Rocky Mountain Element Conversion

[Deleted member 4366]

I have a question about dual thottle's though.
Would it not be possible to join the 2 signals wires and have one thottle and one sensor? the 0V would be commoned by the 0V from the battery. Just wondering if the sensor would sink current from 2 controllers ok? i think they are usually working in micro amps?

They tried it on ES and sometimes one motor would cut at high throttle. Maybe it was specific to the type of controllers they used, so it might be worth a try. Another thing to try is to use a small microprocessor like a Picaxe or Geniie chip. You coould read the throttle signal then send it to two separate outputs. These chips can be powered off the 5v to the throttle. I'm going to try that on my next one.

 

[103Alex1]

I thought it would be easier to get a nice clean shappe with wood. I was also thinking of making a fibreglass or carbon fibre one by making a wooden one first and then taking a mould off it, but in the end I thought wood would be quicker.

Blown away by how neat and good looking that frame setup is and has got me stopped dead in my tracks on the bag to be honest. Did you use drinks bottle holder holes to screw in to the frame on the seat tube and down tube ... and how did you secure to the top tube (is that a bracket I see painted red for this ?)

Also, how do you get in to the box to charge the battery ?

I presume that the solarfilm used is transparent ? Does it offer waterproofing function for the box too ?

I've worked a great deal more with wood than metal and have more of the tools needed already. The concept is extremely appealing, especially being so easy to paint. Just hope the 20Ah battery isn't too wide for a box idea not to be sensible or look out of place.

 

[Deleted member 4366]

The box is fixed on both pairs of bottle-holder fittings and two stainless brackets to the front of the rear suspension unit fixing. They're not in the photo because I took it before fitting them. You get access to the bottle holder screws through the battery panel when the battery's not in.

There's a small panel in the top of the box with the switch, charge socket and USB connector. You can see the panel in one of the photos.

You can get translucent and opaque solarfilm. Mine's opaque silver, black ant metallic red. It's more or less waterproof - depends how well you put it on.

If I did it again, I'd use only plywood and balsawood: 3mm plywood for the sides and edges with 1/2" square balsawood along all the edges so that you can plane them rounded. The access hole for the battery needs to be a bit bigger than the battery so that you can get the wires in more easily.

Your battery's smaller than mine and you have the whole triangle, so it should be a bit easier.

 

[103Alex1]

It's looking pretty much a no-brainer... one more question, is the charger / controller access panel just cut out of one of the sides with a jigsaw and screwed in to inner frame ? I was thinking about hinges but might be tricky to get to work well / secure.

 

[Deleted member 4366]

Sort of. The LH plywood side was in four parts. The outer 3 were glued on, and the battery cover is screwed on. The softwood battery surround holds the edges and allows the removable panel to be screwed on. it might be clearer in this photo:

 

[103Alex1]

Sort of. The LH plywood side was in four parts. The outer 3 were glued on, and the battery cover is screwed on. The softwood battery surround holds the edges and allows the removable panel to be screwed on.

Yes that's clearer - many thanks. Just thinking a bit more on the removable panel, as much to gain access to the charger point more easily as anything else, do you think on a full triangle box that the panel could say be made a full one from the top tube to the down tube over an appropriate portion of the triangle ? Idea would be to hinge the panel along the top (top tube) and then fit, say, angled sprung cabinet closures on the inside along the down tube edge. This would make it easy to open up the flap without having to unscrew the panel to charge or access the battery .. just one tug of the panel along the bottom edge.

If it's likely to work, I'm also wondering whether cabinet closures would wind up rattling / coming loose and if so, whether there's a better way to secure the panel closed when the bike is in use whilst still allowing a one-pull or one push opening mechanism. Just thinking out loud !

 

[Deleted member 4366]

You only need to have a switch and a socket for charging on the outside of the box, and then you'll never need to open it. A hinge will look very amateurish if your're not careful. Here's a thread on ES that might give you some ideas:
Endless-sphere.com • View topic - Show Us Your Homemade Battery Housing

 

[Cyclezee]

Hi d8veh,

Yours look more professional than any other custom conversions that I have seen, the craftsmanship is excellent.

If you don't already, you could make money offering this as service, or maybe you just do it for enjoyment.

 

[cwah]

I'm about to make my purchase via bmsbattery for a dual motor on my brompton.

So I'll get the 24V 328 RPM front motor:
Q100 24V250W-350W Front Driving EBike Hub Motor - BMSBATTERY

Rear 24V 328RPM:
Q100 24V250W-350W Rear Driving EBike Hub Motor - BMSBATTERY

2 * KU93:
KU93 450W 9Mosfets High Speed Controller - BMSBATTERY

front torque arm
EBike Torque Arm

48V Thumb throttle
36V 48V 36 48 Volt LED Power Display Throttle Grips Electric Scooter Bike | eBay

And I'll plug that to zippy compact 14s for a charged voltage of 58V.

Is it good for 25mph constant?

 

[Deleted member 4366]

I think the KU 93 is a bit much for these small motors,especially at 14S. You need a 15 amp controller, but trying to fiind one at that voltage isn't easy. Conhismotor do them, but chech their amp ratings. I think the 200w one is 15A, but I'm not sure. They should be able to tell you. Will you go single-speed again?

 

[cwah]

Do you mean this one?
http://www.conhismotor.com/ProductShow.asp?id=315

Yes single speed again. I'm replacing my inefficient direct drive to a dual motor

 

[cwah]

Oh sorry. Found it:
http://www.conhismotor.com/ProductShow.asp?id=305

 

[cwah]

Can't I mod the ku63 to accept higher voltage also?

 

[trex]

cwah, don't go through with this project.
The diminutive Brompton is never designed for this sort of speed.

 

[Deleted member 4366]

cwah, don't go through with this project.
The diminutive Brompton is never designed for this sort of speed.

Don't worry, Trex. Cwahs an expert at this now. Did you see his other ones?

http://www.conhismotor.com/ProductShow.asp?id=226

Cwah, this is is the one I had in mind because you don't really want two LCD displays, or you could have one of each with the LCD one on the back wheel with the 5 PAS levels, and the other one on the front wheel with just a second throttle. You could even try a Q85 or Q75 on the front. With two motors, you wouldn't mind the little bit less power on the front. I should point out that the LCD won't display speed properly because it picks up the speed from the motor. I think there is a connection inside the controller for a wheel-speed sensor, but I haven't fully investigated that yet.

You can modify a KU63, but you have to change the big resistor, the resistor in the voltage sensing and the capacitors, which is a lot of messing about

 

[cwah]

yes, my current brompton can already reach 30mph. So currently with the dual motor at 25mph I'm going slower ahah

Would it be a problem with 2 differents motor on the front and rear? Speed wouldn't be the same so it wouldn't be that efficient?

 

[Deleted member 4366]

Speed would be the same. They both have the same RPM and voltage. Only the power will be different. I must admit, I like the idea of a lightweight bike with Q75 on the front and Q100 on the back.

 

[cwah]

I haven't found a Q75 24V 328RPM at bmsbattery.

And the controller is already 500g which is quite annoying. No point to get a superlightweight motor if the controller is already half the weight lol

 

[Deleted member 4366]

That's a shame. Q85 then.

 

[cwah]

The Q85 weight 1.9kg, so it's only 200g lighter than the Q100. But it handle only 200W compared to the 300W of the Q100.

Other than the 85mm width, isn't another Cute100 on the front better?