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Proper Motor for Electric Hand Pulled Cart

RE: Low profile hand cart

I have a hand pulled cart and need help with the proper motor for my application.

Cart GVW: 150lbs

Total run time needed: 3 hours

Speed:  3.5 to 4 MPH

Drive Wheel diameter (very small):  Four inches

Will consider a belt rather than chain as also concerns for corrosion.

Cart will be exposed to salt air.  Will seal engine and battery compartment.

Your help appreciated!

Need to order ASAP!


A gear motor would be required to obtain the needed gear ratio for a 3.5-4 MPH top speed. All of the gear motors that carry have sprockets for a chain drive. 

Here are some calculations based on your parameters:

The calculations above are based on using our MOT-24450SP gear motor. For a 3 hour runtime on flat ground a 24 Volt battery pack made from two 12 Volt 44Ah or larger batteries would be needed. The closest battery size we carry is 50Ah. The dimensions of our 50Ah batteries are 7-3/4" long x 6-1/2" wide x 7" high and they weigh 32 pounds each. We added 75 pounds of rider and cargo weight to the calculation above to account for the weight of the battery pack and motor. 

A 14 tooth sprocket for #420 chain has an outside diameter of 2-1/2". This sprocket would have 3/4" of ground clearance when used with 4" wheels. Would the battery size and ground clearance be acceptable for the project?

Thank you for getting back to me so quick!

The 14 tooth sprocket leaving 3/4" ground clearance is okay. What diameter axle size is required, a choice?  I'm now using 1/2"


Are the suggested batteries okay if the cart is turned on it's side or even upside down?  Portable cart will be transported by my customers and need to know limitations.

Any type of battery of less weight available?

Appreciate your help! 


We can get the 14 tooth axle sprocket for 1/2", 5/8", 3/4" and 1" axles. The 14 tooth sprocket for 1/2" axle has a 1/8" x 1/16" keyway for a 1/8" machine key. 

Our sealed lead acid batteries are designed for use and transportation in any position, however, charging the batteries in the upside down position should be avoided.

Depending on how hard the hand cart is used, two 35Ah batteries may be able to provide a 3-hour continuous runtime and they weigh 23 pounds each. For a 3-hour runtime under demanding conditions, we recommend the 50Ah batteries though. 

There are lithium battery packs on the market which are lighter than lead acid battery packs, however, our brushed motor controller which is needed to run the gear motor has a low Voltage battery protection level of 20.5 Volts which is designed for lead acid battery packs so we can not make a gear motor kit that would be designed towards using a lithium battery pack which typically need an 18.5 Volt low Voltage battery protection level. Lithium battery packs also cost around 3 times more than lead acid so for a 24 Volt 50Ah battery pack you would probably be looking at a cost of around $720 for a lithium battery pack compared to $240 for lead acid battery pack.

Please let us know if you have any questions.

Thanks again for replying quickly!

I'll stay with the 1/2' axle and need to know the width of the 14 tooth sprocket?

Staying with the lead acid battery pack and considering using the 35Ah batteries.  You had added 75 pounds for the motor and batteries combined.  How much weight difference between the two battery sizes?  The motor weight?  

Chain length can be adjusted at my end?  The motor mounting distance to the axle will be less the 10 inches.  Not sure of exact length at this time.

Please send me a list and prices for the components to complete the installation.  Batterie pack (both sizes), motor, chain, controller and any other items needed.

Thank you!

The width of the 14 tooth sprocket is 7/8".

The 24V 35Ah battery pack is 18 pounds lighter than the 24V 50Ah battery pack. The dimensions of the 35Ah battery are 7.70" long x 5.12" wide x  6.26" high and it weighs 23.2 pounds. The motor weighs 11 pounds. 

The #420 chain has 1/2" long links so fine adjustments are not possible by adding or removing links. Due to this the position of the motor or axle will need to be adjustable in order to properly adjust the chain tension. This is often achieved by making a motor mounting plate that has oval-shaped holes for the motor bolts to go through so the motor can be moved towards or away from the axle as needed. 

Regarding the parts list and prices, I would like to gather a little more information before I get started on that so I have a few questions. 

Do you need the motor to go forward only, or to have forward and reverse?

Do you want a twist throttle or thumb throttle?

Do you want a panel mount key, or rocker, or toggle power switch, or handlebar mount key or rocker power switch? 

