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Rail Cart Power

I have a Rail Cart ( riding railroads) that I would like to run on DC power. It currently has a 6hp gas motor that pushes it down the track at a scary speed but is very noisy and vibrates really bad.  Can you recommend a DC motor that would push the cart at a max speed of 15MPH.  Starting off is the biggest issue as there is hardly any drag on the cart after it gets to rolling. (we also pedal the cart)The cart would carry 8oolbs not counting motor and Batteries. Cart has 17" powheels. Currently running a #41 11 tooth engine sprocket and a 68 tooth axle sprocket on a 1" solid axle.

Looking for motor, controller, throttle and battery options to push it at 15 MPH for at least an hour if not two.

Thanks

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A 36 Volt 1000 Watt 3000 RPM motor would be a good choice for this and I ran a top speed and gear ratio calculation using it along with a 10 tooth motor sprocket and 100 tooth axle sprocket for #35 chain. Here is the result.



The reason I used #35 chain is that our sprockets for #41 chain are only available up to 90 teeth and that was not providing a low enough gear ratio for the 15 MPH top speed. 


For a one hour runtime at full speed, a 36V 22Ah battery pack is estimated to provide 60 minutes of runtime and a 36V 42Ah to provide 120 minutes of runtime. Since rails have such low friction the runtimes might be longer though because the calculator is programmed for rubber tires. 



We carry all of the parts that would be needed for this project including the 100 tooth axle sprocket and hub for 1" axle. 


Here is an example of a 36 Volt 1000 Watt kit with 22Ah battery pack: https://cart.electricscooterparts.com/ProductDetails.asp?ProductCode=KIT-361000-03


This kit is just an example to give you an idea of what type of parts a kit would consist of. We can make a new version of this kit with whatever parts you need it to have such as; larger batteries, different throttle, different sprocket and axle adapter, etc. 


Please let us know your thoughts and we can take it from there.

I should have said the cart needs to run at least 15mph not max. Can we change the axle sprocket for more speed and still get the low end torque to take off and climb some small grades??

If I call the listed number can they help me with building the package or is it just for ordering?


Our employees who answer the phones would not be able to help with putting together a package or kit for the project because it takes so many calculations to get right. I can help with that here though.


Electric motors have a lot of torque compared to gas engines so low-end torque for takeoff will not be a problem with the right gear ratio for the motor. Selecting the right amount of power and the correct gear ratio to propel a 900-pound vehicle up a small grade will require some calculations to get right though. 


I like to calculate grades for half of the top speed on flat ground so the motor will not run too slowly and overheat. 


If two 1000 Watt motors were installed with a 20 MPH top speed gear ratio then here is a calculation showing the maximum grade percent that the vehicle should be used on and the speed it would travel at when going up that percent of grade.



Here is the sprocket size calculation for two 1000 Watt motors with a 20 MPH top speed.



Here is a chart showing grade percents and degrees.

As you can see a 7 percent (%) grade is very gentle. 


In order not to over engineer or under engineer the powertrain, if possible, I recommend taking an inclinometer to the steepest track that you will be on to see what percent of grade it is. This way there will no guesswork involved and the powertrain will perform as intended and not be underpowered which would be disappointing, or be overpowered and cost more than it needs to. 


If you know the maximum percent of grade that the railroad track cart will be driven up and what the target top speed for the cart will be then I can run some calculations using those parameters to determine what size motor and sprockets would be best to use. 


Please let us know your thoughts and we can take it from there.

Thanks! So lets build that package. Package needs a hand throttle. No foot.  I definitely only want one (1) motor. please spec the highest speed, most torque package you can give me. 7% grade would be ok to use for a calculation. If I need to change either of my gears for optimum power we can work on that also. If the package already specified is the best, with the options to change gears for better performance, lets work from that. 

With a single 1000 Watt motor, the 7% grade speed would be 5 MPH so the top speed on flat ground would need to be geared for 10 MPH. It would need two 1000 Watt motors or one 2000 Watt motor to get the top speed over 15 MPH.


We have 2000 Watt motors, however, they run at 5600 RPM instead of 3000 RPM like the 1000 Watt motor do. I ran a calculation with the 2000 Watt motor and it would require a 142 tooth axle sprocket for the 20 MPH top speed.



The largest axle sprocket for #35 chain that we carry is only 114 tooth, however, you could have a 142 tooth axle sprocket for #35 chain custom made by Rebel Gears if you would like to use the 2000 Watt motor. 


With a 2000 Watt powertrain, the battery pack size would need to be doubled from the calculations above for the 1000 Watt motor. So the estimate for 2000 Watts is 44Ah for 60 minutes or 84Ah for 120 minutes. We would have to round these numbers out to actual battery sizes of 50Ah and 90Ah. 


I need to ask a few questions to know what to include with the kit.


Would you like to use the 2000 Watt motor?


What size battery pack would you like?


Which throttle would you like?


Any of the throttles on these pages could be added to the kit: 

https://electricscooterparts.com/throttlesstandard.html

https://electricscooterparts.com/throttles48volt.html

I am assuming that the first package will not work because we threw the 7% grade into the equation. Is that correct?

