Near field resonant inductive coupling to power electronic devices dispersed in water

► We investigate inductive coupling to wirelessly power electronic devices dispersed in water. ► We calculate and measure the wireless energy transfer efficiency. ► We identify the parameters which increase the efficiency. ► Energy transfer efficiencies are higher than 75% between one large coil and 18 small coils. ► Inductive coupling is a promising technology to power electronic devices dispersed in water.