After Town Day I was very excited about how well the gear had worked …if only I could explain how it could have worked … The numbers I had been using just did not add up.
Something was certainly up … I just had no idea what.
The few e-mails I sent out telling folks about the “experiment” were met with a mixture of curiosity, rolled eyes and one set of “raised eyebrows”.
The “raised eyebrows” belonged to Richard Wood of Wooden Kiwi Productions.
Richard had been hiring me to bring in sound for events around Boston … And he was curious if I thought the battery system could power the sound system for an upcoming event with the Boston Pops Brass Ensemble in Franklin Park.
A great question to add to the others running around in my head.
I was still trying to figure out how two 120 watt solar panels captured enough electricity to run a 1,500 watt sound system for seven hours in just four days … And never mind about where the three batteries “hid” all that power?
My brain was starting to hurt!
Another trip to the electronics supply store supplied a “Kill-A-Watt” meter … an afternoon in the shop experimenting with sound equipment, a couple of cups of coffee, some scratch paper and things were beginning to look like they were making sense … or so I thought!
Most of the gear behaved as I thought it would. Turn it on and it would use about the number of watts listed for it, typically a little less, but pretty close … the exception being the amplifiers. A 1,500 watt amplifier only used about 10% of that when I turned it on. Playing a CD through the amplifier did not seem to have much of an effect on the power consumption … At least until it was turned up to the point where it started to get pretty loud. But even then it seemed to use a lot less power than the advertised 1,500 watts. Even overloading the amplifier would not draw that much power.
I did notice that the readings on the “Kill -A-Watt meter” jumped around a lot with the music on the CD … Hmmmm …
“Armed” with this new information and a calculator I started adding things up for the concert with the Pops Brass Ensemble. Using what I figured would be the average current draw for the sound check and concert … Multiplying that total by the number of hours needed for the sound check and concert … An added safety margin … and It looked like another three batteries would do the trick.
Being me, I bought four!
The person who had asked Richard to bring in the sound system for the event was very excited about using a solar powered sound system and I gave her a “tour” of the power system … She asked when was I going to turn it on … catching me a bit off guard … it was on!
The concert went off without a hitch!
I had all the gear running through the “kill-a-watt” meter during the event and was starting to get a better feel for just how much power was being used …
A lot less than I had expected.
In the mean time I was not the only person getting excited about the project.
Christine Poff from the Franklin Park Coalition was thinking even bigger things.
The Elma Lewis Playhouse in the Park concert series was looking at ways to stay within their budget. The folks from Wooden Kiwi had been brought in a number of years earlier to help with the same challenge … Save money … and keep the concerts going.
It was that time again.
After doing some math it turned out that using a battery system for the Tuesday night concerts was going to be less expensive than hiring a diesel generator for the event. (Gasoline powered generators are not allowed in Boston).
Fifteen very long days and nights later, with a lot of help from my dad, 1,700 amp hours of batteries, 3,250 watts of pulse wave inverters, the wonderful help I received from Fred and Mary at Boats and Motors, too many cups of coffee to count … And …
The E Water Band taking the the new battery rig out for a “spin”