I used Microsoft’s free Windows 11 battery health tool to diagnose my PC – and got helpful results

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ZDNET’s key takeaways

• You can run a report to check battery health in Windows 11.
• This report provides details on capacity, cycle counts, and more.
• If your battery is nearing the end of its life, it can be replaced.

Have you noticed a decline in your laptop’s battery life? Does it randomly fall below 20%, leaving you scrambling for a charger? You can run a report to check your battery’s overall health and if it’s time to replace it. And no, you don’t have to be a pro to access this feature. 

The fact is that batteries are, by their nature, consumable technology. All will inevitably degrade, regardless of how they’re treated. 

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You may have heard about ways to maximize battery optimization, but I wouldn’t stress about these techniques. There’s no need to fixate on unplugging your laptop at a certain point or monitoring the charge percentage like a hawk. Your actions will only affect battery life so much. 

That said, if your battery is a shadow of its former self, it may be nearing the end of its lifespan. Here’s how you can check battery health in Windows 11. 

How to run a battery report

1. In the Windows search bar, type powershell and hit Enter. 
2. In the black text window that pops up, type: powercfg /batteryreport /output “C:battery-report.html” and hit Enter.
3. The device will send an .html document to the C: folder. Navigate to the folder in Windows Explorer and double-click it to open it in your browser. 

This report describes the name of your battery, its chemistry (likely either lithium-ion (Li-ion) or lithium-polymer (LiP)), its lifecycle position, and some recent charging data. Let’s explore the most important metrics in the report. 

Design capacity

First, we have design capacity, which refers to the power the battery could pump out when it was brand new, in mWh (milliwatt-hours). This metric measures energy, not charge.

Full charge capacity

Now check the metric right below that. Full charge capacity reports the battery’s current capacity (also in mWh). The difference between design and full charge is a helpful metric to check for your battery’s overall health. If the second number is drastically lower, it means your battery’s capacity has significantly decreased since it was new. 

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How much are we talking? Well, it depends on the battery size, but for most small to mid-range batteries (45Wh, 48Wh, 60Wh, or 65Wh), if the full charge capacity has reduced by 15% or more, you’ll likely be facing noticeable battery degradation. 

A 20% loss in full charge capacity is generally considered grounds for replacement, and you’ll likely notice a significant loss in capacity at that point. That being said, it’s not a hard rule. You might be around that proportion and feel like your battery is fine. 

Cycle count 

Let’s look at another key metric: the cycle count. This number records how many times you’ve used 100% of the battery’s capacity. 

If you have a 60,000 mWh battery, one “cycle” refers to how many times 60,000 mWh of energy has flowed out of the battery — regardless of whether that’s all at once (going from 100% to 0%) or over the course of two days (going from 100% to 50%, up to full, down to 50%, and back up to full again). 

Most consumer laptop batteries are designed to last around 500 cycles, and it’s around then that you’ll likely see a 20% loss in capacity. How quickly you get to that proportion, however, depends on your usage habits.

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Light office users, who frequently keep laptops plugged in, might only go through a full cycle every few days. Over the course of three years, these users might only reach 200 cycles, potentially extending the battery’s lifespan by another three years. 

On the other end of the spectrum, power users, gamers, or mobile users who subject their batteries to more cycles per week, along with an increased heat load, will see a faster overall degradation of the battery. 

It’s important to note that both of these use cases are ‘valid’ ways to use your machine. You’re not doing anything wrong by pushing your laptop to its limits, and, as I mentioned above, batteries are finite devices meant to be used. Just don’t let your laptop overheat, and that includes putting it in a bag while it’s not powered off or hibernating. 

Battery life estimates

This section reports how long the computer estimates the battery will last based on recent battery drains. Note that these numbers can vary wildly as they represent different usage patterns. 

On the left, the duration figure shows how long the battery lasted. On the right, the figure shows what that duration time would have been when the battery was brand new. If these numbers are dramatically different, it could indicate that the battery has degraded significantly. 

How to replace your battery

You usually don’t need to buy a new laptop for a battery replacement. Most mainstream laptop manufacturers, such as Dell, HP, and Lenovo, offer replacement batteries, either as standalone products bought for specific models or as part of a service plan. If your laptop is still under warranty, you may receive a replacement at no charge. 

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Of course, if you don’t want to send your laptop to the manufacturer or do it yourself, there are third-party repair firms that will do the task for a fee. Just keep in mind that they might not guarantee anything beyond successful installation.