What are your tips for preserving phone battery life?

Was in an Apple Store last week about my husbands iPhone battery. Husband thought the same that leaving it at 100% is damaging. He was told that when it hits 100% there’s absolutely no damage to the battery leaving it on. I However charge my phone before I sleep, once it charged I turn it off, mainly because I don’t want to be woken up by notifications and emails etc.

If you charge a lithium battery to 100% of its capacity it runs for longer before it goes flat (which is also bad for the battery). As you say, you want long battery life – between recharges I assume. Run time is a criterion consumers use to decide what phone to buy initially. Those on contracts in particularl aren’t interested in the lifetime of the phone as they will get a new one in two years. Manufacterers will design phones that customers want to buy.

If you only charge to 80%, and avoid fully discharging it, the overall lifetime of the battery will improve, but you will have to charge it more often. It also means the phone has less capacity for the same weight; the battery is the heaviest component.

I think you’ll find that with a lithium-ion battery, which it will be, there will be a cut off at some point as they have to cut off when charged to a point which is critical, or else they can become dangerous. But I don’t know what the charge percentage will be at that point as they have to cut off at a point which is safest and that won’t necessarily be where you’d prefer it to be.

Malcolm – I’m not aware that not having the latest security updates reduces a phone’s usefulness. I have challenged the Which? position on the vulnerability of older phones without security updates a number of times and never had a satisfactory response. I don’t know who has taken over from Kate, but maybe we can get a balanced view of the risks, as things have moved on since Android 10.

I will ignore Apple – which I no nothing about – but they would not feature in a list of cheaper phones that someone just wanting basic features would buy and keep for life.

It is true that phone manafacturers have been rather economical with the number of Android updates they deploy for their phones, but the Google (Android developers) have been restructuring their software to ensure some core security patches are delivered through PlayStore. These are independent of the OEM updates.

If you have a modern Android phone (mine is an S21 which Samsung undertake to support for at least 4 years anyway), I have two sets of security patches deployed. You can check a modern Android (Version 10+) phone for this as follows:

Go to Settings > About phone > Software information.

Mine shows a Google Play system update: 1 January 2022. This is the patch delivered directly from Google Playstore.

Android security patch level update: 1 March 2022. This is the patch that Samsung deploy.

Having a modern phone even with all the latest patches installed can give users a false sense of security about the need to be alert and take sensible precautions.

From Android Central:

“It’s not exactly feasible to roll out a new software update for each and every vulnerability. Most bugs and security loopholes are pretty minor and will likely not affect the vast majority of individuals immediately. Furthermore, researchers don’t typically make exploits publicly known until a patch is released. This is known as responsible disclosure.”

Vulnerabilities are highly technical and can be difficult to monetize. Why bother, when shoulder surfing in a crowded place or using 1234 as a pin code will offer a £100 tap-to-pay bonus for anyone removing your phone from a hip pocket or bag. That will have an immediate effect and drastically shorten the usable life of your phone.

The Times of India article makes an interesting point that the tracking function of a mobile phone cannot be easily disabled if the battery is sealed. This means you may have more chance of locating it before the battery runs down of its own accord, if the aforementioned theft has taken place and you notice in time.

Not being a tea-leaf myself, it hadn’t occurred to me to remove the batteries when stealing a phone.

Sometimes the phone’s internal charging regulator fails but the phone still works otherwise, but is rendered useless because you can longer charge it, no matter how good the battery is. That’s what happened to an alcatel “simple to use” phone which I had which I had to dump because it’s regulator failed but I didn’t know that at first, I could see that the battery had visibly failed as it was misshapen and I couldn’t get a replacement here in the UK so I had to import one from Berlin which luckily wasn’t that expensive but when I fitted it in my phone and tried charging it wouldn’t work, even with other USB chargers, so the phone’s internal regulator must’ve failed, so the phone was no longer usable. So now I’m left with a good new battery which is no use. So surely the same must happen to some “smart” phones too as it’s common practice with such devices to fit the necessary regulating device inside the phone rather than in the charger, and of course such a regulator is not user replaceable, it’s a professional job.