Power Bank Buyer Guide
What you need to know about our power banks
The first step in choosing the right power banks is to fix your budget and expectations of the device. In general chargers can be divided into three categories:
- Emergency Class – These are sold at the lowest price point, generally under $10.00 and under 3000 mAh. These chargers work great for an emergency cell phone charge. Since all phone batteries vary in capacity, you can expect around a 50% charge to a drained battery. They will disappoint when used to charge a large capacity battery like an iPad or tablet.
- Business Class – These power banks range up to 10,000 mAh. Phone chargers in this class are able to charge phones or tablets. Many have two ports that can charge two devices at once. They will charge most phones 100% and have power left over or more charging.
- Tablet Class – These are tablet charger batteries, able to charge a tablet or notebook computer and a cell phone. Most have a dual input to charge two devices at once. Look for batteries over 10,000 if you need it to charge a tablet. These are larger than the two other classes and feel very substantial.
Power capacity is measured in mAh, or milliamps per hour. When a charger is charging a phone, some of the energy is lost in the transfer. It takes energy to transfer energy. The real capacity of a battery is about 62% of the mAh rating. Charge speed is determined by output current, not mAh capacity. The higher mAh batteries provide between 500 to 800 mAh – up to 1 amp. Most USB ports on a computer provide less than 500 mAh. A high capacity battery will provide more charge over time.
Power banks do not contain software, so there is no issue of platform compatibility. It takes around 3 hours to fully charge an Economy Class battery and up to 5 hours to fully charge a 10,000 battery. It takes a lot longer to charge from a computer USB port because a computer has a smaller charging output. Plug into a wall is faster.
Power banks can be charged 300-500 times. Storing the power bank without any charge can reduce the life of the battery. Store with at least 50% charge to prolong the battery’s life. Fully charge the battery before its first use.
The main component of a power banks is a lithium/ion polymer battery. Although these types of batteries are commonly used, the safety of a battery needs to be considered. Our power banks have passed the UL 1642 test which is a series of electrical, mechanical, environmental and fire exposure tests. UL is the most widely accepted certification that denotes a battery’s compliance with recognized safety requirements. These cell phone and tablet chargers have a protective circuitry “safety valve” which prevents internal and external short circuit.
The car USB chargers you see on this page output about as fast as plugging into a computer. They’re great for an emergency charge but can take up to six hours to fully charge.