Lumsing “Harmonica” 10400mAh Power Bank Test


I recently got sent one of Lumsing’s latest USB power banks. As it coincided with the release of the Model A+ I thought it would be a good opportunity to see just how long the battery could run the latest Pi hardware. With the reduced power consumption of the A+ I was potentially looking at a long wait to find out …

First let’s take a look at the power bank. The Lumsing LUM-008-001 is referred to a “harmonica” style power bank due to its rectangular shape. You have to resist the urge to hold it at either end and blow into the USB ports!

Battery Specifications :

Lumsing Harmonica BatteryLumsing Harmonica Power Bank :

  • Capacity: 10400mAh
  • High quality 18650 Samsung cells
  • Input: Micro USB 5V 1.5A
  • Output: USB 5V (1A & 2.1A)
  • Size: 5.43x 2.32 x 0.82 inches
  • Weight: 238g
  • Shape: Harmonica style design
  • Product Warranty: One Full Year

The box contains :

The Test

As with my other battery endurance tests I added a BerryClip to the GPIO header and ran a basic Python script. The script lights up LEDs on the BerryClip add-on board. This draws an extra 5mA via the GPIO header and ensures the Pi is performing some light work. The LEDs also let you check that the Pi is still running.

Lumsing Harmonica Battery Test

In order to record the run time I configured cron to write the system uptime to a log file every five minutes. When the device eventually ran out of power I could restart it and read the log file. Normally I use SSH from my PC to monitor the run time but that isn’t possible with the A+ due to its lack of Ethernet port.


The Raspberry Pi Model A+ ran for : 66 hours 28 minutes (3988 minutes).

This was a great result and consistent with the predicted range of 57-72 hours I calculated using the Pi Power Estimator Android App. Obviously the endurance is going to be affected by adding more demanding hardware but overall I was impressed with the Lumsing’s performance.

A more detailed review of the Lumsing PBJ-6200 can be found over on


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