Solved the Sounder problem
We have solved the Adversea S400 Multi sounder problem. Because this discovery might help you improve your sounder I have described our journey from despair to success in detail. Your comments about your own system were most helpful and set me on the correct thinking pattern which eventually led to success. I thank you.
In Avanti there are two alternators. A 70Amp alternator fitted to the 50hp Yanmar is dedicated to charging the starter battery only. The 120Amp Bosch alternator, controlled by a BEP ER3 automatic 3 stage controller, charges the 4 house batteries (280AH). The two banks of batteries can be cross-connected by closing the isolator switch.
The Adversea S400 Multi sounder:
Would operate when the engine was stopped (12.5v), and also when it was idling (12.7v). When revs were increased to 1200rpm, the 120Amp alternator cut in and the voltage increased to 14.7v, the screen went blank.
Although the sounder should operate between 9v and 16.5v it was only operating at under 12.7v.
We considered that because of a fault, the display unit could not accept the higher voltage and if we reduced the voltage at the display unit to 12v it would solve the problem.
I purchased a $NZ45 Voltage Controller, that would reduce the voltage from up to 24v down to 12v, which we wired into the circuit. This gave 12v at the display screen.
We were disappointed that it made no difference to the display still going blank!!
I disconnected the wires supplying power to the field windings of the 120Amp alternator so it did not generate (but was still being driven round) and then closed the isolating switch between the battery banks so the 70Amp alternator would be the only one charging into both battery banks.
When I revved up the engine the sounder display again went blank. It seemed the only possible explanation was that although the 120Amp alternator was disconnected electrically and not producing power, because it was still being driven round by the belt, there was some extraneous current still being produced. Perturbation perhaps?
I removed the belt from the 120Amp alternator, started the engine and revved it up. The 70Amp alternator was then charging both banks of batteries at 14.5v and the 120Amp alternator was stationary.
The sounder then worked perfectly.
There is nothing wrong with the Advansea S400 Multi.
The problem was caused by a signal coming from the 120 Amp alternator. A blown diode perhaps or what? Maybe perturbation caused by electrical current of peaks and lows that the sounder display misread?
What to do?
We intend to put the belt back and test the output on a oscilloscope to find where it is faulty. Maybe the diodes can be replaced. Maybe a new alternator is a better idea.
Either that or an automatic selective charging switch so the charge from the one alternator will select whichever battery bank needs charging.
Because the 70Amp alternator is capable of charging the 350APH of the two battery banks, and the sounder is now operating. Next week I will think about how to have both alternators operating.
I am back on the water exploring the gunk-holes of the Otago Harbour where the water sometimes gets thin. There is a spot of nice late winter sunshine promised for the weekend. A day sail and a picnic lunch out on the Harbour sounds wonderful.
Careys Bay, NZ
"The rock you hit is the one ahead".
: North and East Coast of South Island of New Zealand