It is first time i hear about that risk of using rechargeable batteries...i m using them always more than a year without any problem. In the beginning it was GP recyko + Pro 2000mAh, and now it is DURACELL Duralock 2500mAh and they are amazing...4hours running. For practise i use also little usb speakers plugged in keyboard usb. If i need stronger sound i ve got LANEY 4x4 aku speakers two pieces, one can reach about 70 people, and working hours on li-ion batteries.