although australia based , it still applies to north american rangers as well

Ford Ranger Controlled Charge System - 4x4 Earth

what they are saying IS: if you are going to wire in offroad lights YOU MUST:

connect the power lead(s) directly to the battery

( i prefer the alternator output stud as a better connection point )

ONLY connect the negative cable directly to the engine to firewall ground strap bolt

( NOT to the negative battery connector )

that is how the computer controlled alternator works by sensing amperage load on the negative side

this advertisement for 215 continuous amp alternator is just absurd , anybody like melted wiring in the cabin

http://alternatorparts.com/dual-rectifier-big-ford.html ( DENSO )

older model rangers had a constant 13.6 volt lead into the alternator

newer model rangers have a variable voltage lead into the alternator ( DENSO )

the denso alternator controls not only the voltage output but the amperage output as well

the computer can maintain a constant 12.6 volts ( battery fully charged )

but can also increase the amperage separately as well

 

This does not apply to any North American Rangers. This is only for the New Ranger that we don't get here.

It also says that you should not add accessory grounds to the battery post put should attach them to the body. That is the entire document in a sentence.