Solar Power Sound System

[DanKegel]

I had some fun looking for packaged systems. This is just what I dredged up in a random google search; someone who actually works in off-grid solar power would know a lot more.

http://ironedison.com/freedom-package-24-volt-300-ah looks serious, and might do. (Yeah, everyone said 48
volts makes the most sense, but 24 volt systems aren't crazy, and make more sense than 12V systems.)

http://sunreadypower.com/product-line/ has (along with typos) some nifty looking portable lithium-based
systems, but they're a few sizes too small for you.

http://www.mobilesolarpower.net/ms-200/ is a solar trailer, but it's probably out of your price range. It uses lead batteries, I bet.

http://bondsolar.com/houston-solar-e...lar-generators is too small, but is EMP-proof

What's your budget?

[SolarSoundMan]

+1 for keeping it simple like that.

Solar might be useful if you were doing all-day or two-day events
and didn't want to make noise by running the van's engine to charge the batteries.

Their are shows I have that do go all day, yes, I do not want to make noise or pollution if possible. I want people to see the process of how the power is generating and reap the benefits from it.

[SolarSoundMan]

Yes it seems like getting a van with a battery array mounted in back that you can run the sound system, and install a battery charger so the thing charges up on the way back home. If necessary get a higher output alternator. No need for solar panels.

This is not a bad idea and I had thought about putting an isolator in the vehicle to help supplement the charging of the battery's. i may still do this but its just not what I had in mind. First off most of my shows won't be to far from home (at least for now, 1 maybe 40 miles max?) and with that in mind the battery's may not actually have enough miles to be charged. Again, I am trying to be green and look green as possible, running a vehicle to charge the battery's is similar to running a generator, it makes noise & pollution.

[SolarSoundMan]

Yes, and I'm trying to understand what this is really about. You will need to arrive with the batteries
fully charged in case the sun isn't available for the show. Adding solar panels could reduce the depth
of discharge and increase the number of battery cycles. But a small generator could recharge them
between shows without any panels; most battery systems require one as the last ditch "save the
batteries" anyway. I think the battery system complexity is to be justified by not needing to run a
generator during a show?

The 50% DOD instead of 20% may wear out the batteries sooner, but there are FEWER BATTERIES
to be replaced each time. In a thread a while back I estimated the long term $ savings was on the
order of 10%, replacing much larger batteries less often. That would be compensated by not needing
to haul such a huge battery all the time, not to mention reduced loss for other things that might go
wrong. Bruce Roe

Yes Bruce, I will always arrive at the shows with the battery's charged. My plan is to use the panels to charge my battery's while at the show. I will also have shore power to hook up if I need to charge the battery's if its more cloudy that day. My thoughts are to most likely have a generator if I need it in a remote area where shore power is not available. Trying to be green and have a sustainable system I don't want to use a generator any more that possible. The idea of the solar panels is to bring attention to my sound system being powered by the panels.

I understand what you are saying about the fewer battery's, run them lower, but replace them more often. Thanks for helping me to understand that! I do plan to use this at my home when I am not using it for shows, which in reality is where it will be used most of the time.

[SolarSoundMan]

Hang on, you might still not get the difference between kilowatts and kilowatt-hours. Just to be sure:
kW is a measure of power.
kWh is a measure of energy; it's kilowatts times hours.
600 watts (or 0.6 kW) used for five hours totals 3 kWh.

watts = volts times amps
so amp hours = watt hours divided by volts

So 3kWh = 3000 Wh, if supplied by a 48 volt battery, equals 3000 Wh / 48 V = about 62.5 Amp-hours (assuming everything was 100% efficient).

If supplied by a 12 volt battery, it would equal 3000 Wh / 12 V = about 250 Amp-hours.

Make sense now?

To be honest I am not sure how you are calculating this but I think I understand the principle behind using the 48 V system. Thanks for laying out the figures for me, I will keep studying this as well!

