How to avoid a rock strike

Cruise highlights battery problems

By Jack Reed

Before our month-long cruise to Bar Harbor, Maine, my wife, Patricia, and I, and our Maine Coon, Skipper, had never cruised for more than two weeks at a time. The longer cruise allowed us to solve a persistent problem.

Our batteries had been running down over time despite spending significant time under power. To compensate, we used marina shore power for a night or two during each cruise. But this year, we didn’t stop at a marina, and by the time we got to Bar Harbor, the batteries could hardly turn over the engine.

Running a multimeter across the terminals, I discovered that the batteries were producing less than 12 volts of current, which meant that they were less than 50 percent charged and close to being ruined. While moored in Bar Harbor, I ran the engine for three hours at 1,200 rpm and got the charge up to 12.8 volts, but it dropped to 12.2 volts an hour later.

Running a multimeter across the terminals, I discovered that the batteries were producing less than 12 volts of current, which meant that they were close to being ruined.
The batteries never got a charge of more than 13 volts. According to Nigel Calder’s book “Boatowner’s Mechanical and Electrical Manual,” the batteries should have been getting a charge of more than 14.5 volts.

I thought the problem must be the alternator or the battery regulator, so I called the regulator manufacturer in Fort Worth, Texas, and explained my situation. The manufacturer suggested a few things I could try, but none of them worked.

Next I called the alternator maker, Hamilton Ferris in Cape Cod, Massachusetts. I told the operator that I was on a sailboat in Bar Harbor, having trouble charging my batteries and needed some help.

The operator said, “One minute, sir!” Within a minute I was talking to Hamilton Ferris himself. During the next six hours with many phone calls back and forth, it became clear to Ferris that the batteries weren’t getting the charge they needed.

“One last thing,” Ferris said. “Let’s try bypassing the regulator entirely and see what kind of charge current you get.”

With the regulator bypassed, the batteries were getting more than 15 volts of power.

“We’ve found your problem,” he said. “I’ll have my people FedEx you a new battery regulator overnight.”

Although it was a Friday evening and the package had to go to the FedEx shipping center in Philadelphia, the regulator arrived at Bar Harbor at 1215 the next day.

After unsuccessfully trying to reach a local electronics tech to help me install the new regulator, I proceeded to install the regulator myself Sunday morning. Four hours later, I had it up and running, and sure enough, my batteries were now getting a charge of almost 15 volts. Problem solved.

Since installing the new regulator, I haven’t had a problem with the batteries running down.


Cdr Jack Reed Jr., AP, of Beverly Sail & Power Squadron, is a retired healthcare executive and a retired U.S. Army colonel. He and his wife, Patricia, sail their Endeavor 42, Airborne, out of Salem, Massachusetts.

Share this Post