/ Technology

Is it time to replace your iPhone’s battery?

Has your old phone become frustratingly laggy? It might be time for an expensive upgrade… but is there another option?

My iPhone’s been really struggling lately: apps take a noticeable time to open and often crash, it’s laggy when I’m typing and taking spur of the moment photos just isn’t possible anymore (having to hang around for 5 or 6 seconds for the camera to start working).

I’d been aware for some time that I really needed to upgrade my phone, which I bought in 2015, but had been putting it off: nearly £1,000 for a new iPhone seemed a horrendous price to pay (I always buy my phone outright and get a pay-as-you-go contract).

Read: Which? Best Buy mobile phones

So I struggled on with my four-year-old phone, convincing myself that slightly longer load times and an inability to take photos were a small trade off for what was basically a functional phone.

Power problem

Then one day looking through settings, I came across information on my phone’s battery, and this message:

‘This iPhone has experienced an unexpected shutdown because the battery was unable to delvier the necessary peak power. Performance management has been applied to prevent this from happening again.’

With a bit more research I worked out what ‘performance management’ meant: my phone’s processing power was being limited by the operating system because my battery was degraded.

Although I’d had the phone since 2015, it hadn’t occurred to me that the battery might be affecting performance – I didn’t know it could.

But in fact it turns out that Apple deliberately slows processing speeds in older phones to prevent iPhones from randomly shutting down due to lack of juice.

This makes sense, but it wasn’t ever exactly made clear to me that the phone had been locked at a lower processing speed: I’d thought my phone was obsolete rather than just limited.

Apple juice

With this knowledge in mind, I realised I had a new option open to me (beyond splashing out a grand on a new phone): I could simply get my current phone’s battery replaced. So that’s what I did.

I booked my phone into a third party repair centre near where I work the next day for a battery replacement. It was cheap and hassle free – costing £35 for parts and labour and taking a couple of hours.

The only slightly laborious thing was I had to backup my phone before and restore it afterwards – they wipe the memory when repairing it (but you have to go through this process with a new phone as well) .

And is the phone running at a higher performance now? Yes, significantly. Opening and switching between apps is almost instantaneous again and there have been no crashes: not bad for a four-year-old phone.

Repair, recycle, reuse

My regret is that Apple never made it clear to me that my phone had been limited and that getting a battery replacement was necessary to ‘unlock’ the processing power I’d lost.

Apple confirmed in 2017 that for a year they’d been slowing iPhones in order to ‘smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions.’

As far as I remember, this news was never passed on to me – and in my opinion it probably should have been.

But it makes sense from their perspective I suppose – Apple CEO Tim Cook recently said that the company’s sales of new phones had been affected by ‘some customers taking advantage of significantly reduced pricing for iPhone battery replacements.’

So it looks like other people are getting their iPhones repaired rather than buying new ones, which can only be a good thing in terms of sustainability – and avoiding unnecessary new purchases.

But what do you think? How old is your mobile phone – does it still work well for you? Will you be getting your iPhone repaired after reading this?

How old is your mobile phone?
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Nick says:
25 January 2019

I’ve had increasing problems reading The Times website on my iPad and it’s getting worse. Do you think the battery issue could also be affecting the processing power of iPads?

If other websites are working fine then it’s unlikely to be a problem with the iPad. Watching iPlayer or other video content would place greater demands on the processor etc. There is a FAQ for the Times app but only those who are registered can access this information.

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Nick: go to system prefs / general / screen brightness and check what the position is. Sometimes it resets itself after a major update.

I feel a little late to this article, and I’m definitely one who really needs to consider whether to upgrade his mobile phone (from an iPhone 6) or have the battery replaced (which would be the third time). Decisions, decisions!

Great battery improvement tips on the comment thread, and we have plenty of tablet/mobile device advice on Which? Tech Support’s website 🙂

Hi Andrew – Long time no see. Wouldn’t it be nice if you could just pop in a replacement battery and maybe carry around a spare in case it was not convenient to charge the phone?

I’m afraid luxuries like that are reserved for those of us who use nice cheap Alcatel (or similar) smart phones.

Now don’t be provocative telling about your £25 smartphone yet again. 🙂 I’m more impressed in you keeping your Zanussi washing machine for more than 30 years. Phones are still advancing quickly whereas that’s not so much the case with washing machines.

