How to pick best battery for amplifier?

Hello, I ordered this amplifier and I need to pick best battery for this amplifier. Would be great to power it for at least 3-4 hours on maximum volume (200W rms subwoofer and 2x50W rms speakers). I need lightweight battery and powerful battery, size does not matter, budget is low so nothing overpriced I do not want.

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bassbindevil3 months ago

Unless you listen to music with no dynamic range (or have it cranked up to full clipping), the average power consumption should be about 1/10 of maximum, roughly 25 watts. Two 7Ah 12v SLA batteries may be enough.

iceng4 months ago

Want infinity for a penny, yea you do !.

Walmart has a lipo car starter smart battery for $90 about the size 16oz drink bottle and it is amazing... Recharges on a wallwart or through the car lighter. Supplies a gargantuan output, a USB, charge level and even has a flash light.

Neat, but typically 25 Ah capacity....

Even worse 12 Ah at 450 A...

Lipo12Ah_450A_Batt.JPG
steveastrouk4 months ago

Lets do some rough maths. 200W+100W =300W. 300W for 4 hours is 1200Wh. Lets make it a 24V battery, thats 1200/24 Amp hours, or 50Ah. Using normal SLA would be least expensive, and allowing for longest life, you want to only take about 30% of the battery's capacity, so your batteries REALLY need to be around 150Ah. That's for maximum life, 400 cycles of charged to flat.

Those are BIG HEAVY batteries, inevitable, because of the large load. It is VERY unlikely you will be able to use all channels at full power all the time, so make some allowances.

RobertasP4 (author)  steveastrouk4 months ago

Oh my.... I thought about connecting 24V 7Ah battery... :/ Or maybe buying a lot of 18650 li-ion batteries. :/ Maybe I can make less power consumsion then somehow?

Like I said, the chances of you ever actually using the thing flat-out at 300W are very remote.

24V at 7Ah is 167 Wh, so BARELY more than 30 minutes, at full output.....

Downunder35m4 months ago

Asking twice with no patience won't usually bring more or better answers....