Need ideas for a 10mph half ton EV

[veloman]

I need to push an 1100lb food cart at a max of 10mph. Even that is a little fast. Ideally it needs to run on 12v and have good torque.

The cart is 4 wheels, and a hub motor will only work if I build a 5th wheel attachment to push it. So I'm looking at a chain drive, but it needs to be geared for 10mph max at 12v.

Any good motor recommendations? Etek? That's a bit overkill, but not out of the question. The cart doesn't need to climb 10% grades, so it mainly needs torque, and maybe 1000watts max.

I can run a direct chain drive to the rear axle, separate from the pedal drive.

I am leaning towards the BLT-800 on 12v. That would give 10mph on a simple 1:2 gear single gear reduction. (26" wheel)
http://www.goldenmotor.com/hubmotors/BLT-800W%20Performance%20Curve.jpg

controllers: http://www.cloudelectric.com/category-s/239.htm

 

[bowlofsalad]

What kind of route is this half ton traveling on? Are there any hills involved?

 

[Hillhater]

re cycle a wheelchair / mobility scooter motor.

 

[veloman]

It will only be used around town, so maybe 2-3 miles a day. Drive it 500 feet, park for hours, go again.

I think mobility chairs might be under powered. I see those motors rated around 180w. This cart will need around 1000w due to it's weight. I want to say max 5% grade hills, but it would probably be smart to overpower it. Speed is not an issue, 4mph would be okay.

 

[John in CR]

1000lbs up a 5% grade at 5mph takes about 600W. It looks like a job for a brushed motor from a place like http://www.electricscooterparts.com/motors24volt.html. Maybe $200 total in parts with one of the 24V 500W motors, plus batteries. Gear it for 5mph top speed on the flats and that will slow enough on the hills that the motor will have sufficient power.

 

[neptronix]

That motor would burn up on 12v. It's rated for 800 watts on 48 volts. So that would be roughly 200W at 12 volts.

You are going to need many thousands of watts to get the thing started from a stall. Maintaining speed won't be as much of a problem, my wild guesstimate would be 500-1000W continuous.

You're moving half a small car here.

 

[Chalo]

Maybe repurpose a winch motor by coupling it directly to a wheel instead of a spool? Those things are designed to run on 12V.

 

[neptronix]

You're on the right track. A forklift motor might be a good option too.

Something tells me that the shaft on a smaller ebike sized motor couldn't tolerate lifting 1100lbs from a stall. Something industrial grade might be better. Or get an eTek type motor and run it on 48 volts at least, run it through a double reduction, and it will be a light and efficient setup. Those motors come with a 7/8" shaft.

I also have a 2000W MAC motor with a 7/8" shaft that could work good on 36v. The bearings are rather large. It could be worth a try with a dual stage reduction. It's that peak 3kW-10kW to get started from a dead stop is what worries me though.

 

[zombiess]

I know of someone using a Cromotor in a chain drive configuration to move a 3000lb vehicle at 10mph. Sounds like you don't need that kind of power, but a low cost 9C motor or a geared mac motor in chain drive could probably get the job done on the cheap and utilize a 12 FET controller. How much is a motor/controller setup from cellman?

Figure out top wheel size, max voltage, speed needed and gear reduction ratio and then you can figure out what kV motor you need and also what voltage range you need to run. 1000lbs at 10mph is should be pretty easy on everything and keeps the costs down.

*edit* just ran some numbers on ebikes.ca simulator with a 9c 2805 at 48V and a 4:1 reduction.

You can get 1000lbs to go 11mph on 48V with a 4:1 reduction. So assuming a 26" wheel as mentioned, that makes the effective wheel size 6.5". You most likely want a 45-50A controller so you can go up inclines. This setup will go up a 10% incline at 7mph with 75% efficiency.

 

[Accountant]

It is too early to choose the motor in this phase.

You might help a lot by showing picture of your vehicle, presenting measurements, and all details avaliable.

Are you selling ice creams, or what ?

Seems that you need Etek, RC motor or hub motor with special winding (lowest speed/ highest torque)

What power source will be used ? Standard car lead battery 12 V - 100 Ah , or what ?

 

[veloman]

Thanks for the replies guys. I don't think it will need big power to get it moving though.

Look at a pedicabber - with 3 200lb people in the back, 170lb rider, 150lb pedicab, that's about 900lbs and they get it moving fine on leg power alone. Yes, they use a tiny gear, but I am going to use a tiny gear as well. I think i am going to lower the top speed to 6 or 7mph since the driver really doesn't need to go more than that.

