Cordless Phone Battery Replacements

Cordless phone batteries are rechargeable, meaning they're cost effective, but the more they are used and recharged, the less capacity they are able to retain. Most have an effective battery life of one to three years, and will start to beep or show a warning on the LCD screen when low. If this seems to happen faster than usual, it's time to replace your cordless phone battery.

Cordless Phone BatteryIt's important to find the correct battery replacement for your cordless phone, because it will maximize the device's battery life and minimize the risk of malfunction, which can be costly and even dangerous. Choosing the right battery means identifying the battery chemistry, which will then dictate the amperage and voltage output.

Let's figure out what type of battery you need. If you already know what you're looking for, click here to browse our cordless phone batteries.

Check the old batteries for voltage and amperage, or if you still have the owner's manual, it should have the battery brand and model number on the front cover. For most brands like Panasonic, AT&T or Uniden, you can also check the bottom end of the phone handset for a manufacturer's label. If you don't see it there, check the underside of the base unit, or inside the handset's battery compartment.

Cordless phone battery voltage is the amount of energy the battery requires to charge, generally ranging from 2.4 to 4.8 volts. It's usually the first power-related number listed on the battery.

The mAh, or milliampere hour is a measure of the cordless phone battery's capacity, which is usually between 300 mAh and 900 mAh. More often than not it's the second number you'll see on the battery.


Most cordless phone batteries from major manufacturers use standardized part numbers. Here are sample part numbers from the major brands:

Panasonic: P-P123, HHR-P123
AT&T: 1234 (4 digit number)
GE: 5-1234
Sony: BP-T12
Uniden: BP-123
V-Tech: 80-1234-00-00

There are three kinds of battery chemistries used in cordless phones – Nickel Metal Hydride (NiMH), Nickel Cadmium (NiCad), and Lithium Ion (Li-ion), and there are a few major differences between them.

Nickel Metal Hydride (NiMH) vs. Nickel Cadmium (NiCad or NiCd)

These days, NiMH batteries are the industry standard for cordless phone batteries. NiCad batteries have essentially been phased out for most devices due to environmental concerns – cadmium is highly toxic. Also, NiMH batteries have up to 50% higher capacity than NiCad batteries and can last longer in lower drain devices, including cordless phones. Nickel metal hydride batteries also have far less "memory" than nickel cadmium batteries. Battery memory occurs when a battery is repeatedly charged after only being partially discharged, resulting in a loss of maximum capacity. This effect can quickly render a new battery useless if done too often.

But even NiMH batteries don't have the capacity or popularity of lithium ion batteries, which also have no memory. So why don't we see more lithium batteries in cordless phones? It's a matter of production, and cost.

Cordless phones have largely been replaced by mobile phones, which offer more portability and versatility. The range of features cellular phones offered called for a more powerful battery, bringing about the widespread use of lithium ion battery chemistry. As cell phones became more popular, cordless phones, which largely relied on NiCad and NiMH batteries, became less widely used.

These days, when given a choice, most will choose a cell phone over a cordless phone. You may not want a cell phone, but if you're still using a cordless phone that takes NiCad batteries, we recommend you upgrade to a newer model. Cordless phones are far cheaper than they used to be, and the audio quality, range, and battery life of a newer cordless phone are worth the investment.

Replacing Cordless Phone Batteries

Changing cording less phone batteries is a fairly straightforward process. First, turn off the cordless phone, if you can, and open the battery compartment on the back of the phone. To remove the battery pack, pull on the plastic connector that plugs into the phone, rather than the wires, so as not to damage the phone or battery. Each battery will have a red and black wire, so make a note of which side each wire connects to, if it's not labeled.

Once you have removed the battery, check the contacts for dirt or other particles. You can clean the battery contacts with a Q-Tip and small amount of rubbing alcohol. Again, if you do so, ensure that the phone is off, and completely dry before connecting another battery.



Battery Chargers

Different batteries charge and discharge at different rates, so it's important to ensure that the charger you're using is compatible with the battery type you have. We recommend leaving your battery off the charger until you notice the battery is low. Leaving it on can strain the battery and ultimately reduce its capacity.

Refrigerating Batteries – Is it Worth the Risk?

Remember when your parents used to keep their batteries in the fridge or freezer? It turns out they weren't so crazy, though we don't recommend doing so. NiMH and NiCd batteries have some of the highest rates of discharge, and will start to lose power after only a few days of room temperature storage. Keeping batteries in a cooler environment will slow the rate of discharge. However, we don't recommend you put your batteries on ice.

Refrigerating batteries can cause condensation to form, leading to corrosion, and extreme temperature changes can permanently lessen battery capacity. Also, they'll need to warm up before use. While useful in theory, any potential gains of refrigerating batteries will be offset by moisture and temperature fluctuations.

Finding a Cordless Phone Battery

Now that you have an idea of which cordless phone battery you need, it's time to search for it. Batteries.com offers the fastest and simplest way to get the exact cordless phone battery you need. As soon as you start typing in your product details, your results will return below the search bar.