Remove and count the batteries in the device you're adapting. Standard dry-cell round batteries such as AAA, AA, C or D are all 1.5 volts. Multiply 1.5 by the number of batteries. So, four batteries would equal 6 volts; six batteries would equal 9 volts and so on. Find the current or amp (mAh) rating either in the specification sheet in the device's manual or on a sticker on the device itself. This value is the current (mAh) for which the adapter should be. Cut off the low-voltage connector at the end of the adapter's wires. Strip about a half inch of insulation from the wire's ends and pull them apart about by 4 or 5 inches. Identify the neutral wire of the adapter by the white Stripe or raised strip on one of the wires. Attach the neutral wire (with electrical tape or solder) to. Look into the battery compartment and notice that there are two connectors the batteries touch on either side of the compartment. One side.