FPB 64-3 Iron Lady On Passage Marquesas Towards Hawaii: Day 3

Three days into their passage and FPB 64-3 is 750 miles down the track. Mark Fitzer continues his reports:

We have traveled some 750 miles and been at sea now for close to 78 hours. While averaging 231 mile/day we are burning 21 litres/5.5 US gallons an hour or 2.176 litres/ .57 US gallons per nautical mile. Our current position is 2° 21.82 S by 150° 55.85 W. The sea conditions are still aft of the beam and 1M in height. The wind is behaving itself out of the NE at 17 knots. Outside air temp is a balmy 78°F and the sea temp is maintaining 83°F. The weather still looks to continue for the immediate future, as the barometer is nice and steady at 1013. The favorite boat lure disappointed today, and we had to thaw some prior catch out for dinner. What a shame to have to eat a few day old previously frozen fish over the 45 minute fresh catch, but we’ll make do.

As I write this, wham! Mr. Shabby once again proves his worth. Of course, being the sportsman that I am, I let the fish come loose about 5 feet from the back of the boat since we are fairly sure it is a marlin and the guys had previously landed a beauty. However, Mr. Shabby has put me on notice–no doubting allowed. Shortly thereafter we land another Mahi; this one about 35 pounds, a real monster. Thankfully, we all love fish and she will be put to good use.

I continue to be amazed at the gentle motion of the boat with these quartering seas. It makes slipping into life at sea an easy task and the days are quickly lost in watches, sleeping, reading and monitoring the boat. Having ridden nothing bigger than my little fishing boat for a few years, I had almost forgotten how much I love being at sea, and the quality of life while at sea aboard this vessel is pretty darn high.

We think there may be an issue with the Victron Energy power assist algorithm, so we are performing some tests. What we theorize is happening is: with the generator running and batteries fully charged, the inverter/charger input is limited to 38 amps, since Pete doesn’t like to run the generator at 100% load. When running large loads such as the oven and stove drawing roughly 20 amps, everything is okay, the inverters pass through the available power from the generator and all is good, but if another larger load comes on and pushes the amp draw up another 10-15 amps, the inverters kick into power assist mode, shut off the generator pass through and immediately try to carry the entire load. They quickly go into a thermal and overload situation. When the larger load is switched off, the inverter/chargers picks up the generator power again and start passing it through again. We are going to perform some tests with it to see if the inverters are dropping into power assist or trying to support the entire load.

We loaded up the 230VAC system with a constant 24.3 amps, adjusting the Victron Digital Multi Control (DMC) panel to multiple amperages in 2 amp increments starting at 16 amps. We found the lower the we set the current limit input, the quicker the system dropped down into power assist mode. Working through all of the amperages back up to 38 amps, the system runs exactly as it should, regardless of whether we limit the current at the DMC or not.

We did find one small anomaly that we intend to test for a little later, and is most likely the basis for our prior concern. It appears that when the system comes out of power assist mode and reverts back to pass through (charging) mode with the alternator fields active and charging, we get temporary overtemp and overlimit warning LEDs on the Victron inverter/chargers.

We have recently completed some more tests and found that there is indeed a correlation between the Victron overtemp indicator on the DMC and the alternator output. With the generator running and the batteries down enough for the DMC to put the inverter/chargers into bulk charge mode at roughly 130 amps 24VDC, the system runs fine, but the moment you bring the alternators on line to assist in charging the batteries, the DMC indicates an intermittent overtemp indication. We intend to contact Victron Energy for their input.

Posted by Sarah.Dashew  (August 22, 2013)

3 Responses to “FPB 64-3 Iron Lady On Passage Marquesas Towards Hawaii: Day 3”

  1. Matt L Says:

    “While averaging 231 mile/day we are burning 21 litres/5.5 US gallons an hour or 2 litres/ 5.6 US gallons per nautical mile” Math error…

  2. Steve Dashew Says:

    Thanks Matt:
    Too much work late at night… Corrected now.

  3. Jerry Says:

    Mr shabby is a mystical creature that mesmorizes the fish. He should be placed in a place of honor when he retires.