Need some further input on EV build

[Electric Frenzy]

my 14hp gas scooter can go 85+mph with me on it (no easy feat) but it also has a CVT and a 2 stage final drive. So it has 2 transmissions (essentially.)

another FYI, I did speak with Valence today and they're sending me a form to fill out to start the quoting process. Hopefully I can get 12-20 good lightweight batteries for 2 projects. (1 scooter 1 trike)

[dcb]

This scooter says it tops out at ~60
~45 mile range

Vectrix All-Electric Maxi Scooter

Current vetrix lineup:
Vectrix CA :: Products & Accessories: 2009 VX-1, 2009 VX-1E, 2008 VX-1 :Vectrix.com

single speed?

28.2 hp peak brushless hub motor.

125 volt, 3.7kwh nimh battery

515lbs

etc. etc.

[Electric Frenzy]

yeah, that scooter is way too heavy. My 250cc is like 375lbs and it's considered portly.

I was going to buy some cheap 50cc scooter chassis and throw in 48v (4 batts) and do a simple chain drive to the rear wheel. Just curious if it would be the $1k investment before I got started.

[MazdaMatt]

Okay, so your 14hp can get you going pretty quick - now discount the tranny because transmissions don't create power, they just let your engine run at its most powerful point at more speed points.

Now consider, your 14hp motor is only producing 14hp at 1 particular spot on the rpm band, and probably considerably less elsewhere. The electric motor won't have quite the same power profile, so you could just gear it to the same ratio as your 14hp scooter's highest gear and get speed relative to the power difference. You probably won't be pulling wheelies off the line though. Get me?

[dcb]

Originally Posted by Electric Frenzy

yeah, that scooter is way too heavy.

It was meant as an example, an approximate starting point for the various parameters you seek since it is already close, and is another example of a real electric vehicle that does not use gears.

[Electric Frenzy]

Originally Posted by dcb

It was meant as an example, an approximate starting point for the various parameters you seek since it is already close, and is another example of a real electric vehicle that does not use gears.

I'm with you. I was just commenting on its unusual proportions.

but!! to further illustrate my point... the no-trans-vectrix has a very limited top speed and less-than-petrol acceleration. It seems without a trans you have to accept certain compromises that you wouldn't otherwise.

Now I'm very intrigued with the idea of running 2 motors in seriel. Can someone help shed some light on that for me? What is involved and how does this process work?

[dcb]

Borrowing from : KillaCycle - World’s quickest Electric bike while running A123System's M1 Cel's. [Archive] - CleanMPG Forums

>>> Series/Parallel Shifting < <<

Another change we made was to install a series/parallel contactor. The Zilla Controller (Cafe Electric llc) has the ability to operate a series/parallel motor contactor automatically. The motors are initially configured in series. Thus, the full controller output current travels through both motors. This gives maximum starting torque. As the motors spin up, the voltage across each of them increases. When that voltage matches the battery voltage, the current will decrease as motor rpm continues to increase. The Zilla will then switch the motors into parallel connection. This will double to voltage available to each motor, but will divide the current. The motors can turn much faster, but with half the torque. It result is just like shifting a transmission from low to high.

We could not get the contactor to shift automatically during the two runs we had on Friday test and tune session. The 60 ft times were fantastic, (1.169 seconds) but we were not getting the top-end performance we needed. We re-wired the launch button to be a manual shift button and this proved to work quite well for the rest of the weekend. We plan to upgrade the Zilla firmware and we believe this will solve the auto-shift problem.

[Ryland]

Also remember that motors put out their peak power at 0rpm, so you get full power from a dead stop to get you going, with your 6hp golf cart motor that could be as much as 45hp for a few seconds, it's an amazing amount of power, yes it's hard on your batteries and the rest of your drive train and if you are me you learn it's hard on your suspension as well, as just the other day I had the problem of my leaf spring snapping in half, as the axle torque is countered by the cars suspension, those 6hp motors have alot of power from a dead stop.

[Electric Frenzy]

I think I could do this with just some good batteries and the motor directly chain-driving the rear wheel.

I'm wanting to get a deal worked out with Valence first before I start buying other parts. I may buy like 20-25 batteries just for assorted use because I have no idea what I'l; end up building or how much power I'll need.

[theunchosen]

RPM and total velocity are fixed numbers. If you know one you know the other. they are always linearly linked in the same gear.

All you need is a larger gear linkage(where the drive shaft from the motor connects to the wheels is likely a gear, you just need either a smaller one on the engine or a larger one on the wheels whichever is easier).

RPM=speed always no amount of weight is going to change that as long as their is minimal slippage.

If you drop weight though and you add a larger final drive you could probably easily do 40. . .