Please let us know if you have any questions. 

Thanks for your response!

Motor "forward" only

Throttle:  Not sure I understand how the thumb throttle will work?  I was thinking a lever throttle on the handle that could be squeezed and released.  Actually good for safety as releasing your hand the cart would stop.  My cart handle is one continuous tube shaped like a U and guide/pull the cart with it.  Not sure how to fasten the twist throttle?  I assume works like on a motorcycle and at the end of a handlebar?

On/Off Power:  Would prefer the rocker switch mounted on the handle.

If experiencing a dead battery can the cart be moved without disconnecting the chain or adjusting the motor mount bracket?

Chain lengths?  I need to provide exact length to you?

Please explain the two throttles and which one would be best for this application.

Appreciate and thanks! 

The thumb throttle is similar to the throttle on an ATV where moving it by thumb varies the speed of the motor. 

All of our throttles and handlebar switches fit 7/8" handlebars and are one piece designs that need to slip over the end of a tube to install. Due to their one-piece design, they cannot be installed on a continuous tube-shaped handle. 

We carry a cable pull throttle that can be connected with a cable to a mechanical throttle or lever so that may be a solution if you are not able to change the handlebar design to have open ends.

With a dead battery the cart could be moved by hand, however, there will be extra drag from the motor. The motor will not lock up the wheels though and they will be able to be turned. 

We can break the chain to any number of links that are needed so that is no problem at all. 

If you are not sure which throttle or power switch will work right now then we can go ahead and put together a quote without those parts. Do you want to purchase all of the parts and wire them together yourself or would you like them as a kit which has been pre-wired with matching connectors on all of the parts?

Pricing on complete package. I prefer to have a kit to make an easier installation.  The throttle let's go with the thumb throttle control.  I have a few ideas to make that work.  Chain length for now to figure pricing package I estimate needing 16 inches total length around. The two recommended sprockets. On/Off rocker switch to be mounted on the handle close to the thumb throttle.The battery pack will use the smaller 24V 35Ah.  In addition to help me decide please quote a price on the larger 24V 50Ah battery pack as well.

Wiring allowance for the throttle and On/Off switches mounted on handle should be about 60 inches.

What am I forgetting?

Have a great weekend and look forward to your response next week!


Waiting for your response.

Would like to order needed parts and asking for the kit pre-wired and matching connectors.

Any questions?



I have the price quotes prepared. Both of the quotes below are for kits that are pre-wired and have matching connectors. The 10 tooth motor is included with the motor so it is not a separate part. The power switch and throttle both have 60" or longer cables. 

Here is the quote with 35Ah battery pack:

1 qty. MOT-24450PL motor $159.95

1 qty. SPD-24500B controller $39.95

1 qty. THR-38 thumb throttle $19.95

1 qty. SWT-23 power switch $14.95

1 qty. CHR-C24V4AXLR charger $74.95

2 qty. BAT-12V35AB batteries $79.95 x2

1 qty. HNS-127 battery harness $12.95

1 qty. CNX-XLR10 charger port $3.95

1 qty. SPR-42014H 14T 1/2" ID sprocket $14.95

1 qty. CHN-420 x 32 Links $5.76

1 qty. Kit Labor $35.00

Total = $542.26

10% kit discount = $54.23

Grand total = $488.03

Here is the quote with 50Ah battery pack:

1 qty. MOT-24450PL motor $159.95

1 qty. SPD-24500B controller $39.95

1 qty. THR-38 thumb throttle $19.95

1 qty. SWT-23 power switch $14.95

1 qty. CHR-E24V7AXLR charger $149.95

2 qty. BAT-12V50A-ITP batteries $119.95 x2

1 qty. HNS-127 battery harness $12.95

1 qty. CNX-XLR10 charger port $3.95

1 qty. SPR-42014H 14T 1/2" ID sprocket $14.95

1 qty. CHN-420 x 32 Links $5.76

1 qty. Kit Labor $35.00

Total = $697.26

10% kit discount = $69.73

Grand total = $627.53

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

35Ah Battery Pack.  Will order the complete kit and parts.

Total Price $488.03

Thank you

Order now!

Waiting for instructions.


We have got the kit finished. It is our item # KIT-24450G-30. Here is the link to it: 


Please let us know if you would like any changes made to the kit, or if you have any questions. 

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