12v or 24v for a small "Music Studio"

[HelloSean]

Hello everyone!

I am new here and have been learing A LOT about building my own off the grid solar system. I thought I was all good to go until I came across 12v or 24v. I am now hearing 24v may be cheaper and more efficient? What confused me there is now you cant just get a regular inverter for regular household devices? what would you use to convert the 24v to run the 12v devices? could a charge controller do that along with a 12v inverter? SunKing really seems to know a lot around here, its like he made solar panel talk or something, but he said in a thread I read dont go more than 1000W with 12v inverter? What I really am trying to run off this solar grid is i think at MOST 1000W. I am confused on calculating My 100W Egnater Vengeance Guitar tube amp head with 4x12 speaker cab. I heard tube amp output is using more much more than 100W like its labeled as? I am thinking of getting a Killowatt meter to get accurate readings of what im plugging in. Basicallly 1 - 100w tube amp head, and 1 120w tube amp head. and a computer (heard up to 250W power consumed?) and a ceiling fan with light for maybe MAX 5 hours a day if that. I was orginally going to do 4 - 6V batteries wired in 12v. Coming across the 12v vs 24v idea got me re-thinking and wondering how that would even convert through?

Sorry for the long rant and THANK YOU SO MUCH ahead of time for any responses!

-HelloSean

[Matrix]

What confused me there is now you cant just get a regular inverter for regular household devices? what would you use to convert the 24v to run the 12v devices?

What will you be running in a studio that is 12v directly connected? Are you wanting to connect some devices direct to the battery? Most 12v "studio" gear (pedals etc) run 12v thru a 120v wall wort. Is all your needs 120v AC? Then it does not matter the input voltage of the inverter, if it is sold in N America it will output 120v. I would consider a 24v or even a 48v system as I think 12v systems are limiting and more inefficient. And I would get a Pure Sine Wave inverter for a studio.

On your load calculations, you are not concerned with what the label says the Watts of an amp or device is, what matters is Watt Hours used in a 24 hour period. This is the only way to calculate loads. If you use a Killowatt meter, connected it to each device separately and run it for several days noting the number of hours it ran. Try to get in the several days worth and then break that down to a 24 hour period. Then you will get a really good indication of your Watt hours for each device in a 24 hour period. Also, spend a little extra and get the Killowatt meter with the battery. Will save you a lot of hassle the first time you unplug the Killowatt meter before reading the data.

[HelloSean]

Thanks for the reply!

Well yes what I was intially thinking if i went with a 12v system, 4 6v batteries (or as needed), then just get a 2 or 3 prong 1500-2000w (whatever needed) inverter to plug in devices with the inverter. By the way can you run like a 3 input adapter for 3 prong inputs to run more things as long as it doesn't go over listed watts. Reason I would get a killowatt meter is because I am unsure how to correctly add or figure out watts used when I have heard 100W tube amps can give out maybe 200+ watts, Then say solid state amps is more accurate to the wattage of the amp, but tubes are a bit more than the "100watts" not sure if thats true or not? Would the Volts x Amps = watts equation be more accurate in MAX (volume knob wont be on 10) watts? I figure use a kilowatt meter if anything and should show close to correct?
I know about adding up the hours for Watt hours a day. Isnt that how you do it you take the output wattage of device and x it by number of hours you use it? which would be no more than 5. I am just confused on the TUBE amp saying 100w amplifier head but hearing they are half or more higher than that in real wattage output.

So if I did go 24v, which seems to be recommended and as you suggested. Would i still use 6 v batteries to get that 24v? You are saying the inverter wouldnt matter if it was 12v or 24v, just get one it will handle any device you would plug into a wall 3 prong socket? and yes I would be plugging things you would plug into any wall outlet (3 prong) device. Amps. computer. monitor. MAYBE PA system but id have to build the system bigger. PA system would be atleast another 75watts to 100 or so. that was just thought of now thought actually.

Thanks you are really helping me out here. I am literally a newbie but have been researching pretty good for several days now trying to come up the final solution to it all when the room is built.(12x12 room in the backyard) Doing it here little by little as weekends are free from the day job and money is accumulated for the materials again.

p.S. I can look this up but just for conversation. I understand how to wire series and parallel 4 6v to get a 12v system, but now how would i go about wiring the 24v syste, am i going to use 12v instead of 6v batteries and then like you say i can just use any inverter, wattage permitted, to plug in "3 prong home wall outlet" devices, which is 120Vac right? (learned from you) They say 12V works better on 6v but what would a 24v system work better off of 6v or 12v batteries?

OH 1 more thing! solar panels! 24v or 12v or doesn't matter? I understand the charging controller converts no matter which ones you have or dont have so it doesn't matter (correct?), but whats better? series/parallel?

Breaker no breaker? I know I will be wiring fuses to all the postive connections between the solar system set up right? Not sure if a breaker is necessary. If its not to complicated Ill tackle it but if its not necessary cool!

Thanks a lot for the guidance!

