9 Reasons RC Car Batteries Overheat

Like every other piece of RC technology you have in your radio-controlled vehicle, you’re going to have to take care of your battery.

Too many times people will buy a car or truck and just run as they see fit without doing simple maintenance or by not running the vehicle correctly, resulting in everything from overheated batteries to ESC failure.

These are nine reasons that RC car batteries may overheat.

Bad Battery Connectors

battery connectors

RC batteries can have a wide variety of connecting ends (or some have none at all, allowing you to choose which you’d like to put on them). These battery ends can get so hot that they melt when too high a current is passed through them.

One of the quickest ways to mess up your battery is by using a powerful motor or electronic speed control (ESC) with a battery that has connectors meant for stock motors and low current ESCs.

One such low current connector is the Tamiya style connector. These are the white plastic ends typically found on Ni-Mh and Ni-Cad batteries.

broken battery connector

Switching out your old Tamiya connectors to a higher current connector like a Dean’s connector or a Bullet gold plated connector, will mean a longer life for your electronics. Not only are the connectors easy to solder on to your wires, but they will help protect so that you don’t fry your battery by having high end electronics with a low-end battery connector.

Counterfeit Battery Connectors

battery connectors

In the very same vein of thought, if you upgrade your connectors and don’t get genuine Deans or Bullet connectors, you’re likely to melt and fry out your battery just as easily.

Never scrimp on these, buy them straight from a reputable hobby shop or through the company’s website. Buying knock-off connectors may save you a few cents all while watching your $100 battery go up in smoke.

Too Much Pinion

rc car pinion gears

The pinion gear could be off and if so that can make your battery and motor run too hot.

To see if the pinion is the problem, take your RC vehicle out and drive for a couple of minutes. Use a temp gun (amazon) and note the length of time you ran the car or truck along with the temperature.

Next, go down a tooth on the pinion, for example, if it is a 15T go to a 14T. Test the car or truck again by running the same amount of time and see if the temperature turns out to be lower.

Old Battery

old lipo battery

Like everything else in life, the older your battery is the less performance you’re going to get out of it.

This can also lead to overheating issues and not being able to run as hard or as long as you were able to when the battery was fresh. As we charge and discharge batteries, they take a little bit of that life with them. To offset this issue, change out your batteries regularly and keep a note of the voltage draw of them.

Running Too Hard

Traxxas Rustler 4x4 Brushless (Pink)

Alas, if you overwork your RC car or truck you can overheat the system. Making the electronics work harder than they were intended to can have an effect over the entire system.

For example, don’t run an indoor RC car in the tall grass, or don’t push your vehicle to do high jumps and turns if it was not made to do so. The longer you overtax the car or truck’s system, the less performance you’re going to have out of the battery.

Dead Cell

7.2V 5000mAh NIMH Battery for RC Cars, 6-Cell Flat Rechargeable Battery Pack, Replacement Hobby Battery with Tamiya Connector for Car Truck Truggy Buggy Tank Airplane Helicopter Boat Racing (2 Pack)

Just like your own vehicle’s battery, your RC battery can “drop a cell” which means that one of the cells of the battery is not performing or has completely stopped functioning.

If you have a six-cell battery and two of the cells are dead, then your power rating has declined immensely and this can lead to overheating of the battery and the overall electronic system of your RC car or truck.

Not Using Proper Electronics

GoolRC Brushless Motor Upgrade Waterproof 3650 3500KV Brushless Motor with 60A ESC Combo Set for 1/10 RC Car Truck

This is a wide berth of issues in one concise heading. This can mean running a Ni-Cad battery instead of a LiPo, it could mean running a stock motor instead of a high-performance motor, or even a low-grade ESC when it’s calling for a high-performance ESC.

You need to put what is not only best suited for your car or truck but also make sure that all the parts complete each other with cohesion. A high-end battery with a low current connector, running with a stock motor, and a high-performance ESC is not going to give you the outcome you’re looking for.

Make sure that you are upgrading your system with items that complement each other and aren’t battling one another.

Poor Ventilation

Hobbywing Ezrun 5V C4 Cooling Fan & 44 x 65mm Motor Heat Sink System RC Motor Fan for 1/8 Car#86080130 Blue

Sometimes the most common sense answer is the right answer. Not having good ventilation can cause your battery, and other electronic components, to overheat. This is especially true if you’re running the vehicle in the middle of summer. You need a few things to bring the temperature that is surrounding your precious electronics so that they don’t lack performance, or worse, stop running completely.

Heat sinks on the motor will help distribute the heat off the motor and help it stay cooler

Cutting a vent strip in the body of your vehicle over the ESC and battery can help disperse heat and keep the air flowing

Add a fan to the ESC so that it has more air flowing across it to keep it cooler

All of these things are a great way to help increase the air flow ventilation on your RC car or truck and to keep your electronics from overheating.

To keep your RC vehicle ready to go at a moment’s notice and grabbing those checkered flags, you’re not going to be able to just throw it in a corner and forget about it between races or backyard battles. You need to cycle your batteries and keep all of the electrical parts of your car or truck running right.

Without proper maintenance, your system is headed for ultimate failure and your RC vehicle’s life will be cut short. In today’s market, that’s a lot of dough to wash down the drain just to save a few minutes of preparation before and after you run.

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