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If you are researching RC cars then you will certainly find Traxxas as they have been around for decades and are one of the most well known brands in the RC car hobby. One thing that Traxxas does is use a lot of acronyms for parts that are on their cars.
Although most RC cars will do this for general parts Traxxas does it on virtually everything which can get a little bit confusing as to what each acronym actually means.
In this article I will be covering exactly what a Traxxas BEC is as well as how it is used in your Traxxas RC vehicle.
A Traxxas BEC is a battery eliminator circuit. The BEC allows a single battery to send less power to multiple parts of the RC car. Without the BEC there would have to be many different batteries for each small part of the vehicle.
Instead, since the BEC is there then the RC car can have one larger battery. The BEC makes the right amount of power go to each part and in turn can power the entire RC car off a single battery.
The BEC is a component that allows RC models to carry one large battery instead of multiple smaller batteries. Not only that but the BEC has made a big contribution to quadcopters as well . Without this technology, all control would be lost when the battery drained down. .
A BEC-equipped ESC meant for airplane use often incorporates a low-voltage-cutoff circuit which can sense the voltage drop caused when the battery has very little charge left in it. It then cuts the power to the ‘drive’ motor in order to provide the ‘steering’ servo with enough power to be able to bring the model safely back to the operator. The power to the propeller would be cut but the operation of the control surfaces would be maintained in order to perform a dead-stick landing.
Without this technology, all control would be lost when the battery ran out. In some cases, the BEC is actually a part of the radio control receiver.
The above is the short version of what the BEC is and how it functions. In the rest of this article we will take a deeper look at some of the more extensive information about a BEC.
You can also check out the video below for additional information about why a BEC is needed in RC cars.
Is the receiver equipped with a BEC?
A BEC is an Eliminator circuit that means it steps down the battery’s voltage so the receiver does not send too much voltage to the servos. In the early days of RC cars they used to carry a separate battery for the receiver. The circuit used to eliminate the need for the receiver battery is known as BEC.
The Traxxas 2.4GHz receiver is not equipped with a BEC and the same is true with most other mini receivers.
Brief history of the BEC
In modern-day electric-powered radio control vehicles, whether airplanes, boats, or cars, they all have something built into their electronic speed controls that stunts the power from the main battery to the receiver to power the radio system.
This system is called Battery Elimination Circuit or for short known as a BEC. This is a useful and necessary technology but many people don’t know what exactly it is.
Back in the early days of RC vehicles, you had to have two batteries, one for the motor and another to power the radios control system. It took up extra space and also batteries were quite heavy which in turn made the vehicles slower.
At that time someone came up with the concept of the Battery Eliminator circuit.
This device could step down the voltage from the main battery to make it safe for the radio system to use, and eliminate the need for the second battery. The first BECs were built into the receiver, not the speed controls, but eventually, as the need for more powerful BECs grew, the ESC manufacturers took it upon themselves to include them into their products.
Using an external BEC isn’t as easy as simply plugging it in because there are some nuances to using an external BEC correctly. Here I am going to break down all the possible steps.
Things to know:
First of all, you need to know power is provided by the main battery. That means the external BEC needs to be tapped into the power wires before they reach the speed control. There are multiple ways to do it but you can simply solder the positive and negative wires from the external BEC to the power connector on the ESC.
The second thing you have to do is plug the external BEC into any open servo port on your receiver. If you don’t have any open, you can also use a Y-Harness into any servo or ESC-occupied port.
The external BEC replaces any speed control built-in BEC but they don’t play nice together. Before it reaches the receiver the red wire on the ESC’s receiver lead must be either clipped or pulled out. Failure to do this can be harmful to your servos and BECs.
If your external BEC has an adjustable voltage output, make sure to set it properly for your servos’ specs.
Now you know all the basic things and it’s time to set up your external BEC.
Please don’t do this if you are confused in the slightest on how to do it as you can easily ruin your RC car’s electronics. If you are unsure about something you should always reach out to a professional for help. Find a person near you who can do it properly and who has the basic knowledge or experience.
A Modular BEC Setup
Between the ESC and battery, there will have been a couple of connectors added. Users are allowed to unplug the BEC from the assembly so that they can use it in another vehicle.
This also allows the user to protect the warranty of their speed control. The red wire on the speed control’s receiver lead still needs to be pulled, though this can be done without voiding a warranty as well, by sliding the wire out of the connector instead of clipping it.
Is an external BEC really necessary?
Did you know? Most internal BECs only have an output voltage of 5 volts. The 5 volts BEC has to supply power to your servo and any other accessories like lights and switches. Nowadays most servos can easily handle 6 volts, so with the 5 volts, you are in fact underpowering your servo by an average of 20%. If you have never had any issues that it’s perfectly fine, you don’t need an external BEC right now.
Another big issue is a hot ESC. Many users say that they have this problem and it also might be the internal BECs fault. There’s too much power being consumed, which is what leads to a very hot ESC. An external BEC can solve this problem easily.
The advantages of external BECs is your servo will be faster and stronger. Your lights will be brighter than before and other accessories will also be faster and stronger. Modern receivers can handle 9 volts easily so no need to worry about the receiver.
I know this article got a tiny bit technical after simply answering the question about what a BEC is at the beginning. However, it is important to know not only what it means when you are talking about a BEC but also to know how it works and whether you need to add one externally.
For most people, the BEC that comes with your RC model will work just fine however if something is not working right or your ESC is heating up too much then you might need to add an external BEC.