Have you ever Googled “what is charging”? The funny thing is, it seems like such an obvious question until you see the answers.
What even????
Not that kind of charging. Today, when we talk about charging we’re almost always talking about our devices so we can stay connected. But what is charging really?
THE BASICS OF CHARGING YOUR DEVICES
Your phone battery is essentially a tiny compartment of chemical energy. Every time you plug your phone in to charge, you’re basically the catalyst to reset a chemical reaction which inside the battery. For those of you who passed chemistry, charging is the transfer of electrons from the negative end of a battery to the positive end (and for those who liked chemistry, electrons passing from the negative anode to the cathode).
Most smartphone or smart device technology now includes a Lithium-ion battery. Charging works the same way with these batteries, despite slightly modified components within the battery. But we won’t get into the details.
HOW AMPERAGE, VOLTAGE, AND WATTAGE WORK TOGETHER WHEN CHARGING
Amperage is the strength of an electric current often used to measure charging. In fact, amperage is the difference between a lightning quick full charge and an all-day trickle. Amperage is the defining factor of how quickly your device will charge.
Voltage, on the other hand, is the unit of current. Interestingly enough, it is actually a function of pressure – and in this case referencing the chemical reaction that creates charge. In simpler terms (kind of), voltage is equal to the pressure that pushes electrons through their conductive loop (or from the anode to the cathode).
Wattage, on the other hand, is the rate at which energy is either created or spent. Watts represent energy per unit of time. As an example we’ve all run into, when buying light bulbs, a 100W light bulb means that the light bulb will last for 100 Watt hours.
These three concepts tie together in this formula defining charge:
Watts = Amps x Volts
So, for example, a phone charger delivering 5 Watts = 5 Volts x 1000 mA.
According to this in-depth article from Wired:
“For example, consider these charging scenarios for the Retina iPad mini. You could use a Lightning connector plugged into a computer (via USB), an iPhone charger connected to a wall socket, or an iPad charger connected to a wall socket. A PC USB charger delivers 2.5 Watts of power (5 volts at 500 mA). An iPhone charger delivers 5 Watts (5 volts at 1000 mA). A Retina iPad mini charger delivers 10 watts (5.1 volts at 2100 mA).
“While all of these will charge your iPad, using the USB connected to a PC will charge your Retina mini four times slower than if you used the iPad charger it came with. Conversely, if you use a tablet charger for your smartphone, it’d charge up faster than normal (Note: Some devices like the iPhone will only draw up to 1A of current no matter the charger). If you play mix-and-match with these types of chargers like this, don’t worry – you’re not going to blow up your phone or anything crazy like that. And the myth that charging your device at a faster rate will reduce the life of your device’s battery is false. For some older devices, the higher specced charger just won’t work at all, while newer devices will just charge faster.
“Ultimately, it’s really the amperage that determines how fast a charger will supply power to your device. If you want quicker charging, look for a wall or car charger that delivers 2100 mA of current at 5 volts (or whatever voltage the device you’re trying to charge is specced at).”
WHY IS IT IMPORTANT TO UNDERSTAND RECOMMENDED WATTAGE, AMPERAGE, AND VOLTAGE WHEN CHARGING?
The age-old question: how fast of a charger is too fast? As you’ve noticed, the larger the brick, the quicker the charge.
Larger bricks accommodate for larger chemical reactions and pressurization – charging phone batteries even quicker. Naturally, an iPad requires more reaction to charge. Accordingly, an iPad charger will charge your iPhone quicker whereas an iPhone charger could equate to a trickle charge for your iPad.
The best way to know that you are protecting your devices and charging properly is to check their tags or manuals. If you don’t have either handy, a quick Google search will keep you on the right track.
But to reiterate the point from Wired’s article, it’s a myth that you will reduce phone battery life or blow up your phone by charging at a higher wattage than its standard charger offers. Newer, higher wattage chargers simply speed up the charging process.
The wattage in lightbulbs has to do with hours not brightness?
No- the wattage of a lightbulb has to do with how much power it pulls (or energy per hour). How bright the light is will depend on the type of light bulb. LED and FCL bulbs may list the equivalent amount of watts needed for an incandescent bulb to get the same brightness. A 100 Watt incandescent bulb gives off approximately 1600 lumens of light and a whole lot of heat. Most of the electrical energy becomes thermal rather than light energy. An LED bulb that uses 15W will give off the same amount of light but a lot less thermal energy.
How long the bulb will last depends on the type of bulb and its use history.
There is no such unit of time as a Whr. A killowatt- hour is a unit of energy. The amount of electrical energy your bulb uses depends on the power it requires and how long you leave it on.
I’m a bit confused. I have a USB battery charger. The USB multimeter says that I am pulling 9volts and .04amps between the usb adapter that is plugged into the wall outlet and the USB cable. However, the battery charger says that I am pushing a combined total of 2.6volts and 3amps into the batteries.
Could that be right? How does the voltage and amperage change like that?
Thanks.
Hey Michael,
Sorry for the late response. I’ve chatted with a couple electrical engineers here and here’s what I found out.
There are standards for power in USB-A and USB-C connectors. The newer standards have multiple voltage and current levels to provide more power without causing safety issues. The device that is plugged in notifies the charger what standard it uses and how much power it can handle and how much it wants. The charger responds back with the appropriate power it has available to send to the device.
It’s kind of like this:
Device – “Hello, I am the device and I can handle power level C.”
Charger – “Hello, I am the charger and I can deliver power level B.”
Device – “Okay I will take power level B.”
Charger – “Here is power level B.”
So, yes, voltage and amperage can change like that. Depending on the device you’re charging and its negotiation with the charger. Let me know if you have any other questions, or if we left anything unanswered for you. I’m happy to do a bit more digging.
Thanks for your question!