Thinkpads Forum

I have a W520 and a T530. The batteries are from two different manufacturers... LGC and Sanyo. The W520 is a year old and still reads 100% capacity. The Sanyo is 1 month old and is down to 99.9%. This caused me to worry that the W520 was not reading the battery correctly...

So I swapped the W520 battery (which ready 103.9 Wh battery in the W520) in to the T530 and the capacity read less than what it did in the W520 (it reads as 93.2 Wh)... I am curious why two different laptops would read the same batter differently; my understanding is that should not change.

Also, how fast should the capacity decline... or in simple terms should I suspect and issue with the T530 Sanyo battery as it is already showing an issue vs. the W520 battery which is still showing 100% after a year?

My capacity now is down to 98.7%... anyone know what would indicate a defective battery?

Whatever may indicate a defective battery - you are not experiencing. A 1-2% loss of capacity after a few uses is normal. It may even be just a calibration glitch.