I have encountered such requests before, and they also related to Yamaha electronic keyboards.
The answer depends on the situation
If the piano operates on direct current, for example 12V, the customer can be equipped with a suitable battery + protection card depending on the power of electronics. piano.
This situation is more likely. If it is AC work, in addition to a suitable battery + protection board, you also need an inverter with slightly higher power than the electronic keypad to reverse the DC power of the Battery. Operate the electronic keyboard.
With belt. Yamaha electronic keyboard SX900X700X600 outdoor mobile lithium battery 64000 mAh 16V mobile power supply, the Yamaha brand (Yamaha, Yamaha) was founded in Maebashi, Japan in 1887. Yamaha products range from keyboard instruments such as pianos, electric keyboardselectronics and synthesizers, to wind instruments such as brass and woodwinds, and to stringed instruments such as violins and cellos.