> When you connect 2 9000 mAh cells in series, the resulting battery has 2x the voltage but the same mAh capacity. In parallel, the battery has the same voltage but 2x the mAh.
The relevant units are:
* Capacity (Q, in mAh, Ah, kWh, etc)
* Power (P, in Watts)
* Voltage (U, in Volts)
* Current (I, in Amperes)
* Duration (t, in mostly measured in hours)
And the relevant formulas are:
* P = U x I or Power equals Voltage(difference) times Current
* Q = P x t or Capacity equals Power times duration
From this we can establish that connecting batteries in series or in parallel will not change their Capacity. When having 13 batteries of 29000mAh, or 29Ah, you have 13 x 29 = 377Ah or 377000mAh. Connecting batteries in series or parallel does make a difference in voltage and current: a string in series will increase the voltage while keeping the current the same (theoretically, in practice you get less than the current of the weakest cell); a parallel setup will increase the maximum current while keeping the voltage the same (again, in theory).