How to Set a Custom Battery Charge Limit?

We used to live in a world where virtually all mobile phones were released with a removable battery. Over time, companies have chosen to embed these batteries so they can increase in size while also offering water resistance. This has resulted in people needing to optimize their charging patterns to reduce degradation and we can automate part of this by preventing the phone from charging past 80%.

There’s been a lot of discussion within the Android community over the last week or so when it comes to fast charging. I don’t want to dive too much into it here, but the idea is that using any fast charging technology is going to increase the degradation done to the battery (more than would normally happen).

To many, this is fine because it should be optimized to reduce the impact of the customer.

Some people are happy to trust another company but others aren’t. So many people who want to keep their smartphones for longer than 2 years will put in the effort to keep the battery as healthy as possible. One way of doing this is by preventing what Battery University calls “Deep Cycles.”

We do this by preventing the battery from reaching certain battery percentages. There is a ton of research that you can read from the website but I’ll link to this easily digestible best practices guideline article here. Today, we’re going to be focusing on this deep cycle tip by preventing our smartphones from charging past 80%.

Note: Your smartphone or tablet must be rooted in order to use the suggested application below. There are some external products that can work for those who do not have root access. I haven’t had a chance to try them out yet but I am looking into it.

How to Stop Charging the Battery at a Certain Percentage?

Download and install the Battery Charge Limit application

Open up the app and give it root access

Tap the gear icon in the top right corner

And then choose the “Set Control File” option

Tap the “I Understand” button to bypass the pop-up, but this is where we can find out if the app is compatible with our device (see video below).

Back out of the Settings area and back to the main screen

Set the left number to 80%

This is the percentage that, when reached, our device will stop charging.

Set the right number to anything above 30%

The phone will not allow the battery to be charged until it reaches this percentage.

Tap the “Enable Battery Charge Limit” toggle and then close out the app

What’s Special About 80% and 30%?

As mentioned in the Battery University article, we want to avoid “Deep Cycles” when it comes to charging our smartphones. The idea is to avoid stressing the battery out by keeping the battery between certain percentages. Some go by the 80/20 theory but the linked website advises 30%.

When tested, batteries that were fully discharged (charged to 100% and used to near 0%) showed signs of increased degradation compared to batteries that were only partially discharged (charging it back up before it got to 30%). These numbers aren’t exact or anything (which is why the 20% low is so popular) but every little bit helps.

Some OEMs are adding in these additional battery optimization features, but until then we have to rely on alternative methods.

Customize the App to Your Charging Pattern

I feel this is really where this type of feature shines. We all use our smartphones differently but there are only a select number of ways people tend to charge their phones. Some opt for continuous wireless/wired charging throughout the day, others only plug the phone in at night. Some may only need to use the charger every 2+ days.

In any case, we can use the options in this Battery Charge Limit application to adapt these best practices to how fits us best.

For example, I set the “Recharge Below” option in the application to 75% because I only charge the phone at night. But I also like the phone to be at near max (80% in this case) which not letting the app trigger the charger every time it drops 1% (which is how it would be if I set this percentage to 79%).

So for me, I lay down at night and the phone is plugged in. It will charge the phone to 80% and then stop charging. Let the phone idle until the battery falls below 75% and then it will charge it back up to 80% again. This cycle will repeat until I unplug the phone (which is generally around 7 or 8 the following morning).

Now, this could be different for you.

For example, you could use this on a tablet that you only use for media consumption. This device would be plugged in almost all of the time and as we learned, this reduces the longevity of your battery life. So in this case, setting the 30% – 80% range would be better as it would prevent the battery from being at 100% most of the time.

Experiencing difficulties with your Device, check out our “How To” page on how to resolve some of these issues.