What is needed to get started with an electric hobby grade RC kit car?

• I am writing this article based on my experience with building RC kit cars.
• This article may be incomplete or have incorrect information. Please tell me if you find any such content and I shall correct that.
• I will be updating this article as and when I have new information.
• We are discussing only about electric kit cars here.
• The advantage of going with kit car is, you get to understand how the car works in detail and also the different components.
• This also give you added benefit of gaining knowledge on repairing/replacing parts in your car.
• The list below may be huge. Some of them may be already be available with you.
• I am just listing down everything that was needed for me to build/repair the car.
• I tried to list the components in the order of importance.



• Car kit without electronics
• Identify a kit that includes everything but electronics. eg 4WD Truggy and 4WD Off-Road Buggy
• Note: Some kits come without wheels and body shell. In that case you may have to buy those separate.



• Motor
• This is the main motor that is going to power your car.
• There are inrunner and outrunner motors. For the car, we need inrunner motor.
• Motors come in different sizes such as 2845, 3650, 3670 etc. Choose the motor which fits on your kit car. Manufacture might have given the details on the user manual. For eg, a 2845 motor may be too small to fit at the place of a 3650 motor.
• If your kit comes with a pinion gear, before ordering the motor, make sure that the pinion hole size is same as the motor shaft size. 3.175mm is one of the standard pinion/motor shaft diameter size.
• Same sized motors such as 3650 can come in different speed ratings such as 2000kv ~ 7000kv. Choose a motor that the manufacture recommends. For eg, if you install a 5300kv motor in place of a manufacture recommended 3300kv, the car might go faster but motor might get over heated and eventually burn out. Also other moving components in the car may not be designed for such high speeds. If the exact manufacture recommended rated motor not available, you can buy the nearest rating available and adjust the speed by installing a lower number teeth pinion. (gearing is a separate topic)
• Motors also come in brushed and Brushless. Brushless motors are expensive but easy to maintain and provide greater speed.
• Brushless motors also come in sensored and sensorless. Sensored motors are expensive but give greater precision.
• eg. 3650 sensorless Brushless motor



• Electronic Speed Controller(ESC)
• ESC is the part that allow us to control the speed of motor based on how much throttle we provide.
• For a brushless sensorless motor, you must choose a brushless sensorless ESC. Some ESC can support sensored and sensorless brushless motors.
• ESC is typically rated by the continuous current it can provide. Ideally, the ESC you choose should have more continuous current capacity (20%) than the max current A motor has. For eg. for 45A brushless motor you should choose a 60A or more ESC.
• Modern ESCs come with battery eliminator circuit (BEC). This give you the advantage of using same battery to power other components such as servo. There will be BEC rating given such as 6V/1.5A, so the servo you choose should support 6V. If you select a lower volt servo, the more voltage from BEC could destroy your servo.
• eg. Sensorless Brushless ESC



• Servo Motor
• This is the motor that is used to control the steering of the car.
• Servos are available in sizes, such micro, standard etc. For a 1/10 scale car, it is typically a standard servo that can fit properly.
• Servos come in metal gear and plastic gear. Due to the higher speed of 1/10 scale cars, it is ideal to choose metal gear servo.
• The servos are rated by their Torque and speed. For eg, @6.0V – 10.2kg-cm and @6.0V – 0.12sec. It is best to choose a servo that has 10kg above torque and speed less than .15 sec.
• Servo specs will also specify what angle the rotation will be. For the car steering, we need a 60degree rotation servo.
• Note – There are way too cheap servos available. Be warned that, they may not work for longer or work in the desire way. For eg, two cheap servos I bought was having centering issues. Another cheap servo was continuously rotating.
• eg. Standard Servo



• Transmitter/Receiver(Tx/Rx)
• This is the part, that let you control your car.
• Since we are discussing cars, we will talk about pistol grip type car Tx.
• For a car, at minimum Tx/Rx should have 2 channels. One for throttle(ESC) and another for steering(servo).
• Tx are available from basic to very advanced. It is best to go for a Tx which support Dual rates, Exponential Rates, End Point adjustments etc. Also a Tx that can pair and store several receivers in memory would be a good choice. By that way you can use one Tx to control all your cars.(not at same time though).
• eg. 3 channel Tx/Rx



