CALCULATE BATTERY RUN TIME | Electronics › Electronics › CALCULATE BATTERY RUN TIME This topic has 1 reply, 2 voices, and was last updated 10 years, 6 months ago by AJISH ALFRED. Viewing 2 posts - 1 through 2 (of 2 total) Author Posts October 20, 2013 at 4:17 pm #2695 ManuParticipant A 9V 300mAh battery is connected in parallel to two 7805 ICs 1. First 7805 output driving current of 425mA 2. Second 7805 output driving current of 100mA How long the battery runs? October 21, 2013 at 4:54 am #10536 AJISH ALFREDParticipant Hi Ganesh, It is a very simple calculation. 300mAh means the battery can supply 300mA for 60 minutes. Your total current consumption is 425mA + 100mA = 525mA If battery can runs for 60 minutes with 300mA, then it will run for ( 300 / 525 ) * 60 = 32 minutes. Author Posts Viewing 2 posts - 1 through 2 (of 2 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In