Forget phone batteries, why aren’t all devices required to work properly with rechargeable batteries?

Over the last few days, reports have resurfaced that the EU will mandate that phones have replaceable batteries. These reports are based on 2023 legislation with an implementation date of 2027. I won’t go into the full details here, but that legislation covers removable batteries, and many phones are exempt anyway. 

Before we dismiss everything, this kind of coverage presents an opportunity to talk about a different type of replaceable battery: the humble alkaline battery. The non-rechargeable, disposable batteries have been part and parcel of our lives for years, powering everything from game controllers to toys, torches, clocks, scales, smart locks and more.

According to Market Reports World, as of 2023, 8.5 billion AA alkaline batteries were sold (50% of the alkaline market), with AAA coming second and other sizes following.

These batteries will all end up, at some point, being disposed of, which is a huge amount of waste. Sadly, a lot of batteries are just thrown away. According to Business Waste, the UK has a battery recycling rate of just 33-35%.

Cheap to buy, but still disposable

One of the things that the aforementioned EU regulation (New Battery Regulation 2023/1542) covers is alkaline batteries, with improved waste collection targets, restrictions on hazardous ingredients and improved life-cycle assessments.

That’s all well and good, but the question should be, why are so many alkaline batteries out there?

Part of the reason is that manufacturers routinely include a set of batteries with their remote controls, so you can get going right away.

These giveaways are a drop in the ocean, but alkaline batteries are given away because they have a long shelf life, holding their charge for years. Typically, alkaline batteries are sold with a promise of a five-plus-year shelf life, and some even have a ten-year shelf life.

That gives a degree of reliability that the rechargeable alternatives just can’t compete with.

That kind of shelf life means that alkaline batteries are super convenient to have at home, too. When a device runs out of power, a quick swap for batteries in the cupboard and you’re good to go.

And, alkaline batteries are cheap to buy, particularly in bulk. In fact, bulk online sales have grown (24- and 48-pack variants saw 17% year-on-year increases according to Market Reports World). Looking on Amazon, for example, a 40-pack of AA batteries costs £9.03, which is 23p per battery.

Switch to rechargeables and standard NiMH batteries will cost you over £1 per battery. Smaller packs are available, as you don’t need as many batteries.

Over their lifetime, one of our best rechargeable batteries will handle many charge cycles (that is, charging them, using them, and then starting all over again). Say, for example, you get 1000 charge cycles (that’s about average, but some offer 1500 cycles or more), that means that each rechargeable battery does the work of 1000 alkaline batteries; effectively, that’s like paying less than 0.1p per battery.

There’s a cost to having a battery charger and some inconvenience waiting for batteries to charge. NiMH batteries also don’t hold their charge for as long as alkaline batteries (although most will hold 80-90% of their charge for months, so you can have a spare set charged and ready to go). These factors are partly why rechargeable batteries aren’t just routinely used everywhere, but there are other factors.

Some devices just hate rechargeable batteries

Taking the example of AA batteries, NiMH rechargeable and alkaline versions might be the same size (well, give or take a few mm), but internally they are different.

Alkaline batteries are rated at 1.5V, but the voltage drops as the battery is drained, with a faster drop under high loads and a slower drop under low loads (a clock, remote control, or even a smart lock, where the device largely sits idle). NiMH batteries produce a sustained 1.2V until the battery is almost exhausted, so they are better for continuous loads.

The issue is that some devices just hate rechargeable batteries. My Yale Linus Smart Door Lock runs on four AA batteries, but it constantly complains about low battery life whenever I try to put four rechargeable batteries in it.

Similarly, I bought a radio-controlled alarm clock. Stick two rechargeable AA batteries in it, and the clock comes to life, but it refuses to set the time automatically.

Then there are devices like smoke alarms, which, for safety, need alkaline cells, more for longevity.

Li-ion batteries could be the future, but compatibility issues are still there.

More recently, rechargeable Li-ion batteries have become available, such as the Paleblue AA USB-C Rechargeable Batteries. More expensive than NiMH batteries, these ones can be recharged via USB, produce a constant 1.5V, and hold their charge better.

On paper, these seem the ideal replacement for alkaline batteries. And, in many cases, they are. My Yale Linus lock no longer complains about low batteries and is very happy with a set of Li-ion batteries.

The range of rechargeables is very good, too: Paleblue and other manufacturers make AA, AAA, 9V, C, D and CR123A versions. As most charge via USB-C, you don’t even need fancy compatible chargers for them, either.

Prices are higher than for NiMH batteries, but with around 1000 charge cycles per battery, the lifetime cost is much lower than that of equivalent alkaline batteries. A typical set of four AA Li-ion batteries may cost around £20, but over 1000 charge cycles, that’s the equivalent of 2p per battery.

That’s the good news. The bad news is that some devices are still super finicky about which batteries they will work with. The aforementioned clock also won’t set its time automatically with a set of Li-ion batteries in it; switch to alkaline batteries, and it works perfectly.

I tried to go green by using some Type-C Li-ion batteries in my SureFlap Microchip Pet Door Connect. It all seemed to work, but the door would only unlock for two of my three cats.

It appears the microchip sensor wasn’t operating at full power, and the chip in my cat may be in a slightly different location or buried a little deeper. For whatever reason, I can’t use rechargeable batteries with this product.

I tried with the Sure Microchip Pet Feeder Connect, but it refused to open for the same cat, so he couldn’t get his food.

In some cases, manufacturers specifically state that rechargeable batteries should not be used. In fact, Paleblue has a warning to that effect on its 9V page stating that “Most smoke detector and carbon dioxide detector manufacturers do not recommend using rechargeable batteries in their products.”

Devices should be required to work with rechargeable batteries

Whether it’s by design, by mistake or by requirement, too many devices simply don’t work with rechargeable batteries at all, and that’s not good enough. The default position should be that all devices be manufactured to work with rechargeables, even if a requirement is added that a device is only compatible with Li-ion.

We banned disposable vapes in this country (partly due to environmental concerns and also youth addiction), but disposable batteries still seem fair game. Given how many battery-powered devices there are, it’s time more was done to ensure compatibility and reduce the amount of waste that we produce.