Belkin 5000mAh Lightning Portable Power Bank - Black

Yes, you can but only if: 

• The laptop has a USB-C charging port. 
• The power bank has USB-C power delivery (PD).
• The output of the power bank is high enough (typically at least 30W-65W, depending on your laptop.

Using a fast charger and USB-C input can reduce the charge time. 

• Small capacity power bank (5000mAh) is between 2-3 hours.
• Medium capacity power bank (10000mAh) is between 4-6 hours.
• Large capacity power bank (20000mAh) is between 8-10 hours.

The number of times a power bank can charge your mobile phone depends on the power bank's capacity and the mobile phone's battery capacity. Below is a rough guide: 

• 5000mAh power bank: 1 full charge.
• 10000mAh power bank: 2-3 charges.
• 20000mAh power bank: 4-6 charges.

Power bank with LED indicator light.

Depending on the power bank, try the following method, generally speaking the more LED’s on mean the higher the battery charge:

• Press the power button. 
• 4 lit LEDs = 100% charge. 
• 3 lit LEDs = 75% charge.
• 2 lit LEDs = 50% charge.
• 1 lit LEDs = 25% charge.
• Blinking LEDs = power bank requires charging.
• No LEDs = power bank has no charge and requires charging.

Power bank with LCD display.

• Press the power button, plug in a device, or charger.
• The LCD screen will usually display the percentage of charge the power bank has left.