If i give up 5 mph and go from 20 mph to 15 mph top speed will the first package work? If its close I am willing to try. If I read the other post correctly I can always add the additional motor and controller at a later date to this package. 90% of the grades are 1% to 3% I only have one 7% grade to climb (coming and going) less than a 1/2 mile long ( we pedal this track at these grades).If this will work I need the full length throttle with amp gauge for a 1" bar.I also need, 1 freewheel hub for a 1" axle, 1 axle gear, 1 motor gear, 1 chain. all other switches and fuses. No batteries or battery charger. 

If first package its not even close:

I want to stick with the 2-1000 watt motors using two controllers and one throttle. I need the full length throttle with amp gauge for a 1" bar.I also need, 2 freewheel hubs for a 1" axle, 2 axle gears, two motor gears, two chains. all other switches and fuses. No batteries or battery charger. 

1.question about this package. two motors = less strain = less amp draw, so I would  get the same run time on the 22ah batteries as was in the first package?

A single 1000 Watt motor is estimated to be able to do the job with a 15 MPH top speed gear ratio and the addition of human power for the 7% grade. Our calculator estimates that it will slow down quite a bit on the 1% and 3% grades, however, will push the cart at reduced speeds on 1% and 3% grades by itself without pedaling, or the cart could be pedaled to keep it at full speed.


If you want a 15 MPH top speed with twice as much power as a single 1000 Watt motor then two 1000 Watt motors could be installed. Or with two 1000 Watt motors, the top speed could be increased to 20 or 25 MPH depending on how much torque you want the cart to have with the higher the top speed is resulting in slower acceleration and less hill climbing power. 


We have full-length twist throttles for 1" OD round bar. We can put together an axle sprocket with freewheel and hub for 1" axle. We can make all of this including the switch and fuse into a kit. 


Regarding your question; the Amp draw is closer related to the top speed gearing, terrain, and speeds that the cart is driven at than the rated power of the motor or motors. For example, if a cart had a 1000 Watt motor and another cart has a 2000 Watt motor (or two 1000 watt motors) and they were both driven under the exact same conditions and speeds then they would both consume the same amount of power from the battery. However, if the cart with 2000 Watts of motor power was driven faster or under more demanding conditions than the cart with 1000 Watt motor then it would consume more power from the battery. 


We consider a package to be all of the parts without matching and labeled connectors installed on them, and a kit to be all of the parts with matching and labeled connectors installed on them so all you have to do is plug everything together. 


We can put together a package or a kit depending on your preference. There is a $32 charge for the kit over the package, however, any necessary wires and connectors are thrown into the kit for free so the real cost of the kit is less when you factor that in. 


We recommend placing the fuse holder into one of the battery pack jumper wires so it is part of the battery pack wiring harness because this offers the highest level of short circuit protection. We can include a battery pack wiring harness with a package or kit and we have them available for batteries with push-on and bolt on terminals, or you could build the battery pack wiring harness yourself if you prefer.


I believe that we are at the point in this process where I could start putting together a package or kit once I know if you want a package or kit, and what motor or motors you want to use, and what top speed you want the sprockets to provide?


If you have any questions please feel free to let me know. 

OK, I willing to try my luck due to the mostly flat terrain here. I can always add to the system.


Please spec a: 36 volt,1000 watt motor and controller, top speed 15 MPH (+-) geared so it takes of and climbs hill to the best of its ability. Need axle sprocket, freewheel hub for 1" axle, proper size motor gear. full-length twist throttle for 1" OD round bar with amp gauge and all other small parts/wires. Design as a "KIT" No batteries or charger. FYI , due to the current sprocket gearing we can only pedal at a rate of 9 MPH. So we cannot over come the motors for there loss over that. 

I found an online acceleration calculator and it estimated 60 seconds for a 1000 Watt motor to propel a 900 pound vehicle to 15 MPH on flat ground. 0 to 15 MPH in 60 seconds is by no means fast acceleration. Of course if you pedal along with the motor then the 0 to 15 acceleration would be a lot faster. 


I just wanted to run these numbers by you to see if they are okay before I make the kit?

No thank you. I was really excited that this was going to work with your very first reply. This has gotten worse as we have looked at all the variables. Thank you for your help but I don't want to be disappointed when I spend the funds and it does not work.

I agree and have been contemplating that a 1000 Watt motor is not going to be suitable for your project due how slowly it would accelerate a total vehicle weight of 900 pounds. I am concerned that during the first 30 seconds of acceleration when the motor is at low RPMs it would overheat. I am glad to hear that you are on the same page as me and think it is not a good idea. For such a heavy vehicle, two 2000 Watt motors geared for a 15 MPH top speed would be a much better design because they would accelerate to top speed in 15 seconds and only be at low RPMs for a few seconds which would prevent them from overheating. 


This is the first 900-pound vehicle traveling faster than walking speed that I have worked on designing a kit for so it has been an educational experience for me. Becuase of this experience I am going to add an acceleration calculator to our site to help with designing kits like this in the future. 


Thank you very much for starting this topic and helping us along our journey of learning how to design powertrain kits for light (and not so light) electric powered vehicles. 


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