Mongoose MTB Build.

[Tincan]

Howdy,

Well after working on my Vespa type scooter and reading the fun other members here have on their bikes i thought i would have a crack at converting my Mongoose i have collecting dust.

I mentioned it to a family friend what i was going to do and said they had a chinese bike they purchased off ebay that they no longer use and im welcome to have it.

Got it home and pulled it apart.

The tire on it was so thin.. so on with my existing tire, the rear drop outs needed a little "adjusting" to suit the wide berth of the new wheel.

Now being that is a geared freewheel, I'm not expecting anything fast or strong out of it, more just a bit of fun / assistance for a longer ride.

The controller is TINY! but i guess it doesn't need to do a whole lot.

The bike it came off didn't have a throttle either, which i thought was a little odd, only had a pedalic sensor.

Not having a clue how a pedal sensor worked, i decided to just hook it up to a regular 3 wire throttle off my scooter.
Kinda worked, only it was full throttle all the time and when you wind it on, it turned off... Need another solution.
Searching through the bowels of the forum i found a wiring diagram for the controller and the other plug that wasn't used, is actually a throttle input!
Needless to say 30 seconds later i had the thing running as it should!

Took it out for its first ride today and yeh, different kind of experience to the scooter, that's for sure.
Being that it's only a 24v system, i wasn't expecting ball tearing performance, but i was actually shocked at how well it did on its own. Up a hill it would struggle, but pull a high gear, one that would usually be hard to pedal, and it was like i was in 1st gear, so easy!

Need to sort out my brakes. I had to say bye to my rear disc to fit the motor, didn't have a mounting point for the disc I still have a disc on the front that does very well, just would be nice to have two.

So... Plans...

-Get the battery pack and controller out of my back pack. Was good for a test, but bugger having it in there all the time.
-Lipo.
-Lyen Controller. I want to go 48v so this one will be binned.
-New battery position
-Purchase a thumb throttle. It looks dicky with my grip shift AND a twist throttle.
-Brakes. Not sure what / how yet.

Anyway, pics! (forgive the iPhone 3g quality)

Motor with my mongoose tire on it.

"Adjusting" the dropouts

Mounted and motor wires hidden.

No rear disc

Back from my first ride, note Battery and controller in backpack

Controller - Told you is was tiny!

Dodgy photo alert - Motor Phase and throttle wires in a DB9 serial lead.

Really need a thumb throttle...

Let the mods begin

 

[amberwolf]

Could be interesting.

If those really are the phase wires to the motor that you have in that DB9 connector, you might want to rethink it, as I expect it's going to draw more power than that connector and the really thin wires the cable has (assuming a computer-cable-origin) in it are going to be able to handle for very long.

Even if that's the original connector the manufacturer used, I'd still be iffy on using it. Might work fine in practice; time will tell.

If its just the control connections, then I'm sure it'll work fine.


Regarding the disc brake, it might be possible to mount the disc directly to the side case of the motor, depending on what exactly is behind the leftside faceplate, but there might not be clearance for the rotor itself to the frame, and the calipers would probably not line up without a different spacing to the frame themselves, requiring an adapter piece.

 

[Tincan]

Hey amberwolf,

Nah i didn't run the power wires through the serial port.... That would have been a spectical the first time the motor saw some load!

All the DB9 has is the phase signal wires and the throttle signal wires.

The 3 power wires are run separate. you can see the bullet connections in the controller pic.

As for the brake, i might have a look at what you said, staring at it from here, that might just be possible....

 

[amberwolf]

It is something I have been considering doing to one of my Fusin motors, which is perhaps a tad larger than the motor on yours. I'm not sure it will work, but one day when I have time to try, I would like to.

 

[Tincan]

Ok, long time with no updates.

Well I purchased a new Crystalyte HT3525....
Lots of joy today when this arrived on my desk... Thanks MAX!



Taa daa!



First thing to do, rip it apart! The screws were caked in this glue... ewww...



As expected 9x7 wind.



Motor with brake side cover removed.



View of wire channel... It's a little sharp, not razor though...



Been some machining of side covers, both sides are like this



The motor has not been run at all yet and ALREADY has signs of cutting from the channel.



Stator



Hall sensor locations



Quick trial fit of two halls.



Third one in place. Easy way i found to fit the middle is to pull the bamboo out and compress it in a pair of pliers.



Wires over the windings



Another shot of the channel.
I am going to see if i can machine this a LITTLE deeper, just to get something a little more heavy through it.

 

[Andje]

my wires cut through on the inside of the motor channel; they were being twisted by a slight twist of my axle under regen, and it was the inside channel past the bearing that cut them. just you might want to check that too; mine was literally razor sharp. Dremel makes quick work of it though, whatever metal the axle is it is pretty soft.