My yacht has three
battery circuits - one for the
engine starter, one for the house system and one for the bow thruster. It also has a Mastervolt Alpha Pro
regulator (separate to the alternator) and a sophisticated Mastervolt
battery monitoring system.
On occasions (sometimes several times per hour) I noticed the battery charge light on the standard
Yanmar engine instrument panel illuminate - sometimes it will stay on for a minute or so, other times it will stay on for an hour or more. When this light illuminates, the engine tachometer also falls back to show zero
RPM. A look at the battery monitoring system at this time confirms that the
batteries are not being charged. As I make short voyages of two to four hours only and I can use
sails I have not been too troubled by this .... each day I reconnect to
shore power so the
batteries will then be fully recharged.
My batteries are all in good condition, and the battery terminals are also all clean and tight. It would seem to me that the
alternator is working OK, so I'm guessing that the Mastervolt Alpha Pro
regulator has an intermittent fault. Am I on the right track, or could it be something else?
Sometimes when I am returning to my berth I discover that the bow thruster (MaxPower 100 Combi) won't
work. I've figured that this problem is related to the above problem as on the occasions the bow thruster does not
work the battery charge light on the instrument panel is illuminated.
My thinking here is that the control circuit for the thruster is wired to batteries other than the thruster battery bank (i.e. the engine, or more likely the house bank) ..... apparently this is good practice to wire this way ..... and if the voltage for the control circuit falls below a certain threshhold then the thruster will not energise.
On Friday I motored for four hours and the charge light stayed off for the entire time, but then as I slowed (from 2,000
RPM to 600 RPM) to reverse into my berth the light came on and my bow thruster would not operate .... just when I need it !
If I'm right then my "two problems" are connected .... but what is causing this. Is it a faulty Mastervolt Alpha Pro regulator?