Fuse

[tlodge]

One of the protection fuses in my 2014 Carthago e-line is described
3A fuse for OUTD+ simulated output protection
Does anyone know what that means please

 

[autorouter]

The D+ signal is sent out by the alternator when the engine is running, to signal that it is producing charge. When you turn the ignition key, the dash lights come on - that's the ignition. When you start the engine, the alternator light goes off - that's the D+ signal. In most vehicles that's about all it does, ie switch the alternator light off.

However in a motorhome, that signal is used in many ways - to turn the fridge on and off, to switch the split charge relay so that the alternator charges the leisure battery, to retract the step, turn the awning light off, etc. This puts too much load on the D+ from the alternator. So often they use the D+ signal just to switch a relay, and then use the relay to switch a 'Simulated D+' powered from the leisure battery. Then you can have as much load as you want. The Simulated D+ goes on and off exactly when the real D+ goes on and off.

That simulated D+ needs a fuse to protect it, so normally a small fuse, maybe 3A or so, is put into the wire from the leisure battery.