My Battery Tender Flashes Red To Green – What Does That Mean?

Battery Tenders are a great resource to have equipped in any vehicle, but what does it mean when the lights start flashing red and green? There is nothing worse than trying to start your car engine only to find that the battery is drained, which is why so many drivers rely on Battery Tenders for support. However, some people have been reporting that their Battery Tender starts flashing red to green, which could imply that there is an issue with your battery.

My Batter Tender Flashes Red To Green What Does That Mean 1 My Battery Tender Flashes Red To Green - What Does That Mean?

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What does it mean when a battery tender flashes from red to green?

If a Battery Tender is flashing red to green, it means that your battery has either reached its 72-Hour Safety Timer and is in maintenance mode – or that the battery is defective. The 72-Hour Safety Timer implies that you are charging a large battery or that there is a connection resistance. 

Car batteries generally last at least 3 to 4 years, but even during their prime, they can often cause trouble for you when you need to drive your vehicle. Whether you are rushing out the door to head to work or driving out in the countryside, a car battery that dies on you when you need it the most is frustrating to deal with. 

This can particularly be the case if you live in a region that gets colder weather where temperatures drop below freezing, as this can make drained batteries a constant theme in your life. Luckily, you can avoid the headaches that come with a drained battery by using a Battery Tender. This is essentially a support system that prevents the likelihood of your battery draining on you. 

However, your Battery Tender is also equipped with a color-coded light system to indicate the condition of your battery – with a red and green flashing light potentially implying that something is wrong. 

To help you understand this further, we are going to take a closer look at what the flashing red and green light on a Battery Tender means. 

After extensively researching Battery Tender maintenance issues and protocols, I have been able to gather enough information to determine what a red and green flashing light indicates. My research has shown me that you should always confirm the color-coded system of your Battery Tender, as this can often vary depending on the model that you are using. 

Why Does My Battery Tender Flash Red to Green?

Battery Tenders are designed to be there for you when you need them the most. This battery-supporting device ensures that you never have to deal with a dead battery when starting your vehicle. 

With that being said, if you want to count on your Battery Tender through thick and think, then you need to be aware of what the color-coded lights on the device indicate. 

A lot of people have reported that their Battery Tender starts to flash from red to green. 

There are multiple different reasons behind a red and green flashing light on a Battery Tender – with one implying that there is nothing to worry about and the other indicating a bad battery. However, you should also keep in mind that Battery Tenders are made by more than one manufacturer and that each brand could have potentially designed its own color-coded system.

Although the colored lights on most Battery Tenders may mean the same thing, you should still have the manual for your specific model handy when assessing the condition of your vehicle’s battery.

Let’s dive into why your Battery Tender flashes from red to green.

My Batter Tender Flashes Red To Green What Does That Mean 1 1 My Battery Tender Flashes Red To Green - What Does That Mean?

72-Hour Safety Timer

One reason behind the red and green flashing lights on your Battery Tender is that the 72-Hour Safety Timer has been activated. Most Battery Tenders are only designed to support a certain amount of voltage. 

Generally speaking, a Battery Tender will try to reach a charge level of 14.75 volts as its target. If the Battery Tender detects that the voltage has not reached 14.75 volts within 72 hours from when the charging process began, it will switch into maintenance mode. 

This is a safety feature installed in most Battery Tenders and it does not necessarily imply that there is anything wrong with your battery. 

When maintenance mode is activated, the battery will stay at 13.2 volts. Once this happens, the Battery Tender’s light will start flashing from red to green.

Large Battery

If the 72-Hour Safety Timer was initiated on a large car battery, then you probably do not have anything to worry about. A large car battery will take longer to charge and the red and green flashing lights could simply imply that the battery has not reached its maximum charge capacity yet. 

Regardless, given the obscurity of what a red to green flashing light could imply, it would still be wise to test your large battery to ensure that it is in good working condition.

Standard Battery

A 72-Hour Safety Timer on a standard car battery could mean that there is an issue with either the connection or the battery itself. A connection issue could be due to faulty wiring or if there is resistance to the connection in your battery.

Defective Battery

Although dealing with a defective battery is never a fun experience, it is better that you find out about it from your Battery Tender before you hit the road, rather than when you are stranded out in the middle of nowhere. 

The red and green flashing lights on your Battery Tender often indicate that your battery is defective. You may still be able to get away with using your battery for the short term, but you should ultimately start coming to terms with the fact that it will need to be replaced soon. More often than not a defective battery is related to the following issues:

  • Corroded battery terminal
  • Sulfated battery

Sulfated batteries can potentially be reversed with a slow charge – whereas corroded batteries may be fixed with a vinegar solution. With that being said, the best way to avoid a defective battery is to prevent it from happening in the first place by taking care of it.

What do the Other Lights on My Battery Tender Mean?

You Battery Tender is designed to have a variety of different colored lights to tell you what condition your battery is in. This makes observing your battery health incredibly easy so that you always know how to maintain it. 

If you have noticed that your Battery Tender is flashing from red to green, you will most likely be curious about what the rest of the lights on the device indicate. 

Red Light

When your battery is plugged in, connected, and charging, you will see a red light on your Battery Tender. This will let you know that everything is connected properly and that your battery is receiving a stable charge. 

Amber Light

You will see an amber light on your Battery Tender when the device is powered on and plugged in. The Battery Tender will have to be plugged into a wall outlet that is delivering AC power to the device. 

Green Light

A green light will start to flash when your battery is almost fully charged – with most Battery Tenders this is at 80%. Once the battery reaches this stage, it will start to receive a smaller charge until it gets to 100%.

The red light will continue to flash while the green light is on and it will turn off once the battery is fully charged – with only the green light staying on.