Overcharging on BMB300

[simon_m]

I have a recently acquired BMB300 with 2 x KAD32's.

At speed ( > 20 kn) the starboard volt meter on the dash is showing 15.5v whereas the port one is <14. Slow down the voltage drops to just over 14. So of course I aint running at speed at the moment.

I've had the starboard alternator off and tested on the bench under load, and I've been told its fine. Some additional background: Boat has 3 batteries, not sure yet how the distribution is controlled,. waiting answer back from Bavaria, manual is woefully lacking. Also, there's an inverter fitted ( which is off atm).

I was going to try swapping the alternators round to see of the problem moved.

Any ideas as to why this may be happening.

many thanks


Simon

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[halcyon]

Number of posibilities, port could be supplying service loads so is at a lower voltage, starboard is engine battery only and running at a very low load thus higher voltage. The alternator may be over regulating or it is high and the meter is over reading. There could be a bad earth that is giving a false reading, may be a high regulating alternator, some car firms have started using very high voltages.
Get a good digital multimeter and recheck the voltages before you do major work.

Brian

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[ex-Gladys]

First stop must be to try a multimeter across the battery terminals to check the voltmeter reading is accurate. "Dashboard" type instruments are well known for inaccuracy. Make sure you have a problem before fixing it.

High voltage could be a battery going duff....

<hr width=100% size=1>Larry Botheras

Anderson 26 "Amber"

 

[pampas]

Before spending any more money, check battery voltage at fast tick-over. should be similar, if so, check instruments at the same time they have been known to fail as well. the next test that I would do is check the voltdrops along both + & - cables whilst maintaining fast tick-over also across any isolator switches anything above 1/2 volt should be looked at.

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