Category Archives: Outdoor concerts

Failure … At last!

Well … It took some doing … But it finally happened.

The power went out!

I had been pushing things, trying to find the limits … So in a way it was what I was looking for … 

But somehow not what I had been hoping for.

Three different events … Three different scenarios … Three different sets of gear … But the end result the same. 

The power went out.
 

Notice how much a solar power outage looks like a utility power outage!

 

One of the failures was pretty simple to figure out, easy to duplicate and explain mathematically.
It turns out if you ask for too much power from an inverter it will shut down … Not unlike what happens when you ask for more than 20 amps of power out of a standard 20 amp wall outlet.

Apparently running my mixing board, an audio processing rack, a couple of wireless systems , a keyboard set up, a bass amplifier, two guitar amplifiers and three QSC MX1500a power amplifiers on stage with the Houston Bernard band for an outdoor festival was asking too much of my 2000 watt sine wave inverter …

Looking back I probably should not have been so surprised!

The only real question for me now was why it had not happened sooner.

A decent inverter will actually produce more power than the wattage it is rated for … For a while. My inverters are capable of handling up to twice their rated output for very short periods of time (a couple of seconds) … Plenty of time to handle the surge current required to turn on some electrical equipment … Easily handling my 1 & 1/2 horsepower compressor for hours on end.

The compressor needs a 20 amp circuit to run … At home it would pop the glass fuse when I forgot and tried plugging it into the 15 amp outlet in the garage … The required fix used to be running a heavy duty 100′ extension cable to the basement to find a 20 amp circuit. These days I just plug the compressor into one of the 2000 watt inverters in the truck with no muss, no fuss … No extension cords required!

The other two failures I have not been able to duplicate … Or been able to explain mathematically … I am beginning to suspect that a loose connection on the 12 volt DC line may have been the “culprit” … I will keep you posted.

Now to figure out the best way to keep the power from going out!
  

This should help … 4,400 watts now … expandable to 8,800 watts! (time to start adding to my 2,000 pounds of batteries).

  

 

The Truck!

Ah yes … The truck.

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First outing with the new array.

A 1995 Mitsubishi Fuso FH100, and I, the original owner,

What a machine!

The FH100 was a left over model the local dealer “found” sitting on a dock in Florida waiting for something to do … And did I have something for it to do!

I had had the pleasure of working with John Minnehan and his company “the Ultimate Video show” bringing a high tech video night club to lots of college campuses that were … Let’s just say … Off the beaten path!

Lots of miles … Lots of heavy gear … And lots of hours listening to some of the hottest dance music the 90’s had to offer … I am still in recovery!

But the truck was amazing at it. With a GVW (Gross Vehicle Weight) of over 17,000 pounds and weighing in at under 9,000 pounds empty the amount of gear it could handle was beyond belief … It surprised a lot of weigh station officials over the years … The sad look that would cross the faces of the DOT guys as they opened the door and read the GVW tag was always priceless!

But I digress …

The truck seems to have been built for my solar project. With it’s small size and super heavy duty frame, brakes, suspension and cargo restraining system moving a bunch of batteries around with the truck was going to be the easy part.

I wanted to find a better way to solar recharge the batteries between shows, and with business picking up I started looking up. With 120 square feet of flat roof on the truck, adding solar panels to the “attic” seemed like a good idea. If I could find a way to permanently mount an array on the truck I was going to save a lot of time and trouble moving batteries around.

I wanted to have the panels “rail mounted” flat above the box of the truck … With the rail system designed to protect the panels and any low hanging tree branches from each other!

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The rail mounting system

I was curious as to how well the panels would work laying flat … (Instead of being angled at the sun) … But was pretty certain after 2013’s experiment that I would be able to recharge the batteries … I was just not sure how much the process would speed up, or how much power I would get … Never mind what, if anything was going to happen on those short winter days with the sun low on the horizon.

Time would tell.

