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Swinging Tach and Amp Gauges

PostPosted: Mon May 13, 2013 8:43 pm
by bjrichar
I have a SAR V3 Regulator, DAC, and two 4023 Alternators on the boat providing charging and power. This past month while cruising, occasionally, the tachs have been going to zero and the amp gauges swinging between 0-60 amps at the same time on both tachs and amp gauges, when the EMON indicates the charge level in the house batteries is at or near 100% or slightly higher. Today, when the batteries reached 100%, the tach and amp gauges swung wildly between 0 and 1800 RPM and 0 and 80 amps perhaps 20 times before coming to rest on zero. During this time, the voltage and amperage on the EMON also changed rapidly. The gauges did this repeatedly until after this 10 minute plus "show", the instruments settled down and the amp gauges showed a charge of around 40 amps each. I had tried energizing additional loads, running the microwave even, and changing the rpm but all without impact or results during the ten minutes the gauges were swinging. I realize that an electric tach has issues when the batteries are full but I would like to be sure another issue has not arisen before we head out for the summer.
Any chance of sending the SAR and the DAC in for service and a checkout? Thank you for your assistance and time.
Best Regards, Byron

Re: Swinging Tach and Amp Gauges

PostPosted: Wed May 15, 2013 11:26 am
by Coulomb
When two alternators are regulated through a DAC, ground connections become very important.

Connect all ground connections from the regulator and the DAC at a single location where there can be no high current flow intervening.