[SolarSoundMan]

Actually much less than that
Do the off grid cAlculator in my sig line.
You actually used 1.5 kWh
At 48 volts that is 31.5 amp hours ( means the same thing but is how batteries are rated)
So as not to drain your batteries below 20% depth of discharge ( meaning 80% left in them at the end of a show) which increases battery life)
You would need about a 150 amp hour 48 volt battery.
Now a few more questions.
How many shows like this do you do per year. The 20% rule will get the most cycles out of them but they will die about year 5 or six anyway.
If you only do say 100 shows a year that is 600 cycles in that case you could use a smaller battery and go to say a 50% DOD.
that would take a much smaller battery ore like 75 amp hour battery.

Thanks for pointing me in the direction of your off grid calculator, I will have to check it out. I do understand your example now what you are saying about draining your battery's to much.
The amount of shows I will do a year with this might be 10 at this point but hope to pick up more sustainable type events once people's know I have this solar power to power a sound system for their event. I understand also what you are saying about the cycles and replacement for the battery's depending on how hard or how many cycles I use/need, thanks for sharing that info!

[SolarSoundMan]

Time to explain the difference between a watt and a watt hour
A watt or a KW which is 1000 watts is an instantaneous measurement of power used you would use this to calculate wire and inverter sizes and to a lesser extent batteries.

A watt hour or KWH which is a function of watts x time. This is primarily what is used to calculate battery sizes.

From what I read in the op post about what the kill a watt read is he used 1.5 KWH over a 5 hour period.
This would be an average load of 300 watts

300 watts x 5 hours = 1.5 KWh

Within that there may be peak and valley loads. ( loud vs no sound)

For inverter sizing see if the kill a watt will measure and save the peak load.
This is what you will use to size inverters and to some extent batteries.

Thanks for the break down of the specs! I will keep trying to study and understand this. I also understand what you are saying about measuring peak load. It does seem to me that it would come the same either way i.e. if I have a peak it will make more KWH or in quieter passages of the show KWH would be less. but I am probably wrong about that.

[SolarSoundMan]

Yes and Yes. Using a higher voltage reduces the current and thus resistive losses everywhere, which lets you use thinner wire without it overheating.



Packaged systems are starting to trickle into the market, e.g.

http://www.freecleansolar.com/mobile/product.aspx?ProductCode=Tesla%2DPowerwall%2D7

but that's not meant to be mobile.

BTW if you need 5kWh of energy, you probably want a bigger battery than that, e.g. 10kWh, if the show must go in rain or shine, since batteries wear out quick if discharged too far.

Dan, thanks for the clarification on these things. I will now focus on a 48 V system. Thanks also for the links to these 2 V battery's. although I do need to have the battery bank be Mobil.

[SolarSoundMan]

What I meant is that you used 3 KWH over a 5 hour span
That works out to be an average load of 600 watts per hour.
That said you have 8 times the inverter needed to run that load.
Or did you use 3 kW for 5 hours which would be 15 kWh

The meter is reading in KWH over a 5 hour span, that being the case from what you say above this would be an average load of 600 watts per hour. I would rather have an inverter with more output than what I would need as I do have even bigger sound systems I may be able to use this solar power system with and use it at my home. My primary goal is to at least be able to run the sound system I am talking about in this thread for 5 hours.

[DanKegel]

Yes it seems like getting a van with a battery array mounted in back that you can run the sound system, and install a battery charger so the thing charges up on the way back home. If necessary get a higher output alternator. No need for solar panels.

+1 for keeping it simple like that.

Solar might be useful if you were doing all-day or two-day events
and didn't want to make noise by running the van's engine to charge the batteries.

[posplayr]

Yes, and I'm trying to understand what this is really about. You will need to arrive with the batteries
fully charged in case the sun isn't available for the show. Adding solar panels could reduce the depth
of discharge and increase the number of battery cycles. But a small generator could recharge them
between shows without any panels; most battery systems require one as the last ditch "save the
batteries" anyway. I think the battery system complexity is to be justified by not needing to run a
generator during a show?

The 50% DOD instead of 20% may wear out the batteries sooner, but there are FEWER BATTERIES
to be replaced each time. In a thread a while back I estimated the long term $ savings was on the
order of 10%, replacing much larger batteries less often. That would be compensated by not needing
to haul such a huge battery all the time, not to mention reduced loss for other things that might go
wrong. Bruce Roe

Yes it seems like getting a van with a battery array mounted in back that you can run the sound system, and install a battery charger so the thing charges up on the way back home. If necessary get a higher output alternator. No need for solar panels.

