Re: [Amel Yacht Owners] Alternator and Masse leak detector

ngtnewington Newington

HI Alan,

Thanks, all good info. When I get back to the boat next Saturday I will check it again. I am toying with the idea of buying a 3 stage regulator too. 

I have Lifeline AGM bank of batteries. I have noticed that the Alternator brings the bank up to 28.55v but then stays at that voltage rather than drop back to float slightly lower. According to Lifeline AGM website the batteries can tolerate 28.8v so that should be ok. On the recent transatlantic passage we motored for 18 hours straight at one point and obviously the batteries were full and kept being charged at 28.55v. I checked the bank by feeling them and listening. There was no boiling or even warmth. So I reckon the current internal regulator is OK nevertheless I am not 100% about a long motor, say of 24 or even 48 hours. My new bank was expensive! I want 8 years out of that bank! I have a very good charging system, new Mastervolt 30A and new Xantrex 70A inverter charger as well as twin Rutland 1200 wind generators and 530w of solar all set to AGM’s plus of course the 175A alternator. Our wind solar combo covers pretty much everything even 24 x 7 autopilot. The only regulator not set to AGM is the Leece_Neville. So I am toying with changing the regulator. What brand/model do you have?

As for my leak I am not convinced that a diode can not be faulty and stuck in the short position whilst still charging, or that the alternator can not leak to ground and still work. when I get back to the boat it will be simple to remove the negative cable from the Alt and then try the “Masse” tester. I also wonder if the bow thruster could be at fault, carbon build up from worn brushes could leak. Tracking these problems is always tricky but a process of elimination is the only way.

Last time I was in Fiji was 1992, is Musket Cove still a yachtie hang out? I loved the Great Astrolabe reef area and Nevandra, Malolo Lai Lai. Suva YC was rainy but had good G+T’s


On 18 Jun 2018, at 20:50, divanz620@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Nick,

Another possibility (and I completely forgot about this until I was reminded by a friend) is the little red light at the bottom left of the 24VDC panel.
If your 24VDC alternator has the standard automotive type internal regulator then this lamp is what provides the excitation current.
If everything is working normally, when you turn the key on, this lamp should light. When you start the engine and the alternator is spinning, this lamp should go out.
Have someone watch this lamp when you turn the key on and then start the engine. If the lamp doesn't light at startup this could be your problem...blown lamp or bad connection somewhere.

BTW the reason I forgot about it is that our little red lamp is disconnected as we have an external 3 stage regulator connected to the 175A Leece Neville 24VDC alternator (the internal regulator is disconnected) in order to charge (and more importantly not overcharge) the house batteries in a proper manner.

Good Luck
Elyse SM437

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