Many of the older powerpacs had an i8 V transformer whivh is run through a rectifier to convert to DC. This usually produced appx 13 v DC no load. These power pacs had four output terminals marked something like "DC tracks only, and A.C. accessoties. They were the standard 40 years ago, and most likely hard to find any more. Since most Accs. are not polarized , you can most loikely get by with DC ouput not fed through the throttle control. If you can, ask your hobby shop about this. Some accs. will only operate on DC, LEDs other small motors, etc. Remember that 18 v accs. may not be the norm any more, gut you still may run into older designed accessoties. Good luck!