and the throttle is probably maxed at one range or the other so the ESC might not arm.

A pot is nothing more than a resistor that has a sliding wiper that when centered on the resistor will read half of what the total value is. So if you are in the middle the outside (lets say left) leg and center will read 2.5K and from the other outside leg (lets say right) and the center it will read 2.5K. As you move more to the right the left and center will start to increase in value while the right side and center will decrease.

Jeff

BL_RV0 08.06.2009 01:03 AM

Also had a idea for the throttle:
Get a twist throttle for gas conversions (I ordered this one: http://cgi.ebay.com/ebaymotors/ws/eB...m=360176795063 ) and make a arm for the pot on the servo saver, then attach the throttle cable to the arm.

Metallover 08.06.2009 01:05 AM

Quote:

Originally Posted by BL_RV0 (Post 310592)
Awesome! That's the same bike I'm doing the gas conversion on!!

No Way!:lol: That's awesome... Honda Minimoto?:party:

Have you managed to fill up the rear tire? How did you change the rear sprocket? Those are the two things I need to know, besides the throttle.

Quote:

Originally Posted by J57ltr (Post 310593)
Break out your meter and measure the wires on the pot installed on the servo tester. The outside pins should read about 5K. The middle is the wiper, it moves along from highest to lowest. so if you are on one of the outer pins the resistance will rise (or fall) as you turn the pot. The leads on the throttle will be the same if they both are the same resistance then you'll be OK. basically you will have to just remove the pot and replace it with the throttle control. Although since most ESC's have to be in a neutral position and the throttle is probably maxed at one range or the other so the ESC might not arm.

A pot is nothing more than a resistor that has a sliding wiper that when centered on the resistor will read half of what the total value is. So if you are in the middle the outside (lets say left) leg and center will read 2.5K and from the other outside leg (lets say right) and the center it will read 2.5K. As you move more to the right the left and center will start to increase in value while the right side and center will decrease.

Jeff

So will my throttle work?:neutral: Maybe yellow in the middle and ground to the right and pos to the left? Do I need to make some circut crap or get a new throttle? I hope it's easy as soldering on the wires in place of the pot..:angel:

Metallover 08.06.2009 01:07 AM

Quote:

Originally Posted by BL_RV0 (Post 310594)
Also had a idea for the throttle:
Get a twist throttle for gas conversions (I ordered this one: http://cgi.ebay.com/ebaymotors/ws/eB...m=360176795063 ) and make a arm for the pot on the servo saver, then attach the throttle cable to the arm.

Might have to do something like that. I'll either use a bike handle or mod the thumb throttle to turn the pot. Hopefully I can just solder this on..:whistle:

BL_RV0 08.06.2009 01:12 AM

Quote:

Originally Posted by Metallover (Post 310595)
No Way!:lol: That's awesome... Honda Minimoto?:party:

Have you managed to fill up the rear tire? How did you change the rear sprocket? Those are the two things I need to know, besides the throttle.



Yah, the minimoto. I used an angled nozzle attached to my air compressor to fill the tire. The way the big plastic pulley is held on is just fuckin' stupid. It is glued on to a small freewheeling sprocket on the rear wheel. I took it off just bu cutting it into quarters and prying each section off. I put a different sprocket on, simply by welding it next to the existing sprocket, then welding the freewheel mechanism closed, so the drive is locked, having the motor drag help slow the bike down. If you get on AIM we can talk about the bike and such.

J57ltr 08.06.2009 01:54 AM

Quote:

Originally Posted by Metallover (Post 310595)
No Way!:lol: That's awesome... Honda Minimoto?:party:

Have you managed to fill up the rear tire? How did you change the rear sprocket? Those are the two things I need to know, besides the throttle.



So will my throttle work?:neutral: Maybe yellow in the middle and ground to the right and pos to the left? Do I need to make some circut crap or get a new throttle? I hope it's easy as soldering on the wires in place of the pot..:angel:

There is no way of knowing till you test it. Never guess going by wire color. it tells you nothing, There is never a "cut the blue wire".

I am guessing it was already an electric bike, since the throttle is wire and not cable. 5K ohms is pretty much a standard value in a lot of items that use a pot.

