J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment basic electrical

So I thought something might be up when starting the engine or using the electric head was switching off the stereo/gps. Batteries, though the standard lead acid ones) are fairly new. I was thinking ground and sure enough, I found 2 issues. The ground wired to the keel bolts was corroded in one spot and the buss bar connection to the ground running from the engine was reduced to more easily connect to the buss bar. The corroded spot was cut out and a new bus bar was connected with correct gauge wire.

This is leading up to my question, with all my crawling around with my voltmeter made me realize that my battery bank would drop from 12.9 volts after running the engine for a long time to 12.5 volts 30 hours later... Not a precipitous drop and plenty to start the engine but what might account for this voltage drop?

Assuming that you have a battery switch or similar method of removing all loads from the battery, battery voltage will decrease over the course of 12-24 hours, and then settle out. The time it takes depends on the battery as well as temperature. In very warm conditions, it will settle out faster. Once settled out, the battery voltage should not continue to drop until a very long time. Also, this final resting voltage can be used to judge the state of charge with ~12.65 being 100%, ~12.55V being 80% and ~12.2V being about 60%. These alternators often don't get the battery quite up to 100% like a dockside charger would.

If the battery voltage continuously drops, then that would obviously be more concerning.

Chris provided a great answer with the voltage drop associated with lead acid batteries.

On the wiring topic.... when I rewired Rhapsody I found many old ground connections that were suspect with some having grown green vertigree and wiring that was degraded by moisture that had turned brittle. These boats were not built using tinned marine grade wire now required by ABYC standards. I upsized the wire size one gauge smaller (larger diameter wire) for the ground and ran new marine grade tinned wire from the battery to the electrical panel. I did the same with the wiring from the battery switch to the power panel, and replaced the "hidden" fuse socket by the battery switch to one the was more accessible.

There is an old thread on the DC electrical panel you may be interested in going through which includes a schematic for the primary DC wiring.

huge help, thanks. Was able to get everything ship shape, it may look a little "rat's nesty" but everything is connected to what it should be (more or less). That was the last item on the "imperative" list for this season. Just in time for the "Around Monhegan" race this weekend, our first true ocean race from Casco Bay to Monhegan island and back again.

Forecast is calling for 20kts with gusts to 30, but its from the WSW so it should blow us straight there by early Sunday morning. Anyone have a lot of experience flying spinnakers in 20+ kts of wind for sustained periods? I'm feeling some trepidation...

I found twig lines helpful to keep the spinnaker a bit more manageable.

I agree with the twings, keep them down tight and keep the boat under the chute. I would keep the #3 up under the chute. It helps to relieve some pressure off the chute, it also will help you get back on your feet if you wipe out. With those winds coming in watch out for the waves, they can spin you out in no time.

Hello.



Goodbye.



Was a bit tamer than foretasted, thankfully, but still managed to fly the spinnaker in 16-18 kts with gusts to over 20. Surfing the open ocean swells was exhilariating/a bit scary but we hit 11.6 kts, the boats record for me. Whew.