Radio and Fat Sac Pump Cutting Out

[joelhern2]

Yesterday while driving down the lake at about 25 mph the radio kept cutting in and out. I also noticed that when I was filling the fat sacks up the power to the raido and the pump cut out. The power immediately kicked back on for both the radio and pump, but both had to be flipped back on.

I assume this might be a battery issue?? I have two batteries in the boat which work in tandem, along with a battery switch. Let me know if you have any thoughts...

[Flux]

Keep a steady eye on the voltmeter when running. You should be pulling around 14+ volts while cruising even with the stereo on. The head unit will cut out at low voltage, sounds like something is not charging, you have a bad battery, or your alternator is fritzing

Check your batteries to see if they have taken a charge, if they are low, you may have a shorted battery. How are your batteries connected?? Are you running them both at the same time?? If you parallel your batteries, a bad one will drain a good one, essentially giving you one bad battery. A fully charged battery should be around 12.6 volts just sitting there. 12 Volts and they are pretty drained, less than that and they are dead. Check this with a voltmeter to start. Maybe only put one use one of the batteries at a time on the water. If one is bad, you will know it. Since you are having problems while running, there could be an alternator problem.

It could also be that your alternator or it's voltage regulator may be fritzing. Check the output at idle with nothing on, should again be in the 14-14.5 range.

What kind of boat and year?? How is your battery switch setup?? Did your breakers pop while you were sitting and filling and listening to the stereo??

[joelhern2]

Flux,

Thanks for the info. Here are the answers to your questions:

1991 Barefoot Nautique.

The battery switch just has an "off and on" position. The two batteries share a common cable which runs from either the positive or negative terminal.

Yes, I did hear a little "pop" before the power went out on the radio and the pump.

Thanks again Flux

[Flux]

Joel,

I helped my buddy install a new head unit on his 92 sport. We were out on the water running and it was throwing the main breaker once we installed the new unit. We were pretty clueless on what to do so we replaced the alternator. I also checked the stereo wiring. Seems the previous owner had wired it into the clock with very small wire gauges. There was an extra breaker on the panel, so we wired it into that with a better gauge.

From what I can recall about posts that folks helped me out with is that you can have issues if you use small wire gauges, even the head unit can put a wierd strain on your alternator's voltage regulator if it is using a tiny wire gauge. Something about how it tries to compensate on the amp draw that cannot get through the small wire by upping the voltage. We were getting massive voltage spikes, like 16+.

I would say you are having problems with the HU getting a low voltage, but it could be several things. Get yourself a cheap multimeter and check the batteries for charge. I would also check the stereo wiring and make sure it is wired into the breaker panel on the dash and the wire gauges are decent, 12 or 14 would be plenty safe.

You can take your batteries to any shop and they can check them for you, you may have one that is shorted. Also consider taking your alternator to have it checked. We replaced the one in the 92 for piece of mind. It had an integrated regulator. It was easy to swap out. Just check these things and you will probably find the culprit.