How many times have you fully charged your device put it in the drawer then the next time you pull it out it’s dead and wonder why isn’t it charged? Well, the short answer is, all batteries lose charge over time….
Batteries are a little like a bunch of school children all squashed into a classroom. The children fidget about, full of energy, really wishing they could be outside the classroom and racing around the playground. The energy packed away in your battery is like those fidgety kids, practically dying to be free and bouncing around again. Even when your device is completely turned off or disconnected, the chemical reaction inside the battery is still active, albeit in a much more subdued way. This continued low-level activity within the battery slowly depletes the stored energy. It’s called self-discharge—electrical discharge in the absence of an external load placed upon the battery—and it’s unavoidable.
But different battery type’s discharge at different rates
- Lithium-ion batteries are the kind of batteries most of us have. That’s the kind of batteries used in smartphones, smartwatches, tablets, laptop computers, and a wide variety of other consumer electronics like drones, action cameras, Bluetooth speakers, and so on.
- Nickel-metal hydride (NiMH) batteries are rarely used in portable consumer electronics these days but are used frequently in power tools as they cost less than lithium-ion batteries.
- Nickel Cadmium (Ni-Cad) batteries are an older technology, now improved upon by NiMH, that was the original portable rechargeable battery type.
Here is a general list of the batteries we use and their discharge rate.
| Battery Type | Self-Discharge Rate Per Month |
| Lithium-Ion | 2-3% |
| Nickel-Metal Hydride (NiMH) | 25-30% |
| Low-Discharge Nickel-Metal Hydride | 0.25-0.50% |
| Nickel-Cadmium (Ni-Cad) | 15-20% |
| Lead-Acid | 4-6% |
You can’t fully stop batteries from discharging, but you can do a few simple things to lower the discharge rate.
Keep them Cool
Give your device a break so that it can cool down, or you can move it to someplace with a lower temperature. Many modern laptops have sealed batteries, in which case shutting the machine down and letting it cool is highly recommended if maximizing the battery’s lifespan is your concern. Consider purchasing a laptop riser with a fan installed to keep airflow underneath otherwise keep the laptop off of your lap.
Avoid placing your device anywhere it might become hot. That includes your car on a hot summer day, beneath a window that gets direct sunlight, or near a space heater. Unusual conditions such as these can do a lot of damage to a battery in a short period of time, though you may not realize it immediately.
Keeping your battery in the Zone
In ancient, less enlightened times, there was a problem called “battery memory” that caused nickel-metal hydride (NiMH) batteries to “forget” their full charge capacity and start charging at lower and lower levels. This problem doesn’t exist any longer thanks to modern lithium-ion batteries, but it has led to a lot of poor advice and arguments about battery care based on outdated information.
Contrary to some recommendations, you don’t need to routinely discharge a lithium-ion battery completely and then recharge it to somehow reboot or calibrate it — this is a destructive practice that’s very hard on your battery. Generally, the consensus seems to be that letting your battery discharge (without bottoming it out — aim for around 20%) and then charging it when possible is the best practice.
Next, there was a time when users were advised to refrain from keeping their devices plugged in, based on the idea that letting a battery charge to 100% could wear the battery out more quickly. Today, however, modern devices are designed to stop charging at 100%, so keeping them plugged in doesn’t impact the battery’s lifespan.
As with many battery-related questions, the issue of keeping your laptop plugged in when it’s reached full capacity is hotly debated, so there’s nothing wrong with turning your machine off and unplugging it if you feel more comfortable doing that. But generally speaking, the best thing you can do for your lithium-ion battery is to avoid letting it discharge below 20%.
Plug it in and charge it when you can, and then rinse and repeat. The good news is that with modern batteries and systems, there’s really not much else you need to do — outside of anticipating that your battery will eventually start losing its overall capacity.
Leave it plugged in (but not all the time)
It’s safe to leave most modern laptops plugged in. In fact, most high-powered gaming laptops work best when plugged in. The most important aspect of battery health is the discharge cycle. No matter how cautious you are, your battery will degrade over time as you discharge and recharge it. Whenever you’re running an intensive application — such as a game — you can run it while your laptop is plugged in to reduce the number of discharge cycles on your battery. So, if you’re not moving around and running an intensive application, it’s a good idea to leave your laptop plugged in for the duration of that time. But if you’re just performing day-to-day tasks that don’t consume as much power as quickly — like browsing the internet — you can just rely on the battery alone.
If your batteries are discharging rapidly enough that you practically need to leave them on the charger to ensure they are ready to use when you need them, then it’s time to replace them. Batteries degrade over time, even with the best of care, and if a battery is no longer properly holding a charge, it should be recycled and replaced.