[bcroe]

Actually much less than that
Do the off grid cAlculator in my sig line.
You actually used 1.5 kWh
At 48 volts that is 31.5 amp hours ( means the same thing but is how batteries are rated)
So as not to drain your batteries below 20% depth of discharge ( meaning 80% left in them at the end
of a show) which increases battery life) You would need about a 150 amp hour 48 volt battery.

Now a few more questions. How many shows like this do you do per year. The 20% rule will get the
most cycles out of them but they will die about year 5 or six anyway. If you only do say 100 shows a
year that is 600 cycles in that case you could use a smaller battery and go to say a 50% DOD.
that would take a much smaller battery ore like 75 amp hour battery.

Yes, and I'm trying to understand what this is really about. You will need to arrive with the batteries
fully charged in case the sun isn't available for the show. Adding solar panels could reduce the depth
of discharge and increase the number of battery cycles. But a small generator could recharge them
between shows without any panels; most battery systems require one as the last ditch "save the
batteries" anyway. I think the battery system complexity is to be justified by not needing to run a
generator during a show?

The 50% DOD instead of 20% may wear out the batteries sooner, but there are FEWER BATTERIES
to be replaced each time. In a thread a while back I estimated the long term $ savings was on the
order of 10%, replacing much larger batteries less often. That would be compensated by not needing
to haul such a huge battery all the time, not to mention reduced loss for other things that might go
wrong. Bruce Roe

[DanKegel]

... I would need 625 AH of battery's to run 3 KWH FOR 5 hours...

Hang on, you might still not get the difference between kilowatts and kilowatt-hours. Just to be sure:
kW is a measure of power.
kWh is a measure of energy; it's kilowatts times hours.
600 watts (or 0.6 kW) used for five hours totals 3 kWh.

watts = volts times amps
so amp hours = watt hours divided by volts

So 3kWh = 3000 Wh, if supplied by a 48 volt battery, equals 3000 Wh / 48 V = about 62.5 Amp-hours (assuming everything was 100% efficient).

If supplied by a 12 volt battery, it would equal 3000 Wh / 12 V = about 250 Amp-hours.

Make sense now?

[Naptown]

Actually much less than that
Do the off grid cAlculator in my sig line.
You actually used 1.5 kWh
At 48 volts that is 31.5 amp hours ( means the same thing but is how batteries are rated)
So as not to drain your batteries below 20% depth of discharge ( meaning 80% left in them at the end of a show) which increases battery life)
You would need about a 150 amp hour 48 volt battery.
Now a few more questions.
How many shows like this do you do per year. The 20% rule will get the most cycles out of them but they will die about year 5 or six anyway.
If you only do say 100 shows a year that is 600 cycles in that case you could use a smaller battery and go to say a 50% DOD.
that would take a much smaller battery ore like 75 amp hour battery.

[SolarSoundMan]

What I meant is that you used 3 KWH over a 5 hour span
That works out to be an average load of 600 watts per hour.
That said you have 8 times the inverter needed to run that load.
Or did you use 3 kW for 5 hours which would be 15 kWh

Thanks for trying to help clarify this and to help me understand, I really appreciate it! I see you have what looks to me like to different figures, 1 is 3 KWH the other, 3 kW, are these different values?

The P-4460 Kill A Watt meter I used to take the calculations is KWH (kilowatt hours). In 5 hours the monitor speaker system used 1.5 KWH. I couldn't check the font of house speaker system but was allowing 1.5 KWH during 5 hours run of time for it. Both the FOH & MSS each would use 1.5 KWH in 5 hours. I am trying to calculate how many amp hours of battery's FOR EACH SYSTEM that I would need.

From what the OP said (and how I understood it) using a 48 V system I would need 625 AH of battery's to run 3 KWH FOR 5 hours. Since each system uses 1.5 KWH is it OK to assume I would need 312.5 AH of battery's for each of these systems? OR, should I have 625 AH for each of the systems? Sorry for the thick skull on my shoulders but it is allot to understand,