Solar Power Sound System

[SolarSoundMan]

Hi Everyone,
I am looking to see what kind of a battery bank I will need as well as any other suggestions and help to build a portable solar power system to power a sound system for outside shows mostly during the summer. I would also like to use it at home when I am not using it to do shows.

Sound system specs are:

Front of house (FOH) speakers are rated at 2520 watts
Monitor speakers (MS) are rated at 2000 watts
Backline (Bass amp, 2 guitar amps, sound board, FOH EQ, CD player rated at 700 watts
In round figures this is a 6000 watt system.

Time and hours of use: Most shows would be in daylight hours. Bands normally play "3" 45 minute sets (2 1/4 hours total performance time). One hour setup with sound check break music in between sets. This is approx up to 5 hours total the system would be on with 2 1/4 hours actual performance time.

My thoughts are to go with 2 Go Power! Extreme kits. 1 kit would power my FOH speakers and 1 kit would power my MS, backline, sound board, EQ, CD player. Here are the specs for 1 kit including 480 watts of solar panels:

160 watt solar charging kit + 2 x 160 watt expansion kits (GP-RV-160 + GP-RV-160E)
3000 watt pure sine wave inverter for AC power (GP-SW3000-12)
30 amp pulse width modulated digital solar controller (GP-PWM-30)
75 amp smart battery charger (GPC-75-MAX)
30 amp pre-wired automatic shore power/inverter AC switching kit (GP-TS)
DC inverter install kit (GP-DC-KIT5)
Inverter Remote on/off (GP-SWR-B)

I had read somewhere (if I understood it correctly) that in round figures if you have 600 AH in your battery bank you would want 600 watts of solar panels. If this is correct my thoughts were to add 1 more GP-RV-160E solar panel to each system for a total of 640 watts of panels per system. My thoughts are to have each panel on a stand so they would be portable to move around at the shows or at my home

While considering weight I realize it would cost more but I am thinking to go with "2" 300 AH battery's pèr each Go Power Extreme system. The battery I have been considering is the "Smart Battery 12V 300AH Deep Cycle / Starting Lithium Ion Battery". Maybe there is a better option out there, maybe not? It was appealing because I would have less weight than AGM or FLA battery's and it appears to be less units to carry. After talking to the company (Smart Battery) they said the battery's have a 5 year warranty and are fully rebuildable and they would not charge to rebuild them if and when they would need to have that done.

To charge the 12V 300 AH Smart Battery it was recomended to get the DP-PS4 12V 4 Bank 15A Lithium Ion Battery Charger made by Smart Battery to get the battery's charged up to the 14.4 volts. The GPC-75-MAX charger that comes with the Go Power! Extreme Kit will not charge to this voltage and not get the Lithium Ion Battery's up to the correct voltage. If using these battery's I would not get the charger that comes with the Go Power Extreme Kit.

Questions: Does this sound like something that will do what I listed? If using the Smart Battery listed is 600 AH enough to power this type of system the hours I have listed? Are there better options out there to do what I am trying to do?

Although this is most of what I have been thinking about (I may have missed a few things) but it will hoipfully get the discussion going. Thanks for any insight on this or thoughts on other things to consider for this type of system. Thanks so much for any insight, help and thoughts on this. I am very excited to hopefully make this work using solar power!

SSM

[sensij]

There is a lot to work with here, I think you've done a good job outlining your requirements. Without digging too deep into it, I think you'll want to be looking at a 48 V system to support your loads.

You mentioned in your intro post that you want to do this because you tried a solar setup once and were impressed by the sound quality. Did you happen to note any of the PV/electrical equipment that you were using when you did that show?

[SolarSoundMan]

There is a lot to work with here, I think you've done a good job outlining your requirements. Without digging too deep into it, I think you'll want to be looking at a 48 V system to support your loads.

You mentioned in your intro post that you want to do this because you tried a solar setup once and were impressed by the sound quality. Did you happen to note any of the PV/electrical equipment that you were using when you did that show?

