The 18650-battery must be flat and the length is 65MM. The pointed battery cannot be used. If you are using old batteries, different capacities, the assembled battery is guaranteed to be at least 3.5V per voltage. If the voltage is too low, it will not be charged.
It is possible to connect only one lithium battery or multiple lithium batteries in parallel. The capacity of connected battery is no more than 200,000 mA, As long as the battery with a voltage of 3.0-4.2V can be used.
The protection circuit of the boosted lithium battery has been integrated, prevent over-discharge, over-charge, overload short circuit protection, over current protection, and over temperature protection.
Charing-cable: support three USB data cable charging, including for iPhone and Android.
Size: 6.5 * 2.5 * 0.1cm; Dual output current: 5V 2.4A; Input voltage B+ to B-: 3.0 - 4.2V.