But you need to get a meter (DMM,VOM, Ohm meter their called by a lot of names). Select it to the ohms scale. There are a lot of different styles of meters but it;s going to be the same test. Set the meter to read ohms around 20K to start, then read between and 2 of the leads coming out of the throttle. Record your reading. Leaving the leads in the same place Move the throttle through its range and see what the meter does, does it increase/decrease or stay the same? (BTW if the readings are like only 5 or 6 then go down to a lower scale on the meter, then again some are auto ranging).

Do the same with the other wires.(Red/Green, Red/Yellow, Green/Yellow).

At some point you will have a high reading; this will be the value of the pot located in the throttle.


Scratch out most of this because the pot is basically just set up as an adjustable resistor.

Just measure between the 2 pins that are tied together and the one by itself. Fully CCW should have the highest resistance, and CW will have near 0 ohms.


This part is more for how a pot is set up in circuit.
((Now take the reading between the pot located on the board on the outside legs (the 3 that connect to the board) Turn the pot all the way CCW record your reading. Turn the pot all the way CW and record the reading.))

The higher reading will be the value of the pot and should match the one for the throttle control.

Looking more at the board I can see that the center and outside legs are tied together. This makes this a little easier. You still need to figure out the throttle. Then when you have that straightened out you will just configure the throttle wires in the same manner.

If you increase throttle it should read the same as the pot that is already there, so if with the servo tester you crank it CW to make the speed control increase speed and you already know (because you checked that earlier, with your or someone’s meter), which way the resistance needs to go in order to increase the throttle. Wire the throttle to correspond with what you found out while testing.


It sounds harder than it is. As far as soldering buy a flux pen you can find them at better electronics stores.

Jeff

killajb 08.06.2009 11:33 AM

1 Attachment(s)
Those little bikes usually come with a nozzle extension hidden inside one of the handlebar grip ends. Pop 'em off and see if it's still in there. Also.. for the $$, there's much better ways to go about this albeit not brushless..

Metallover 08.06.2009 11:46 AM

Tired out the ohm thing. Never could get the reading to change by moving the throttle...

20k
Black/Red (contacts)

Green/Yellow 7.64
Green/Red 9.08
Red/Yellow 1.68
Yellow/Red 1.69

200k
Black/Red

Green/Yellow 53.2
Green/Red 55.1
Yellow/Red 1.6
Red/Yellow 1.6

2000k
Black/Red

Green/Yellow 433
Green/Red 433
Yellow/Red .1
Red/Yellow .1

None of the other wire combinations got a reading except the ones listed above. I think I may have a different type of throttle then what's required?

brushlessboy16 08.06.2009 12:13 PM

to find the overall resistance rating put the probes on the outer pins on the pot. that is your Pot resistance. you need a pot with the same resistance for it to work properly.

J57ltr 08.06.2009 12:44 PM

Looks like tht throttle is a 10K pot, and may be broken, if the reistance does not change while rotating the grip.

Yuo didn't give specs on the pot located on the servo tester.

Jeff

Metallover 08.06.2009 02:19 PM

With the pot on the servo tester, two leads are together and when I put the probes one way I get 5.29 and if I reverse them I get 11.49 while on 20k.

I might take apart the throttle thing to see what the problem is.

J57ltr 08.06.2009 02:25 PM

Ok you are getting different readings because you are "reading" other parts in the circuit. The 5.29K would indicate to me that's a 5K pot. Do one more thing. Place your leads where you read 5.29 and adjust the pit and see if the resistance starts to decrease.

Jeff

Metallover 08.06.2009 02:38 PM

The pot on the servo tester works fine, it decreases when I turn the knob.

Theory with the throttle: I think it has a few levels of throttle position. All the way down is neutral, then when you push it a little it goes to "step 1" which is something around 1.68, then it goes to "step 2" as you increase throttle some which is probably either 1.69 or 7.64, and so on. It doesn't use a pot but rather different resistance switches to give a few speeds rather then a full spectrum.

So now I'll try to incorperate the pot into the mechanical throttle mecanism.


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