Hi sensij, thanks for the info and helping me to figure out how to do this! A couple of questions. Is the Go Power! Extreme kit a good one to work with for this application? If so would it work using a 48 V system that you think I will want to support the loads? When I did the show with the company that provided the solar power I did look at it but being so new to this I am not sure what all he had? I do remember seeing the name "Xantrek" but I am not exactly sure which Xantrek unit I was looking at, maybe the charge controller?

I did take a picture of the trailer he brought in, but have no idea how to post here, as I am not the most computer savvy person. Anyway, it looked to be about 10 ft (or so) in length with approx 3 panels mounted on top and I believe 3 panels on both sides. They hung down for transportation but were propped up with what looked like little shock absorbers and level with the panels on the roof (at the event). The battery's were in the front part of the trailer that were charged from the roof panels. He then had other portable units that he brought to the event to power different areas around the festival and the sound system area.

One unit he called the "regular TOT" was used to power my sound system. He then used a "mini TOT" to power the backline guitar and bass amps, and another mini TOT to power the LED stage lighting. He said he did this so if there was a problem it would be easier to diagnos. I am not sure but I think he used the panels to charge the battery bank within the trailer and then hooked the TOT's up to that, but this is only a guess?

If you suggest using 48 V could you please help shed some light on why that is opposed to using a 12 V system? I would assume I would need 4 12 V battery's wired in series to do that (or is it parallel)? Please feel free to ask any questions and I will do my best to give accurate answers. Thanks again for any more help on this, I appreciate it!

[bcroe]

Audio Power

Often audio equipment is rated for the absolute peak instantaneous power that
can be delivered. With a steady tone the average power is only half the peaks,
and typical music or voice are not steady tones at all, so the average power is
much lower yet. Some measurements of the actual (average) power consumed
would be a good starting point for a design. Bruce Roe

[inetdog]

Get a KillAWatt power meter or reasonable equivalent. It is worth the investment. Instead of looking at current readings bouncing up and down it will allow you to play a reference mix at a comfortable volume for an hour or two and find out the average power it used.

[SolarSoundMan]

Often audio equipment is rated for the absolute peak instantaneous power that
can be delivered. With a steady tone the average power is only half the peaks,
and typical music or voice are not steady tones at all, so the average power is
much lower yet. Some measurements of the actual (average) power consumed
would be a good starting point for a design. Bruce Roe

Thanks Bruce for making me remember I forgot to put how much power it is drawing. I had a guy check my 26,000 watt system this weekend during a pretty loud performance. I was using a double pole 30 amp breaker and he said one leg was drawing 8 amps and the other 7 amps.

I would think the system I have listed above is drawing less power than the big system that was tested this past weekend. The smaller system is only 6000 watts. So, I am going to say the 6000 watts system is drawing 5 amps or less per leg meaning 5 amps for FOH and 5 amps for the monitors and backline.

[SolarSoundMan]

Get a KillAWatt power meter or reasonable equivalent. It is worth the investment. Instead of looking at current readings bouncing up and down it will allow you to play a reference mix at a comfortable volume for an hour or two and find out the average power it used.

This sounds like a great idea! Do you have a model # to reference? I googled Killawatt meter and one for Home Depot came up. Pretty cheap and looks simple to use too! I will look into getting one of these, thanks for the tip on that!

[inetdog]

This sounds like a great idea! Do you have a model # to reference? I googled Killawatt meter and one for Home Depot came up. Pretty cheap and looks simple to use too! I will look into getting one of these, thanks for the tip on that!

The Big Orange model should work just fine for you.
Also look into the DC clamp-on ammeter from Sears. A great buy at about $60.

One of the problems with just measuring Amps is that it may show a high number for an unloaded transformer because of the inductive current (not in phase with voltage) that does not actually demand any power from the inverter.
The KAW shows both actual watts and the complex power, VA (volts times amps without regard to phase.)

[SolarSoundMan]

The Big Orange model should work just fine for you.
Also look into the DC clamp-on ammeter from Sears. A great buy at about $60.

One of the problems with just measuring Amps is that it may show a high number for an unloaded transformer because of the inductive current (not in phase with voltage) that does not actually demand any power from the inverter.
The KAW shows both actual watts and the complex power, VA (volts times amps without regard to phase.)

This one at Home Depot is the Kill-A-Watt EZ Meter P3-4460, I am not sure which one you mean when you say the big orange one?