[Matrix]

Let's Take this one piece at a time. And hopefully someone way more qualified will jump in and fill in the blanks.

First, why are you setting up an off-grid studio? Is grid power not available? If this is a small shed or building with no power off a main grid tied house, you would be lower cost to trench a sub-panel out to the building. Why go Off-Grid?

Well yes what I was intially thinking if i went with a 12v system, 4 6v batteries (or as needed), then just get a 2 or 3 prong 1500-2000w (whatever needed) inverter to plug in devices with the inverter. By the way can you run like a 3 input adapter for 3 prong inputs to run more things as long as it doesn't go over listed watts.

Your battery banks size and inverter should be based on loads. You cannot know loads until you do your load calculations. I would think a hard wired inverter with a load panel (breaker box) and wired outlets would be better than a plug type if you were setting up a permanent studio in a building.

Reason I would get a killowatt meter is because I am unsure how to correctly add or figure out watts used when I have heard 100W tube amps can give out maybe 200+ watts, Then say solid state amps is more accurate to the wattage of the amp, but tubes are a bit more than the "100watts" not sure if thats true or not? Would the Volts x Amps = watts equation be more accurate in MAX (volume knob wont be on 10) watts? I figure use a kilowatt meter if anything and should show close to correct?
I know about adding up the hours for Watt hours a day. Isnt that how you do it you take the output wattage of device and x it by number of hours you use it? which would be no more than 5. I am just confused on the TUBE amp saying 100w amplifier head but hearing they are half or more higher than that in real wattage output.

More or less correct. But a Kill-a-watt meter used on a device over an extended period of time will give you a really good picture of daily Watt hours - for that device. for instance, I used one on my fridge for about 51 hours. Then divided the Watts used by the number of hours the device was connected to the meter and multiplied that by 24. This gives you a really good idea on your daily needs. You would want to test an amp for the total time you have it one over several days in various conditions from idle to playing at full volume.

So if I did go 24v, which seems to be recommended and as you suggested. Would i still use 6 v batteries to get that 24v? You are saying the inverter wouldnt matter if it was 12v or 24v, just get one it will handle any device you would plug into a wall 3 prong socket? and yes I would be plugging things you would plug into any wall outlet (3 prong) device. Amps. computer. monitor. MAYBE PA system but id have to build the system bigger. PA system would be atleast another 75watts to 100 or so. that was just thought of now thought actually.

Inverters are 12v/24v/48v Input. This has nothing to do with output. Out put (in North America) is either 120v or 240v split phase in small inverters.

I understand how to wire series and parallel 4 6v to get a 12v system, but now how would i go about wiring the 24v syste, am i going to use 12v instead of 6v batteries and then like you say i can just use any inverter, wattage permitted, to plug in "3 prong home wall outlet" devices, which is 120Vac right? (learned from you) They say 12V works better on 6v but what would a 24v system work better off of 6v or 12v batteries?

You wire 6v batteries in series to achieve whatever input voltage the inverter input requires. 6v x 2 for 12v or 6v x 4 for 24v etc. You can get 220ish ah 6v golf cart batteries for around $110-180 give or take. 4 220ah golf cart batteries (GC) wired in series would give you 24v. 24 x 220 = 5,280 Watt Hours of storage. But you do not want to discharge those batteries more than 50% (and 70% SOC - state of charge - would be better). But 5,280 x .5 = 2,640 usable Watt Hours.

This is why load calculations are critical BEFORE you buy equipment.

1. Determine your loads in Daily Watt Hours
2. Determine how many days your system should run without sun: number of cloudy days with out sun
3. This will tell you the battery bank size you need
4. And the battery bank size will tell you how big your solar array needs to be to get the bank charged back up with in the available sun hours (and do not make the mistake of assuming sun hours is sun up to sun down. At best in North American your solar exposure in Miami will be 4.5 hours, in Seattle it's 1.4 hours. That means you will have to build an array large enough to charge the battery bank you chose back to 100% in that amount of time.
5. Plan a charge controller that will accommodate the array size you need.
6. Buy a generator for days when there is no sun (this means that you either buy an extra charger or buy an inverter that also has a charger)

OH 1 more thing! solar panels! 24v or 12v or doesn't matter? I understand the charging controller converts no matter which ones you have or dont have so it doesn't matter (correct?), but whats better? series/parallel?

Get an MPPT charge controller and it will not matter. Then you can use the cheaper Grid-Tie type panels. You can use the large 250 and up size. I use 9 285watt REC twinpeak 2 panels to supply my 435 ah 24v battery bank. My daily Watt hour needs are about 3200 Watt hours. I discharge to about 70% SOC each day.

Breaker no breaker? I know I will be wiring fuses to all the postive connections between the solar system set up right? Not sure if a breaker is necessary. If its not to complicated Ill tackle it but if its not necessary cool!