Can you please advise us on the security risk of using a phone that can no longer be updated, assuming it would not be used for banking?

Wavechange, I’m not really an expert on mobile phone security.

That said, any personal computing device that is no longer receiving updates is, in principle a greater security risk than one that is being updated.

One specific instance of this would be that, once any new vulnerability is discovered, it ought to be remedied by means of updates to support devices. But, with some rare exceptions, corresponding updates won’t be rolled out to unsupported devices.

With regard to specific threats, I did manage to find a some interesting articles:




In general, it looks as though the risks would be lowest for iPhone users.

The potential threats will also vary according to what apps the phone is used for. I doubt that browsing W?C with an unsupported device would generate many risks, whereas wide ranging surfing and downloading obscure apps would pose much higher risks, as too would extensive use of public wifi.

I accept the disclaimer and will look at the links. 🙂 Sadly, the only people I know with older phones know even less than me about security.

I’ve long since stopped using public WiFi, not only because of the established risks but because improved network coverage has removed the need.

Information about ‘vintage and obsolete’ Apple produces is here: https://support.apple.com/en-us/HT201624 It’s a pity that Apple does not do what Microsoft does and publish information about software lifecycle well in advance.

Yes, long time no see wavechange and all! 100% agree, but I can’t imagine it happening. Luckily we can use power banks to charge on the go, although they’re a bit of a nuisance to carry about (including the USB wires).

@katebevan Perhaps a future report for Which? Computing? 🙂

I bought a power bank when my iPhone 5s battery seemed to be failing. I’ve not really needed it for the phone but it keeps the sat nav working on long journeys without needing a cable to the power socket.

I did notice that Which? found power banks fell short of their stated capacity, which is disappointing: https://www.which.co.uk/reviews/mobile-phones/article/best-portable-power-bank-chargers

I have a samsung Galaxy A3. about 3 years old. When i am abroad it does not work. Have put roaming feature on. Had thsi happen whenever i have used it abroad, always within EU. is this a problem with this phone or am I doing somthing wrong,

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Duncan, t

That link doesn’t seem to work. This one might do better:


I’ve looked at the helpforsmartphone.com roaming guides for both A3 and A3-2016 models and they seem to be the same, so either should do for David.

In my experience, most Android phones will automatically roam for voice calls, but, for internet uses, they may need to have data roaming turned on, as per the above guides.

thanks guys, discussed the matter with carphone warehouse upshot is got a new phone

On the previous page of this Convo I reported that the battery of my iPhone seemed to be failing over Christmas. I managed to improve the performance with a little housekeeping but since Derek had suggested a useful video and Ian suggested where to buy the battery from.

Replacing the tiny screws needed patience and after five years the battery was stuck very firmly in place, but the phone is back together and working. The cost of replacing the battery was £16.20, including some sticky tape and small tools.

With some phones it is necessary to remove the screen to change the battery, which requires heat to be applied at the edges to soften the glue. I would not even try.

After 38 hours my phone is down to 25% charge and it was used quite a lot yesterday. Hopefully it will not need any further attention until it is pensioned off. I cannot remember how long the battery lasted when the phone was new.

I would not describe myself as a “tree hugger”, but it does concern me how many manufactures fail to understand the fact that a satisfied user of older equipment, is probably one of their best selling tools.
“I’ve had an XYZ phone for ##years, and it’s never let me down – so yes I would definitely recommend an XYZ for you!” is to me a far better way to promote sales.

Interestingly, It’s thought to be the major reason why Apple iPhone sales have slowed. Because Apple gear is extremely reliable and lasts for a long time, users are not so keen to upgrade as they used to be, partly because the newer models aren’t offering much in the way of ‘must have’ new features but mainly because older Apple gear still works perfectly.

We have, between us, two iPhones: a 6 and a 7, and there’s really no need to upgrade, since both do everything we need them to do. Apple computers have the same issue: I have several, perfectly functioning Apple Macs lying around, simply because they’re not fast enough to handle the latest in Video processing with the speed I need. I re-purpose them into running a media server, DVD extraction and a acting as music servers for the house.

My 11 year old MacBook still works great (except for its letter box DVD drive).

