LiPo Label Voltage and More!
The voltage on the label is the 'resting voltage' just after it is activated (just finished being manufactured) and at no load. The standard 2S pack resting voltage is 7.4v (and you charge them to 8.4v). The HV ('High Voltage') packs have their resting voltage at 7.6v (and are fully charged at 8.7v).
This 'resting voltage' number is used on the label to satisfy ROAR and shipping regulations. You also see another number (WH) which is needed for the same reason and is based on the 'resting voltage'. WH is 'Watt-Hour' and is the power the battery may store at the resting voltage. For international shipping, the regulators want this number displayed.
We generally use mAH (mili-amp hour) as an indicator of how much power a LiPO pack will store for use, but is not quite accurate.
Simply put, mAH is a measure of the potential charge delivered by the battery and WH (Watt Hour) is a measure of potential energy delivered.
There is a relationship between the two. Specifically, capacity (mAH) is a component of an equation that helps to determine power stored (WH).
However, the problem with quantifying the storage capacity of a battery is that the amount of energy stored is dependent on the battery’s discharge rate. The greater the discharge rate, the lower the delivered capacity; this is true for all battery types.