Battery Powered Sound Rig

Dynyd

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Oct 11, 2017
Location
Santa Barbara, CA
Hey all,

I'm curious if anyone has done anything similar as I find myself trying to prep for a show that will be faaaaaar away from a source of power.

Here are the show requirements:
Mixing console
Q-lab on a Macbook
8 Channels of wireless microphones
2 P.A. speakers
3 hour long show.

The P.A. speakers I think are a non-problem as they exist ready to buy and can last the show (or at least get to intermission for a battery swap).

A good quiet generator I understand is probably the preferable option to power everything; but I'm worried that this will be a fairly loud option for the type of show we are trying to produce.

I'm curious if anyone has had any luck with creating an almost entirely battery operated sound rig, my power consumption is looking to be about 200W max (less the speakers). I'm looking at the Furman F-1500 UPS (with external backup batteries) and wondering if it can't power all I need for cheaper and quieter than a generator (assuming it doesn't beep to let me know I'm not plugged in of course).

I figure the power needs should be good go as the Furman backup batteries are (8 cells) 12V with 9Ah each; I figure with a PF of 0.6 I should get about 2 1/2 hours out of 1 battery.

But I have no real world experience trying to make a UPS run my rig by its lonesome. If it turns out this is infeasible any recommendations for quiet, relatively low cost generators (or how to make them quiet?)

Any and all thoughts or suggestions are appreciated!

-D
 

DrewE

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Mar 18, 2019
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Vermont
My suggestion: buy or rent an inverter generator, such as the Honda EU2200i, and a long enough extension cord that it can be a little ways away. They are remarkably quiet, particularly under a fairly light load, and will reliably provide sufficient power without much futzing about or having to haul a lot of heavy junk around. I know that's probably not what you want to hear, but I really think it would be the best result and possibly the most economical in the end. At the very least, rent or borrow one to see how the noise is in actual practice.

Your UPS has nowhere near enough battery power to support 200W for 2 1/2 hours. 9 Ah at 12V is 108 watt-hours, and the inverter is probably about 80% efficient at most, which means about 85 Wh total until the batteries are entirely discharged. If they're lead acid batteries, it's best not to discharge below about 50% capacity or they will not survive many cycles at all, so you're down to maybe 60 Wh or a tenth of what you compute your (worst-case) need is. Also check to see if the output of the inverter is pure sine wave or modified sine wave; if it's an inexpensive inverter (or UPS), it's highly likely to be "modified sine wave", or basically a discontinuous square wave, and that can very, very easily lead to noise entering audio signals. In general, most (consumer-grade) UPSs are designed mainly to give enough power for you to properly shut down your desktop computer when the power goes off, and not much more than that.

Similarly, make very sure that the speakers you're looking at will actually provide the runtime you need at the sound levels you need. Many of the cheap battery powered ones are more or less overrated in terms of power and/or runtime--sometimes vastly overrated--presumably on the assumption that they will generally be used more as a boombox than an actual PA speaker.

I suspect the most economical battery power solution (that would stand a chance of lasting well with some care--as in a couple seasons or more) would be a pair of 6V GC2 golf cart batteries, wired in series to make a 12V battery, and a pure sine wave inverter of perhaps 1000W capacity, or as needed. The UPS part (switching from line to inverter power automatically) is not needed here. GC2 batteries can generally be had for $100-$120 each from Sam's Club or BJ's, and are genuine deep-cycle batteries, as opposed to car batteries that are not designed to be discharged too deeply but rather to be able to supply high current for a short time when starting the vehicle. 1000W pure sine wave inverters from known companies start at around $300ish. By the time you add in suitable cables and a fuse and some way of toting it all around, you've spent about as much as a new Champion inverter generator, and are well on the way towards buying a Honda one.
 

egilson1

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My buddy does this exact thing, charging his batteries via solar panels.

 
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StradivariusBone

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I'd second the Honda inverter gennies. We rented lighting/staging for a Christmas outdoor event and the company brought two. They were parked maybe 200' from the stage and the noise was negligible. The tradeoff for that vs. a battery array would be you know pretty accurately how much runtime remains with a gas powered generator vs. a battery setup you put together.
 

FMEng

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Tool and machine rental places have small, diesel generators, on trailers, in the 10-30 kW size range. I have seen some that were so quiet that I had to get within 30 feet of them to even tell they were running, quieter than a Honda.
 

macsound

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Jun 15, 2018
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San Francisco, CA
I think it does become a cost tradeoff. Knowing the Honda generator will run as long as it has gas but hoping the portable power station will last is rough.

