Cordless Power Understanding Volts, Amps and Amp hours

Cordless Power Understanding Volts, Amps and Amp hours

As cordless technology strides along…the power of your battery is critical for you being able to spend a productive day onsite.

Types of batteries in cordless power tools

There are three different types of batteries which can be used by cordless drills, or any other kind of cordless tool: nickel-cadmium (NiCd), nickel-metal hydride (NiMH), and lithium-ion (Li-ion).

Let’s take a good look at each of them.

Battery Technology is Evolving Quickly

Nickel-Cadmium Batteries

NiCD is one of the oldest types of batteries, however, is still used widely by many trade professionals. Its strong durability is ideal if you plan to use your batteries for regular, intensive work every day. It’s also important to mention that their one of the cheaper battery options, with a pretty impressive life span.

In fact, NiCD batteries can be recharged more than 1,000 times before showing any signs of deterioration. However, as they are the oldest type on the market, they weigh in heavier than other options and also carry a lower capacity level. They may not be as advanced as the other 2 options, but this battery type has retained its market share and rightly so.

Nickel-Metal Hydride Batteries

NiMH batteries are more advanced than the above, but this comes at a slightly more expensive price. This type of battery is favoured for its’ capacity levels, which can be 2 or 3 times higher than those of NiCD. Similarly to NiCD, these batteries are sensitive to improper storage and charging conditions which can have an adverse effect on its efficiency.

NiMH batteries can offer up to 40% higher energy density, meaning they are much smaller and lighter whilst still providing the same amount of power. Although, they aren’t as durable of NiCD batteries and are best used for lighter work as high temperatures may cut the lifespan of the battery from 300-500 charge/discharge cycles to only 200-300.

Lithium-Ion Batteries

The newest and most probably the best battery for cordless tools on the market right now. Li-Ion batteries are more expensive than the other types mentioned and are extremely sensitive to heat – which has the potential to deteriorate their internal components. Boasting being the lightest battery out of the 3 options, they also offer an energy density twice that of NiCd batteries.

Li-Ion batteries have a higher capacity and are able to charge quickly, making them a popular choice amongst many tradesmen. Being unaffected by the memory effect, this type of battery doesn’t require much maintenance and can be used in any way you like. With a superior charge/recharge cycle it’s no surprise that so many trade professionals are giving it a go.

Explanation of Watts, Volts and Amperes

Electricity is described by three terms: Amps (amperage), Volts (voltage), and Watts (wattage). Most commonly used in electronical products, manufactures show one or more of these values to provide information on the energy that will be consumed or how much current they will draw.

  • Voltage is measured in volts (V)
  • Current is measured in amps (A)
  • Power is measured in watts (W)

Let’s dig deeper into what they actually mean…

A watt is known as the base unit of power in all electrical systems. Its primary task is to measure how much energy is released per second in a system.

The formula for calculating wattage is:

W (joules per second) = V (joules per coulomb) x A (coulombs per second) where W is watts, V is volts, and A is amperes of current.

This figure comes in handy if you have to get rid of the heat generated by the device consuming the watts or if you want to work out how much you will have to pay your utility company to use your new tool.

Volts is the base unit used to measure voltage, where one volt is defined as ‘the difference in electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points.’

Then we are left with amperes, often shortened to "amp" or A. This is the base unit of electric current and is used to measures the rate of flow electricity. Electricity consists of a flow of electrons through a conductor, for example a wire or cable.

When it comes to looking at battery life, one of the most useful indicators we can use is the battery’s amp hour rating. The amp hour is a rating used to tell customers how much amperage a battery can provide for one hour.

For smaller batteries that you will find around the home, the amp hour rating is usually given in milli-amp hours, as known as mAh. However, for larger batteries used in big pieces of equipment the rating is abbreviated as Ah.

The future of cordless batteries

Already we are seeing battery systems that are entering the market with 40v / 60v capacity and a recent innovation from DeWALT saw the release of the 15AH FLEXVOLT battery which will be a first in the marketplace.

The new DeWalt 15Ah battery uses the brand’s FlexVolt technology which will automatically switch between voltages to match the tool and application it’s being used with. This means it can operate at 60V Max for FlexVolt power tools and 20V Max for DeWalt’s XR cordless tools.

This is the highest capacity lithium-ion battery offered by DeWalt and looks designed to increase the maximum runtime in heavy. This battery certainly looks designed to provide maximum runtime in heavy-duty scenarios.

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