Lithium-ion batteries: why we’re changing our tests

Most consumer laptop batteries can still be replaced but this does now require opening the laptop case instead of just detaching the battery. For example, see:- https://www.ifixit.com/Guide/MacBook+Air+13-Inch+Early+2015+Battery+Replacement/40697

Many other laptops now crib the form factor developed originally for machines such as the MacBook Air. With this design, almost all the space under the palm rest is taken up by the battery.

Some more recent laptop designs (see for example:- https://www.vice.com/en_us/article/gybwxw/the-5-year-quest-to-unglue-the-macbook-pros-battery) now have glued in batteries, which is not so great for sustainability.

The iFixit videos are very good and helped me replace the battery of an iPhone 5s. It was stuck in with hot-melt glue, which will probably need to be heated before the battery can be removed. Glued-in batteries are common in Apple products and perhaps others. I’ve not opened other makes but seen glue used to retain the battery in sat-navs. I don’t see why batteries cannot be retained in other ways, which would make replacement much easier, but what we really need is batteries that can be replaced without tools.

Another challenging problem for those who want to replace batteries in phones and tablets is that removal of the screen usually requires heating with a hot air gun or a powerful hairdryer to soften the glue around the edges so that the screen can be prised away. This may not end well for the beginner, though it is routinely done to replace broken phone screens.

Sadly, I am not aware of any popular modern smartphone with a battery that can easily be replaced.

Happy to see mention of iFixit here. As far as I know there is no UK equivalent.
I have long thought that IFixit was a natural partner for Which, sharing many of the same objectives. I would like to see Which reports include a repairability index, perhaps sourced from iFixit. Unfortunately most of the Which reports seem to be dumbed down and any non trivial technical information is omitted.

I would certainly like a Which best buy requirement to be an affordable, available replacement battery where applicable most certainly including mobile phones.

A big problem with non-manufacturer batteries is all the fakes out there that can be dangerous.

That certainly puts me off buying cheap replacement laptop batteries. Hence, some of my older laptops are just used as “mains only” devices.

I’ve replaced phone batteries and faced the same problem of deciding whether they were “proper” batteries, even though sold as Nokia. Just like any other on-line purchase it is always tempting to buy on price but I try to find reputable vendors, or the manufacturer’s outlet.

Maybe Which? could do some of this hard work for us and advise of reputable sources online.

I found this video quite interesting:- https://www.youtube.com/watch?v=h0G8y-Nur7w&t=555s

Thanks Derek. I had been looking for a YouTube video showing the electronics that is used in lithium battery packs, and this is very good example. I don’t understand why such complex electronics are needed. Lithium battery packs will perform best if there is cell equalisation to compensate for the fact that some cells in a pack are always weaker than others. Without equalisation, the run time of the product will decrease faster.

The electronics can be in the charging unit rather than in the battery pack, as the Bosch one demonstrates – seemingly. I’d like to see battery replacement made as easy as possible and sources of reputable batteries listed.

Unfortunately, it’s not that simple. As I explained elsewhere, lithium batteries must be protected to ensure that none of the cells over-discharges, otherwise the battery will be wrecked. That means that there must be electronics in the battery pack or in the product that it powers. Additional electronics is needed to control the charging because lithium cells can also be damaged by overcharging. This electronics can be either in the battery pack or the product itself. An advantage of having all the electronics in the battery pack is that if there is a failure the product does not have to be replaced or repaired, which would probably not be economically viable.

I have a small and a large Bosch cordless drills, both for convenience and so that I can do work where there is no source of mains power. I don’t know whether or not the battery packs contain electronics, but some Bosch battery packs certainly do: https://www.protoolreviews.com/tools/power/cordless/batteries-chargers/bosch-batt622-6-ah-battery/16453/

Looking to see if it would be possible to buy a spare battery for my small Bosch cordless hedge trimmer I found one on the RS site. The price is more than I paid for the hedge trimmer. 🙁

Out of interest I opened the battery pack for a Bosch cordless drill and found that it contained five Samsung 18650 lithium cells, a temperature sensor stuck to the side of one cell, a diode a resistor and a non-replaceable fuse. Anyone who could wield a soldering iron could replace the cells and the cost of replacement would be about £30, buying from a reputable but expensive source. Even if a battery pack contains a mass of electronic components it may still be easy to replace the lithium cells.

The Bosch battery pack did not contain complicated electronics, as the video demonstrated, and there seemed no problem with reliability. Is there evidence to the contrary?Nevertheless the key is to make battery replacement in whatever appliance simple. Hopefully any electronics necessary will match the life of the appliance.

I’ve given you a link that shows a Bosch battery that does contain complicated electronics, Malcolm. That is important for frequently used products such as cordless drills used by tradesmen otherwise the effective working capacity of the battery will progressively deteriorate. Here is some information on Wikipedia: https://en.wikipedia.org/wiki/Battery_balancing Anyone who buys a cordless vac will not want one that gradually loses run time. Cheap power tools like my Bosch cordless drills don’t have this refinement but I don’t use them much.