I’ve just given it to my girlfriend’s daughter, as a swap for a Dell Latitude ultrabook.

In France they take a class action against Apple, and here in the UK Which? regret Apple didn’t inform us!

Which? really need to take account of repairability/longevity/sustainability as a core part of all reviews so that we can make more informed consumer choices.

A premium product should not become obsolete after 4 years of use! The fact that we even think it has just shows how ingrained our obselesence culture has become.

Where are the 10 year warranties on products? In fact where are the lifetime warranties on products?

Have a read of Vance Packards “The Waste Makers” from the 1960s, it’s sobering reading

Having recently helped with the reassembly of a partially dismantled iPhone 6, I can attest to their availability of inexpensive 3rd party spares and straightforward repair ability.

So if you have the courage and the necessary funny screwdriver, DIY battery or screen replacement only then needs a moderate degree of dexterity.

ifixit.com provide helpful repair guides.

daes0707 – Apple reduced the performance of certain phones when the battery was starting to fail to reduce the risk of unexpected shutdown. Their mistake was not to give users the choice or even inform them and UK owners were subsequently offered a replacement battery for £25.

I have an iPhone 5s and replaced the battery for £16.20 after five years, with the help of an iFixit video:
https://conversation.which.co.uk/technology/iphone-battery-replaced-power/#comment-1558177 I will carry on using it until security updates can no longer be applied.

Many people have been convinced that a smartphone should be replaced after two years. This is a combination of marketing hype and advances in technology. I suggest that it would be better to focus on household products such as white goods, vacuum cleaners and the like, where a newer model does not offer any great advantages. Manufacturers are now promoting cordless vacuum cleaners. These are convenient, but in a few years the batteries will start to fail and if spares are available they are likely to be expensive. Incorporation of ‘smart’ features into everyday products plus marketing will mean that we are expected to upgrade to the latest, greatest product.

I have suggested a requirement for a MINIMUM guarantee of five years on supposedly durable products. As car sales have shown, a decent guarantee is a good sales feature. Many faults can be fixed by a competent DIY enthusiast.

I realised a few days ago that I my most versatile power drill is a Black & Decker one I bought in about 1980. In those days, I believe they were made in the UK.

I have a B&D blue single-speed drill that I bought in 1982. It is not used much these days but being faster than my cordless drills it’s handy for use with a wire brush.

I also have, and occasionally use, an old B&D power drill coloured orange and grey. I believe I bought it in 1969. It has never required any attention. It is a two-speed drill but does not have hammer action. It will do most jobs around the home except tough masonry.

I also have a blue single speed B&D drill of similar vintage to Wavechange’s but that does not get much use these days.

I’m sure my grandfather’s hand drill is still around at my brother’s house. Here I have my late father’s hand drill, complete with a broad arrow and a 1944 date stamp.

As I’m sure you know, that is the War Department mark – something that predates me.

It would be encouraging to hear of more people who have replaced the battery in their iPhone, Samsung or any smartphone where the battery is not intended to be user-replaceable. I think I might be called on to replace another iPhone 5S battery, so my pentalobe screwdriver is at the ready. Having learned that the battery is held in with hot-melt glue, it should be an easier task second time round.

I’ve also a grey and orange B&D 2-speed drill from the mid ’70s that did a huge amount of work renovating two houses, furniture making and fitting out kitchens, bathrooms and bedrooms . It had attachments – circular saw, jig saw, sander, shaper like a router, hedge trimmer. Still works but noisy.

In the early days there was a B&D shop in Harrow where you could buy “refurbished” power tools and the spares to fix your own.

(Not to be left out) we have 2 B&D power drills form the 1980s.😁

Mine will probably last another 100 years at the rate it gets used.

I have a B&D ‘Proline’ hammer drill dating from the late 80s or early 90s. That and the one I mentioned earlier are likely to outlast my two Bosch cordless drills, which are likely to be scrapped when the lithium batteries fail. Rechargeable power tools are not a good choice for anyone who does not use them fairly frequently.

Malcolm – my blue B&D drill was a cheap ‘refurbished’ one from a B&D shop. It was actually new but came without a case, accessories or instructions.

It’s well worth dismantling power tools to clean and lubricate them, particularly gearboxes.