How to Make Power Wheels Faster: 3 Simple Methods for Faster Speeds

Fisher-Price Power Wheels ride on cars can make for hours of entertainment and outdoor playtime. However, some children may quickly tire of the maximum speeds that they are designed to operate at and will want faster speeds.

For parents looking for a way to make their kid’s electric car go faster, this article provides research and helpful step by step instructions from one of the world’s leading Power Wheels aftermarket specialists, Lance Cheney, on how to safely and effectively make your toy car faster. Whether you’re looking to make an upgrade to the battery, replace the motor, or make other modifications, Lance’s helpful article will assist you to get faster speeds from your Power Wheels toy.

No-Load Speed Explained

The “no-load speed” is regularly quoted on a motor’s datasheet, it refers to the toy’s velocity when there’s nothing inside it to slow it down. On flat terrain, most Power Wheels toys will eventually reach the motor’s no-load limit due to low environmental friction. Using this knowledge, we can replace the motor with one of a similar size with a higher no-load speed at the same voltage, resulting in faster speeds.

Most Power Wheels only reach a maximum speed of 5 mph (miles per hour). However, with this modification, your little one can speed off at 7mph, offering a faster speed while keeping the car safe for young drivers. Although, please note these engines aren’t suitable for running at higher voltage — more on this later!

Looking for a more detailed overview of common Power Wheels car motor characteristics? Look at the example table below, where we compare six vital electrical specifications in several different Mabuchi Motors:

Here’s a breakdown of what each metric means

• Nominal voltage: The electrical voltage present during the motor’s regular operation and the basis of all the other specifications, including the no-load speed and current and stall torque and current.
• Operating voltage range: The manufacturer’s recommended voltage operating range.
• No-load speed (RPM): The actual motor’s speed when it’s not subjected to any external load and is supplied with the nominal voltage. It increases in proportion with the applied voltage.
• No-load current (amps): The amount of current required to overcome the motor’s internal friction when running at the no-load speed. Two sources are primarily responsible for this waste — brush and bearing (also known as bushing) friction. The no-load current is an essential parameter in Power Wheels cars as this frictional loss heats the engine, reducing its efficiency and lifespan. It increases with the RPM but is not linearly proportional.
• Stall current (amps): An inferred parameter indicating the amount of current a motor would draw when stalled (0 RPM) and powered by the nominal voltage. A higher-stall engine will create a more stressful electrical environment for Power Wheels toys with simple switches for motor control.
• Stall torque (mN*m): An indication of how much torque (rotational force) a motor will exert when supplied with the stall current’s amps. kV is a derived parameter acquired by dividing the no-load RPM by the nominal voltage (RPM/volts). A higher kV motor will run faster at a given voltage than one with a lower kV.

Okay, so now we’ve learned about the motor specifications, let’s examine a few trends from the table.

We have four motors – two 550-sized and two 775-sized. To make life easier, Mabuchi uses decodable motor names. For example, the RS-550PC-7524 includes the engine’s case size of “550”, its winding wire diameter of “75”, and the number of turns of wire on each pole, “24”. For the same case size, more turns mean a lower kV but a higher torque per amp.

If you want to pick a motor suitable for your Power Wheels purely for top speed, you need the highest kV possible:

Motor	kV	RPM @ 12v	Stall Current @ 12v	Stall Torque @ 12v
RS-550PC-7524	1717	20600	76.5	421
RS-550PC-7527	1375	16500	70.8	490
RS-775VC-8015	1071	12857	80.7	731
RS-775WC-8514	1083	13000	86.7	810

How to Modify your Power Wheels Voltage (Battery Power Increase)

Ride-on Power Wheels toys are usually supplied with a 6v, 12v or 24v battery. A battery powered motor’s no-load speed will increase linearly with applied voltage, presenting one of the simplest ways to get additional speed from children’s Power Wheels vehicles. Converting the toy from a 12 volt battery to a 18 volt battery will give your Power Wheels toy approximately a 50% faster top speed, while adding a 24v battery to the car will double its velocity.

However, before you make this change, there are a few things you need to consider:

• Are the toy’s electronics able to tolerate higher battery voltages? – Many newer Power Wheels come with remote or soft-start controllers that can’t handle higher battery voltages without further amends. While more basic Power Wheels have no electronics whatsoever, they use a set of switches to turn the motor on and off, move forward and back and change speed.

• Will the motor overheat? – Terrain plays a significant role in the temperature of the engine. Hilly or high-drag landscapes, such as thick grass, place a much higher energy load on the actual motor, and running it at full voltage can quickly push it out of the safe operating range, causing motor or gearbox failure. Switching from a 12 volt battery to an 18v battery will generally make 2.25x as much waste heat (V-squared).
• Will the starting torque damage the gearbox? – Increasing the battery voltage also amps up the current the motor consumes as it accelerates. Since the engine’s torque is typically proportional to the current, moving from a 12 volt battery to an 18v battery will result in a 50% rise in the peak stress.
• Will the increased current draw damage the switches or metal wiring connections? – The controls in a stock Power Wheels vehicle are usually rated for 30A continuous and are wired with 14ga wire. When your budding driver presses down on the pedal switch, both motors connect to the battery, pulling over 100 amps of current. While this is fine for a 30A switch as it is relatively low duration, increasing the motor to 24v would double the current and quadruple the heat-related losses.