While the truck was being worked on I went through and rebuilt the charging station I had made for the project back in 2013, tidying things up a bit, adding a web monitor and a wireless router to connect the rig to my I-phone and maybe someday even the world!image

I think I’ll need to rent a teenager to get that far … Any leads on finding one would be greatly appreciated!

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The new array! Four Sun Tech 235 watt panels.

I got the truck back from the shop with the four solar panels installed on July 3, 2015 and spent the next two days adding the electronics and cabling … Personally drilling two holes in the truck roof for the “glands” that the cables were going to run through seemed really wrong … But the glands, and the silicone sealant that were used have kept everything nice and dry.

The next day I got up before sunrise and made it down to the truck as the sun was clearing the trees on the horizon and found I had already harvested .194 kWh of power … Before the sun had even hit the panels!

 

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Rise and shine … Time to get to work!

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“Old Guy” taking a “screen shot”, 7/6/2015

The readings I took from the web monitor at the end of the day showed that the charger went into “float” stage around noon … With a total harvest for the day of 1.41 kWh of power … I was not really sure what that meant … But I was impressed!

As I sit here on a Sunday morning in late January, with six months of learning “under my belt” I am still impressed!

As for the short days of winter … Yesterday, a sunny January 30, 2016 the Sirus Solar DS-201 web monitor showed I had put 143.7 amp hours of power back into my 12 volt battery bank … 1.72 kWh of power … Not bad for four 235 watt solar panels laying flat on a winter day in New England … Not bad at all!

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Screen shot from 1/30/2016

Watch me build a new battery / inverter box!

I thought it would be fun to have you tag along as I put together my fourth battery / inverter system.

My current battery rigs work incredibly well … But are too heavy to get in and out of my truck with two people.

I’m hoping that a smaller, modular approach will work. The idea of having a box of batteries that could be used by itself for smaller events … But could also be plugged into a larger system for larger events is very intriguing.

I had an old amp rack sitting around that I decided to try out as a battery system. It was a well made case that I had the good luck of not being able to sell on e-bay … And with this year’s Dance for World Community adding another stage to power I decided to give it a try.

The case turned out to be an almost perfect fit for four group 31 AGM batteries … A total of about 5 kWh of power if I’m doing the math correctly … I only plan on using about half of that in an attempt to keep the batteries working in top shape for as long as possible.

The case was made of 1/2″ luan plywood with some sort of plastic laminate covering, all held together with very heavy duty aluminum extrusion … It was built like a tank!

My biggest question … Would the case be able to handle all that weight?

The case did make it a lot easier to wire up the batteries and inverter. The removeable front and rear covers were now going to be the top and bottom, with the main body of the rack becoming the walls of the battery pack.

Four Group 31 AGM batteries installed on back cover of amp rack

Four Group 31 AGM batteries installed on back cover of amp rack

The former rear cover had a nice set of casters mounted on a Baltic birch caster plate … And with the addition of a 3/4″ birch “sub floor”, a layer of KYDEX and another 3/4″ “collar” around the batteries it looked like a good place to start.

The next step was to figure out how best to wire the batteries to the inverter.

A circuit breaker and fuse are added to keep things safe and a metering system is added to keep an eye on how the batteries are doing.

Wiring layout for the new battery / inverter box

Wiring layout for the new battery / inverter box

Here I have the two panels I will be using with the buss bars, fuse holder, shunt and circuit breaker mounted on them. Adhesive backed shrink tubing will be added over the crimped on lugs for safety … and to help protect the wire from corrosion.

I am using 00 marine grade wire for the interconnecting all the parts and I will be using #2 marine grade wire to connect the 12 volt batteries to the bus bars.

It is very important to use the right size wire when working with low voltage DC. The general rule of thumb is to use the largest, shortest wire you can … Otherwise the resistance in the wire will rob you of too much power.

I am already thinking of swapping out the #2 cable for #1 … We’ll see!