[inetdog]

This one at Home Depot is the Kill-A-Watt EZ Meter P3-4460, I am not sure which one you mean when you say the big orange one?

I mean the big orange store (Home Depot), similar to Big Blue (Lowes, not IBM).
Other interesting nicknames are Harbor Fright (Harbor Freight) and FleaBay (eBay).

[SolarSoundMan]

I mean the big orange store (Home Depot), similar to Big Blue (Lowes, not IBM).
Other interesting nicknames are Harbor Fright (Harbor Freight) and FleaBay (eBay).

Thanks for the clarity on that!

[bcroe]

Thanks Bruce for making me remember I forgot to put how much power it is drawing. I had a guy check my 26,000 watt system this weekend during a pretty loud performance. I was using a double pole 30 amp breaker and he said one leg was drawing 8 amps and the other 7 amps.

I would think the system I have listed above is drawing less power than the big system that was tested this past weekend. The smaller system is only 6000 watts. So, I am going to say the 6000 watts system is drawing 5 amps or less per leg meaning 5 amps for FOH and 5 amps for the monitors and backline.

Your current drain is going to vary hugely. What you need to know is the average power.
The P3 will tell you that on the KWH function over some operating time at power. Bruce Roe

[SolarSoundMan]

Your current drain is going to vary hugely. What you need to know is the average power.
The P3 will tell you that on the KWH function over some operating time at power. Bruce Roe

Thanks Bruce! I just called Home Depot and they have the P3 in stock. I am going to get it today and will update my usage to this thread as I know it. Thanks very much for the tip on this! This seems to make sense knowing how much power I am drawing and then apply that to how big a battery bank I would need, why couldnt i think of that, duh. I would rep you but I don't know if there is that function or even how to do it if there is, thanks again!

[SolarSoundMan]

I got the P3-4460 Kill A Watt meter yesterday at Home Depot, a $30 unit with different functions, amps, volts, watts, KWH, cost, etc. I had a show tonight but operated another bands PA system, so I thought I would take the P3 with me to give an idea of what this system would put out. These were not powered speakers I was running tonight like my system posted in post #1. The speakers were powered from separate rack mounted amps for each frequency range. Probably using more power than my powered speakers.

Due to the way things were setup I was not able to check the KWH of the bass and mid amps for FOH or the backline instruments such as the bass guitar amp, and 2 guitar amps, and fiddle amp. I was able to check the KWH of the Monitor amps, hi end amp (for FOH), sound board, EQ, CD player, and effects unit. I had the system on for 5 hours it used 1.5 KWH.

I realize this isn't exactly the same as my system but does give an idea of what I could expect with my system. I am going to say in round figures my system with everything I have listed and running for 5 hours would be around 3 KWH, maybe less?

Now the BIG question: If in fact my sound system would draw 3 KWH in a 5 hour period how would I calculate how big of a battery bank I would need? Thanks!

EDIT: I should say that 3 KWH is for my whole system. If I was running "2 3000" watt inverters each one would be using 1.5 KWH per inverter for 5 hours. How big of a battery bank (or AH) would I need to draw 1.5 KWH for 5 hours.

[inetdog]

Now the BIG question: If in fact my sound system would draw 3 KWH in a 5 hour period how would I calculate how big of a battery bank I would need? Thanks!

EDIT: I should say that 3 KWH is for my whole system. If I was running "2 3000" watt inverters each one would be using 1.5 KWH per inverter for 5 hours. How big of a battery bank (or AH) would I need to draw 1.5 KWH for 5 hours.

Fairly simple. Assume first a 48V battery bank (it will be harder to build with a 12V battery bank.)
3kWh is 62.5AH at 48 volts. You should try not to run your battery bank down by more than 20% per use before recharging, so your 48v battery bank would need to be 625AH.

It is hard to get 625AH batteries except at 2V each, so one solution would be 24 batteries, each 2V, 625AH, all in series.

If you tried to do this at 12V, you would need 2500AH of 12V battery.

The other reason for using 48V is that the battery bank current will also be lower, allowing for more reasonable wire sizes.
1kW at 12V would be 83A. At 48V it would be just above 20A.