Boat Starting battery just dies

[apaseman]

Hello

Awhile ago i went to the garage to take my boat out and the starting battery (fairly knew) was dead, and wouldnt take a charge. I figured i must had left something on amd that killed my battery. So i replaced it. I have a 3 bank charger, and 3 batteries, 2 hooked up for 24 volt trolling motor and one for the starter/fishfinder and trim.

Now I have slipped my boat and leave my 3 bank charger plugged in. Despite that, today when i went to take the boat out the starting battery was dead. It had been olugged into my marine 3 bank charger, so i assume that again it wont take a charge. I know to diagnose properly, you need more info. I will be going tomorrow tomorrow to replace the battery, but I have no idea what to even check. As far as i could tell nothing was left on. I would assume that beeing plugged in to the charger that the battery wouldnt die.

I suspect i might have wired something wrong and will take diagrams with me. Not sure if there is any way to wire it so that it takes juice out of the battery or not.

However, i suspect beeing an old boat i have a short somewhere. I do not know where to even start to figure this out or how.

Any ideas on things to check and info to gather would be much appreciated.

 

[Silvertip]

Re: Boat Starting battery just dies

Shorts blow fuses so that's not likely the issue. Something is draining the battery but it must be a rather substantial current draw if the charger cannot keep up with the discharge. You haven't said whether your boat is an I/O or outboard but I suspect outboard. As such, an engine charging system problem could create a fairly high cuirrent draw. Does the voltmeter on the instrument panel show that the battery is charging when the engine is running?

 

[MH Hawker]

Re: Boat Starting battery just dies

Have the battery load tested before you make any choices. That will tell you if its the boat or the battery its self.

 

[apaseman]

Re: Boat Starting battery just dies

Shorts blow fuses so that's not likely the issue. Something is draining the battery but it must be a rather substantial current draw if the charger cannot keep up with the discharge. You haven't said whether your boat is an I/O or outboard but I suspect outboard. As such, an engine charging system problem could create a fairly high cuirrent draw. Does the voltmeter on the instrument panel show that the battery is charging when the engine is running?

It is indeed an outboard. I do not have an engine charging system, and do not have a voltometer on my instrume t panel. Boat is a 1987 champion bass boat. I will check the load once i figure out how to do that!

 

[Silvertip]

Re: Boat Starting battery just dies

You have a 1987 Chapion Bass boat and the engine has no charging system???? Just what engine is this??? Yes - a bad battery will not hold a charge.

 

[apaseman]

Re: Boat Starting battery just dies

You have a 1987 Chapion Bass boat and the engine has no charging system???? Just what engine is this??? Yes - a bad battery will not hold a charge.

Aparently im ignorant on the fact that i have a charging system on my engine...so let me rephrase, I do not see a voltometer on my dash nor am I familiar with a charging system on my engine (1988 Mariner 175hp). I do have an onboard 3 bank charger.

 

[Jlawsen]

Re: Boat Starting battery just dies

Aparently im ignorant on the fact that i have a charging system on my engine...so let me rephrase, I do not see a voltometer on my dash nor am I familiar with a charging system on my engine (1988 Mariner 175hp). I do have an onboard 3 bank charger.

1. Your engine has a charging system.
2. Your battery draining down to zero.

Your starting battery is also your house battery. If it wasn't the other two batteries would be going dead. That said, there will be one large positive battery cable and one smaller (usually 8ga) red wire for your house needs. Take the battery out and have it tested and charged if possible othewise replace it. When you re-install it, do not connect the smaller 8 ga wire for the house circuit. If any other wires are connected to the positive terminal other than the main cable going to the motor disconnect them also. Do not connect your onbaord charger to the starting battery. Monitor the batteries condition over a few hours. If voltage drops below 12.6v then you have something in the engine draining your battery.

Re-check your onboard charger wiring and make sure your onboard charger is setup to charge the correct types of batteries. I have seen instances where AGM batteries are used for the trolling motor and a standard battery is used for the charging circuit. The charger is set for AGM charging cycle/voltage and over time, this will sulfate the starting battery and cause it to fail.

If your battery maintains itself at 12.6v for a few hours then reconnect the house wiring and monitor it again. If in a few hours you're still at 12.6v then it's probably not the house wiring. If it doesn't then you get to start your easter egg hunt.

If all is good then your problem is most likely your onboard charging system. Repair or replace it.

 

[Silvertip]

Re: Boat Starting battery just dies

If your engine did NOT have a charging system -- what do you think has kept that starting battery charged over the years? Of course it has a charging system. Just because you don't have a voltmeter does not mean it doesn't have a charging system.

 

[apaseman]

Re: Boat Starting battery just dies

If your engine did NOT have a charging system -- what do you think has kept that starting battery charged over the years? Of course it has a charging system. Just because you don't have a voltmeter does not mean it doesn't have a charging system.

Well, I assumed My on hoard marine charger kept it charged all these years. I fail to see why you seem to find my logic to be unsound. I do not claim to be knoweledgeable on boat mechanics. Its my first boat, hence why I have come here to gain some information. If I have to take it to a mechanic, I will but Id like to at least attempt to figure it out myself, regardless of whether or not i can get to the route of the problem, I will learn things along the way.

Thanks for everyones input.

 

[chriscraft254]

Re: Boat Starting battery just dies

Sounds like to me you have a bad charger. Also be careful, chargers when left in can cause batteries to explode if fluid levels are not kept up in the batteries. Best advice is if you have not a clue about the system get a pro to look at it for you. may cost you some money, but may save you a bunch also.

 

[apaseman]

Re: Boat Starting battery just dies

Sounds like to me you have a bad charger. Also be careful, chargers when left in can cause batteries to explode if fluid levels are not kept up in the batteries. Best advice is if you have not a clue about the system get a pro to look at it for you. may cost you some money, but may save you a bunch also.

Thanks for the heads up, went over today to check the water levels on the batteries.

 

[SteveMcD]

Re: Boat Starting battery just dies

Does your voltmeter do DC amps? You will have to disconnect a battery terminal and connect it in between. That will tell you if you have a current drain before you start spending $$$. I had the same problem with my truck. Found the alternator drawing 5 amps when everything turned off. The new one drew 0.

 

[apaseman]

Re: Boat Starting battery just dies

Does your voltmeter do DC amps? You will have to disconnect a battery terminal and connect it in between. That will tell you if you have a current drain before you start spending $$$. I had the same problem with my truck. Found the alternator drawing 5 amps when everything turned off. The new one drew 0.

Sorry I am a bit confused by what you mean by connect it in between? Do you mean to disconnect one terminal and touch the voltmeter to the battery terminal that has no cinnections? If so, does it mater whether its the positive or negative?