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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Louis Miller on June 18, 2019, 10:35:22 am

Title: Will This Lithium Battery Pack Run My Powered Speakers For Busking?
Post by: Louis Miller on June 18, 2019, 10:35:22 am
Hi Forum,

I'm planning to busk using two Yamaha msr100 powered speakers, rated at 70W power consumption, and I'm interested in purchasing a lithium ion battery pack.  Can anyone help me to know if a battery pack such as this one

https://www.amazon.com/ExpertPower-Portable-Generator-Inverter-Emergency/dp/B07KXDDX7Z/ref=sr_1_1_sspa?crid=R1UCSDMQ38RU&keywords=lithium%2Bgenerator&qid=1560866486&s=lawn-garden&sprefix=lithium%2Clawngarden%2C179&sr=1-1-spons&th=1

or perhaps this one

https://www.amazon.com/ExpertPower-Portable-Generator-Inverter-Emergency/dp/B07CYMCLDN/ref=sr_1_1_sspa?crid=R1UCSDMQ38RU&keywords=lithium%2Bgenerator&qid=1560866486&s=lawn-garden&sprefix=lithium%2Clawngarden%2C179&sr=1-1-spons&th=1

would be up to the task?   I'm not sure how to tell if  these will supply the necessary wattage/voltage/etc.

I hope to get at least 2.5 hours performance on a charge but won't likely turn the speakers past volume level 4.  Thanks!
Title: Re: Will This Lithium Battery Pack Run My Powered Speakers For Busking?
Post by: Art Welter on June 18, 2019, 02:05:46 pm
Hi Forum,

I'm planning to busk using two Yamaha msr100 powered speakers, rated at 70W power consumption, and I'm interested in purchasing a lithium ion battery pack. 
I hope to get at least 2.5 hours performance on a charge but won't likely turn the speakers past volume level 4.  Thanks!
Louis,

Either unit will work for what you want to do, though the larger unit providing 444 watt hours (that would be 444 watts for one hour, or 44 watts for 10 hours) would power a 2 x 70 watt load for about 3.1 hours.

Lithium batteries can actually provide their rated power far better than lead acid batteries, you'd probably need a 888 watt hour lead battery (weighing about 4 times more) to get equal output if drawing even close to 140 watt peaks.

The larger unit is a better value in terms of dollar per watt/hour and lighter weight per watt/hour, as well as having an aluminum frame compared to plastic.

Although your speakers are rated at 70W power consumption, they may average considerably less than that, I'd be surprised if the pair drew 70 watts average if not driven hard.

While we are at it- a pair of speakers require approximately 3dB (half) the power for the same SPL (sound pressure level) as one speaker, so could last twice as long on the same battery power. That said, if the electronics (amp, mixer, meter lights etc.) have a high parasitic loss, that is, draw 70 watts even when the amp is putting out only 1 watt, you might be better off using a single speaker.


Art