<$1k DIY Neighborhood Electric Motorcycle - Page 22 - Fuel Economy, Hypermiling, EcoModding News and Forum

captainslug · 10-11-2009, 01:32 PM

I've ordered the relays I need to make the motor wiring adjustable from a toggle switch on the handle bars that will control a pair of relays.

Doing this will give me a 2-speed manual electric speed selection.
Series wiring will be used for acceleration. Parallel will be used for top speed.
Doing this should also GREATLY reduce the power consumption during acceleration without sacrificing any performance (since it will in fact give me more available torque).
I will have to do practical tests once the relays are installed to determine what positive effect the configuration has on range. I'm hopeful that it should be a noticeable increase of 20 to 40%.

Christ · 10-11-2009, 01:36 PM

Wondered about if you were going to do anything like that... seems like a waste of dual motors to not use them to their highest potential, right?

Does the torque effectively double for the duration of the low-setting?

captainslug · 10-11-2009, 03:15 PM

Quote:

Originally Posted by Christ

Does the torque effectively double for the duration of the low-setting?

Correct. Peak consumption in series will be 1kw, but will have double torque.
Peak consumption in parallel will be 2.5kw.
I will accelerate to 18mph in series mode, then cut throttle and quickly switch to parallel to reach 38mph.

Christ · 10-11-2009, 09:44 PM

How difficult would it be to design a controller that will automatically "shift" between the two circuits for you?

I know it won't be hard to just flip the control switch, but it would be neat if it just did it automagically, so you never had to let off the throttle or remove your attention from normal operation.

captainslug · 10-11-2009, 11:34 PM

I have hardly any experience with electrical engineering and I'm not ambitious enough to want to bother with something like that when a simple toggle switch will do the job just fine.
For best operation without requiring much higher rated relays such a circuit would need to be interfaced with both the motor controller (intercepting or metering the throttle signal while shifting) and the digital speedometer (to know when to shift).

Christ · 10-12-2009, 12:14 AM

I see.

Nevyn · 10-12-2009, 11:48 AM

I'm getting browser warnings for captainslug.com again - might need to re-scan?

dcb · 10-12-2009, 12:16 PM

oh cap'n, I think you got some problems.
http://safebrowsing.clients.google.c...p/saulbass.gif

captainslug · 10-12-2009, 12:19 PM

Guh, thanks. I fixed all the affected html files. I just have to wait for Google to recognize the changes.

captainslug · 10-16-2009, 04:30 PM

Finally, a video of some sort. Albeit just one to show the drive-train.

http://www.youtube.com/watch?v=ndVJ5Ost25E

I was worried that the freewheel had seized, but thankfully it was just in need of some chain lube.

I have a handful of things to do next.
1. Move bolt-holes on battery rack 1/2-inch back to allow space for larger front sprocket.
2. Attach motor relays to motor-mount plate.
3. Make bracket, then wire in switch to control motor relays.
4. Make storage box.