Is there anything one can plug the charging jack in to on most synths, and or laptops, namely a dell inspiron 3500 and a dectalk express that would give me external power without needing an outlet? Is there a device I could plug the charging cube in to that would have a battery in it that one could use for this purpose? Someone told me that if I just got an adapter with the proper voltage, that one could hook it to some external battery and plug it in to the charging jack, does this usually work OK? The idea of it being, having wires wrapped around the positive and negative terminal on one end, and the connector on the other to plug in to the dectalk or laptop.