Living with a huge, 5000mAh-battery phone, and why 1000-dollar phones don't have one

A couple of weeks ago, my SIM card found itself inside a phone quite unlike the rest. I switched to the Asus ZenFone 6, a Snapdragon 855-powered phone that stands out with its no-notch display, flippy camera module, and $499 starting price. But its best feature could be its big battery – a 5000mAh cell that keeps going and going.

Now, if you want to learn more about the ZenFone 6 as a whole, I encourage you to read my ZenFone 6 Preview article where I share my initial thoughts and first-hand impressions. Here, I will focus on one particular aspect of the device – its battery life – and how it has affected me as a user.

This thing lasts forever!

A phone's battery life is dependent on three main factors: the capacity of its battery, the efficiency of its hardware, and how well its software is optimized. Since a phone maker may not have much control over a Snapdragon chip's efficiency, and since fine-tuning Android's battery management algorithms could be hard work, the easiest way to deliver a phone that truly lasts long is to put a bigger battery in it.

Case in point, the Asus ZenFone 6 can easily last me two to three days on one charge. I get a day and a half to two days from most other phones. I admit that I'm not the heaviest of users, but the leap in battery life compared to anything I've used recently is definitely there. It's a difference you'd most certainly feel, no matter how demanding of a user you are.

The not-so-obvious benefits of having a huge battery

Having your phone last forever is awesome, and so is knowing that you can go on a flight or explore the great outdoors without having to lug a power bank along. But the benefits of having a huge battery do not end here.

Since I started using the ZenFone 6, I noticed that battery anxiety as a whole is no longer a thing for me. Surveys show that a significant portion of people feel elevated stress levels when they're away from an outlet and their phone's battery is getting low, and being less stressed is something few people would mind, I'm sure.

My charging habits have also shifted. Until recently, I'd usually let my phone charge overnight so that I know I have a full charge at the start of the day. An incomplete charge would somehow feel wrong with any other phone, but with the ZenFone 6, even a quick, 30% burst at any point during the day means up to an extra day of usage, so I do not feel obligated to charge it religiously every night.

And on the technical side of things, bigger batteries do tend to have a longer lifespan. This makes perfect sense as batteries degrade after each charge-discharge cycle, and about 500 charges is enough for a cell to lose 20% of its original capacity. Having to recharge your phone less often means it takes longer to reach that threshold. In Asus's lab tests, the battery in the ZenFone 6 retained 90% of its charge capacity after simulated 2 years of use while the 3300mAh cell of an unnamed competitor could hold 85% after the same stress test.

So, why don't all phones have batteries this big?

It's not because rechargeable lithium-ion batteries are expensive. It all comes down to priorities, and these priorities may differ vastly depending on who is a particular phone made for. The ZenFone 6 is a phone for enthusiasts – for people who do their research, who like big numbers, who know well what specs mean. In this case, having a huge battery is a very strong selling point.