Many of us use cordless electric screwdrivers. Whether that's for taking the elbow work out of light DIY or for more heavy-duty work, an electric screwdriver can make the job go faster and easier. And many of us don't stop to think about battery technology.
But battery technology has changed sharply in recent years. For years, the challenge for cordless power tool manufacturers has been to create a tool that can combine more power output and a longer battery life without becoming so heavy that it's almost as hard to hold the power tool as it would be to just use the screwdriver.
The older generation of power screwdrivers used a battery type known as NiCad, for Nickel-Cadmium. While these were the state of the art when they came out, they have several major problems. It's hard to get a high voltage out of one, and the power output decreases as the battery nears the end of its charge. That's a problem we're al familiar with, trying to get a last couple of jobs done with the screwdriver turning at a quarter of its right speed. They also suffer from a phenomenon called 'memory effect,' which means that if a NiCad battery is recharged frequently after being only partially discharged, it gradually loses its capacity to hold charge. Additionally, NiCad batteries suffer from a gradual los of charge even when not in use, leading to the familiar problem that you charge the screwdriver, put it away and find it dead when you need it!
Lithium Ion (Li-ion) batteries don't suffer from these problems. Originally developed for miniaturised consumer electronics like mobile phones, Li-ion batteries have among the best energy densities of any kind of battery, they don't suffer from 'memory effect' and they do lose charge when they're left unused, but at a far slower rate than NiCad cells do. As a result, manufacturers across the world are introducing NiCad cells into more and more of their top flight power tools.
A screwdriver powered by a Li-ion battery will usually be lighter and by comparison will keep its charge far longer than an equivalent NiCad powered product. That means less time spent switching out batteries, if you have two, or waiting for it to charge if you only have one. And it means more reliability when you need it. With their long-lasting power and light weight, Li-ion batteries are set to replace NiCad cells throughout the cordless screwdriver market.
But battery technology has changed sharply in recent years. For years, the challenge for cordless power tool manufacturers has been to create a tool that can combine more power output and a longer battery life without becoming so heavy that it's almost as hard to hold the power tool as it would be to just use the screwdriver.
The older generation of power screwdrivers used a battery type known as NiCad, for Nickel-Cadmium. While these were the state of the art when they came out, they have several major problems. It's hard to get a high voltage out of one, and the power output decreases as the battery nears the end of its charge. That's a problem we're al familiar with, trying to get a last couple of jobs done with the screwdriver turning at a quarter of its right speed. They also suffer from a phenomenon called 'memory effect,' which means that if a NiCad battery is recharged frequently after being only partially discharged, it gradually loses its capacity to hold charge. Additionally, NiCad batteries suffer from a gradual los of charge even when not in use, leading to the familiar problem that you charge the screwdriver, put it away and find it dead when you need it!
Lithium Ion (Li-ion) batteries don't suffer from these problems. Originally developed for miniaturised consumer electronics like mobile phones, Li-ion batteries have among the best energy densities of any kind of battery, they don't suffer from 'memory effect' and they do lose charge when they're left unused, but at a far slower rate than NiCad cells do. As a result, manufacturers across the world are introducing NiCad cells into more and more of their top flight power tools.
A screwdriver powered by a Li-ion battery will usually be lighter and by comparison will keep its charge far longer than an equivalent NiCad powered product. That means less time spent switching out batteries, if you have two, or waiting for it to charge if you only have one. And it means more reliability when you need it. With their long-lasting power and light weight, Li-ion batteries are set to replace NiCad cells throughout the cordless screwdriver market.
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