Measure Power Consumption of Battery Charger?
How to measure power consumption of battery (Li-On 18650) charger module (TP4056 and USB Boost) and the total power consumption, ... 


Method 1. Take a USB lead and access the power feed wires.
Break the V+ wire and insert an ammeter OR a low value resistor
(R ~= 0.1/Iexpected A) (eg 200 mA R ~~= 0.1/0.2 = 0.5 Ohms).   

Measure voltage from load side of resistor or ammeter to V-. Measure current or drop across resistor to calculate power = V x I. 

Repeat with and without downstream modules and load. 

Adding a capacitor from the load side of the resistor to ground will smooth out short term variations. (10 uF - 100 uF typically) 

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Method 2. Use a USB voltmeter/ammeter module in the USB lead. Cheap and widely available. 

Many examples on ebay here

eg Remarkable value $US4.76 free shipping (from China) here


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