Undervolting reduces battery life?

[Abyssalx]

I had seen some videos about undervolting the A8 Apu in my DV6-6135dx, (not exactly this model) and it increased battery life by an hour or more. Without undervolting, I get about 5 hours of battery life with light web browsing. But when I do a moderate undervolt, checked with intelburntest to be stable, Windows says I only have about 3.5 hours at 99%. Is windows battery life accurate? or should I use a different application or something?

 

[jaguarskx]

The estimated battery life can change from moment to moment depending the processes currently running on the laptop. If the CPU clock up for whatever reason, the estimated life will decrease. Once the CPU go back to idle, the battery life estimate should increase.