01 Nov. 2006
SETI League
PriUPS Project

Trial By Wind

The Northeast had a major windstorm this weekend.  Power failures everywhere.  Although the power company almost let us down, we finally lost our utility power at 13:02 Sunday afternoon.  Even better, this failure lasted long enough to give the PriUPS system a proper workout.  Finally!

Hour 1 Hour 2 Hour 3
Power Failure, 29 October 2006 at 13:02   Click on each hour for larger graphs.

About 20 minutes into the first hour, AC power went off (blue line).  I found out later that the wind had blown down some trees, which presumably broke a power line, although the power company failed to provide the written report I always request.  At that point, the UPS battery, which alone was supplying the household load (green line), started discharging (yellow line).  As always, I waited for a while before connecting the Prius.  About 20 minutes into the event, I plugged the Prius into the system and and went about my business.

For the first 20 minutes after the Prius was connected, it supplied voltage (red line) but no power, since the UPS battery was at a higher voltage.  Just at the end of the first hour, the Prius battery, which was being charged at that time by the car's engine, reached the same voltage as the UPS battery as it was discharging, and the Prius both charged the UPS battery and supplied power to the house.  For the first 40 minutes of the second hour, the Prius and UPS battery voltages tracked each other.  At the 40 minute mark, AC power was restored and after waiting a bit into the third hour, I disconnected the Prius, at which time the red line disappeared.  You can also see the aftermath of this period, hour 4 and hour 5, during which time the UPS battery charge started creeping back up to normal.

I apologize to the non-nerd blog reader since this item is only marginally more interesting than the previous failure, which did not require the Prius to actually supply power.  In justification, I offer the fact that the PriUPS project is why this site exists at all, and that the power failure gave me an extra day to work on "How To Bananafy The Bun." 

Richard Factor

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