Solar Power Sound System

[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]

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]

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]

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]

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]

+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.

[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?

[posplayr]

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.

For the OP:

There is a little bit of loose terminology going on in this thread. I have seen "watts per hour" used twice to represent 3000 kw*Hr consumed in 5 hours.

Watts is Power which is a rate of energy consumption (i.e. Kw*Hr per Hr of just Kw). "Watts per hour" is an energy acceleration not an energy rate and I don't think anybody means to describe such a thing.

600 Watts for 5 hours would be a proper statement. If you ever need a mental reminder, just remember that watts is rate and there is an associated speed analogy. Watts is how fast you are burning energy. So if you have say 60 mph (analogous to 600 watts) and you went for 5 hours you would have covered 300 miles (analogous to 3000 watts*hr). In this analogy the miles are analogous to Joules which is a measure of energy. Watts is Joules/sec

Another way to remember is that your total energy usage (as measured by the meter) is 3000 Kw*hr which represents the energy you used at a rate of 600 watts over a period of 5 hour.

Yet another way, when the equipment is on it is using 600 watts. For discussion purposes is more or less constant. The longer you leave it on the more energy you use and the Kw-hr keep going up while the Kw stay the same(unless you turn the equipment off).

[SolarSoundMan]

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?

Dan, thanks very much for the links! I have been looking at them and there is allot of information in them as well as explanations of values we have been discussing here. I feel I am slowly getting a grip on some of this terminology. I am not sure how you found these links but I have done searches for portable solar systems and not come up with anything like this! I will be calling some of these company's to see what ideas they may have to help me. A trailer is not really what I wanted but it may be the best and simplest option for a mobil solar system.

As far as my budget I am still not sure? If I can find the right system that I know will do what I want it to do (including using it at my home when not using it to power my sound system) I would probably be inclined to spend more. This is a very exciting adventure for me! I want to TRY and make the best decisions the first time around. I realize you have to make mistakes sometimes to learn but that is also how you learn. Thanks again for all of this info! This will keep me busy asking more questions and learning what I will need to make the dream of having a solar power sound system become a reality!

[DanKegel]

As far as my budget I am still not sure?

Put another way, how much money do you spend on power now,
and how much extra income could you make if you had a visibly and attractively
"green" power solution for your gigs?

[SolarSoundMan]

for the op:

There is a little bit of loose terminology going on in this thread. I have seen "watts per hour" used twice to represent 3000 kw*hr consumed in 5 hours.

Watts is power which is a rate of energy consumption (i.e. Kw*hr per hr of just kw). "watts per hour" is an energy acceleration not an energy rate and i don't think anybody means to describe such a thing.

600 watts for 5 hours would be a proper statement. If you ever need a mental reminder, just remember that watts is rate and there is an associated speed analogy. Watts is how fast you are burning energy. So if you have say 60 mph (analogous to 600 watts) and you went for 5 hours you would have covered 300 miles (analogous to 3000 watts*hr). In this analogy the miles are analogous to joules which is a measure of energy. Watts is joules/sec

another way to remember is that your total energy usage (as measured by the meter) is 3000 kw*hr which represents the energy you used at a rate of 600 watts over a period of 5 hour.

Yet another way, when the equipment is on it is using 600 watts. For discussion purposes is more or less constant. The longer you leave it on the more energy you use and the kw-hr keep going up while the kw stay the same(unless you turn the equipment off).

>i am sorry as i have probably been guilty of this at least one of those times (maybe both) but i am also trying to understand the differences. My kill a watt meter for what i assume is kilowatts has in capital letters KWH. I understand that to be kilowatt hours. So that is the value i thought i was referencing when i tested the sound system.*

> thanks for the examples, it may sound easy, and i will do my best to understand it.

> i believe i understand what you are saying in the last paragraph, i am just not sure how to apply it for my application? [/quote]

[SolarSoundMan]

Put another way, how much money do you spend on power now,
and how much extra income could you make if you had a visibly and attractively
"green" power solution for your gigs?

When you say " how much money do I spend on power now"? I assume you mean at my home? If so I would guess an average of $100 month. This does not include coal I use for 6 months a year to heat the house, cost for that is $800-$900 for that 6 mo. My plan is to stop using coal and hopefully use the solar power system to supplement our electric bill and to use electric heat. I do not spend much when I am out doing shows as there is usually power available or I have to rent a generator.

To answer your question "how much extra income could I make if I had a visibly and attractively
"green" power solution for my gigs?" I don't know for sure? I do know that I like the idea of using solar power after getting a taste of it at the festival where I got to experience it. I have been spreading the word about my plans to have this type of system and the people I have been talking to are very receptive to the idea even to the point of having full promotion for the shows using solar power. I am now getting involved with others who are hosting solar power events and are reaching out to me as they know I am trying to go green with my business and now with the solar sound system they are very excited.

I believe the potential is there to keep making a living not getting rich, I have been in business for 23 years making a living doing what I love to do. As they say, it's not work when you like what you do! The thought of having a solar sound system, although complex learning what I will need to make it happen has been fun so far! This would be the only solar power sound system in my area. I believe that once people see it, hear it, and know that it is a sustainable system others will want to have this as part of their event! So far everything has been positive to be able to offer this. Being part of and having the experience with different festivals I am hoping to be able to have my own sustainable festival in this area.

I am not sure if that answers your questions? In a nut shell I believe the potential is there for this to become a success and be a very integral part of my business!

[bcroe]

>i am sorry as i have probably been guilty of this at least one of those times (maybe both) but i am also trying to understand the differences. My kill a watt meter for what i assume is kilowatts has in capital letters KWH. I understand that to be kilowatt hours. So that is the value i thought i was referencing when i tested the sound system.*

> thanks for the examples, it may sound easy, and i will do my best to understand it.

> i believe i understand what you are saying in the last paragraph, i am just not sure how to apply it for my application?

[/QUOTE]

Your "kill a watt" meter is capable of measuring both instantaneous power (KW), and accumulated
total energy over time (KWH). Just a matter of picking the range. Bruce Roe

[SolarSoundMan]

Your "kill a watt" meter is capable of measuring both instantaneous power (KW), and accumulated
total energy over time (KWH). Just a matter of picking the range. Bruce Roe[/QUOTE]

Bruce, when I got the meter to do as you suggested to see how much power I was drawing from the sound system to determine how big of a battery bank I would need I was referring to the KWH scale. In 5 hours it used 1.5 KWH.

When you say my meter will show "instantaneous power", is that watts? I'd do see watts listed on the meter but I don't see anything that shows KW but I will double check that.

[bcroe]

Your "kill a watt" meter is capable of measuring both instantaneous power (KW), and accumulated
total energy over time (KWH). Just a matter of picking the range. Bruce Roe

Bruce, when I got the meter to do as you suggested to see how much power I was drawing from the sound system to determine how big of a battery bank I would need I was referring to the KWH scale. In 5 hours it used 1.5 KWH.

When you say my meter will show "instantaneous power", is that watts? I'd do see watts listed on the meter but I don't see anything that shows KW but I will double check that.[/QUOTE]

OK, it directly displays watts. 1000 W = 1 KW. Bruce