Hi i'm wanting to make a portable speaker, but i'm not sure how to power it. I want to use this this 2.1 2x50w + 100w bluetooth amp to power it, with 2 45w speakers and a 40w bass driver. The amp says it can take 12v-24v. I was looking at this 12v 3a battery pack. Its the perfect size for what I need and is a good price, but I wasn't sure if it would be enough to power everything. Is there any better way to power this?
The amp probably uses a tpa3116 or 3118 circuit. You can check the data sheet - 200 w is very optimistic - only possible with max supply voltage and 2 ohms bass driver. So, providing only 12 v you will have less power (around 25% of maximum) but also less maximum current, which is good and could be perfectly ok for a small box.
I built a portable bluetooth box with a similar amp and a power tool 18 volts 4Ah li-ion battery that gives plenty of volume and lasts nearly for ever ...
(... And welcome to the forum!)
I built a portable bluetooth box with a similar amp and a power tool 18 volts 4Ah li-ion battery that gives plenty of volume and lasts nearly for ever ...
(... And welcome to the forum!)
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Thanks for the info. I like the power tool battery idea. I can get a 24v kobalt battery and get an adapter. A 1.5Ah or a 2.0Ah would be best because they are smaller. This is the adapter. Do I just connect the wires to a plug like this and then im good to go?
Maybe, but you´ll have 15 minutes running time, as mentioned above.
Divide amp consumption in A by battery A/H and you´ll get running time.
Since advertised values are optimistic, halve them.
With 12 v and 6Ah?
I think it will last very long, if not driven constantly at the limit.
A TPA3116 is what I'd consider low power, and efficient. Perfect candidate for a battery powered bluetooth speaker imo.
Let's be realistic - A TPA3116 will make about 2x10W into 8ohm loads or 1x20W into a 4ohm load with a 12V powersupply. The amps that have a stereo output AND subwoofer output generally have two TPA3116 amplifiers in them so you get 2x10W + 20W.
Running it at 'max volume' on music, even clipping slightly, you won't even consume 20W per amp from the battery but let's assume you do.
12V * 6Ah = 72Watt hours, so it will last close to 2 hours. Practically I think you will see more like 3-4 hours out of it because music is not a sine wave test tone.
The 3A output capability is probably pushing things a bit but I think it will be ok - worst case you might melt the barrel plug running it at full tilt for a long time. If you could find a battery with a 12V @ 5A capability that would be safer.
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