J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment 2GM Motor Fuse

When Bill told me last summer that little fuse holder hanging off the battery switch was the master fuse for the fuse panel it astounded me. It was basically a 20 amp fuse holder with what looked like a #14 wire that came off the battery switch and then was connected to a #10 wire to run to the fuse panel.

Over the years I had worked around it running separate leads for my ham radio equipment directly off the battery.

Last year I added a second #10 red and black line to the fuse panel from a third battery that i keep in the plastic settee bin aft of the fuel tank. the red goes to the load side of one of the auxiliary switch and fuse holders on the main fuse panel and through that fuse and on/off switch to the main + buss at the fuse panel. The black just goes to the main black buss screwed on the hull. This way I can switch the spare battery in when I need it. For sailing/racing/overnights we turn the main battery switch to off and click on the third battery for lights, GPS and radio ... and run it to useless. Then switch it off and put one of the main batteries on.

I used to use a #27 battery and that would last most of the night, but that is too heavy for me now. The smaller #24 battery is no where near as good.

This year I changed the original fuse holder at the battery switch to an ATC 30 amp blade holder as I was having low voltage warnings at the GPS. That didn't help ... so I ran another set of Red and Black directly from engine to the master fuse panel...I now have three sets of #10 wires feeding the master fuse panel.

I am still experimenting to get the voltage at the GPS stronger for a longer time. But three batteries is nice if you want to gobble up amps.

The line from the engine as well as the one from the battery switch have 15 amp ATC fuses which I think will both blow if I get up over 30 amps. When you start to add up amps for gps, instruments, auto helm, radio and a few lights, bilge pump, fresh water pump, CD player you can start to chew up amp hours. and as I remember these Dual Purpose batteries have just about 120 hours ... but the voltage drops continually during that time.

Surprisingly we can charge the spare battery by leaving it on when the motor is running and have not yet blown out a fuse. And if the starting battery is a little weak clicking on the fully charged spare battery easily helps start the motor.

The line from the spare battery has a 20 amp glass fuse it goes through at the master panel.

All that said there are different water pressure pumps available and you are better off with the smallest one available, which I think is a 1.9 gal flow.