Grounding between two batteries?

[wesbradshaw]

Hey there everyone!

I had posted a thread a couple of months ago about an electrical problem with my 2003 21i with only 90 hours on it. It turned out that the stereo had been wired backwards and (not sure if they are related) the alternator was shot. So those two things are fixed.

The new problem has many of the same symptoms as the first:

The gauges momentarily fail and come back on (Perfect Pass, Voltage, etc.)

One time when the boat was on batteries 1&2 the boat would not start, after I had just had it on 5 minutes earlier. Switching the battery to 2 (the starting battery) the boat fired up.

The way the gauges die, and come back on, and I can never get a solit reading from the Voltage gauge, it makes me think this is a grounding problem. Since, the boat wouldn't even turn over when it was on battery 1&2, it makes me think it is a grounding problem between the two batteries.

I always get a good manual reading from the alternator of around 14 volts when the boat is running.

Anyone have any ideas?

Thanks

[dogbert]

With a battery switch, you should have a ground connection between the two batteries and one to the engine block. The two positives should be connected to either side of the switch and your starter/electronics to the center of the switch (assuming it's a Perko switch).