thanks for your reply. what am saying is this: i used 0.33uF, 50V (as input capacitor), 0.1uF, 50V (as output capacitor) and LM7820 Regulator ,with a 24V, 45AH battery to power a load of 19V, 2.1A. But the problems are: the regulator is heating very much (good heatsink was used), the load was tripping off after some times, the battery charger used was rated 24V, 170AH- 350AH and it's not automatic, measured input voltage on the battery (when charging) was 32.2V. I observed that the increases of the power loss (32v - 19v)*2.1A, i.e 27.3W, result in subsequent decrease in output voltage (from 19V to 17.85V). Are the values of the capacitors ok! Pls, i need solutions. Thanks!