There are also several options for increasing the Power Wheels toy’s voltage supply from a 12 volt battery:

• Fit an additional battery alongside the original – This extra battery should have the same ampacity as the first to ensure it doesn’t get over-discharged during operation. The most straightforward way to do this is by replacing the stock battery with a new matching set of either 6 volt or 12 volt batteries to make an 18-volter.

• Replace the original battery with a higher voltage one – Many DIY-loving parents use an 18v power tool battery — these typically have a 5S lithium-ion construction. However, do check the tool battery isn’t over-discharged, as this can cause permanent damage to the battery or even start a fire. Also, a tool battery will not have a built-in shutoff, building it into the power tool itself, so you’ll need to add similar functionality to your Power Wheels toy. The best way to achieve this is by adding a battery voltage meter (potentially with parental monitoring) or active shutoff.
• Utilise a step-up (or boost) converter that will convert a 12 volt battery to a higher voltage output. Although this is a possible solution, high-power off-the-shelf converters are expensive, so we suggest sticking with one of the above-mentioned methods.

Another point to remember is that a Fisher-Price Power Wheels car battery has circuit (thermal) breakers built into each unit. When replacing this with a standard sealed-lead-acid or tool battery, you must also add a 30A or 40A circuit breaker in series with either of the two supply leads.

Get Faster Speeds by Swapping the Gearbox or Changing Gears

The majority of Power Wheels toys use a multi-stage gear reduction to transform an electric motor’s high-RPM, low-torque output into a low-RPM, high-torque drive capability to push a 100+ pound vehicle.

How to work out the RPM of Fisher-Price Power Wheels

Most Power Wheels 12 volt toy cars utilise a “7R” gearbox containing four gears. By counting the teeth on each gear, we can determine their RPM:

	Input Teeth	Output Teeth	RPM
Motor Pinion		15	16000
First Gear	72	25	3333
Second Gear	78	14	1068
Third Gear	45	12	332
Final	38		105

Theoretically, with a 15-tooth motor pinion, a no-load 16000 RPM motor would reach about 105 RPM at the output, with an effective gear reduction ratio of 152:1. This calculation means the output torque is 152 times the input torque, although friction losses will reduce the output torque in real life.

For example, here’s how you would calculate the average speed of the 15-tooth pinion on the Jeep Hurricane Power Wheels, which has a ~16″ diameter tyre:
105 Rev/min * (60 min/hour) * (16 * pi in/rev) * (1 ft/12 in) * (1 mile/5280 ft): 5.0 mph

Effective ratio is (16000/161) = 99:1
161 RPM * (60 min/hour) * (10.5 * pi in/rev) * (1 ft/12 in) * (1 mile/5280 ft): 5.03 mph

Essentially, by taking that same gearbox and putting it in the Jeep Hurricane, you could give the Power Wheels toy a higher top speed (7.66 mph). All you’d need to do is drill out the hole to fit the bigger axle.

Another thing to consider is that the gearbox in the Jeep is under more stress than the quad bike as the torque applied to every gear is higher. The pinion on the quad (which has 23 teeth) has a larger radius than the 15-tooth pinion on the Jeep. Force = torque/radius, so a larger radius means less force at the gear tooth’s surface. This logic allows you to put in a higher-torque motor or increase the voltage on our 23-tooth gearbox with less worry about breakage vs 15-tooth gearboxes.

Maximum Theoretical Wheel Torque

The theoretical maximum wheel torque is the stall torque multiplied by the gear ratio. However, this is not a realistic number due to internal wiring and battery resistance. By modelling that as 0.2 ohms, you get a more accurate max wheel torque, which is about as good as it gets, even with a quality sealed lead-acid battery and 14-gauge wiring.

A Quick Note About the Electronic Speed Controller

Some advanced Power Wheels enthusiasts use speed controllers, motor controllers, ESCs, or “scooter” controllers. These allow the wannabe racer to proportionally vary the throttle or speed of the car and is a must-have feature for high speed tuned vehicles.

These controllers use a transistor-based design, typically MOSFET (also known as metal–oxide–semiconductor field-effect transistor), to rapidly turn on and off the motors with a varying duty cycle (% of ON-time). Almost all of these controllers will limit the current they provide to the engine to ensure they remain safe.

Also, in no case do the modified scenarios with the speed controller achieve the torque (and gearbox stress) of the bone-stock configuration, suggesting that reliability will be high, but acceleration and terrain flexibility will be poor. The drivability will be substantially improved across the board with a 60-amp controller.