The battery can be recharged from any PC or laptop USB port or any USB AC adapter.A USB AC adapter with 0.8A or more output current will maximize charging speed. Lower currents will prolong the charge time.
The efficiency of this battery is around 68%-80%. The internal circuit board is 90%efficient, this accounts for power lost through circuit heat and voltage conversion(this is standard for external power bank chargers), which is up to 5% above the industry average. Energy is also lost within the charging cable and the device being charged (approximately 15-20%).
You will want to first fully charge the Ultra PLUS prior to using it to charge your device. Use the provided micro USB cable to charge the Ultra PLUS by plugging it into a USB power adapter and the other end into the micro USB port located on the Ultra PLUS.
For a fully charged Ultra PLUS it can take up to 6 hours depending on the output power of the customer provided wall charger. Depending on the wall charger output power the fourth LED Power Meter light will stay blinking. To check the current charge level unplug the Ultra PLUS and tap the on/off button. The LED Power Meter lights will then illuminate and 1 LED light is 1% to 25% charged, 2 LED lights is 26% to 50% charged, 3 LED lights is 51% to 75% charged and 4 LED lights is 76% to 100% full charged.
For Android smartphones and Android tablets we recommend using our provided micro USB 2.0 charging cable for the best results. If you are using Apple products please use your own charging cable. *When charging your Ultra PLUS, approximately 20% to 35% of the external battery’s capacity will be consumed due to power lost from heat produced by circuit, the conversion of the voltage and the cable charging/your device. Industry average is currently 35% for the efficiency rate.