It had been a bit of a rush to put the new battery bank and inverter system together.
With no time to add solar panels for the much larger system, a plan “B” was going to be needed for recharging the new battery bank.
Christine from the Franklin Park Coalition came to the rescue!
She made a couple of phone calls and a place was found in the Franklin Park Zoo maintenance yard where the battery boxes could be parked between shows to plug into the grid and recharge each week. Not exactly solar powered … But we would not be needing a generator for the series!
Everything was ready … Well at least everything seemed ready …
The morning of July 10, 2012 started off nicely … sunny and warm.
A local community group had agreed to provide the sound system for the morning events and everything was sounding great … But when a third self powered speaker for the stage was added, it buzzed … a lot.
The poor stage monitor was not even close to happy.
After checking the cables to see if a bad connection was causing the noise, running a power cord to the new battery / inverter system to see if that might help … and watching the clock tick as show time got closer and closer … I pulled an amp and speaker from my truck, set them up and turned them on … The silence was golden!
Something about that self powered speaker did not like the battery / inverter power.
The rest of the morning show went smoothly, with the smaller solar powered system running for a little over two hours, using .23 kWh of power (according to the “kill a watt” meter), with the inverter’s battery meter still showing “full”!
And … aside from the buzz … a success!
The evening show, with one of my sound systems, started out fine.
I had hired Clara Rhee to mix the show so I could keep an eye on the battery systems for their “shake down cruise”. No hums or buzzes showed up in the sound system or on any of the band’s gear, but the battery powered LED lights that had been rented for the series were not going to be able to compete with the evening sun as it set.
As the concert progressed the meters on the 1,250 watt inverter powering the PA started to blink yellow on some of the louder parts. … The meters on the 2,000 watt inverter powering the stage seemed fine …. So I warned Clara, and in between songs (with fingers and toes crossed) I unplugged the amplifier powering the six stage monitors from the smaller rig and plugged it into the larger rig …
No sparks, smoke or buzzes … or blinking yellow lights.
I don’t think anyone noticed … though someone may have wondered what the huge sigh of relief coming from back stage was for!
The concert ended as scheduled … 3 hours and forty five minutes after we had turned everything on for sound check … Using a total of 3.49 kWh of power between the two systems …. Most of that coming from the smaller system powering the PA.
My assumptions about how much power would be needed for the PA and the stage were way off base … But nothing that could not be fixed by just swapping power sources and loads … The morning’s buzz had me a little more concerned … It looked like I would be visiting the electronic supply store again in the morning!