How to transfer computer acoustics 2.0 powered by 18650 batteries?

And how are you going to make 220 from 3.7V? In general, the speakers have a power supply, the amplifier itself is powered from 4.5 to 25 volts (according to the Internet - it costs TDA2030). Most likely, the columns contain a 12V transformer power supply (you will find this out when you disassemble it. So you need to remove the power supply from the circuit and connect the batteries directly to the board.

You can connect from one battery, but you need a boost converter. At the same time, it is worth considering that the power of these speakers, according to the characteristics, is 40W (yeah, while the TDA2030 gives up to 18W, with power supply from 18V and a load of 4 Ohms ...).

This means that the current consumption from one battery at the peak at full volume will be about 10-12A, which means that the batteries and the converter must provide such a current.

Modern high-current lithium banks 18650 will give up to 30-40A, but there is already a problem with the converter - you will either have to connect the common low-power converters (up to 2 amperes each) in parallel to increase the output current, or look for a powerful converter, or assemble it yourself.

Therefore, it is easier to assemble a battery of lithium batteries in series and parallel to provide the desired voltage and runtime.
To calculate the operating time, convert milliamp hours to watt hours, i.e. 3.7 * 2600/1000 = 9.6 W / h.

For the column to play 1 hour at maximum power, you need 40 W / h. So you need already 5 of these batteries, regardless of the connection diagram and the solution for organizing the power supply (converter or series / parallel assembly).

In order for it to work 12 hours 5 * 12 = 60 pcs. Such a column will come out gold and it’s cheaper to buy a car lead battery immediately the cheapest, with a capacity of at least 60 Ah. At a voltage of 12V in it 720A / h, provided that it can not be completely discharged, but only up to 40-50% - this capacity should be enough for you.

In practice, most likely, you will not use it at full capacity. In addition, if you want to use it as a device for playing music somewhere in nature, then most likely it will be easier for you to carry 1 column with you, so you can just turn off the second one, then the power consumption will become 2 times less and the number of batteries is reduced by half.

By the way, on aliexpress you can buy a batch of 40 pieces from 18650 at 100-115r / pc.

In order to obtain accurate data, it is necessary to measure what consumption the columns have in the operating mode in which they will be exploited.