Yes breakers.
If you have 3 series strings of panels or more, you will need a combiner box with DC breakers at or near the array. You will want another DC breaker where the + and - come in to the building from the array in another box. You will need the appropriate size breaker from between the battery and inverter. You will need battery cable from the battery to that breaker based on the number of amps that will be drawn off the battery at any given time.

If you design for 12v x 1000 watts that is 83 amps
if you design for 24v x 2000 watts that is 83 amps
if you design for 48v x 4000 watts that is 83 amps

You see where this is going ... load calculation is critical. If you need 4000 watts for 10 minutes (not Watt Hours) and you build a 12v system, you will be pulling 333 amps from the batteries. Too much or very large and expensive battery bank, Huge wire, Huge DC breaker, Dangerous. See where this is going? Read the Off-Grid Sticky posts in this forum.

Load Calculations first. And after than, Add up what it will all cost, and then ask yourself, "Why am I not just connecting this to the grid an paying .08-.35 per kWh rather than paying over a dollar per kWh off grid."

Your reason may be valid, but it needs to be asked. But the bottom line - Being off grid will NOT be cheaper. (and IMHO does not save the planet)

[Matrix]

I have no idea what your loads may be and how many Watt Hours you will need, But if you want to know what it takes to build a Medium sized 3200 Watt Hour system, this is what i did

Other things to consider, Will I need permits? Will it be inspected? Will the insurance company cover if I burn my house down due to faulty wiring? What about my neighbors house? Will I also be required to design in a Rapid Shut down System? And what about Grounding? You are dealing with sensitive hi tech equipment in a studio. How will you protect the gear from buzzing, having buzzing in your recordings, grounding, overload protection, etc.

Yes I know what I am talking about. I have a studio I built. 2 computers, Live Broadcast equipment, Presonus StudioLive 32 digital console, DBX Drive Rack, 5 amplifiers, 5 FOH Renkus Heinz top boxes and a Sub. I do not, could not and would not run this system off grid.

[HelloSean]

MATRIX!

Hows the week going? I would definitely agree you know what you are talking about. Thanks so much for all the teaching. You have really cleared up a lot of things I was questioning.
I guess I didn't realize that it would actually be more a kwh to run off grid then on. I kind of thought it as being more like a project, but as you say, not as efficient and a bit complicated. You have a pretty big studio, sounds sweet! We were just thinking of running it mainly for practice with 2 guitar amps up to 100-120watts, maybe a small couple hundred watt p.a. maybe for up to about 4 hours a day IF that, and not everyday.

Would be thinking if mainly 2 100w guitar amps running, plus computer once in a while, and a small (just for vocals) P.A. once in a while, it would add up to somewhere around 600ish watts an hour for up to 4 hours. But, I dont know, maybe we should just extension out of the house like you were saying. Its an older house with older electrical, sometimes if we have a bunch of stuff running inside at once we trip the breakers and blow the old round circular glass fuses. I suppose it could handle it though, it doesnt happen often. Maybe if we have those plug in heaters running, and the microwave and just everything running at once in house.

Anyways, Thank you so much for the guidance, you have really helped and cleared up a lot of things. This stuff is just all very interesting to me, and i always like learning about new things. A lot of stuff interest me and this is one that popped into my mind recently. Maybe its more of a hassle and I should just plug in to the grid. It is just cool learning about it regardless and cool they have sites like this with people like you to help others learn new fun things.

Thanks a lot! I'll be back on here maybe can check over new thoughts or questions. So far its been great!

[Mike90250]

A couple 12V led lights and a car radio is a small system, worth playing with in an outbuilding. Much more than that, and you are looking at serious money

[Matrix]

FYI... Mike knows his stuff. I'm a hobbiest.

[Sunking]

So please answer this question because you really do not know much about solar and this is the most important question you MUST ANSWER and you cannot lie to yourself unless you are a democrat?

Why on earth do you want to pay 10 times more for power with extreme daily power limitations, and become a heavy polluter robbing future generations of energy resources? .

In other words you have a choice to pay 10 to 15-cents per Kwh from the power company, or make it yourself for $1.50 to $2.00 per Kwh. In addition you are very limited to how much power you can generate and use in a day, vs no limitations of the utility. Last is why do you want to become a very heavy polluter and rod our children of energy resources. Off-Grid Solar has a Negative EROI which means you input a lot more energy than you get out of of.

To build a system that generates 1 Kwh per day using off-grid solar is going to cost you right up front $1500 to $2000 with $750 of that in battery cost alone you replace every 2 or 3 years. All amplifiers use a lot more than their rated output capacity. Class A/B transistor amplifiers run at roughly 40 to 50% efficiency, tube amps are less efficient because they require heaters which consumes power. So that 100 watt amp will draw more than 200 watts. If your system is only a toy sized system of $1500 gives you less than 20 minutes per day. Well that might be a good thing because your ears will not be exposed to loud noises causing you to go death like most musicians.

So I repeat my question:

Why on earth do you want to pay 10 times more for power with extreme daily power limitations, and become a heavy polluter robbing future generations of energy resources? .

Let me guess. It makes you feel good and look cool.