A depleted battery usually acts as a second load on the circuit but it can also be a second power source if the three are in parallel with one another (as opposed to being isolated and switched). In the case of an inadequate power supply, a high current draw will pull from both sources at once. This is not necessarily common or desirable but you do see it in things like a vehicle alternator+battery, for instance.
A depleted battery usually acts as a second load on the circuit but it can also be a second power source if the three are in parallel with one another (as opposed to being isolated and switched). In the case of an inadequate power supply, a high current draw will pull from both sources at once. This is not necessarily common or desirable but you do see it in things like a vehicle alternator+battery, for instance.