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geekmaster · 09-03-2012, 12:14 PM

What hawhill suggested can find a "totally dead" battery.

But in many cases, voltage measurement alone is not enough. A battery needs to be tested under load over a time period to determine its remaining useful capacity. Lithium batteries are considered "dead" when their remaining mAh capacity is too small to be useful. The portion of lithium in the battery that no longer holds a charge is called its "rock content". A battery that is almost entirely "rock" still can show full voltage, but it will disharge quickly under load. Lithium battery chargers usually refuse to even charge a battery that is beyond its useful life, to prevent even a minimal risk of fire

For more info, here is a good place to start:
http://batteryuniversity.com/learn/a..._ion_batteries

According to this, most "portable device" batteries are only good for 300 to 500 charge/discharge cycles:
http://batteryuniversity.com/learn/a...e_battery_life

09-03-2012, 12:14 PM	#3
geekmaster Carpe diem, c'est la vie. Posts: 6,433 Karma: 10773668 Join Date: Nov 2011 Location: Multiverse 6627A Device: K1 to PW3	What hawhill suggested can find a "totally dead" battery. But in many cases, voltage measurement alone is not enough. A battery needs to be tested under load over a time period to determine its remaining useful capacity. Lithium batteries are considered "dead" when their remaining mAh capacity is too small to be useful. The portion of lithium in the battery that no longer holds a charge is called its "rock content". A battery that is almost entirely "rock" still can show full voltage, but it will disharge quickly under load. Lithium battery chargers usually refuse to even charge a battery that is beyond its useful life, to prevent even a minimal risk of fire For more info, here is a good place to start: http://batteryuniversity.com/learn/a..._ion_batteries According to this, most "portable device" batteries are only good for 300 to 500 charge/discharge cycles: http://batteryuniversity.com/learn/a...e_battery_life Last edited by geekmaster; 09-03-2012 at 12:26 PM.