As for burning up the motor - this is not a typical EV application. He won't be driving it more than a few minutes at a time.

I decided on this motor, with a 24v 1000watt controller. http://www.monsterscooterparts.com/36-volt-600-watt-gear-reduction-motor-mounting-bracket-10-tooth-40-chain-sprocket-1020z.html

12v is too little to get reasonable power at reasonable amps, and the lack of controller options. So I decided to get another 12v 17ah SLA to series it with his current 12v 180ah (marine lead acid batteries). The 17ah SLA will be many times more energy than he needs, as he will only do a few miles a day. A separate 12v charger will take car of that battery.

Geared for 6mph, it's going to have tremendous torque. 1000watts will get it moving no problem. A typical pedicabber might peak around 1000watts if he has to sprint off the line to get moving. Plus add some torque for driver input.

I was a little worried about rolling resistance since analyticcyling.com shows a big increase in power with an increase in crr at 500kgs. The cart has four WTC airless (solid rubber tires).

 

[neptronix]

If you're OK with going 48 volts, you can have my golden motor 650W motor for $10. I believe one of the hall sensors is busted, but you can find cheap china sensorless controllers anyway.

Run 4 12v SLA batteries in series and throw the guy a cheapo SLA charger.

Just a low cost option if you're interested. I think you will need more watts ultimately, but this is a cheaper way to experiment, vs buying a $90 brushed motor that might not be adequate.

 

[-dg]

If you're OK with going 48 volts, you can have my golden motor 650W motor for $10. I believe one of the hall sensors is busted, but you can find cheap china sensorless controllers anyway.

I don't think a sensor-less controller is going to work here due to the high mass of the load. For the controller to detect the rotor position it has to move the rotor, which for a bike softly connected to a person it can do. But with a rigidly connected 1100 lb load I don't think it will move it enough or fast enough for the controller to recognize the rotor position. Also, even on a bike sensor-less controllers kind of hammer just at start-up, which maybe be hard on the rest of the drive-line in this application.

 

[neptronix]

Well, i can't dispute that. +1.

 

[amberwolf]

Why not use old brushed powerchair motors and wheels? Four of them should easily haul that load, if you use ones from heavyduty powerchairs, intended for 400lb people. One at each corner, and you could more tahn easily haul the load. Even just a pair of them could do short runs with plenty of cooling time between them.


They are typically setup for 8MPH max using the powerchair controllers with 24V of SLA, but you could do it with say a Curtis golf cart brushed controller with slightly higher voltage and go whatever speed you want, using the wheels and tires included with the motors.

Or you can use larger wheels bolted to the axle hubs for the original wheels (larger diameter for greater speed but lower torque).


Would be pretty simple to do if you don't have any restrictions on how to attach the wheels/motors/etc., and they are designed for carrying loads like that.


Cheap, too, if you poke around for old powerchairs with dead batteries or go to powerchair service centers and see what they have in their scrap pile.


You could use brushless PC motors too but that would not be quite as simple to setup, requiring two controllers and a synced throttle and whatnot. (or using the original PC controller and joystick/etc).


EDIT: link to my trailer idea thread:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=48718
and some pics of the motors I mean:
Heavy duty motor on lower right, normal duty motors on left:

Wheels with tires and axle hubs:

Variety of wheels:

 

[veloman]

Thanks for the offer Nep, though I already ordered that gear reduction motor. If it doesn't work out, I'm sure I can find a different project for it

 

[veloman]

I used a gear reduction motor from monsterscooterparts (600w version), #40 chain, and 1:4 gear ratio. It runs on 24v lead acid, (12v was already on the cart, so I added another 12v 17ah in series). 1000w brushed controller from site above. It has a top speed of about 7mph which is perfect.

This is a Worksman Front Loader pedal cart.

 

[Chalo]

That looks like a simple, reasonable solution. If the axles hold up to the load, it should work out well.

How are you coupling the wheel to the axle? The usual Worksman square-hole-on-one-side hub leaves something to be desired, and your axle doesn't look like the corresponding part.

When I re-engineered my Worksman Adaptable trike, I opted for a pin through the 7/8" diameter drive axle. (I made the axle and the hubs, so I opted not to neck down the axle end.) A pin also has limitations, but it was easy to implement and not quick to develop slop.

 

[lbz5mc12]

would that motor fit on a currie electric bike mount?