Red flashing lights are usually not good news. And so is the case when it comes to Traxxas ESCs. But why is my Traxxas ESC blinking red?
Your Traxxas ESC blinking red may indicate thermal shutdown protection has kicked in to prevent overheating. Another possibility is that LiPo battery voltage is nearing its minimum discharge level. On some ESCs, flashing red light means there’s been a current spike.
I know a blinking red light can be annoying because it’s often accompanied by a shutdown. And because a blinking red light can mean several things, it’s important to know the difference between blink types. That’s what I’ll explain below.
Different Traxxas ESCs
Why a Traxxas ESC blinks red depends on which Traxxas ESC I’m dealing with. On some Traxxas ESCs, there’s one light. On others, there are four lights.
Why Traxxas XL-2.5, XL-5, or Velineon VXL-3s Blinks Red
To determine why my Traxxas XL-2.5, XL-5, or Velineon VXL-3S ESC is blinking red, I need to look at how fast the light is flashing. That’s because there’s a difference between a fast flash and a slow flash. The Velineon VXL-3S also has a very fast red flash.
Fast Blinking Light Indicates Thermal Shutdown Protection
Fast blinking lights on the XL-2.5 and the XL-5 mean something slightly different than those on the Velineon VXL-3s.
XL-2.5 and XL-5 ESC
If the red light on the XL-2.5 or XL-5 is blinking fast, this tells me the thermal shutdown protection on these ESCs has kicked in. Thermal shutdown is a safety feature that prevents the ESC from overheating. If the system detects temperatures that are too high, it’ll shut everything down to avoid overheating damage.
On Velineon VXL-3s, a fast blinking red light is again a sign the ESC is in thermal shutdown protection mode. However, what it means is a little different, depending on whether I still have power to my RC vehicle.
- If I still have power and can run my RC vehicle, I’m in stage 1 thermal shutdown protection. The system reduces the power, so I can still run my RC vehicle, but at much slower speeds. The purpose of reducing the power is to prevent overheating.
- If the power to my RC vehicle has gone, that’s stage 2 thermal shutdown protection. The system has cut the power completely because the ESC got way too hot. So I can’t operate the RC vehicle at all until the ESC cools down.
Very Fast Blinking on the Velineon VXL-3s Is Total Shutdown
If the red light on this ESC is blinking very fast, it means that both stage 1 and stage 2 of the shutdown protection have occurred simultaneously. Essentially, my RC has no power because the ESC has shut everything down until the temperature drops.
Slow Blinking Light Is Battery Related
A slow flashing red light on either of these three Traxxas ESCs means the same thing. It tells me the ESC has triggered its low-voltage detection (LVD) system. That means the battery’s voltage has dropped too low for me to continue using it without causing severe damage to the battery.
The LVD is only applicable when using LiPo batteries. In fact, It’s crucial to have the ESC set to LVD mode when running on a LiPo. That’s because LiPos must never discharge below their minimum discharge voltage.
If they discharge below their minimum level, they can suffer serious damage. It’ll turn a LiPo into an expensive paperweight.
The LVD on Traxxas ESCs senses the LiPos’s voltage level. Once the voltage starts to drop close to the minimum discharge voltage, the LVD reduces power to 50%.
However, if I keep running the LiPo, even with reduced power, the LVD will shut me down completely if the voltage starts to drop below the minimum level.
Frustrating, yes. However, it saves the expense of having to buy a new LiPo.
Why Traxxas Velineon VXL-4s, 6s, or 8s Blinks Red
On the VXL-4s, 6s, and 8s ESCs, the blinking red light issue gets a little more complicated. That’s because they have four lights. The problem that’s arisen depends on which light is blinking and the blink speed.
From left to right, the lights on these ESCs are:
- Power indicator
The power indicator will generally be a solid red or green light. When solid red, it means I can use a NiMH battery. When green, it means LVD is on, so it’s safe to use a LiPo battery.
On its own, the power light shouldn’t blink red – except when it flashes along with the other lights, which I will discuss in a moment.
Here’s what a blinking red light means for each of these specified lights:
Current Light Blinking Indicates Current Spike Protection
The first thing to note about these ESCs is that there’s no slow red blink for the current light, only fast. If the current light is blinking red fast, the ESC is in overcurrent protection stage 2. That means the ESC has shut down power to protect against a spike in current.