Eventually I will be adding a 350 amp ANDERSON SB connector to the pack (to connect multiple packs together) and have included an “extra” set of buss bars to make it easier to do when the time comes.

The AGM batteries I am using are supposed to be safe to mount in any position … And I suspect someday someone will tip this case on end to get it off of it’s wheels. I’m curious to see how the spacers hold up under that!

I've added spacers between the batteries to hopefully keep everything in place should someone ever tries to test the

I’ve added spacers between the batteries to hopefully keep everything in place should someone ever tries to test the “mount in any position” feature of the AGM batteries!

A top “deck” will be mounted on the two power panels for the inverter, battery meter and the ANDERSON SB connectors.

A little paint and it’s time for the “final” assembly.

Wiring of the

Wiring of the “positive” side off the battery bank

I like the modular approach of this system a lot … Making changes as I learn will be a lot easier … In theory!

Having this kind of access to all of the connectors was wonderful … You should have seen (heard?) me trying to wire my previous rigs!

Almost done ... Just need to add the cover and a fan!

Almost done … Just need to add the cover and a fan!

Shrink tubing added … Circuit breaker and fuses installed … Notice the “trap door” for getting at them … as well as the 175 amp ANDERSON SB connector for plugging into my chargers.

With the cover closed up and the fan on the system has been working wonderfully.  The next step will be to add the 350 amp  connector and assemble a larger inverter / power distribution system.

A great project for this winter … Will keep you posted!

Ready to go to work! Trimetric 2035 battery meter on the top left ...

Ready to go to work! Trimetric 2035 battery meter on the top left, “Kill-A-Watt meter to it’s right and 1,100 watt sine wave inverter and the connector for plugging into my  60 amp solar charge controller below.

2013

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2013 was looking to be pretty exciting with the St. Patricks Day parade and the Easter sunrise service working so well … Though I was a little behind schedule with my plans to get meters installed and upgrading the wiring on all of the battery systems.

The rest of the parts had arrived … Finding time to install them was another story.

More shows, putting another battery system together and getting the meters installed in three of the systems kept me very busy through June … And I was starting to get some data that seemed to make a lot more sense … But I still had lots to learn.

One of the battery banks with the TRIMETRIC 2025 battery meter installed.

One of the battery banks with the TRIMETRIC 2025 battery meter installed.

I was planning on using the 2013 Elma Lewis Playhouse in the Park series to test how feasible the project really was. I had hoped to solar recharge all of the batteries between the weekly shows this year … And had ordered an MPPT (Maximum Power Point Tracking) solar charge controller to do it with … After doing a little math it seemed like my three 120 watt solar panels would be able to capture enough sunlight to recharge all the batteries during the week … Even allowing for a 50% operating efficiency … Something I hoped would be a conservative estimate … Especially with rain and clouds being a fairly common occurrence here in the Boston area.

My initial plan of setting up the solar panels and batteries on site for the series turned out to be a little naive … I had to scramble a little to get a “Plan C” up and running … My truck would be parked from Wednesday night until Monday afternoon and with a little help and a couple of tall ladders the solar “array” would be strapped to the top of my truck, the charge controller hooked up… And … Time would tell.

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PS … It worked great!

Easter Sunrise Service, Castle Island, Boston.

In the mean time …

Easter sunrise service on Castle Island in South Boston …Wow!

The view to the east is amazing. I am not going to try to describe it, but it is worth getting up early for … At least once!

I had been providing the sound system for the event for a couple of years and had really enjoyed setting up the sound gear in the dark and watching the new day arrive.

Easter morning view from Castle Island

The airplanes are not landing at Logan airport across the harbor at 4:00 in the morning and you can actually hear the harbor, the sound of the waves hitting the shore, some large ships going by … Add the flash of light from Boston Light and the slightest hint of change out on the horizon … It is very nice!

This year I had asked my contact with the Castle Island Association if I could try powering the event with one of my solar powered battery rigs and he said yes!

