Battery Drainage?

singram

Cadet
Joined
Aug 20, 2009
Messages
19
Hi. while I have trolled this site for quite sometime this is my first post so please go easy! :redface:

I purchased a 1994 20' Sunbrid Corsair Bowrider with a 4.3L OMC. Soon realized this required a complete new deck, transom and stringers. i have finally got the boat back together and ready to use.... Finally. it has been a 2 year project.

I launched the boat approx 1 week ago. started on first turn of the key. ran it for approx. 1 hour to make sure all systems were good etc...

Tried to launch this past weekend. Again started with one turn of key. Idled at dock for approx. 2 min. When I shifted into forward the engine died. I could not get it started again.

Took the boat home, hooked up the charger/tester. Tested at 15% full charge and 10.5V. Charged battery, installed mufflers and started the engine no problem.

in the 2 years since I rebuilt the boat the battery (a 12V, deep cycle battery) was on charge once every 6-8 weeks.

The only thing that has changed between the 1st launch and successful run approx. 1-2 weeks ago and this weekend is the installation of a new stereo.

Here are the questions:

1. Why would the boat stop, after shifting into foward? Is this a separate issue from a low battery? The boat was already started and running/ideling fine.

2. It appears the old stereo was simply wired directly to the fuse panel, not via ignition. The old stereo did have a distinct on-off. the new stereo was wired the same way but there is always some power to it, even when the key is not in the ignition. is this enough to drain the battery between uses? Shouls it be wired to the ignition or to another unused switch (i.e. wipers)

I am willing to accept that the battery may be old and simply in need of replacement. purchased in 2008.

I charged the battery to 100%, 13.4V. After 2 hours the values were the same, whether connected to the boat or not. After 14 hours, connected to the boat, the readings were 95%, 12.4V

thanks in advance
 

boat1010

Senior Chief Petty Officer
Joined
Mar 10, 2009
Messages
781
Re: Battery Drainage?

First I would take the battery and have it tested. The radio if it isn't turned on should not drain enough to drain the battery. That voltage is just to keep the stations in memory. I can't think of any reason that it dies when put into gear. Is the battery charging when running in the boat? When you hook up the battery do you get a spark? If so then there is a drain somewhere on the battery.
 

singram

Cadet
Joined
Aug 20, 2009
Messages
19
Re: Battery Drainage?

Boat1010. Thanks for the quick reply.

I'll do what you suggest andf take the battery somewhere for testing. when I hooked up the new stereo I simply used the wiring that was there from the old radio. Red = Power and Black = ground. The new stereo did indicate that the yellow wire could be used for memory, hooked directly to the battery. Unfortunately, the old connections were directly from the battery, via a fuse panel. Therefore, I connected the red and yellow to the red/power from the fuse panel.

sorry not sure what you are asking when you refer to "when you hook up the battery do you get a spark"? When I connect the black wires back to the battery, there is occasionally a small spark.... I still believe this is from the new stereo.

Am I correct in my thinking re: the engine stopping when I shifted into forward? Perhaps unrelated but there was simply not enough charge left in the battery to re-start?

cheers.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Battery Drainage?

The engine stall is very unlikely due to the battery. It is likely the engine is simply idling too slow, needs a tune up, carb cleaning, fresh fuel, or in other words, a "good going over". And just so you know, the engine still requires power to operate the ignition system. At idle, with a dead, dying, or low state of charge the battery may not have enough oomph to keep the engine running. Get the battery load tested.
 

singram

Cadet
Joined
Aug 20, 2009
Messages
19
Re: Battery Drainage?

Thanks. I took the battery for testing. Hydrometer readings were fine. the batteries failed under load. dropping from 13.4V to 10 or less under load (approx. 250-300amp load).

Looks like I need a new battery. I will also test the alternator to ensure that it is working before installing a new battery.
 

Rick.

Captain
Joined
Jul 30, 2006
Messages
3,740
Re: Battery Drainage?

I just have to say, another good call by one of this forums Top Guns. Thanks from us all Silvertip. Rick.
 

singram

Cadet
Joined
Aug 20, 2009
Messages
19
Re: Battery Drainage?

Just wanted to provide a quick update...i left my batteries with my mechanic for overnight charging in his shop and testing in the morning. when I called he said the batteries tested fine without and with load. While I am still not convinced.... i will be looking at the alternator to ensure it is working as should be.. perhaps all of this is simply due to poor battery charging habits. as I mentioned it has in the boat, hooked up for approx. 2-2.5 weeks and used for a total of 1 hour.?? hopefully nothing significant, my kids sure want to get out on the boat
 

singram

Cadet
Joined
Aug 20, 2009
Messages
19
Re: Battery Drainage?

Just wnted to update as I always like the posts that follow through to let everyone, that reads the thread or comments, know what happened. As I mentioned my local garage tested my batteries after being on deep charge overnight and they tested fine under load. Unfortunately, I guess nothing tests the batteries like using them. My mechanic installed the battery for me, hooked the boat up to the mufflers/water and started the engine. The batteries would not hold their charge under load. My alternator also tested fine. New battery and the boat seems fine.

A few side notes:

1. the mechanic I referred to is my auto mechanic that also knows boats. I happened to have my truck in for a standard tune-up and he suggsested I simply tow the boat over at the same time and he would test the boat and batteries. He didn't charge me for this. Nice surprise.

2. I guess load testers can only do so much

3. the marine mechanics that installed my engine after a restoration did not do a good job, leaving some wires simply disconnected, or improperly installed. I did find one distribtor cap boot improperly installed. the post was slightly oxidized. I cleaned it up, pinched the boot to tighten the connection and re-installed. I also have a black wire, that I believe is connected to my fuel gauge, that is not working, not connected to anything. I will likely re-post (with pictures) for some advice.

cheers and thanks
 
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