Alternator regulation Amel 54

Arno Luijten

Dear forum,

I'm in the process of extending the charging system for out batteries as preparation for Solar panels and ultimately a nice set of Lithium batteries. Currently I'm looking at the grey box that sits at the rear wall of the engine room, above the Volvo engine (see attachment). In this box there is an (Alpha Pro) alternator regulator for the 110A/24 Volt alternator, two relays and a bridge rectifier.
It must have something to do with the activation of the 24V charging circuit but there are numerous 12 Volt wires as well. Before re-inventing the wheel, did anyone already reverse-engineered this box? I talked to Bill Rouse about this thing and he is guessing it has something to do with the excitement of the field-wires in one of the alternators. I was also thinking it has to do with delaying the 24 Volt charging circuit until the engine is running properly as the 24V alternator creates substantial drag, even at idle. What mystifies me most is the rectifier. Are they using a part of the 12 Volt Alternator to sense the state of the engine?

Thanks for your insights
Arno Luijten
SV Luna,

Maybe your Alpha Pro manual can throw light into the subject?

We have an Alpha Pro 2 installed since 2013.  Its start time is user-programmable from 0 to 60 seconds.  You can also set it so it does not start charging at low RPM.  Were these not options on Alpha Pro 1?  If these software options were not available, it would make sense for Pochon or for Amel to have done something via hardware.  

Our installation, which was not done by Amel, includes one of those little black cubes you have, but the schematic is not readable without some disassembly, so I am not sure what it does.


sv Peregrinus
underway by sail, Wadden Sea