2 cells in series = 1.5v, 2000 mAh
2 cells in parallel = 3v, 1000 mAh
2 * 2 cell series pack in series = 1.5v. 4000mAh
2 * 2 cell series pack in parallel = 3v. 2000mAh
Should be
1 cell = 1.5v, 1000 mAh
2 cells in parallel = 1.5v, 2000 mAh
2 cells in series = 3v, 1000 mAh
2 * 2 cell series pack in series = 6v. 1000mAh (basically 4 cells in series)
2 * 2 cell series pack in parallel = 3v. 2000mAh
3 * 2 cell series pack in series = 9v. 1000mAh (6 cells in series)
3 * 2 cell series pack in parallel = 3v. 3000mAh