What might be the voltage sag and duration during start-up with a 12Vdc water pump like this powered from a ~85Ah 12V deep-cycle flood-cell lead-acid battery? I have a travel trailer (RV) with a system like this where the **broken link removed**turns off momentarily whenever the water pump starts.
I connected the stereo to a lab power supply, and it will shut off as the dc input voltage is reduced below ~10V. It re-boots as the voltage comes back up beyond 10.2V. It draws somewhere between 0.5A and 0.75A depending on program loudness.
I'm thinking that the pump start-up transient momentarily pulls the battery/bus voltage below 10V. I am thinking of putting a Schottky diode into a large electrolytic storage capacitor (say 10,000 uF @15V) across the input of the stereo. The diode would make it so the capacitor discharges only into the stereo (not the pump), holding up the input voltage long enough for the pump to come up to speed and stop drawing its start-up current.
Questions: how long does it take the pump to come up to speed so that its own back emf reduces its current draw? Based on that duration, I can figure how big a capacitor I need...
I connected the stereo to a lab power supply, and it will shut off as the dc input voltage is reduced below ~10V. It re-boots as the voltage comes back up beyond 10.2V. It draws somewhere between 0.5A and 0.75A depending on program loudness.
I'm thinking that the pump start-up transient momentarily pulls the battery/bus voltage below 10V. I am thinking of putting a Schottky diode into a large electrolytic storage capacitor (say 10,000 uF @15V) across the input of the stereo. The diode would make it so the capacitor discharges only into the stereo (not the pump), holding up the input voltage long enough for the pump to come up to speed and stop drawing its start-up current.
Questions: how long does it take the pump to come up to speed so that its own back emf reduces its current draw? Based on that duration, I can figure how big a capacitor I need...