I have had my Battery Tender charger for over a year now, it is my go-to trusted charger for my lithium batteries. It has really helped me through a lot of last-minute saves, the only time I run into problems is when it starts flashing error lights.
Once I learned what those flashing lights meant, troubleshooting became very easy. Here’s what I found out about the flashing lights, read along if you have doubts about what they mean.
By the way, I also have a short video about this topic and you may watch it first before you continue reading this article. The video is down below.
Here’s what they mean: solid red light means the battery is charging, flashing red light indicates a bad battery, flashing red and green indicates a dead battery or reverse polarity, flashing green means the battery is more than 80% charged and a solid green means it’s now fully charged.
Know the Different Meanings of Battery Tender Lights for Easy Troubleshooting
Solid Red Light
The most common light indicator that I have seen on the Battery Tender charger is a solid red light that appears when the charger is connected to a discharged battery.
It shows that the battery is charging and has a steady voltage of 12V. Sometimes, it takes a while for the light to switch to green, but as long as the light is solid red, the connection is strong.
Flashing Red/Yellow Light
Now unlike the solid red light which indicates a solid connection and charging battery, flashing red or yellow lights indicate an issue with the battery.
In my case, the charger kept flashing a red light even after replugging a few times, turns out it was a faulty battery and the voltage was below 3V. If you are facing the same issue, maybe it’s time to get the battery checked.
I also have a short video about this topic and you can watch it below. On the video, I showed how I was able to fix this issue by jumpstarting the battery which was already below 3V.
Flashing Green and Red Light
Another common light configuration is the flashing red and green light which indicates that the polarity connection to the battery is reversed. It might seem like a silly mistake but it is one that I have made far too many times.
The red and black battery clamps have a positive and negative marking on them, remember to match those to the terminals on the battery before turning on the charger.
I also made a short video where I showed how I fixed this issue and you can watch it below. On the video, I just connected the positive to positive and negative to negative again correctly.
However, if the polarity is correct and the battery is still showing green and red, this means it could have develop internal short circuit.
Solid Red Light Not Changing
Sometimes, the Battery Tender charger light keeps displaying a solid red that does not change no matter how long the battery is connected.
This happens usually with my old batteries that are unhealthy or drain too fast. This is a good indicator to get your battery checked.
I also have a short video about this topic which you can watch below. On the video I gave a detailed explanation how this could happen and what you can do if you encounter it.
Flashing and Solid Green Light
These indicators are also very common, the green light displays a healthy charging battery with no issue. When the green light is flashing, it means that the battery is over 80% charged.
After the green light flashes for a while, it changes to a solid green light which shows that the battery is fully charged indicating that it’s a good time to stop charging.