Current spikes can occur when my RC vehicle gets stuck against an obstacle and I keep the throttle on instead of releasing it. They can cause motor failure, which is why these ESCs have overcurrent protection.
Voltage Light Blinking Fast Says Overvoltage Protection Is On
A fast blinking red voltage light on these ESCs tells me the ESC’s overvoltage protection has triggered. This can happen when the voltage from the batteries exceeds the maximum voltage level for the ESC.
Those limits vary depending on the ESC, as I’ve set out below:
- VXL-4s — 16.8V
- VXL-6s — 22.2V
- VXL-8s — 33.6V
Exceeding these limits will likely fry the ESC and potentially cook the motor. Overvoltage protection shuts down power, thus preventing damage.
Voltage Light Blinking Slow Warns of Shutdown
On these ESCs, a slow red blinking voltage light means LVD has shut down the system. That happens to prevent my LiPos from draining below their minimum discharge level. I also get advance warning that a shutdown may be imminent, as the slow red blink is preceded by a solid red voltage light.
A solid red light signifies the ESC has entered the first low-voltage protection level by reducing power to the throttle. And that’s my chance to bring my vehicle back in to do a battery change before losing power altogether.
Temperature Light Blinking Fast Signifies Overheating
If I’m faced with a fast red blinking temperature light on these ESCs, I know the ESC has shut down power to prevent overheating damage.
This is the same thermal shutdown protection mentioned for the other ESCs above. It works in the same way as on the VXL-3s, with two stages. The fast blinking red light is the second stage — shutdown.
The first stage of LVD on these models is signified by a solid red temperature light. That’s when the ESC reduces power output to try to bring down the temperature. So, it’s the early warning before a complete shutdown.
All Four Lights Blinking Red Means Multiple Issues
According to the manual, four blinking red lights mean the ESC shut down due to thermal protection and low voltage protection triggering simultaneously. Or, there’s some critical issue with the ESC.
Either way, the problem seems to be terminal, as confirmed in this video:
How To Stop My Traxxas ESC Blinking Red
Once you’ve corrected the issue (or just given your ESC time to cool down) the light will stop blinking. But maybe you’d like to avoid blinking lights from occurring altogether? Here are some ways I keep my ESC from blinking red in the first place.
1. Reduce the Risk of Thermal Shutdown
Remember, thermal shutdown protects from overheating. To avoid the issue, I generally try to keep the motor and ESC below 190°F (88°C).
Often, installing a fan on the ESC is a possible solution. However, it also helps not to run my vehicle too hard for too long. Sometimes, it’s better to take it slower.
It’s also a good idea to keep a check on motor and ESC temperatures. A pocket thermometer like this Mini Digital Infrared Thermometer can come in handy for this when I’m out with my vehicle.
2. Prevent LVD Shutdowns
To avoid a low voltage shutdown, I’m always alert to the first warning sign that my LiPo is getting close to its minimum discharge level. That’s when my vehicle suddenly loses some, but not all, power.
Then, I know it’s time to bring my vehicle back using the reduced power. I can then swap over to a fully charged battery and recharge the old one.
3. Avoid Current Spikes
Current spikes can occur when my vehicle gets stuck against an obstacle and I keep hold of the throttle. The solution is simple. I should release the throttle as soon as I see the vehicle get stuck.
Then, I can free up my vehicle manually and continue using it without the interruption of an overcurrent shutdown. I just stay mindful to not accidentally increase the throttle, thus increasing the risk of spiking the current to unsafe levels.
4. Stick to the ESC’s Voltage Limits
The ESC’s LVD is crucial to prevent LiPo damage, and overvoltage shutdowns can be prevented by sticking to the ESC’s voltage limits. While it’s tempting to get more speed out of my RC vehicle by using batteries that exceed the ESC’s voltage limits, I avoid doing this.
Why? Best case scenario is I’m lucky and the vehicle will run for a while. But soon enough, the overvoltage protection shuts it down to prevent damage.
The other possibility is as soon as I turn on the vehicle, the ESC will fail because of the excess voltage. And if I exceed the voltage limit, it can affect the ESC’s ability to provide LVD.