Several supermarkets sell own-brand batteries but these are not included in this guide as only Morrisons sold both a rechargeable and a non-rechargeable battery. See our guide to supermarkets to see how they compare.
Score table highlights
The batteries market is a poor performer across the board when it comes to corporate social responsibility. None of the companies included in this report scored above 10 on our Ethiscore scale. All companies, except for Philips, received the worst rating for managing workers’ right in their supply chains and all except Panasonic and Fujitsu were rated worst for reporting on their environmental performance.
||Conflict minerals rating
Philips and Varta both received our best rating for their sourcing of conflict minerals from the Democratic Republic of Congo (DRC). These minerals, such as tin and tantalum, are used in electronic products.
Panasonic and Energizer managed a middle rating for their conflict minerals policies. They would have done better if they had required suppliers to adopt a strong conflict minerals policy and given more detail about the smelters or refiners in their supply chains.
Berkshire Hathaway’s conflict minerals policy was insufficiently detailed and lacking in commitments to continue sourcing from the DRC and surrounding region. Gold Peak Group and Fujitsu had no conflict minerals policy at all. These companies received our worst rating for conflict minerals and lost marks under the categories Habitats and Resources, and Human Rights.
The battle of the bunnies
The two market leaders are Energizer and Duracell, both US companies but they appear at opposite ends of our score table - Energizer at the top, Duracell at the bottom. In the battle of the bunnies, Energizer wins on ethics.
Duracell scores poorly because of its ownership by Berkshire Hathaway, a holding company which owns a multitude of businesses from energy to insurance. See 'Company behind the brand' below for more details.
In 2006, the world was a different place. Back then the European Batteries Directive was just about to be introduced in order to prohibit the use of the most harmful chemicals in batteries, and to increase battery recycling rates across the EU, recovering valuable materials for use in other products and reducing the risk of hazardous substances being released into the environment.
In 2006, rechargeable batteries were also still in the ascendancy. The 2008 financial crash and subsequent recession provided a boost to the rechargeables market. In 2009, rechargeable batteries made up 23.2% of all batteries bought that year.
Standard (non-rechargeable) batteries continued to dominate (64% of all batteries sold in 2009) but the market had been in decline for several years. Although rechargeable batteries are, on average, 3 times more expensive, and they also require charging equipment, but they can be recharged up to 200 times before they lose performance.
The cost of recharging batteries from mains power is difficult to quantify, as it depends on the size of the battery being charged, the kind of charger being used and the cost of your electricity supply. If you have a renewable energy supplier or generate your own power, then rechargeables are an even more environmentally sound choice.
Optimising your rechargeable batteries
Previous rechargeable batteries needed to be fully discharged before recharging in order to maintain the life and performance of the battery. This is not strictly necessary with NiMH, so you can charge them as and when you need to and only occasionally do a full discharge and recharge.
Also, according to Which?, the best rechargeables can retain more than 85% of their charge if left unused for 50 days. That means you can charge them up in advance and have them ready when you need them.
The biggest thing to watch out for with rechargeables is under- and overcharging. Undercharging is when batteries are removed from charge before they have regained full capacity, which can mean that the batteries go flat faster. Overcharging is when batteries are subjected to a constant electrical current even after they are fully charged, which can cause long-term damage.
Preventing both of these comes down to the kind of charger you use. Basic chargers won’t tell you when batteries are fully charged or stop charging them when they are. Trickle chargers, which push a low charge through batteries for a long period of time, replace the charge that naturally leaks away over time and are an option if you want to keep batteries topped up. Trickle chargers often work on timers rather than battery charge, so under – or overcharging are still possible.
‘Smart’ or ‘delta-V’ battery chargers monitor the voltage levels in each battery and stop charging (or switch to a low trickle-charge setting) when they’re full. Many smart chargers are advertised as able to charge batteries in under an hour. As you might expect, these types of chargers are more expensive but they are a good choice for maintaining rechargeable battery performance by preventing under- or overcharging.
In terms of battery performance, in April 2016, Which? recommended Energizer Recharge Power Plus and Panasonic Eneloop Ready-to-Use. These batteries maintained 80% of their original stated capacity for over 400 hours of use and they also retained more than 85% of their charge if left unused for 50 days. The only other brand that Which? covered that is in this guide is Duracell.
As long as you recycle them, non-rechargeable batteries need not be a stain on your environmental credentials. All the materials that go into making the battery can be used for something else although, of course, you’ll be sending them for recycling more often than if you had rechargeables.
Chemicals recycled from batteries aren’t often used in the making of more batteries (see ‘recycling’ below) but Energizer are making an effort to change that with their ‘EcoAdvanced’ battery.
This is the first consumer battery to be made partly from recycled material. The proportion is currently 4% but Energizer plans to increase the proportion to 40% by 2025. Many people keep some non-rechargeables for smoke alarms and other emergency uses and it’s good to know that there are more responsible options when it comes to non-rechargeables. Also, if EcoAdvanced is a success, it may spur other manufacturers to follow suit.
Most non-rechargeable batteries are alkaline batteries, using zinc, manganese oxide and potassium oxide chemistry. If poorly handled (e.g. opened, recharged) these leak potassium hydroxide, a caustic agent that can cause respiratory, eye and skin irritation. You can also get AA and AAA batteries that use lithium chemistry. These can make power-hungry devices last longer, but don’t last as long in devices requiring less power.
Some rechargeable batteries use alkaline chemistry but most use nickel-metal hydride (NiMH) chemistry. The chemicals used in NiMH batteries are described as only ‘mildly toxic’ but in large quantities they can still threaten human and animal health. Nickel is a known carcinogen, can cause cardiovascular disease and high blood pressure, and can also damage the liver and kidneys. Improper disposal of NiMH batteries can also cause aquatic and atmospheric pollution.
Nickel Cadmium (NiCad) rechargeable batteries are no longer available since cadmium, which is carcinogenic and environmentally toxic, was banned under the 2006 EU Batteries Directive. A small number of Nickel Zinc (NiZn) batteries are becoming available, as a replacement for NiCad technology, but these more likely to be found in devices requiring high power and high voltage, such as power tools.
When we last covered batteries, 600 million were being sent to landfill every year in the UK, which contaminated the environment and wasted the valuable, recyclable resources contained in those batteries. Under the 2006 EU Batteries Directive, the UK was required to achieve recycling levels of 25% by September 2012 and 45% by September 2016. Although the UK government has not published any information on its progress towards this target, the last time data was released on battery recycling rates (in 2014) the UK appeared to be on track to meet its 45% recycling target.
This still means that over 600 million batteries are being sent to landfill or incineration annually in the UK.
Under the European Batteries Directive, battery producers and retailers are responsible for waste battery collection, treatment, recycling and disposal. In the UK, it is illegal for companies to send batteries to landfill or incinerators. Germany has gone further: there, individuals can be fined between €50 and €2,500 for failing to separate batteries from general rubbish.
It takes 50 times more energy to make a battery than it gives out during its life so the case for recycling batteries once they reach the end of their working life is a no-brainer.
Nickel, as used in NiMH batteries, is one of the most valuable non-ferrous metals in common use and, therefore, a substantial industry exists for recovering and recycling it. The majority of nickel recovered through the recycling of batteries is used by the stainless steel industry. Ferromanganese concentrate and zinc concentrate from non-rechargeable batteries also have industrial uses, while silver can be used by jewellers and lead can be reborn in another battery.
Batteries (rechargeable and non-rechargeable) can be taken to your local household waste and recycling centre. There are also bins in many supermarkets where you can drop off your batteries for recycling. Look up places that recycle domestic batteries