Laptop batteries wear out. It is not a fault, it is just how they work. Every battery has a limited number of charge cycles, and after a few years it holds less and less. The question is knowing when yours has actually reached the end, and how to order the right replacement.
Here is how to check, what to watch for, and how to get the correct battery the first time.
What are the signs a laptop battery needs replacing?
You do not need tools to spot most of these:
- It drains fast. A full charge that used to last hours now lasts a fraction of that.
- It shuts down suddenly. The laptop dies without warning even though it showed charge left.
- It only works plugged in. Unplug it and the laptop switches off immediately.
- Windows warns you. You may see a "consider replacing your battery" message.
- It is swelling. This one is important. If the laptop base is bulging, the trackpad is lifting, or the laptop rocks on a flat surface, stop using it and have it looked at. A swelling battery is a safety issue, not just a performance one.
If you are seeing the first few signs, your battery is probably worn. If you are seeing swelling, act on it sooner rather than later.
How do I check my laptop battery health for free?
Windows can give you an honest health report on your battery. It is free and takes a minute.
- Click the Start menu, type cmd, and open Command Prompt.
- Type this and press Enter: powercfg /batteryreport
- Windows saves a report file and tells you where (usually your user folder). Open that file in your browser.
In the report, look for Design Capacity and Full Charge Capacity. Design Capacity is what the battery held when new. Full Charge Capacity is what it holds now. If the full charge number has dropped well below the design number, your battery has worn down. The bigger the gap, the worse it is.
This report is useful because it gives you a real number instead of a guess. It also shows your cycle count, which is how many times the battery has been charged over its life.
How do I order the correct replacement battery?
Once you know you need a battery, ordering the right one matters. Batteries are model-specific, so a battery for one laptop usually will not fit another.
The most reliable way is the part number printed on the battery itself. If you can safely open the laptop or the battery is removable, look for a code on the battery label (for example something like "45N1126"). That part number identifies the exact battery.
If you cannot get to the battery, your laptop's exact model number helps us find the right one. Have a look at our guide on finding your model number if you are not sure how.
What is the difference between internal and external batteries?
Some laptops, certain ThinkPads in particular, use two batteries at once. There is an internal battery inside the chassis and an external removable one that clips into the base. They are different parts with different part numbers, and they work together.
If your laptop is one of these, make sure you know which battery you actually need. Ordering the internal when you needed the external (or the other way around) is an easy mistake to avoid once you know to check for it.
Is it worth replacing a laptop battery?
Honest answer: it depends on the laptop.
If the machine is otherwise in good shape and does what you need, a new battery is usually well worth it and far cheaper than a new laptop. If the laptop is very old, slow, and starting to have other problems, spending money on a battery might just be delaying the inevitable. We are happy to give you a straight opinion if you are on the fence.
How do I make sure I get the right battery?
We stock replacement laptop batteries and can help you match the correct one for your machine. Run the battery report if you want to be sure it is actually the battery, check your part number or model, and if you are not certain, send us a photo and ask.
Frequently Asked Questions
How do I check my laptop battery health? Open Command Prompt, type powercfg /batteryreport, and open the report Windows saves. Compare Design Capacity to Full Charge Capacity to see wear.
What are the signs my battery needs replacing? It drains fast, shuts down suddenly, only runs while plugged in, or Windows warns you. A swelling battery is a safety issue and needs attention promptly.
Is it safe to use a swollen laptop battery? No. A swelling battery, shown by a bulging base or lifting trackpad, is a safety risk. Stop using it and have it replaced.
How do I find the right replacement battery? Use the part number printed on your original battery, or your exact laptop model. Batteries are model-specific and a close match is not always correct.
Not sure if it is your battery, or which one you need? Run the free battery report above, then send us your part number or model and we will help you order the right one.
