Began upgrading my Stuart to 6mph (To Scale) speed.

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Tech-Com
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Began upgrading my Stuart to 6mph (To Scale) speed.

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After brushing up on my physics, determining minimum torque for the inclines I wanted to climb, studying different motors and available gearboxes, and determining I needed 500rpm, I was surprised to find I already owned exactly what I needed. Some trusty Black+Decker drills I bought years ago seemed perfect. I ordered 2 more from ebay, both for only $30 shipped.

I needed at least 500rpm, and these output 550rpm with 65inlb of torque. This should be all I need for climbing even the steepest inclines. The stock board won't be up to handling the 10amps each needed, but I am working on my own motor controllers that will work with the 2.4ghz heng long board.
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Last edited by Tech-Com on Wed Feb 20, 2019 2:32 am, edited 1 time in total.
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Son of a gun-ner
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

Post by Son of a gun-ner »

What a fantastic idea, and you get built in adjustable clutches.

I'm guessing you'll use the motor power output of the board to control a pair of power transistors.
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

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Yes I'll be able to limit speed mechanically or at the very least prevent motor stall with the clutchs.

Yes, using some Mosfet's will let me have the same On/Off motor function like the orginal electronics. For now this is how I'm controlling it while I wait on the HL 2.4ghz stuff to arrive.

Hopefully, I can come up with a solution for a variable throttle.
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

Post by Son of a gun-ner »

I'll be following your motor controllers with great interest, I had wondered about using transistors or mosfet's to control more powerful motors with standard Heng Long electronics, but I also wanted the controllers to supply the motors with power from a separate higher voltage battery than what the Heng Long board used.
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

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So my main battery is 12V. To run the HL board I will use a DC-DC step down converter 12V to 7.5V. They cost about $6.
Typically they are 3A - 5A max, with some going as high as 10A, so you can build in whatever level of protection by selecting one that handles your HL board without compromising it.

I started using them years ago when I wanted to wire a USB plug into the overhead light console on my 2005 Mustang so I could run a USB dash camera.

Now the motors could be directly connected to the battery, with Mosfet as the switch, and some form of current regulation to keep them around 10A max. I might utilize the drill electronics since they are already regulating the motors to the RPM I require.

Another option I will explore is using the DC-DC step down converters as current regulators for each specific motor. For example, coming off the stock 21st board is 12V to each motor, if were to install a 12V to 7.5V 5A between the motor and the board I might be able to protect the stock 21st board, but may loose a lot of speed in the process since I desire up to 10A for each motor.
Last edited by Tech-Com on Tue Feb 19, 2019 2:43 pm, edited 1 time in total.
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

Post by Son of a gun-ner »

Thank you again :thumbup:

Although I've had experience of motor speed controlling with transistors and mosfet's, from a single power source, I didn't have any other circuitry that needed a different voltage, and I was only copying from plans.

I'll look for those step down converters :thumbup:
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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

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My HL transmitter and receiver arrived. I began studying it to determine how I will utilize it with my 12V battery. I want to be able to throttle my motors for low speed operation and fine turning, but also have them kick in to e full 12V speed. To do so I tested the HL board to determine what I would consider my limits before it might suffer failure. It may be able to handle a lot more watts, but I stopped it when I thought I observed thermal runaway.

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Re: Began upgrading my Stuart to 6mph (To Scale) speed.

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First Test is a Success! With exception of melting wires lol.

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