• Lithium polymer (Lipo) Battery
• If you are going with a brushless system, then Lipo is the way to go.
• Lipo has several specs. Voltage (2S, 3S, etc), storage capacity (mah), burst current(C).
• Lipo voltages are said in 3.7 (1S), 7.4(2S), 11.1 (3S) etc. The maximum voltage of you Lipo should not be more than maximum voltage of your ESC. For eg, if you ESC max voltage is 11.1 (3S), you should not use a 4S with it.
• More mah capacity, give more run time. For eg. my 5300 mah battery is giving me 45 min or more run time easily.
• Generally higher C is better. It is like, how fast the battery can discharge. More C should give you more punch.
• Lipos also come with soft case and hard case. In my experience, chances of cars to crash is more, so it is best to buy a hard case lipo to protect Lipo against crashes.
• Lipos should be taken care appropriately to avoid damage, explosion and to get longer life span (separate topic). In short, never discharge them below 3.7V per cell. Never store the lipos full charged for more than a week. In such situation store them with 3.8V pe cell.
• eg. 5300mah 65C 2S Lipo



• Lipo Battery Balance Charger
• If you are buying you must buy a Lipo Balance charger too.
• A balance charger allow you to charge the Lipo in balanced mode. It also has option to discharge the Lipo (for storing Lipo long time).
• There are several Lipo Balance chargers available in market. Typically they can be used to charge 2S to 6S Lipos.
• Charging current is set as per your battery capacity (mah). If you Lipo is 4000 mah, never charge it setting current above 4A.
• I use SkyRC iMAX B6.



• AC to DC power adapter for Lipo balance charger.
• If your Balance charger does not come with a power source (mine did not), you will have to buy a 12V/5A DC adapter.
• If you have a laptop power adapter with such specs, you can use that.



• T-Connector/Deans connector
• If your ESC does not come with a power connector soldered, you should buy this connector and solder it yourself. (assuming that your Lipo has the same connector)



• Lithium White Grease
• While assembling the kit, it is a good idea to grease the moving metal parts. For eg, gear box, ball bearings, steering knuckles etc.



• General Purpose Grease
• This is optional. If you feel, your differential is acting indifferent or too tight, you can open the differential case and apply some general purpose grease after making light the grease using some mineral oils.



• PROGRAM CARD for Car ESC
• This is an optional accessory. Program card can be used only if your ESC support it.
• For eg. HobbyWing 60A SL ESC support programming. You can use this programming CARD to program the ESC easily.
• Using the card, we can set the reverse speed, low voltage cutoff, brake force, motor timing etc. HobbyWing ESC's support lot more options.
• You could also program the ESC using the button on the ESC without this programming card.
• I use HobbyWing LED Programming Card for my HobbyWing 60A Brushless Sensorless ESC



• Lipo Voltage Checker with Low voltage Alarm.
• Again another optional accessory but very good to have.
• As previously mentioned, you should not drain the lipo below 3.7 per cell.
• This voltage checker can display total voltage and each cell level voltage. It can also sound alarm (based on the level you set) when voltage reaches a level.
• I installed it on the body shell. So I can see the voltage in between run.
• I use Lipo Voltage Checker with Low voltage Alarm.



• Male to female jumper cable
• If you plan to install the Lipo voltage checker outside the car, this might come handy.



• Tools


• Soldering Iron, Lead Solder, Solder paste/Flux
• If there are soldering involved for connectors, this is a must.
• For eg, hobbywing ESC and motor does not have any connectors pre soldered.



• Infra Red Digial Thermometer.
• The art of tuning an electric car lies with temperature of components. Especially temperature of motor.
• If your car is not properly geared, the motor can run fast and heat up and burn itself and other electronics.
• To prevent damage, I always monitor the temperature using an IR Digital thermometer.
• Note: It is ideal to keep the motor temperature in between 120F to 130F. I would never go above 150F.
• I use Infra Red Digial Thermometer.



• Vernier Caliper Digital
• Some kind of measuring scale may be needed to measure length, width and height.
• I use Vernier Caliper Digital 150 mm.



• Electric Screw Driver with bits
• Trust me, in the beginning you will be opening the car very often to fix things. An electric driver can save time and your screw threads.
• Note: Never use it to tighten the screws completely. Do ¾ with electric driver and then use manual driver. Use a electric driver which has torque adjustment.



• 1.5/2.0/2.5/3.0mm Hex Screwdriver Set
• In RC cars, there may be several hex screws. Having a set of hex screwdrivers will definitely be helpful.



• 4.0/5.5/7.0/8.0mm Hex NUT driver Wrench Set
• This set would be useful to work on hex nuts. Eg, on wheel nut.



• 3.0/4.0/5.0/6.0mm Phillips Screwdriver Set
• This set would be useful to work on Philips/star screws.
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• Nose plier
• A nose plier is another good handy tool to hold things from moving, or pulling pins or bend things etc.
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• Hobby Knife
• When working with kits, some times there would be a need to cut stuffs. A hobby knife will come handy at times.
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• Double Side Tape
Double sided tapes are used fix ESC, voltage checker etc on the car.


• Insulation Tape
If soldering is involved, you would need insulation tape to cover the joins.


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