Replacing AA power source with 18650s

[jasonvincenzo]

A while back i made a pretty killer portable speaker out of a case, small amp, 2 decent speakers. Currently i have had it running off of 8 AA batteries to get the 12v dc that the amp takes. Right now it doesnt last very long and it does not like to get very loud. (i have tested with with 2 very nice shelf speakers and it got very loud when using the power supply) So i was wondering, i have a few old laptops and i use the 18650 cells in my camping flashlight and lantern. Would it be possible to use a few to power the amp? Sorry, new to this sort of thing.

The power supply that came with the amp outputs 12v and 3 amps.

Any more information needed and i can get it for you.

EDIT:

18650s and Samsung branded ICR18650-22F cells.
Just using normal AA Duracell coppertops.

[Zero999]

A while back i made a pretty killer portable speaker out of a case, small amp, 2 decent speakers. Currently i have had it running off of 8 AA batteries to get the 12v dc that the amp takes. Right now it doesnt last very long and it does not like to get very loud. (i have tested with with 2 very nice shelf speakers and it got very loud when using the power supply) So i was wondering, i have a few old laptops and i use the 18650 cells in my camping flashlight and lantern. Would it be possible to use a few to power the amp? Sorry, new to this sort of thing.

The power supply that came with the amp outputs 12v and 3 amps.

Any more information needed and i can get it for you.

EDIT:

18650s and Samsung branded ICR18650-22F cells.
Just using normal AA Duracell coppertops.

Have you tried connecting a large capacitor, 10 000µF, in parallel with the 8 AA cells? The voltage might be dropping when the audio power reaches its peak. Adding capacitors will reduce the AC impedance of the supply, allowing it to provide high current spikes.

Have you measured the voltage of the power supply the amplifier came with? It might actually be more than 12V, which would mean you need more than 8 AA cells.

The AA cells probably still have lots of charge left in them when the amplifier. Try measuring the voltage when the amplifier stops working or sounds distorted.

Yes, you can replace the AA cells with lithium ion but the problem is charging them and ensuring they don't discharge too much, which can cause them to fail which makes any attempts at recharging them dangerous.

[amyk]

With 18650s you'll need to put the cells in series and use one of the various cell-protection ICs to stop any individual one from being overcharged/discharged. If you don't mind taking the cells out and charging them individually, then the circuit becomes much simpler.