Alternative use of the screwdriver battery.

[costi_b]

Hi:
I am trying to use a screwdriver battery to power a class D amplifier.
My problem is that the battery automatically disconnects the output voltage after a few tens of seconds. This happens both when empty and with the amplifier connected.
If I connect a constant load of 150 mA it does not stop.
If I connect the constant load in parallel with the amplifier it still disconnects.
It is about a Lexman Li-Ion battery, 20 V, 2.5 Ah.
It seems that it complies with the UP20 (Universal Power 20V) specification, about which I did not find much information.
Do you know a method to be able to use it?
I have several batteries of this model and they would be extremely practical for powering the boombox.
Battery model:
https://www.leroymerlin.ro/produse/accesorii-unelte-motorizate/1053/acumulator-lexman-li-ion-20-v-2.5-ah/126814