Alternator Regulator Questions - with Sterling A2b

[B40-Lefkas]

Good Morning,

Has anyone fitted a Sterling alternator to battery charger?

Mine is fitted and sort of working however it's fighting with the inbuilt regulator on the alternator. The sterling raises the output to the house batteries and the alternator then drops it's output voltage to compensate.

How can I best disable the built in regulator?

Many thanks
Chris
2008 B40 MD30

[Symphony]

You really should not need the Sterling device as I assume you have a D1 engine which has a 115A alternator. The Sterling was useful when alternators were relatively low powered (previous engines had 55A) and traditional batteries which were slow to take a charge, plus often diodes (which cause a voltage drop) to split the charge. The device boosts the voltage to compensate for both these limitations.

So, don't think you have voltage reducing diode and the alternator both puts out higher voltage and greater amps. Even better if you have AGM batteries which will take the higher charge rate more easily.

[IslandAlchemy]

You have the voltage sensing wire set to battery sensing rather than machine sensing.

[Ricd]

Agree with symphony
I changed from MD2020 to a D1-30 and dumped the Sterling. 115Amp altinator is charging batts at 4.4V.

[tiger79]

You really should not need the Sterling device as I assume you have a D1 engine which has a 115A alternator.

His signoff says he has an MD30 engine.

[tiger79]

Has anyone fitted a Sterling alternator to battery charger?

Mine is fitted and sort of working however it's fighting with the inbuilt regulator on the alternator. The sterling raises the output to the house batteries and the alternator then drops it's output voltage to compensate.

How can I best disable the built in regulator?

I don't think you have to do anything, as it sounds like the Alternator to Battery charger is working correctly.  In the Sterling manual, it says "In order to maximise the alternator output current, the alternator-to-battery charger pulls the alternator output voltage down to about 13V. Then this low voltage is amplified to a higher voltage suitable for effective battery charging, ie 14.1V to 14.8V."  Are you getting a decent charge voltage at the batteries?

[IslandAlchemy]

But you need to make sure that the regulator is machine sensed, otherwise the Sterling cannot work its magic.

[Symphony]

You really should not need the Sterling device as I assume you have a D1 engine which has a 115A alternator.

His signoff says he has an MD30 engine.

But not sure that can be right which is why I assumed he had a D1 30 because the MD 2030 was discontinued in 2005 and not therefore fitted to a 2008 boat

Perhaps the OP could clarify.

[Rampage]

Irrespective of which engine the OP has and the size of the alternator, most Volvo Pentas use a battery sensed alternator.  There’s a thin (usually yellow) wire which runs from the alternator to the positive terminal of the batteries.  If you don’t disconnect that wire from the batteries and connect it to the B+ terminal on the back of the alternator (turning it into a machine sensed alternator) then the Sterling AtoB will do little or nothing. 
Cut the yellow wire reasonably close to the alternator, fit a ring crimp terminal and connect that to the B+ terminal on the alternator.  Use the yellow wire, still connected to the +ve terminal of the batteries, to connect to the battery voltage sensor of the AtoB.
If that’s already been done, no idea what’s the matter!

[B40-Lefkas]

Thanks all for your comments and help.
Changing to machine sensing did the trick - it's a pink wire on my alternator which yes, is a D1-30.
Now getting 80+A charging instead of 20A and full 14.4V at the batteries!

Greetings from Greece - still hot and sunny here

[IslandAlchemy]

Jolly good.

[Rampage]

Greetings from Greece - still hot and sunny here


Getting a bit windy though....