3 Myths Busted About Household Batteries

Just because you've been buying batteries for half your life, doesn't mean you know all there is to know about them. There's every chance that your ignorance is costing you dearly. Believing hese three myths could be

Myth number one: You cannot recharge disposable alkaline batteries

This may have been a fact once upon a time, but whilst science has moved on, the battery manufacturers are not rushing to tell the consumer about it.

It clearly says on the sides of most alkaline batteries that they are not to be recharged; the warnings are fairly dire. "Batteries will explode" is the usual line, but is this the truth? Emphatically not.

Testers willing to put their lives 'at risk' by going ahead and recharging, found they were not even risking their eyebrows in the manner of some cartoon scientist, let alone their life. Even when using brief bursts of charge from a high-voltage car battery!

What testers did find was that the batteries would get hot if Over-charged, but the worst eventuality was a battery that gradually - and undramatically - split along one side, leaking a very small amount of acid. Hardly the impressive firework display consumers have been led to expect.

Whilst using a car battery for recharging alkaline batteries is not something any sensible person would recommend, there are alternatives. You definitely shouldn't use your standard recharger - these are not able to let you know when an alkaline battery is recharged which could lead to the overheating problem mentioned above - but there are devices available which are specifically designed to recharge alkaline batteries, sometimes alongside rechargeable Ni-Mh and Ni-Cd cells.

In the strictest sense, what is happening to the alkaline batteries is a 'recondition' rather than a 'recharge', giving a potential 90% power top-up to batteries low on energy. But as the potential is there to get 10 times or more use out of the battery's chemicals before throwing them in the bin, it is still both a money saver and more environmentally friendly.

Care still needs to be taken: individual batteries can have unseen faults causing them to leak or split under charge, which could damage the charger or its environment. Some chargers will let you know if a battery is dead, but it is a good idea to purchase a separate battery tester to check the condition of all batteries you intend to recharge. This is important for alkaline batteries, as the battery will live longer the more frequently you recharge it. And wise for all other batteries, as even the best quality can develop faults.

If you have any doubts about the quality of the batteries you are using, it would be wisest to avoid placing reconditioned alkaline batteries in your most precious equipment.

Myth Two: Battery 'memory' is a real problem with rechargeable batteries

The concept of battery memory is not wrong, but it doesn't apply to all rechargeables, and it's a problem that is slowly becoming something from the past.

But first, what is 'battery memory'? Anyone with a rechargeable device may have noticed that the battery life seems to get shorter as the battery gets older. You may have had your own theory about why that is, but when it comes to Ni-Cd rechargeables, the short answer is 'crystal formation'.

With Ni-Cd batteries, crystals begin to form inside as the battery ages. The larger the crystals get, the more difficult it is for the charge to move beyond them. Eventually whole areas of the battery become unreachable for both use and recharge. Failure to completely discharge the battery before recharging has been highlighted as one major cause of the problem.

Luckily, the problem isn't fatal: completely discharging the battery before beginning a recharge will usually sort the problem, and most of the recharging devices now sold do a full discharge for you. Manufacturers also continue to improve their batteries to get around the problem.

Ni-hm and Li-ion rechargeable batteries - the preferred power choice for devices such as cameras and mobile phones - work differently. These battery types do not suffer this problem and therefore do not need to be discharged before recharging.

In fact, Li-ion batteries last much longer when charged little and often. Allowing them to die before recharging can shorten their life. And in the case of cameras, allowing the battery to die could result in you losing your work.

Li-Ion batteries shouldn't be confused with the Lithium batteries available in standard sizes. Li-Ion batteries are the block kind that come in your mobile phone, whilst Lithium batteries are the long-life - but non-rechargeable - batteries sold for cameras and other high-drain devices.

Myth three: Expensive is better

Manufacturers of known brand names would certainly like you to believe that their 'quality' batteries are far superior to the generic or 'own brand' batteries on the market. And there's nothing to say that you don't get what you pay for.

However, a quick scoot around review sites shows that plenty of people are getting great service out of cheap batteries. 7dayshop's own rechargeable Ni-MH batteries have consistently received great reviews and very favourable comparisons with the big known brands. The internet is your friend when it comes to shopping around for the truth about low-cost versus supposed high quality batteries.

The biggest factor in getting the right choice for your device is knowing the differences between the various types and how they apply to your need. Alkaline and Lithium batteries have a good high voltage (1.5 and 1.75 respectively), whereas Ni-MH and Ni-Cd are lower (1.2), which can make them unsuitable for devices that need four or more batteries.

However, Alkaline batteries steadily lose their voltage with their energy, unlike Ni-MH, which maintain a fairly steady charge until they expire. Your choice could be important if your device has a power reading.

If you are after the greenest choice, you should be aware that Lithium batteries, whilst having an incredibly long life, cannot be recharged and are particularly toxic, as are the rechargeable Ni-Cds.

Using something like a camera, which is a heavy-draining item? Ni-Cds discharge swiftly, making them a problem for devices which use up lots of energy. In fact, both Ni-MH and Ni-Cd self-discharge over a matter of months: important to know for seldom-used devices.

There are many types of batteries, so before you pick up a generic pack from the supermarket, reassess your needs, your assumptions and your lifestyle. You could save yourself both time and money.