Confused about volts, amps, and watts?

I believe that everyone is familiar with the words Volt (V), Ampere (A), and Watt (W), from the general socket (110V), but a converter may be used abroad (ie: 220V to 110V), to cables that we carry around (ie: 1A), and mobile phone battery markings (ie: iphone5 3.8V 5.45Whr). These three words actually exist in our daily lives. It might seem very familiar to us, but we might not know exactly what it means? Let us explain it to you!

Volt (V)

Volt is actually the unit of voltage.  And if the electricity is imagined as water, the voltage corresponds to the water pressure, in simple terms, it is the power of electricity.  Here, we will not only introduce to you where you’ll find volts in your daily life, but also list the precautions for volts.  Because if the voltage of power supply terminal and the voltage of the appliance do not match, it may cause the appliance to burn or be damaged!

Precaution 1: When traveling

US sockets are generally 110V, therefore electrical appliances plugs for the US are also designed to match the voltage of 110.  However, the socket voltages in China, Europe and other places are all 220V!  If you don't pay attention and plug it in directly, it is very likely to burn and damage the appliance for good!  Hereby we remind the readers to confirm the socket voltage of the destination before traveling.  If you are traveling to a destination different from the US, please remember to carry a converter!

Precaution 2:  Choosing a power bank

So far, the standard voltage of USB is 5V±0.25V.  However, the output voltage of some power banks on the market will be higher than 5.25V or lower than 4.75V, so it is easy to cause the phone to burn out or cause internal circuit damage.  Pengo is here to remind the readers to pay more attention when selecting power banks!  Also don't be greedy and cheap, you get what you paid for.  

Ampere (A)

Ampere is the unit of current. If the electricity is imagined as water, the current corresponds to the size of the water flow.

The main influence of current is the speed of charging - in fact, this is not entirely correct.  What really affects the charging speed is actually Watts, and Watt = Volt x Amps.  Therefore, the larger amperage is to increase the input wattage under the same voltage to increase the charging speed.

Most of today's mobile phones have current management chips.  If the current is large, it will automatically adjust to the current that the mobile phone can charge, but the charging speed is relatively limited by the mobile phone itself, and it will not increase indefinitely.

Be aware that when the current required by the electrical device (ie: 3A) and the current that the converter can provide (ie, 3A) are greater than the current that can be applied by the charging cable (ie, 1A), the charging line is likely to be damaged.  This is why Pengo is able to charge 3A, 5A devices with our charging cable!  If a charging cable can load up to 3A or 5A, it has a wider range of devices that this cable can charge.  In 2012, USB-IF (USB Developer Forum) proposed USB-PD, which is to meet the power supply requirements of various devices through a single charging cable.  Whether the charging cable can load the corresponding current is also an important aspect!  (For more information on USB-PD, URL)

Watt (W)

Watt is the unit of power, as we previously mention watt = volt x ampere.  Devices or electrical appliances that consume electricity are usually related to watts. 

Let’s talk a little bit about Watt-hour (Wh) and milliampere-hour (mAh)

Milliampere-hours (mAh) unit is not a scientifically formal usage, but a unit that is easy for consumers to understand! mAh = mA × hour. For example: If a cellphone has a battery capacity of 1500 mAh, and it is charged with 1,000 mA (1A), it will be fully charged in about 1.5 hours; if the capacity of a battery is 10,000 mAh, with a continuous current of 1A, it can last up to 10 hours.

As for Watt-hour (Wh), most people are unfamiliar with it, but if you look at the carry-on baggage restrictions for batteries, you cannot bring more than 100Wh of battery!  Most of the battery or power banks will only list the amount of volts (V) and the amount of milliamperes-hours (mAh) but does not tell you the watt-hour (Wh).  Let us provide you the formula to calculate Wh:

Watt-hour (Wh) = (milliampere-hour (mAh) / 1000) x volt (V)

Based on the below image of power bank, (13000mAh/1000) x 5V = 65Wh. It’s below 100Wh, therefore you can bring it on your carry-on bag.

Hopefully after reading this article, you have a preliminary concept of these terms.  Now when you want to buy power banks or charging cables, you can pay attention to the specification markings and know what they mean!  Finally, if you want to know more technical information, LIKE our Pengo FB page.  We will have occasional giveaways or promotions for you and your friends!  Follow us!