Outer Limits 4x4 Board

i have just installed a steed dual battery charger and need to know which lead comes from the alternator to connect to the common.

The unit is not being used for a full time duel battery but goes to an anderson plug and then a camper trailer there is a solid state relay inline with the positive controlled by a in cab switch.

If anyone has the wiring diagram it will be helpfull or knows which is what lead

cheers

If you could send through a pic of the unit i should be able to put you on the right track