Sterling Pro Alt C AB1280 wiring diagram

AB1280 accepts a 12 V alternator system rated up to 80 A, with a boosted domestic-bank output and a separate starter-bank output. That 80 A is the permitted alternator rating, not a guaranteed 80 A delivered to the domestic battery. Output depends on alternator capability, temperature, wiring and charging stage. The manufacturer product guidance warns against lithium use without external current limiting: this charger is not itself a current limiter.

Route alternator B+ to the alternator input, starter positive to the starter output, and domestic positive to the domestic output. They are not three posts of a battery combiner. Connect the charger's negative reference to the common negative/alternator negative as instructed; the manual calls for cable suitable for 60 A for this connection. An alternator with external voltage sensing may require moving its sense connection back to alternator B+. See installation instructions, PDF p. 2.

Fit the battery temperature sensor to the specified negative battery terminal and the alternator sensor to its case or negative connection. Never put those sensor lugs on a positive terminal. The domestic voltage-sense lead is a separate circuit. Protect battery-fed conductors according to their sizes and the actual alternator installation; this manual does not supply a universal AB1280 fuse value. A fuse opening in an operating alternator circuit also needs consideration in the installation design. See sensor and fuse guidance, PDF p. 3.

Select the domestic battery profile before charging. Check engine-off isolation, excitation at startup, both battery voltages and alternator temperature during sustained charging. Some installations require the ignition/excitation connection because the alternator otherwise cannot start producing voltage. The catalog intentionally leaves predicted output current blank until an operating point and safe alternator limit have been established.