The Meade #1812A Electronic DC Adapter is a 2-amp capacity DC transformer designed for field operation of Meade's 16.0" LX200, LX200GPS & LX400 telescopes.
The Meade #1812A is a 12-volt to 18-volt transformer with a male DC cigarette lighter plug upon the end of a short cable. The male cigarette lighter plug inserts into the female cigarette lighter output of an automobile, or into the cigarette lighter output of a rechargeable 12-volt battery. This increases the 12-volt DC output of these devices to the 18 volts of DC power required for proper operation of the 16.0" Meade scopes' drive motors. A high capacity battery is required, due to the substantial current draw of the mammoth 16.0" scopes. To put it in perspective, even a 17 amp-hour battery may not get you through a full night of observing is the ambient temperature is low and you employ substantial dual-motor slewing.
Also part of the Meade #1812A is a 25' power cord with inline fuse protection: one end connects with the transformer, and the other end has a female pin jack which connects to the scopes' 18-volt DC inputs within the drive bases.
If these large scopes are connected to 12-volt power supplies without using the Meade #1812A Electronic DC Adapter, the scope motors operate at slewing rates far below normal and there may not be enough available torque to move an improperly balanced telescpope. There also exists the possibility that the drive systems of the scope could be damaged in a way which would void warranty protection, so the #1812A is highly recommended.