I was simply going by the video Derek posted.
I’ve no problem with battery packs containing more complicated electronics to control charging and optimise appliance performance but clearly they add to the possibility of shorter life and increase the cost. If the cell life is such that they need replacing – either through failure or just reduced charge – then I am suggesting they should be easily replaceable, and the electronics should be robust.

The question is, how do we weed out the good from the bad when testing? Generally with electronics it is excessive component temperature that determines life (assuming good quality components are used); the industry I was in used electronics in arduous situations with long life – necessary for commercial products but it was not at untoward cost. I wonder if Which? do any such tests?

Cell balancing circuitry is necessary to maximise battery life, as I have explained. It has to be in the battery pack or in the product itself. If circuitry is well designed it should outlast the product. The introduction of microcontrollers has led to a considerable reduction in component count, which is a cost saving for consumer products.

Lithium batteries can have very respectable lives if little used and lose little charge in storage. For example my Dremel has a 2006 battery. The problem arises when these batteries are used heavily, which is why mobile phone batteries can fail after two years.

I don’t know how long batteries for cordless vacuum cleaners last. Obviously use will be a factor but so will circuit design. Because of the high currents involved and the need for reliable connections, it’s not really practical to have cells that can be changed in the same way that we do with a torch or a remote control. I would like to see cells that are easily replaceable without the need for tools, say using push-on tags rather than having to solder the connections.

It would be interesting to know how long cordless products such as vacuum cleaners last. I cannot remember if this has been covered in Connect surveys.

My concern is to support Which? in making batteries replaceable and, although they don’t state it, at sensible cost. I’d hope this will develop into replacing cells in existing housings, rather than replacing a whole assembly, to help reduce the waste of resources. I’d also like to see incentives to recycle the used cells to help the environment.

I think it’s great that Which? have are looking at sustainability. We and others have discussed batteries many times in numerous Convos.

I gave the example of a lightweight hedge-trimmer where a replacement battery cost would more than what I payed. Fortunately I have found cheaper sources of the battery in question but price is often a problem. It would be great if Which? could give us the approximate cost of a spare battery in reviews, which could make a more informed choice about which make and model to buy.

As an incentive for recycling used batteries I’ve suggested a charge on new batteries and a refund for trading in old ones. Maybe there is a better solution.

It is very easy to have user-replaceable batteries for products such as cameras with low power requirements, but once again it would help if Which? provided advice on cost and availability of spares in its reviews.

I agree with that, alfa. There is the minor (very) inconvenience of having a trailing mains lead but you don’t have to carry the weight of the battery around with you, and it only dstops working when you want to. There are conversion losses in charging the battery, as well as the resources needed to manufacture it. Derek’s video of power tool battery packs was quite illuminating, most of which seem to have complex electronics that can shorten life. A small battery cleaner is convenient for the car, but I’d stick with a mains one for the house.

Mobile phones are rightly criticised as being environmentally unfriendly because of the batteries and electronics they contain, but the same applies to cordless vacuum cleaners, power tools, etc. I’m happy with using corded vacuum cleaners and the one I use most of the time is about 20 years old. I use an older one to clean the car or for a quick clean I have one that plugs into the cigarette lighter socket. I chose the plug-in car vac in preference to the rechargeable version because it was cheaper, more powerful and there are no batteries to fail.

I don’t know many people who have cordless vacs (but it’s not something I discuss very often), but they are popular. Perhaps Which? could give us some information about how long the batteries are likely to last in reviews and that might encourage consumers to decide whether or not it’s worth going cordless.

Alfa questions the wisdom of leaving products on continuous charge and so do I. Whatever the manufacturer may claim, I cannot see any benefit in doing this. With older NICd and NiMH batteries it gradually damages the batteries and these are still widely used in small electrical goods including electric toothbrushes. Modern products use lithium batteries that are protected from overcharging and their chargers often consume little power. It’s easy to check with a plug-in power monitor.

Alfa, the 16 rare earths are indeed rare: Lanthanum,Cerium,Praeseodynium,Neodymium,Promethium,Samarium,Europium,Gadolinium,Terbium,Dysprosium,Holmium, Erbium, Thulium, Ytterbium and Lutetium. Holmium is used in a medical laser used to remove enlarged prostates. Gadolinium is used in medical MRI scanning work.
I think that an alloy of Neodymium and tin is used to make the screen of mobile phones.
Most of them are mined in China. I hope that they are all being recycled.

I wonder if the answer would be set up a scheme that would pay a few pounds for scrapped products containing rare materials to discourage them landing up in landfill. This could be funded by a charge on new products. This already happens with car tyres.

Welcome back Dave. We don’t see you here very often.

It looks as if your Vileda uses a single 18650 3V lithium rechargeable cell, Colin. As you have discovered, lithium cells will not recharge if over-discharged. I expect that the cell will be wrecked but maybe try connecting a small 9V battery – the type used in smoke alarms across the lithium cell for a short time with the charger disconnected. There is not enough energy to cause an explosion. 🙂

Replacement 18650 cells (often marked 3.6 or 3.7 volts rather than 3 volts) are widely available but if the original is soldered in place you would need one a tagged cell. It’s worth bearing in mind that lithium cells are always sold at least partly charged and must not be short circuited or installed the wrong way round.