The rig I will build...when I get the cash!

What do you all think of this setup?

Five 12volt 100AH AGM Deep-Cycle batteries -

The large E-Tek Motor -

1 CVT (Continuosly Variable Transmission) - Look on Wikipedea or

1 Kelly DC Controller 24-72 Volt 200AMP w/ Regeneration -

LED Turn-Signals, ?Low-power Headlights, LED brake-lights, and proper BMV registration and what-not to make this street-legal.

What I’d like to hook this motor up to the CVT in a 60-volt configuration (Up to 7200 watts MAX). I seen some videos on youtube that give me hope to make a kart that will perform in terms of power and miles traveled before recharge. The idea is to keep this vehicle low-wieght, but not so low it can’t hold to the road in a safe manner.


Five 12volt 100AH AGM Deep-Cycle batteries -

I think that’s a bit overkill. You would only need 50Ah bats for a kart.

The large E-Tek Motor -

Might be a good match, depends on how heavy you are and how much the kart weighs.

1 CVT (Continuosly Variable Transmission) - Look on Wikipedea or

not worth the money for the efficiency loss. You won’t extend range, but you may effect your acceleration, but it’l be at a loss, due to the loss of the CVT. You won’t need this in a kart, my kart will go ~50mph (Holds an NEDRA record) and is hell on the tires. Just pick one gear ratio and you’ll only have the loss of the motor, and the chain.

1 Kelly DC Controller 24-72 Volt 200AMP w/ Regeneration -

200 MAX amps, 100Continuous is NOT enough for what you want… try something more like the 600A version. I draw 350A in my motorcycle accelerating from a stop.

LED Turn-Signals, ?Low-power Headlights, LED brake-lights

All good choices for an EV

frodus, What kind of motor do you have that can take 350Amps of power from the get go?

Also, what kind of voltage are you using with that motorcycle?

Got a link?

Also, The CVT I plan to use is a low friction CVT pully system. Gonna have smooth bearings to help reduce friction. I can easily spin the pullies that are now locked inside the ATV gasoling engine. I give a bit of spin, and they both keep going for a few seconds.

Sure, I may loose some effeciency upfront, but in the end, the result will be much improved top-speed and fewer rpms needed by way of volts available.

Suprised you haven’t seen me around… I’m on Visforvoltage, here, evmotorcycle, ecomodder, elmoto, diyelectriccar… is my website … take a look at the video of my bike.

Anyway, I’ve got an Advanced DC K91-4003 motor (actually a 4009, but without a baseplate), custom 156V 700A Synkromotive controller. Currently wired for 72V but I’ll be going 144V. I’ve got 12 12V 18Ah batteries, 2 sets of 6 in parallel for 72V 36Ah. Not big, but they were free, and it gets up and goes. Currently running a 4:1 ratio, will be running a 5:1 ratio, maybe a 5.5:1 (just got a 60 tooth rear sprocket).

CVT’s are NOT efficient. The gain you would get by not loading the motor is NOT enough to offset the loss of AT LEAST 6%. You could use it, but the motor I’ve got in my go kart (advanced DC A00 series) will spin the tires no problem. DC motors have a flat torque curve, so its not bell shaped like in a gas engine. Why do you THINK you need it? Just wondering where your coming from.

Question, have you played with this stuff before?

(Oh, and I work for an electric Vehicle company as an R&D engineer, so you know where I’m coming from)

The reason I want to at least try to use the CVT is to get a better gear ratio on the fly. Either that, or get a small manual tranny, perhaps a 3 speed. Not sure how much a small one would weigh. I just hate to mess with having a clutch to deal with.

The CVT I am using will weigh less than 10 lbs with the belt. I’m not looking to increase the torque. The motor I am getting will have loads of that. I’m just wanting to increase the top speed. If I can get away with using 36 volts and get tons of amp hours in reserve, then it’d be worth it for me.

From what I’ve read, the more volts, the more rpm, and more rpm means more top speed. Is that correct so far?

Maybe I just need to see it in action.

how fast do you want this thing to go?

56 miles per hour is FAST AS HELL when you’re 3" from the ground… you’re seriously going to die if anything goes wrong.

What is your goal of speed? Work backwards… you want 60 miles per hour, and have x circumference wheels, and you’re motor has y RPM at 60V (i’d do 72V and do 3 smaller bats on each side). Then u can calculate z, the ratio of the gears to get u that fast.

Once you know that, you can take the torque of the motor at 0rpm, full load amps, and calculate what the torque to the rear wheel is, and see if its enough acceleration.

you have something like 5500-6000RPM to work with, not 1-2000 like an ICE. Its a flat curve.

I will help a little on the CVT idea, as frodus said they are not very efficient. I raced karts and ran an engine building shop for 10 years. On an application where you have limited energy (battery) you want to be a efficient as you can get. Belt drives or anything that uses a belt relies on tension on order to keep the belt from slipping. This tension eats power. I agree that you would be much better using a direct chain drive.

Even though I called this thing a sreet-legal go kart, it’ll be more like a street-legal dune buggy. It’ll have large tires, maybe 20 inchers at max, and it’ll have a simple suspension. That’ll keep my well off the ground and a wide wheel base will keep me nice and stable.

That’s why I want to go real highway speeds (up to 75 mph max), but not to drain the batteries while trying to reach that speed using one gear no matter how much its size is optimized.

Are their better gearing solutions?

if its that size, its not going to be that light (esp with batteries), so you’ll need a larger motor to drive it. You might actually need a small gearbox or CVT. This isn’t a “small” go kart. Its a dune buggy with 20" wheels… and they’re not exactly as light as a kids kart, or a motorcycle. You may well need something, but I’d recomend a small gearbox, and not a CVT. The torque you need is going to be alot, and the belts WILL snap.

and you’re going to have some issues when you try to get it registered as street legal as well.

What is the frame based on?

As far as registration goes, it’ll be considered a dune buggy. I seen them on the streets every once in a while. And they have plates.

Where the wieght is concerend, I agree, this wont be a light ‘kiddy’ rig. The batteries alone will be Five batteries * 67lbs a piece = 335lbs. But then again, with them being 100 amp hours that’ll be some juice.

The frame will be made with elmers glue and toothpicks. :wink: But seriously, it’ll be aluminum and simple as possible with regards to weight handling and other saftey concerns.

I would like to get a pre-built aluminum frame, but I tried to look on the net already. I may have to build this one from scratch.

I’d be willing to get a bigger motor if I knew it’ll handle the payload weight of 700+ lbs with the driver and a passenger onboard.