Lipo battery mAh vs Wh

Hi,
I am a bit confused about the the mAh and Wh specifications for a 3.7v lipo.

For example I have a routejade battery YE402025C 3.7V 160mAh, 0.592Wh.

Now I have a varta batter VKB: 56416 201 026 which is 3.7v 150mAh, 0.6Wh.

So is there no relation between mAh and Wh for a battery ?

Till now I thought if we know mAh we can calculate Wh since the average voltage is 3.7v but now I am a bit confused how can these two things (mAh and Wh) is not relative ?
8-O:-|

My assumption till now was that ( 3.7 * mAh (in A ) * 3600 ) Joules is the total capacity of battery in terms of energy. Is this not correct ? Coz the Wh is not matching properly with this value.

It is just rounding of the results of V * A * 3600 - or at least that can be part of the reason for the difference.
Additionally, the Watt hours is the volts * amps under the area of the discharge curve, which is not maintaining a constant 3.7VDC as the battery discharges - and the voltage will change depending on the rate of discharge.

To get a completely accurate result, one would have to apply a constant current load and integrate the voltage curve to obtain the result. But, this level of accuracy is seldom necessary, and the simple
V*I*3600 is often sufficient.

Additional note - one cannot FULLY discharge a LiPo battery without incurring some amount of permanent damage/diminished capacity. Discharge below 1V / cell will almost surely reduce capacity, and generally it is avoided to discharge below approximately 1.7V to 2V per cell to maintain longer life.