How To Tell If a Deep Cycle Battery Is Bad

Irrespective of the type, batteries have one thing in common. They all deplete with time. Keeping an eye on the overall condition of your battery will help you stay safe from hazards like short circuits. Bad batteries can also damage your home appliances. So, we recommend you keep checking your deep cycle batteries to see if they are damaged or not. 

There are three basic ways to see if a deep cycle is the battery is bad or not. You can either perform a physical inspection of the battery, use a load testing device, or check the voltage and current. 

In this guide, we will walk you through all the ways you can check if your deep cycle battery is bad or not. In addition to this, we will also provide you with tips that will help you maintain a healthy battery for a longer period. 

Three ways to check if a deep cycle battery is bad 

There are three ways to check if a deep cycle battery is bad:

1. Do a proper physical inspection 

The first way to check if your deep cycle battery is in good or bad condition is to perform a proper physical inspection. You need to ensure that, 

  1. There is no leakage of liquids from the battery. 
  2. There is no bulging. 
  3. The battery is not losing color. 
  4. There are no cracks on the battery. 
  5. The terminal connections are not damaged. 

If there is leakage in your battery, this can expose the plates to oxygen. It will result in sulfation of the battery. And, sulfation will result in a depleted battery earlier than it was supposed to be. 

Apart from this, if you see bulging on any side of the battery, it means that your battery is overcharged.

Conducting a physical inspection should be your first step when you’re finding out about the overall health of your battery. It will save you time and will also help you identify problems early on. 

old deep cycle battery

2. Use a load tester device

This is a tricky test. Even though these load tester devices can be purchased from any store nearby, we recommend taking your battery to an automotive repair shop to conduct this test. We recommend it because the test is complex and may require expert guidance. 

After you have decided to go with either of these two options, it is now time to perform the test. It all starts with removing all the cables and connections from the battery. Then, move ahead and connect the load tester device. 

A load tester device will apply a certain amount of load to the battery and will also tell you the minimum passing voltage of the battery during the load test. Now, to check the overall health of your battery, you need to first see its CCA ratings. These ratings are used to define the battery’s capacity to start an engine at a very low temperature. 

When you know the CCA ratings of your battery, set the load to 50% of that. Now, if the minimum passing voltage shown in the load tester is lower than the minimum defined in the manual of the battery, your battery is damaged. 

3. Check voltage and current

It is the easiest way to check if your deep cycle battery is bad. The only thing you’ll need is a digital voltmeter that will show you the voltage of your battery at a certain point in time. 

The outputs of the digital voltmeter will differ based on the battery condition. If it shows 0, a short circuit has happened. If no, then check for the second scenario by putting it to charge. While charging, if it can’t go ahead of 10.5, one of the cells is probably dead.

If you run both of these tests and the battery shows normal voltages but doesn’t provide any charge, it is most probably sulfated. You will need to replace the battery!

Required Equipment

To conduct these tests, you won’t need any big machinery. All you’d need to perform these tests on your battery is:

  1. A Battery Charger
  2. A Load Tester device 
  3. A digital voltmeter and,
  4. A refractometer

Although, if you’re using lead-acid batteries, you will also need a bottle of distilled water. It is recommended to replace the water/liquid inside the battery before performing these tests on lead-acid batteries. It will help you achieve more accurate results. 

Tips to maintain the battery health

Testing the overall health of your battery is not the end. You need to decide either to replace them or keep them. If your battery’s overall health is severely damaged, you might have to replace them with newer ones. But, if the damages are minor, you can maintain the battery health for better performance in the future. 

Also, even if your battery’s overall health is not mentioned, you should follow certain tips to keep it running safe and sound. After all, prevention is better than cure!

Following is the list of tips that you need to follow if you want to keep your battery healthy for a longer period.  

1. Program your chargers properly or buy the right ones. 

When you are installing your setup, you will probably need to program your chargers for optimal output. It happens with most of the modern-day setups that require you to take your systems online at the start. 

Make sure that you program your chargers with the right settings that match your battery’s requirements. You can find that information on the manuals that come with your setup. Failure to properly program your chargers is also one of the major reasons for damaged battery health. 

If your system doesn’t involve programming your chargers, make sure to buy the correct type of chargers. 

2. Keep the battery clean and well-connected. 

Damaged and loose connections with the terminals are one of the biggest reasons for decreased battery lifespan. Because of these damaged connections, batteries can not be properly charged, and in the worst case, can not provide appropriate current to power up your stuff. Consumers fail to regularly check these connections, and if they are left broken or damaged, they can harm the overall health. Also, damaged terminal connections can result in short circuits. 

3. Regularly check to make sure there is no physical damage. 

Doing a proper physical inspection of your battery will not only help you identify the problem with it, but it will also help you deal with them before they do any damage. Make a routine to inspect your battery for any sort of leakage, damaged terminals, bulging, and color change. It would help you identify the issues before they occur. 

4. Keep an eye on the battery’s state of charge (SoC). 

The last tip to maintain your battery’s health is to keep an eye on its state of charge (SoC) regularly. You will need a device called a refractometer to measure it for your battery. Refer to your battery’s manual to see the ranges for all the gravity levels. And if your battery’s state of charge (SoC) is not equal to that defined in the manuals, your battery is most probably losing capacity. 

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