Do I need to turn battery chargers off?

Not many years ago, electrical equipment was pretty well fixed in position by a cable with a plug in the wall. Now we expect to carry everything around with us and to be able to use it anywhere, but this needs batteries and batteries need charging, so we have a box full of different sized and shaped chargers and have to keep remembering to charge each device regularly. There are many different types of batteries, but most of them store low voltage DC (direct current) electricity, whereas mains electricity is high voltage AC (alternating current), so a battery charger has to convert from one to the other and this unfortunately means a loss of efficiency. If you feel a battery charger while it is charging it's warm, and that heat is wasted energy, so if we want to reduce our energy consumption and carbon emissions we do need to be careful about how and when we use battery chargers.


What kind of chargers are there?

Leaving aside car battery chargers, which charge big lead acid batteries, many small devices like phones, MP3 players and some cameras have batteries built in, and the charger just plugs straight into the device. When the battery is fully charged however there is still some electricity being used, so it's important to unplug it as soon as you see it's finished. Chargers for rechargeable batteries - the usual AA or AAA type - often have an 'intelligent' control which senses when the battery is charged and switches itself off, so if you're buying one make sure it has this control. Increasingly though small devices can be charged through the USB port of a laptop or desktop computer, which gets round some of the energy losses from a normal charger. Finally and best of all from an energy point of view there are solar or hand driven chargers. Solar chargers will take much longer then the mains equivalent to fully charge a battery, but if you plan things so you always have a spare set of batteries in the charger you can have a constant supply of fully charged batteries at no cost at all. You can get solar chargers with connectors for just about every kind of device, often designed specially for travellers.Hand driven chargers are useful for emergencies in remote locations but are unlikely to be used for everyday purposes.


How can I make the batteries last longer?

The standard type of rechargeable batteries are now mostly NiMH (nickel metal hydride) which may suffer from something called the 'memory effect' which means a battery can take less and less charge over time and discharges quicker. The way round this is to run the battery to empty about every 30 charges which helps it keep its full charge. Lithium ion batteries, which are used in phones and many other devices now, don't suffer from this effect and in fact last longer if they are kept frequently topped up. If the device they are in has a display showing how much battery power is left however, it will become increasingly less accurate unless the battery is again full discharged every so often. So it looks as though whatever type of battery you are using it will last longest if occasionally allowed to run down to nothing.

If you're interested in more technical information about battery charging, the wikipedia page is good - http://en.wikipedia.org/wiki/Battery_charger#cite_note-ProlongLith-17, as is this webpage - http://www.batteryuniversity.com/parttwo-34.htm.

Does standby really use that much electricity?

Consumer electronics like hi-fis and TVs are the single biggest energy user within the average UK household and it is growing! As technology has developed and our lifestyles have changed we increasingly have access to iPods, digital radios, DVD players and much more. An important step we can take towards saving electricity in the home is to take care not to leave all these devices on standby when we are not using them.

Flicking your TV or hi-fi onto standby before going to bed using a remote control might seem like the easiest option but by turning it off properly once you have finished with it you could save the equivalent of 60% of the electricity you use playing music or watching TV.

Digital radios have grown in popularity in recent years, but few people realize that they use up to four times the amount of energy as traditional analogue radios when running. It is even more important to know that when they are switched off (but not at the wall switch) they continue to use up to 5 watts on average.

The level of power being used by a device on standby is usually much less than when it is fully operation however if left on standby 24 hours a day it can often match or exceed the amount of power consumed during the shorter periods it is fully operational. The simple act of switching your entertainment systems fully off when they are not in use will save you a lot of money over the course of a year while also helping to reduce your carbon footprint.

what's all the fuss about low energy light bulbs?

Last up to 15 times longer and save 20% of your energy



That’s the green credentials for switching to low energy light bulbs. Reduce your energy bills and help protect the environment – it couldn’t be simpler

Will it make much of difference?

Low energy light bulbs or Compact Fluorescents Lamps (CFLs) to give them their technical name use around 80% less energy than traditional light bulbs. Swapping a single bulb will save you £2.50 - £9 a year whilst fitting all the lights in your house with low energy equivalents could be saving you around £70. But the savings don’t stop there! They last up to 10 times longer than a standard bulb so over their lifetime they could save you £40 or £540 for the average house. Plus you don’t have the hassle of replacing blown bulbs every year.

Still doesn’t sound like much? It might seem like a small change, but if every home in the UK changed just 3 light bulbs, enough energy would be saved to light the UK’s street lamps. Now that would make a significant contribution to cutting carbon dioxide emissions.

They look ugly and give off a strange light

True the first generation of CFLs were a bit ugly looking, took a while to warm up and many people complained they gave off a harsh, cold light. Well a lot has changed since then as the market for low energy bulbs has matured. Candle shaped, stick shaped, traditional, screw fit, bayonet cap, dimmable, soft tone – you name it, they are now available in almost any style to suit all your lighting needs (see the picture on the right above). So if you were previously turned off by low energy lights its time to give them another try.

What about LEDs?

If you’re still not convinced by CFLs you could always opt for LEDs which are by far the most energy efficient option and last up to 10 times longer than CFLs. Originally used for instrument panel lighting, recent advances in technology have produced LEDs suitable for all domestic lighting applications (see the picture on the left above). They will cost you quite a bit more to install than traditional bulbs or CFLs but their lifetime energy savings are very substantial. They are also available in whole range of colours and tones providing a wealth of opportunity for creative domestic lighting applications.

Need more information?

The Energy Saving Trust website is a good source of information about climate change generally including lighting:

http://www.energysavingtrust.org.uk/Home-improvements-and-products/Lighting