I hope you can follow this. I have a 1997 2900 Open, twin Crusdaer 454 efi. Of course I have two wet starting batteries and two gel mat house batteries.
I have used the boat in the Chesapeake during trophy striper season about 6 times, then had a cruise to watch the Bluer Angels perform at the Naval Academy. On that trip the transmission on the starboard engine went bad. I had to replace it with a new transmission. The repair marina had all of the battery systems turned off. Subsequent to the transmission work I have taken a few cruises of 2-3 hours. Last week I left my home port to take a trip, my gauges looked fine. Then as I got into a slow speed zone I noticed both volt gauges were reading at idle below12 volts. I think I would have noticed them reading below 12 volts before then, but I can't say for sure. I do watch my gauges, but mostly the oil pressure and engine temperature gauges. After I saw the low volts, I accelerated and the meter responded to just above 12 volts. I made the trip, 1.5 hours running at cruising speed, plugged in over night to shore power and made the return trip with the same voltage readings.
That afternoon I checked my batteries one at a time with a multi meter, they read above 12 volts and when I started the engines, one at a time, the multi meter showed an increase in voltage at the battery to 13.6 volts. After some thought, I thought I should check the volts at the volt meters, it seems I shorted the meters, they now both read over 16. I check the volts coming to the volt gauges and they read 16.5. Then I checked the large breaker inside the engine, there is one from each engine. They were popped, so I reset, then I checked the batteries with the multi=meter. Both batteries are reading 16.5 volts w/o engines running.
This concerns me, I generally drive the boat to a marina for service, vs. paying for service call. Can anyone advise me.
Looks to me like you have a bad meter. You cannot get anyway near 16 volts from a lead acid battery with the engine and battery charger off. Check your meter on your car battery. It should read about 13.8v with the engine running and 12 something with it off. We can go on from here if the meter checks. And remember the old saying "if it works, don't fix it". What concerns me is the wet battery and gel battery combination. That is usually a no-no. How does your battery charger know what it is charging and how much voltage to put out? Same goes for the regulators on your alternators. One more thought, do you have the battery selector switches in BOTH? That will really confuse the issue. Capt. George
I am not 100% on this but we had a similar issue with our crusaders; the alternators on the engines have voltage regulators; some won't start charging your batteries until your RPMs are between 800-1000; so at idle we noticed below 12 volts on the engine batts, but as soon as we got up to around 800 voltage regulators opened up and the batts were reading as they should. You can look up the part number on your alternators for a description of this.
Also, only one engine charges your engine batts and the other charges your house batts; at least that is what it says in our manual.
You may want to put batteries threw a load test or better yet buy deep cycle type for each engine. If you have exturnal Balmar regulaters they can take a minute to tell the alternater what and how much to charge with engines running.
Thank you for your responses. I'm not trained in marine electronics, but I generally try many repairs myself before going to a professional. The multi-meter question was valid, so I checked it on my car as recommended, it works as it should.
The deep cycle starting batteries are only 2 years old, I keep distilled water level up in them. The Gel Mat batteries were also replaced two years ago, I bought the boat 10 years ago and there were gel mat batteries for house batteries in the boat then, expensive, but they lasted 14 years before I replaced them 2 years ago. I've gotten 3-5 years out of the starting batteries.
My VDO voltage gauges always gave me good readings before this issue, now I'm concerned about why both would go bad, first with show below 12 volt, now after I put the multi meter on them they show pegged over 16 volts. A mechanic I know from a tavern I visit, said there must be a bad ground, I looked over things, I could not find anything, but I know when I checked things I did pop the breakers when I checked them, probably crossed the hot & cold spades accidentally because they are so hard to reach. But, when I reset the breaker, that is when the gauges, one at a time started pegging.
I had new belts put on at the beginning of 2013 season.
As Capt George said, the batteries themselves cannot possibly get up to 16 V. Do I understand you correctly that when you use a hand-held multimeter to measure directly across the battery terminals, with the engines off, you see 16 V? And is the battery charger off? Is the ignition key off? Let's please sort that out first. Please forget about using your vessel's built in battery meter, as those are too prone to failure.
If all answers are yes, then the 16 V is coming from someplace other than the battery and this could potentially be a dangerous situation. Your next step would be to disconnect the positive (red) lead from the battery. Then confirm a direct reading on the battery terminals with a multimeter reads below 14 V DC as it must, and then measure both AC and DC volts between the disconnected positive battery lead and (1) the negative battery terminal and (2) the engine block. Both (1) and (2) should give identical results. Report any DC or AC voltage you get and that may give a clue to the problem.
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