The battery rated at 14.8 volts but starts out 16.8 volts with a meter . The volts at unit shows 16.1 and dropped to 14.1 , did not recheck at battery but suspect it was about 14.8 volts . This battery is so small , amazing it is running Garmin 1242 xsv and Black box for livescope for 9.5 hours . Next time I might run 2 trips to see how long it will run before quitting . They say it will stay over 12 volts till it quits . Shuts off when it gets down to 12 volts .