There is a difference in voltage between rechargeable batteries and ordinary dry batteries. I don't know if you have noticed that the voltage of rechargeable battery is 1.2V, which means that when the battery is fully charged, it is only 1.2V, while the voltage of dry battery is 1.5V, so the voltage difference between each battery is 0.3V I don't know how many batteries you have connected in series, but the voltage difference is too big. It is not that there is no electricity here, but that the voltage is too low.