Guide written by:
Sebastian, self-taught DIY-er, Exeter
247 guides
Broadly speaking, there are three main types of power tool battery. That said, most cordless power tools on the market will use one of two different types of battery technology. To narrow it down even further, it's fair to say that most mid-range power tools (such as cordless drills) will be equipped with a lithium-ion battery.
Nickel cadmium batteries represent the oldest generation of batteries on the market. These batteries are heavy and usually take a fairly long time to charge up. They also have a memory effect which means that if the battery is not sufficiently discharged before you attempt to recharge, the battery will fix a lower point of charge as its maximum level the next time it's plugged in. Over time, your battery will not be able to hold a full charge and won't be able to deliver as much power. Nickel cadmium batteries are used to charge low-end power tools. However, these batteries have largely been replaced by lithium-ion batteries. It is recommended to allow Ni-cd batteries to discharge fully before recharging. You should also ensure that you don't leave them on the charger once they are fully charged. These batteries can withstand a high number of charge cycles.
Lithium-ion batteries are, without a doubt, your best option! These batteries are lightweight, quick charging (an hour and a half on average) and do not have a memory effect. A Li-Ion battery will really give it all it's got until it eventually runs out of juice; in fact, this can be quite misleading if the battery doesn't have a battery indicator! Generally speaking, lithium batteries are found on most power tools as they offer the greatest user comfort.
Nickel metal hydride batteries are fairly heavy (heavier than nickel cadmium) but don't have much of a memory effect. This type of battery generally withstands a lower number of charge cycles than nickel cadmium (about three times less). Ni-Mh batteries are not very common these days.
The power of a battery is based on its strength and how long it lasts between charges; this translates into battery voltage and capacity.
In order to choose the right battery for your cordless tool, you'll have to find the right balance between voltage and capacity. While you will need to match the voltage of the battery to the power tool to avoiding damaging your tool, you can go for a higher Ah rating for greater autonomy. It's worth bearing in mind that if you are comparing two batteries with the same voltage, the one with the higher Ah rating will be more powerful. It is also essential to use the correct charger!
Guide written by:
Sebastian, self-taught DIY-er, Exeter, 247 guides
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