How To Tell If Cordless Phone Battery is Bad

The convenience of having a quality cordless phone is indisputable. In addition to freedom from a cord, cordless phones grace us with a myriad of benefits, including a large coverage area, substantial range, expandable handsets, long-lasting and rechargeable batteries. These batteries vary from one cordless phone model to another and are designed to serve you for three years. Even with proper maintenance practices, cordless phone batteries usually lose functionality once the charging cycles are depleted. Such an occurrence could be a deal-breaker, especially when it happens unexpectedly. Fortunately, these batteries often exhibit warning signs before they seize functioning. Therefore, it is crucial to know how to tell if cordless phone battery is bad to plan beforehand.

Cordless phone batteries deteriorate gradually, especially after prolonged use. You can tell if your cordless phone’s battery is bad by looking for specific signs such as rapid discharge. Failure of your phone’s battery to hold a charge for as long as it used to is among the major indications that the battery is defective.
Other common signs to look out for include bulging, overheating, and battery failure to power on or attain maximum charge even after charging for the required amount of time.

An image showing a battery charge in a cordless phone
Read on to know more about the signs of a bad cordless phone battery, which will help you establish whether a repair or a replacement is the way to go.

How To Tell If Cordless Phone Battery is Bad

After efficiently serving you for at least one year, your cordless phone may misbehave depending on the usage and maintenance practices. During such instances, most cordless phone users often purchase a new handset when all they could have done was repair the battery. Therefore, before you embark on replacing your handset, consider looking for the following signs of a bad phone battery;

Battery bulging

You can confirm whether your phone’s battery is swollen by placing it on a flat surface such as a table and looking out for any wobbling. Whether subtle or prominent, you shouldn’t ignore the swelling as it could be hazardous.

Battery swelling is often a result of overcharging your phone or repeatedly using an incompatible charger. If your cordless phone battery is swollen, it is advisable to avoid using your phone in that state. Fortunately, the problem can be easily resolved by a phone technician.


One of the most emphasized maintenance practices for cordless phone batteries is storing them in a cool, dry place. Exposing the battery to a very high temperature will most likely result in overheating. Excessive charging is also a probable cause. Overheating may cause malfunctioning and, in the long run, compromise the battery’s ability to hold charge efficiently.

Failure to hold a charge

Having to constantly recharge your phone’s battery within short intervals due to rapid discharge is a sign of a faulty battery. Some cordless phone models use nickel-cadmium (NiCad) batteries, which are prone to memory effects. Due to the memory effect, failure to completely use up your battery before recharging compromises its runtime since the battery becomes unconscious of the unused percentage.

Failure to attain maximum charge

If you have plugged the battery into the charger for a significant amount of time, but it still fails to attain a full charge, the battery is faulty. However, ensure you confirm whether the charging system is effective by testing the charger on a different handset before concluding that the problem lies in the battery.

On-Screen Display Signals

The advancements in technology have brought massive changes in the devices we use today, and cordless phones are no exemption. The cordless telephones have LCD screens incorporating information such as the date and time readouts, menu items, particular function labels. The LCD screens can also show if the phone’s ringer is switched off.

Moreover, you should not worry about the determination of the strength of your battery indicator. Most cordless phones come with a battery-strength indicator, often a set of bars or hands that fade out one by one as the battery power reduces.

Besides, cordless phones can signal for a low battery by displaying the words such as a low battery or a flashing icon that designates the status of the battery on the screen. The displays help one determine when their batteries are due for a recharge.

Recharge Indicators

You can guarantee effective charge retention by placing your cordless phone in its charging place or cradle. The cordless phones are characterized by a recharge indicator that will help you determine the strength of the battery while the phone is out of the cradle. The indicator also shows when the charge is in progress. You can also know when the charge is completed from the indicator. 

The video below illustrates how to tell if a Cell Phone Battery has gone bad

Cordless Phone Battery Troubleshooting

Your cordless phone battery dying when you least expected can be one of the most unfortunate circumstances to experience with the cordless phone models. Worst still, this can happen when you are on an important call or waiting for an important call. 

However, equipping yourself with cordless phone battery troubleshooting tips can help you resolve this frustrating situation with certain basic practices without consulting an expert. Below is a list of the trouble shooting tips;

Reset the Phone 

One of the most effective troubleshooting methods for your cordless phone is resetting the whole phone. Locate the position of the reset button in your phone and press reset. 