Normally … By the time most of the people arrive for the Church service the generator is already running with its constant drone covering up everything but the “red eye” flights coming in and the occasional overhead sea gull.

This year the first sound breaking the harbor “soundtrack” was the “Good Morning” from the priest celebrating the Mass … I’m sorry if it startled anyone!

The system ran for 2.5 hours and used .35 kWh of power … a tiny amount by any standard. Basically the “idling” current draw from having the four wireless microphones,  mix rack and amplifier on … With no background noise to compete with, the overall sound level did not need much power to cover the audience standing an an area almost the size of a football field.

The small “solar system” I brought to power the event was about the same size and weight as the generator that I helped off load from the park rangers utility tractor in previous years. Something else to think about … Eventually!

But back to rewiring …

The battery systems had worked wonderfully at powering the events so far. But I had unknowingly been getting a little help from good old fashioned “dumb luck”.

If this project was to get out of the tinkering stage I wanted to do it without needing that help.

Adding the battery meters was going to provide some very useful information, adding fuses was going to keep everything and everyone safe … and spending a little “quality time” with my coffee pot and calculator was going to get the systems performing as well as they could … For a long long time!

To find out how long you will have to check back later … Hopefully much later!

In working with 12 volt DC power it is very important to size everything for what you are trying to do … In my case … Powering all the equipment needed for an outdoor concert.

Sizing the wire used and laying out the equipment so that as little power as possible is lost to resistance in the wiring of the system … Ideally keeping the loss between the batteries and the inverter to less than 1%

To do that I needed to use the largest, shortest wires possible.

Using a voltage drop calculator like the one found in  “rapidtables.com”  you can see what size wire you will need to use. For this part of the project I used short (18″) #2 cables to go from each of the batteries to a pair of insulated buss bars, and total of about 8′ of #2/0 cable to get from the buss bars, through a circuit breaker, fuse and shunt to the inverter and back again.

If I’m doing my math correctly I am only losing .1463 volts (1.17%) to voltage drop with a 200 amp, 12.5 volt DC load … A little more power than what you could get from a standard household 20 amp circuit.

It sounds like an awfully small amount of loss to get excited about, until you realize almost everything in a 12 volt system will shut down when the voltage drops below 10.5 volts. Losing .1463 volts from 12 volts does not seem like much … But if you only get to “play” with the 2.4 volts between 12.9 volts (a full battery “at rest”) and the 10.5 volt “shut off point” … Losing that .1463 volts means I would lose between 5 and 8% of my total power at full current … And if I wanted to keep the batteries alive as long as possible I do not want to discharge them fully … I could be losing over 10% of my power … to wire!

Yikes!

I am hoping to give you a little “photo” tour of how I wired one of the systems in my next post.

Luck of the “Irish”!

In the mean time … The show must go on … The rewiring project was going to have to wait.

3/17/2013 … If you live in Boston that date can only mean one thing …

The South Boston St. Patricks Day Parade … Where being Irish is not really required!

I got a call from Mike Majorowski wondering if my battery system would be able to power a float for his band in the parade.

Hmmmmm…..

To see if it could be done I set him up with a couple of “Kill-A-Watt meters to use at his next gig to see how much power they would need … While I started to worry about the weather. Rumor has it that batteries do not like the cold!

With the readings he got from the “Kill-A-Watt meters It looked like my smaller battery system would do the job … At least if the weather co-operated and we got that perfect 77 degree day the batteries were rated for (this is Boston … and I’ve shoveled snow in May!)

I explained my “concerns” to Mike and we decided to try the parade using my larger system … At the smaller system’s price.

We had a beautiful sunny day for the parade … If you don’t mind a little cold wind … We started sound check at 10:00 am at 28 degrees And got all the way up to a “balmy” 37 degrees somewhere along the parade route!

Five hours of run time, 1.83 kWh of power used … We even got a nice “Cool!” From the Boston Police Truck team inspecting all the floats when they asked where we were getting our power from … apparently we did not need a special permit for using a generator on the float … Cool indeed!

