Dmitry asks:
We have Dialog W-203 computer music speakers operating from a 220V network, I want to rewire them to operate on a battery, such as lithium-ion batteries 18650 standard with a capacity of 2600mAh, there is a question: how long will such a column work on one such battery and how many of them will be needed to work at least 12 hours
Alexander Myasoedov
You can connect from one battery, but you need a boost converter. It should be borne in mind that the power of these speakers, according to the characteristics, is 40W (yeah, despite the fact that the TDA2030 gives up to 18W, when powered from 18V and a load of 4 Ohms ...).
This means that the current consumed from one battery at its 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 18650 banks will give up to 30-40A, but there is already a problem with the converter - you will either have to connect in parallel common low-power converters (up to 2 amperes each) to increase the output current, or look for a powerful converter, or collect yourself.
Therefore, it is easier to assemble a battery of lithium batteries in series-parallel to provide the desired voltage and run time.
To calculate the operating time, convert milliampere-hours to watt-hours, that is, 3.7 * 2600/1000 = 9.6W / h.
In order for the column to play at maximum power for 1 hour, you need 40 W / h. This means that you already need 5 such batteries, regardless of the connection diagram and power supply solution (converter or series / parallel assembly).
In order for it to work 12 hours 5 * 12 = 60 pcs. Such a column will come out in gold and it is cheaper to buy the cheapest car lead-acid battery at once, with a capacity of at least 60 A / h. With a voltage of 12V, 720A / h in it, provided that it cannot be completely discharged, but only up to 40-50% - this capacity should be enough for you.
In practice, however, you probably won't be using it to its full potential. 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 with 1 column, so you can simply turn off the second one, then the power consumption will be 2 times less and the number of batteries will be halved times.
By the way, on aliexpress you can buy a batch of 40 pieces of 18650 at 100-115r / pc.
To obtain accurate data, you need to measure the consumption of the speakers in the operating mode in which they will be operated.
