Skip to main content

Top of
Page
We Are Open Offering Curbside Pickup Mobile

Batteries and Chargers
Understanding Volts,
Amps & Watts

Phone on a wireless charger

Have you ever used a new cell phone battery charger and discovered it takes twice as long as usual to charge? While different batteries and chargers might power the same device, they don't always deliver the same strength. In this guide, we'll explore volts, amps and watts, and learn how much power you need for popular devices and chargers.

What is Battery Voltage?

When you buy batteries, you might notice a variety of battery options with different voltages. But what is battery voltage? How does it affect the performance of your battery and your device?

Voltage is the unit of current in your battery and is measured in volts. If you think of your battery as a water pipe, the voltage would be the water pressure in the pipe. This pressure makes the current flow through the battery, delivering power to your device. If you were to increase the pressure in your pipe, more water would flow through. The same is true for your battery – higher voltage means higher pressure, so more current flows through the battery.

What are Amps?

The strength of a current – how fast it flows – is measured in amperes or amps. Thinking back to the battery as a water pipe, the current would be the flow rate of the water. Higher amps mean that electricity is flowing more quickly and delivering more power to your device.

What Does Wattage Mean?

Wattage is the total amount of energy being created and is measured in watts or energy per unit of time. The simple formula for wattage is:

Watts = volts x amps

If you increase either the voltage or the amps, you'll create more watts and generate more power.

How Volts, Amps and Watts Charge Batteries

So how do all these things work together to power your device? Wattage is the overall measurement of power that flows through your charger, so a higher cell phone charger wattage means that your device will charge faster. If you're shopping for a new charger and the wattage isn't listed, you can also calculate it with the formula: watts = volts x amps. For the quickest charge, pick the device that offers the highest wattage.

One of the most common questions about phone charger wattage is "how many amps does an iPhone need to charge?". Some devices, like the iPhone, have a built-in mechanism that only lets them draw one amp of current, even if your charger can offer more. However, you can still buy a charger with higher amps – it won't hurt your cell phone battery.

It's not just cell phones and small devices that rely on chargers – you can also use your knowledge of volts, amps and watts when shopping for car and truck batteries and other common appliances. If you're not sure whether your device has a limitation on the type of charger that can be used, check with your manufacturer or drop by your local Batteries Plus Bulbs location and one of our experts will be happy to help you find the perfect cell phone charger, car and truck charger and more.