Cycle the battery 

Cycling the battery is another essential aspect that should first come into your mind. When you notice your cordless phone cannot hold a charge, let it die completely and then put it on the charge to ensure it is full before you begin using it. One cycle means allowing the phone to die completely then charging it to a full charge before using. 

Check the connection and the base unit 

Check if your base unit is correctly plugged into the wall and also determine whether your wall is receiving power. Also, check whether the phone is connected properly.

Remove and Replace the Battery 

You should remove the battery for about five to ten minutes and then replace it. This is an effective tactic for troubleshooting a cordless phone batte

When should I replace my cordless phone battery?

The lifespan of your cordless phone’s battery mainly depends on its total number of cycles. A cycle consists of complete battery depletion followed by a full recharge without any disruptions. Most cordless phones feature up to 1000 cycles, which can last for about twelve months. It is therefore advisable to replace your cordless phone’s battery after every twelve months.

Additionally, if your phone’s battery exhibits one or more of the signs mentioned above, it may be time to replace it.

How long do batteries last in cordless phones?

Rechargeable batteries in cordless phones are designed to last for up to three years. However, their longevity largely depends on whether or not you handle the battery with care. Proper maintenance practices such as storing the battery at room temperature can go a long way in extending your cordless phone’s battery life. However, the battery tends to rapidly lose its ability to hold a charge without these practices and may last for barely one year.

How to test cordless phone batteries

You can test cordless phone batteries using a multimeter by following the steps below:

  1. Charge the battery for the required amount of time as stated by the manufacturer.
  2. Subsequently, ensure you turn on your multimeter and set it to the direct current voltage setting, often labeled as DCV.
  3. Connect the multimeter’s red probe to the battery’s positive terminal.
  4. Similarly, attach the black probe to the negative terminal.
  5. Check the voltage reading on the multimeter. The reading should correspond to the battery’s total voltage (usually indicated on the battery) to indicate that the battery attained a full charge for a well functional battery.

Frequently Asked Questions 

What happens if you put normal batteries in a rechargeable phone?

Putting normal batteries in a rechargeable phone may come in handy during emergencies when the rechargeable batteries are depleted. However, note that not all rechargeable phone brands are compatible with normal batteries.

More importantly, even if your rechargeable phone is compatible, refrain from charging non-rechargeable batteries as this is hazardous. Non-rechargeable batteries feature an irreversible electrochemical reaction. Charging them may therefore cause overheating and leaking of harmful chemicals or, even worse, an explosion.

Can you replace batteries in cordless phones?

Yes. If anything, you should replace cordless phone batteries at least once in three years, depending on usage. These batteries are made up of chemicals that generate many replenishable electrons. However, once the chemicals are depleted, you remain with a defective battery, and even recharging the battery may not renew the electrons. At this point, you should opt for quality and compatible replacement batteries.

Does putting batteries in a freezer recharge them?

Putting batteries in a freezer barely recharges them. Rather than recharging, freezing the battery mainly slows down its discharging rate. Freezing, therefore, extends the battery’s runtime by enabling it to retain charge for a longer time than usual. However, you should ensure the battery reverts to room temperature before reusing it for safety purposes. Moreover, the action may have detrimental effects on your battery and should be done only during an emergency.

Do rechargeable phone batteries wear out?

Yes, they do. The rate of wearing out, however, depends on how well you maintain the batteries. The battery can last for two or more years with proper maintenance; otherwise, the battery may begin malfunctioning in a year or less. Here are some effective maintenance tips to help extend your battery’s lifespan:

  • Clean the battery terminals every once in a while, preferably using rubbing alcohol to prevent the accumulation of debris.
  • Exercise the battery rather than leaving it idle for months.
  • Cycle charge the battery at least once a month by discharging and recharging it fully.

Additionally, despite proper maintenance, the battery is bound to wear out eventually. Once the battery uses up all its cycles, it’s time to replace it so that your phone functions efficiently.


Having to replace your handset’s battery every once in a while may be a bitter pill to swallow, but it is necessary so that you can continue enjoying the convenience of your cordless phone. It would be best if to avoid waiting until your phone’s battery fails before contacting a technician or getting yourself a replacement. The functionality of cordless phone batteries declines gradually, giving you ample time to prepare yourself beforehand.

During this time, look out for warning signs such as battery swelling, overheating, and failure to hold or attain maximum charge. Consider reaching out to a technician once you notice any of these symptoms. Although inevitable, battery incapacitation can be slowed down by exercising the aforementioned maintenance practices.

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