At the end of the day the inverter battery meters still showed 90 – 100% full … It would have been nice to have the new meters installed … The parts had arrived … the extra time needed to install them was still on back order!

It was my first event moving the battery boxes around by myself and one thing was certain … Those battery boxes are heavy … Very heavy!

The larger battery system with the Trimetric 2025 meters installed

The larger battery system with the Trimetric 2025 meters installed

The larger system consists of a pair of “Site Safe” tool boxes with each box weighing in at about 500 pounds! … So “portable” is a relative term!

Moving them from the truck to a loading dock, or in this case … To the back of the “roll off” tow truck that was used for the float was pretty easy … Pushing them up the ramp to my truck? … Not so much!

Moving them around was going to take three or four people … Or a lift gate on the back of the truck … I will need to figure that one out later …

My to do list keeps growing!

Back to the drawing board!

Oh well … It turns out almost everything I did on my first attempt at going solar was wrong.

Wrong wire sizes, wrong lengths, wrong assumptions about how a bank of batteries should be wired … All of which made for a lot of possible failures.

Overestimating how much power I would actually be using … And more than a little good luck keeping any of those failures from happening!

So … Back to the drawing board …

The first “order of business” was to get a real metering system installed … It was time to find out what was really going on with the batteries.

I needed a “gas gauge” I could trust.

The Trimetric meters from Bogart Engineering are highly recommended by a lot of folks. … I decided to try the 2025 RV model for the project.

The 2025 is a very neat device that keeps track of the power in Amps  going in to and out of the batteries … A quick look will tell you the voltage. Press a button and you will see how much power is going into or out of the batteries. Press the button again and the meter will tell you the batteries are 87% full (… Or 18% full … It might be time to start thinking about worrying … Soon!).

In any case … More information than I could have hoped for!

The folks from Bogart Engineering have designed the meters to do a lot more … But those three things were going to answer a lot of my questions … And keep me out of trouble … For a little while at least!

Adding the meters to my “rigs” was going to take some rewiring … and some math … More on that later.

Since I was going to have to get in and do some rewiring to install the meters it made sense to go in and fix as many of my wiring mistakes as possible … My good luck was only going to get me so far!

If  you’ve been following along since the beginning you may remember my first big battery powered show having some yellow “warning” LEDs flashing on one of the inverters. The band had not gotten any louder … But something had changed … It took over a year to figure out what had happened … the power in the batteries was not getting to the inverter.

Resistance was “robbing” the system of power.

The wire I was using was too small and too long for the current that was trying to get from the batteries to the inverter … Causing a voltage drop … Causing the inverter to “ask for more power from the batteries … Causing the resistance to go up …causing more voltage drop … Causing …

It was a good thing I pulled the amplifier from one inverter and plugged it into the other inverter when I did … Or that show might have been the last!

My common sense approach was not helping at all … Luck … On the other hand … Was!

When using batteries to power something you do not want to waste anything. Leaving a 60 watt light bulb on overnight will “eat up” a lot of your battery reserve. It can be done … You just need more batteries … And solar panels to make it happen.

A little common sense would tell you … If you do not need it … Turn it off!

Common sense probably won’t tell you how much power will be wasted by using the wrong wire. Too small or too long of a wire could waste as much power as that 60 watt light bulb.

When using DC power a good “rule of thumb” is always use the largest, shortest wire you can.

So … I bought a bunch of larger wire to replace the stuff I had started the project with, ordered some meters, shunts, heavy duty buss bars, fuse blocks, fuses, lugs, heat shrink tubing … and my new favorite tool … A hand held crimper capable of hand crimping up to # 4/0 cable!

I wanted my systems to perform as well as they could … The solar powered equivalent of a finely tuned sports car as it were.

I’m afraid I’m going to be  seeing lots of 4/0 in the near future …