Personally, I've used the Honda EU2200i on a parade float with 4 UPAs, 1USW, 6 wireless HHs, and an LS9 for about 5 hours. The generator was so quiet at idle and it only increased engine speed as we increased volume output, so we could never hear it, and it was only about 10' since we were all on a truck trailer.

In other uses like for filming, positioning a generator on the other side of a bush and leaning a sheet of plywood against the bush helps with distance, sound diffusion and reflecting the sound away from your intended audience.
 

steine

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Denmark
A different take, that I have used a few times:

The Wireless receivers are most likely with a 120(240) to 12V psu
Perhaps you could find a console with 12V psu as well

That way you could run the receivers and console direct of 12v batteries, and eliminate the 12-120 + 120-12 up/down conversions
(not to mention the hassle with pure/modified sine wave)

Only the speakers would require the inverter then.

We did that with a walking show once, running most direct from 12V and the two power speakers as the only ones via an inverter.
 

MRW Lights

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Jan 4, 2017
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NYC
So here's how we do it in the film world, if you get yourself a DC powered mixer this rack mounted cart battery system which is also expandable will do the ticket. Lots of nifty accessories are out there too that let you monitor amperage and watts and all that sparky stuff. Get it AC when you can and it should do the trick.

Though I will also second that a generator is still the "best" option if you can swing it. You always need more power!

https://remoteaudio.com/products/power/meon-life/
 

macsound

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Jun 15, 2018
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San Francisco, CA
And while we're all talking about our experiences and best practices, nothing beats a real test. Buy or rent the thing you want, charge it up or fill with gas and do your expected show.

Make sure to set a stopwatch so you get real results. Even add a Kill A Watt so you can keep track of your draw.

Recently I was wondering if I could put 3 of these powered speakers on a single circuit since the manufacturer rated them at 2000 watts, I had no earthly idea how much AC power they actually drew. Hooked up the Kill A Watt and found if I ran them as loud as I could bear (not really, I'm not trying to make myself deaf) the unit displayed one speaker was drawing between 19 and 21 watts.

Reading labels and doing math is important but something can be said for a real-life test, with measurement, to solidify your theory.
 

Dynyd

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Oct 11, 2017
Location
Santa Barbara, CA
Thanks for all the advice everyone!

I'm leaning towards recommending a generator for this production now but it is great to know there is a solution with battery power too so long as we can keep it in the 12V supply range.

-M
 

MRW Lights

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Jan 4, 2017
Location
NYC
Milwaukee makes a nice battery-powered generator. This would have no noise and no exhaust compared to a gas-powered generator. Maybe a local tool rental house has one to rent.
https://www.milwaukeetool.com/Products/Equipment/Power-Supply/MXF002-2XC
I might be mistaken, but I don't think they're rated for a continuous load. At least not for any significant period of time. Now I'm wondering how many scene changes on my QL5 equates to a 1000w microwave meal... and is that a Kids Cuisine or a Hungry Man? How many scene changes do I have to sacrifice for my dino nuggets? Decisions Decisions....🤔
 

EmilBarnabas

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Feb 27, 2012
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Raleigh NC
The description on the website says "1800 continuous watts of pure sine inverter energy, powering everything from your high demand 15A tools to sensitive electronics." They are designed to give contractors power working inside buildings when there is no electricity and no place to vent the exhaust. They truly are like a battery-powered generator. The power output is no different than a gas-powered generator, using a large UPS, or using a Tesla to power your sound system.
 

EmilBarnabas

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Feb 27, 2012
Location
Raleigh NC
I poked around and found this specification for the Milwalkee Power Supply. "With two MX FUEL XC406 extended run battery packs, you get 864 Wh (Watt-hours) of power."
You said you have a draw of 200 watts, so that means about 4 hours run time. You actually said "my power consumption is looking to be about 200W max (less the speakers)." Have you figured out what the power requirement will be with the speakers? Hook up the system and run it with a Power meter, and see what your real power draw will be.
 

Malabaristo

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Jul 11, 2008
Location
Wisconsin
This video gives a less than stellar review of the Milwaukee product, although some of the criticisms are more opinion than practical (depending on your priorities). Also, it does have an always-on cooling fan--still quieter than an actual generator, but not silent. The comments mentioned Jackery Power Stations as better (and cheaper) alternatives, with a few different size options.

A local rental place has 1600W Honda Inverter generators for about $150/week, so for a one-time gig that's probably the direction I would go. There's something to be said for being able to just add more gas if you need it rather than possibly getting stuck with dead batteries if something unexpected happens.
 

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