Not quite. In our latest test, we ran the same ESP32-based temperature sensor on two battery configurations:
3S1P (3 AAA cells)
3S2P (6 AAA cells)
…and got more than 2.5x the battery life.
The hidden factor isn’t capacity. It’s internal resistance.
Read the full breakdown using the Otii Battery Life Estimator 
https://www.qoitech.com/blog/does-twice-the-batteries-mean-twice-the-runtime/