Alternator regulator

[mowa]

I want to charge a new service battery with higher voltage. The boat is a B39C-2005 and the engine is a Volvo D2-55C. Is it possible to change the alternator regulator to obtain 14.5V instead of the current 13.something? Where it is located?

[tiger79]

You'll probably find it difficult to upgrade the alternator's internal regulator.  You could fit an alternator booster (Sterling, Adverc, etc) and this will increase the charge voltage and also make it battery-sensing (so will overcome voltage drops in cables, diodes, etc).  Or you could fit a Sterling Alternator-to-Battery charger, which supplies a boosted output to the service batteries and an unboosted separate output to the starter battery.  One advantage of this unit is that there's no need to make any modifications to the alternator (which are needed with simple boosters).

[Yngmar]

PO had a Balmar Max Charge multi-stage regulator fitted, which is suitable for various battery types and needed for AGMs. Very pleased with it, and while I haven't fiddled with it yet (because it always worked fine), it seems to be a very nice bit of kit.

I've just looked up the price though. Ouch.

[Nigel]

If you are only getting 13.something volts then I suspect there is a fault. Is this at the battery or the alternator?

[Lazy Pelican]

I have a similar boat B39-2006 with a D2-40 engine. The alternator is voltage sensing but only produces about 13.5A at the battery.
My solar panels take them up to 14.3ish.
When I bought the boat I spoke to Adverc regarding fitting a smart regulator- they said it was a waste of time because of the voltage sensing alternator.
I suspect that changing the standard splitting diodes for something more efficient might help, but when I last investigated I persuaded myself it wasn't worthwhile- can't remember why!

John

[Ziffius]

I've got the same boat with a 2030d 29hp engine and get 14.1 at the batteries. How are you measuring the voltage - with a meter or just the fitted dial.? I use the nasa bm1 I fitted and it shows the voltage usually starts at 13.5 the builds up to 14+ . I. Have a digital multimeter as well which I don't trust as it gives variable readings depending on how good the probes make contact (a cheap Greek meter)

I also fitted the sterling proreg  D so had to open up the alternator subsequently the alternator packed up and the windings replaced. The technician believed the sterling product wasn't working. I've subsequently checked and can't see any difference to charging profile whether it is in or out of the circuit.

[Lazy Pelican]

Hi Ziffius,
I checked this morning when I left & you're correct . I had 14.4v at the starter bat & 14.1v at the domestics.
I normally only check when the engines off and we're either sailing or at anchor, when they both drop to 13.5v without Solar or Wind input.

[mowa]

If you are only getting 13.something volts then I suspect there is a fault. Is this at the battery or the alternator?

I checked it yesterday, is 14.3V not 13.something. But still not enough.

[mowa]

If you are only getting 13.something volts then I suspect there is a fault. Is this at the battery or the alternator?

measured with the nasa bm-1

[Lazy Pelican]

Be wary of relying on the BM-1 readings. Mine reads 0.2-0.3v higher than I measure with a digital multimeter. Interestingly the reading on the Bav control panel are about right.

John