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Author Topic: Battery power for small PA  (Read 2458 times)

Brook Hovland

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Battery power for small PA
« on: June 07, 2017, 10:14:38 am »

Are any of you aware of and have any experience with battery packs that could power a small (think 2 QSC k12 on sticks) for a speech only event like a wedding or groundbreaking.
I am also looking at the anchor systems but packs that can be used for other tasks would be even better.
Appreciate any info.
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Nathan Riddle

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Re: Battery power for small PA
« Reply #1 on: June 07, 2017, 10:28:59 am »

A emergency car starter (with cig receptacle) and 300w power inverter works well.

I measured (forget measurements [I remember 2-2.5A and deep mode made it 3.3A, but I forget which voltage it was at :( ], but calculated the inverter/battery would last for 1-hr general music levels).

Honestly, I want to make some lithium-ion battery packs with 300w inverters for cheap (for K12's) and mod my LED lights to include the lithium-ion pack inside the fixture. They would be light and compact for their output/WH amount.
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Mike Sokol

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Re: Battery power for small PA
« Reply #2 on: June 07, 2017, 10:45:20 am »

A emergency car starter (with cig receptacle) and 300w power inverter works well.

I measured (forget measurements [I remember 2-2.5A and deep mode made it 3.3A, but I forget which voltage it was at :( ], but calculated the inverter/battery would last for 1-hr general music levels).

Honestly, I want to make some lithium-ion battery packs with 300w inverters for cheap (for K12's) and mod my LED lights to include the lithium-ion pack inside the fixture. They would be light and compact for their output/WH amount.

I've used something like this out the field for wedding audio when generators weren't allowed and we were 500 ft from any power source. https://www.amazon.com/Duracell-852-1807-Outlet-Rechargeable-Source/dp/B000S0VFTM

Worked really well, but be aware that many of these are not pure sine-wave inverters so they can add a little "buzz" to the audio. I've also been toying with the idea of putting up some big solar panels and using them to recharge a few of these battery packs for the hippie-green shows. That's actually getting traction with a few of the local solar cell installers offering to supply me a few panels for these gigs. Believe it or not, the "green" musicians say that the solar power sounds cleaner than that dirty AC from the coal power plants. I try not to roll my eyes while I ask how much "clean" power they need for a gig.

Nathan Riddle

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Re: Battery power for small PA
« Reply #3 on: June 07, 2017, 11:09:02 am »

I've used something like this out the field for wedding audio when generators weren't allowed and we were 500 ft from any power source. https://www.amazon.com/Duracell-852-1807-Outlet-Rechargeable-Source/dp/B000S0VFTM

Worked really well, but be aware that many of these are not pure sine-wave inverters so they can add a little "buzz" to the audio. I've also been toying with the idea of putting up some big solar panels and using them to recharge a few of these battery packs for the hippie-green shows. That's actually getting traction with a few of the local solar cell installers offering to supply me a few panels for these gigs. Believe it or not, the "green" musicians say that the solar power sounds cleaner than that dirty AC from the coal power plants. I try not to roll my eyes while I ask how much "clean" power they need for a gig.



Oh my goodness  :o I do have solar panels I could tell my promoters I can give them 'clean' "green" energy ;P

My thing with the Duracell is it is so expensive. A sine-wave inverter & deep cycle battery is wayyy cheaper. Though obviously it has risk involved now.

Also, with my setup there was no "buzz." On others though, that would certainly depend ;)
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Mike Sokol

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Re: Battery power for small PA
« Reply #4 on: June 07, 2017, 11:19:05 am »

Oh my goodness  :o I do have solar panels I could tell my promoters I can give them 'clean' "green" energy ;P

Yeah, I was having trouble not laughing when the solar panel guy suggested it. I have the same sort of reaction when the promoters start talking about their DJ "artists". Not sure why they need line-array monitors to play-back MP3s hacked up on a computer, but if they're willing to pay for it....  8)

Frank Koenig

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Re: Battery power for small PA
« Reply #5 on: June 07, 2017, 09:34:48 pm »

Some years ago I ran a small amplifier (with DC power input) directly from a 36 W photovoltaic array (PV, or "solar panel") with no intervening battery or other energy storage, just to see what would happen. I wasn't sure how the amp would like what's essentially a voltage-limited current source. It worked fine in full sun but any time someone cast a shadow on some part of the array the amplifier would break into wild synthy oscillations. Sort of WOOOOEEEEEZZZZIIIIIIP, which got everyone's attention.

The small array consisted of 33 single-crystal cells in series to achieve an open circuit voltage of ~16 V, suitable for charging 12 V nominal lead-acids, of course. Anytime one of those cells is even partially in the dark its impedance soars, effectively opening the entire series string, in this case causing the now current starved amp to break into song.

--Frank

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Frank DeWitt

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Re: Battery power for small PA
« Reply #6 on: June 07, 2017, 10:28:55 pm »

There are some you tubes of people building boxes with something like a Pelacan case. Batteries including Litheium,  a inverter, and a battery charger.  Some also use big folding soled panels.  I have been researching Litheium cells for a friend with a wheel chair that could use them.  Discharging them is not trickery.  Charging is, but the right chargers with cell balancing are readily available.
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Mike Sokol

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Re: Battery power for small PA
« Reply #7 on: June 08, 2017, 12:24:25 pm »

There are some you tubes of people building boxes with something like a Pelacan case. Batteries including Litheium,  a inverter, and a battery charger.  Some also use big folding soled panels.  I have been researching Litheium cells for a friend with a wheel chair that could use them.  Discharging them is not trickery.  Charging is, but the right chargers with cell balancing are readily available.

Maybe this: https://www.markertek.com/product/pv-150/tripplite-pv-150-ultra-compact-powerverter-150w-inverter at least I think it has a 12-volt cig lighter output.

and this: https://www.markertek.com/product/pv-150/tripplite-pv-150-ultra-compact-powerverter-150w-inverter

The price is right, and you just plug it together. You could get a little bigger 300-watt inverter for a few dollars more.

How long it would run on a charge depends on music crest factor and equalization, but the idea is valid.

Jay Barracato

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Re: Battery power for small PA
« Reply #8 on: June 08, 2017, 12:48:56 pm »

Hey Mike

I have one of the 7 amp Coleman solar panels for my camper. What I have found is that it is useless with any type of load on the battery. I am not sure but it sounds like there is some sort of relay in the control box with the blocking diode.

Sent from my XT1254 using Tapatalk

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Frank DeWitt

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Re: Battery power for small PA
« Reply #9 on: June 08, 2017, 01:08:36 pm »

This seems to be what people are trying to duplicate with DIY
https://www.amazon.com/Goal-Zero-Portable-Power-Station/dp/B007Q23YC6/ref=sr_1_4?ie=UTF8&qid=1496941152&sr=8-4&keywords=solar+generator+yeti

Lithium =  high price, and lower weight.    This one is Led Acid 103 lb and  1200Wh, 100Ah (12V)

the Lithium is 46 lb  Battery Capacity: 1425Wh (10.8V, 132Ah)
http://www.goalzero.com/p/424/goal-zero-yeti-1400-lithium-portable-power-station
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