Originally posted by Turion
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it looks like you only use ~5 watt-hours for the test. I suggest using a DC wattmeter which displays watt-hours between the charger and battery as well as the killawatt meter on the AC outlet. This will give you an efficiency of your charger as well as energies required to recharge the battery.
Lithium cells are noted for being virtually 100% "charge" efficient, meaning Ampere-hours in equal Ampere-hours out. The battery's charge-discharge energy efficiency then is equal to (V-I'*R)/(V+I"*R)*100%, where V= open circuit battery voltage, I'= discharge current, and I"= charge current. This assumes constant current discharge (I') and constant current charge (I").
Nice tests. Thanks for sharing.
bi
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