Looking into connecting a dual batterypack to my Fenix HP12, a dual Magicshine 7.4v pack, cutting he cable and inserting a Magicshine plug on the HP12. This is a single 18650 battery lamp, both using the same Cree XM L2, so the regulator must be different in the lamps. So switching so serial connection in the pack or using a generic dual 18650 batterycase. With a dual pack, I can use turbo mode twice as long.