Boat Battery Short

[bass1980]

I used the boat last Sunday and with night temps creeping to 32 degrees in the next few days I decided to leave the motor down while I parked it to drain any leftover water in the lower unit. I store my boat outside but 2 weeks ago my boat cover ripped so I have not been covering the boat and it rained on Friday. On Saturday I went to check on the boat to get it ready for one last outing of the season and noticed the motor was trimmed back up. I tried to trim it back down but it made a few clicking noise like it had no battery power. I grabbed the charger and attempted to charge the battery but while lifting the lid that covers the batteries there was a burning smell. I looked and the positive side of the battery had melted the power cables and also melted the wires for my sonar. Wire didn’t completely melted off but plastic is sure melted. The battery itself had melted plastic right below the terminal. I notice that my terminals was right under the edge of the lid so maybe water leaked down. I attempted to disconnect the battery but there was spark. I was all dressed up to go to a funeral and the ground and boat was wet so I didn’t want to get all dirty looking into it.

 

What do you guys think the problem is? I put the motor down and left it there? Water leaked and shorted the positive side? Will be busy for the next 2 days but after that I will have time to check it out.

[BKeith]

If I had to guess, a couple of thngs happened. A trim switch or something activated the trim and kept the motor running. The battery had a bad connection that over heated because of the running trim motor, melting the terminal and wires connected to it.

[Fishing Rhino]

If I had to guess, a couple of thngs happened. A trim switch or something activated the trim and kept the motor running. The battery had a bad connection that over heated because of the running trim motor, melting the terminal and wires connected to it.

 

That has happened to me.  While visiting our daughter in GA, we had a deluge.  The next time I went out, I noticed that the motor was tilted up and the front of the transom saver had fallen to the ground.  I thought maybe someone had played with one of the trim switches.  I lowered the motor, putting the front yolk of the transom saver over the back roller on the trailer.

 

I was doing some work in the vicinity of the boat when I heard a hum.  I looked up to see the motor tilting up again.  It turned out that the horizontal switch on the bow had filled with water, which activated the tilt.  I put the transom saver in place, and disconnected the cranking battery while I got a battery switch to disconnect the cranking battery.

 

Would not have been fun if the motor had tilted and the front of the transom saver dropped to the roadway like a vaulting pole.  It probably would have broken the transom saver and not the motor, but who knows?  Now, whenever the boat is not in use, the circuit to the battery is turned off. 

[Slade House]

real simple solution is to put a fuse on that before the battery,

[WRB]

Your boat should have a 40 to 50 amp circuit breaker(s) to prevent overheating the wiring when a short occurs. The cranking battery should have a 40 to 50 amp on/off switch from the battery to the big engine to prevent battery charging current from damaging the engines or electric sonar circuits when you charge the cranking battery. Apparently you may not have breakers or heavy duty switch?

It's sounds likely the bow engine trim switch shorted.

Tom

[Way2slow]

Fuse would not have prevented it. It was not a short or over current situation. The trim motor has a pretty heavy current draw and that current through a bad connection for an extended time can be like a several hundred watt heating element wrapped around the post.

No different than a loose TM connection heating or melting a terminal. Fuse ain,t gonna prevent that either

[WRB]

It doesn't require a lot of current to run the engine trim motor that has 3 switches; manual sealed switch on the engine, manual trim switch on the operators engine control and a remote bow switch. One of those switches shorted on from moisture, more than likely the bow remote switch.

The cranking battery powers the engine trim motor,the trim motor has a limit switch to prevent over travel and shuts off the trim motor. A loose battery cable will overheat from arching, not current draw. If over heating occurs from a battery short the 40 to 50 amp circuit breaker trips.

The safe thing is a 40 to 50 amp battery on/off switch to isolate the cranking battery when stored or trailering.

Your boat should have circuit breakers and battery switch if it's rigged properly.

Fuses only protect individual wire circuits and the boat should also have a fuse panel or in.ine fuses to protect the wiring if there is a short on those wires.

Battery maintenance is always an issue with bass boats.

I know I am repeating myself, didn't mention fuses in the first post because this wasn't a fuse problem.

Tom

[BKeith]

Not sure we're you learned your electronics but it dang sure was from none of the schools I got my associates degree from, which went along with about 45 years experience in the military and private life.

I'm not even going to try explaining all the things that post has wrong with it. I'm just going to say good luck to the OP and hopes he gets it figured out.

[Way2slow]

Somebody just rewrote ohms law and physics. Current passing through a bad connection does not produce heat!!! A dirty/bad connection creates resistance. I always thought as current passes through resistance, it produces heat. The higher the current or the higher the resistance, the more heat it produces.

Let see now, depending on the size of the motor, a starter can pull a hundreds of amps when cranking a motor. A starter gets it's power from the engine cable connected to the battery. What's suppose to happen to that 40/50 amp fuse/breaker that someone says "should" be connected to the engine battery cable when you try and crank the motor.

A trim motor only pulls three amps??. Why do they have a 10-12 gauge wire going to them and I wonder what happen to that relay those switches are normally connected to. I always thought they just energized the relay and the relay ran the trim motor because there was no way those little switches and wires could ever handle the current the motor itself pulls.

I guess I need to get some more learning on how all this stuff works. Looks like I've always had it wrong. Oh well, maybe I will get it figured out one day, ya'll have a nice day.

[Fishing Rhino]

Okay, I'm going to chime in here on heating and circuit breakers.

 

I have a circuit breaker on my trolling motor, the rating recommended by the manufacturer.  I never had it trip.  It is kind of a clunky thing because it is installed on the power lead from the motor to the battery.  That necessitated having a jumper from the breaker to the battery post.

 

I made the mistake of removing it because it was so clunky.  my mistake.  I fried the speed controller and some of the other wiring in the head of the unit.  I "repaired" the wiring, replaced the speed controller, reinstalled the breaker and off I went.  Some time, and a few trips later, the motor quit.  Checked the circuit breaker and it had not tripped.

 

So, back to the house and opened up the unit.  Again it had melted down.  Why?  Because I did not do a thorough job of examining all the components.  One of the main power leads had several strands that were broken.  What remained could not draw enough amperage to trip the circuit breaker, but it could overheat because it was probably only operating with half of the strands broken.  So I ordered a new power lead and the thirteen dollar speed controller, and all is now well.

 

Removing the circuit breaker allowed the first melt down.  Failing to notice that one of the main power leads was about half frayed allowed the second, in spite of the circuit breaker being installed.

[BassnChris]

  I put the transom saver in place, and disconnected the cranking battery while I got a battery switch to disconnect the cranking battery.

 

Would not have been fun if the motor had tilted and the front of the transom saver dropped to the roadway like a vaulting pole.  It probably would have broken the transom saver and not the motor, but who knows?  Now, whenever the boat is not in use, the circuit to the battery is turned off. 

 

I learned from hearing Tom's story.....installed the disconnect switch on the starting battery with 2 days of hearing the story.

Hope you find it is something simple and inexpensive.

[Way2slow]

Battery disconnects are always a good idea, but they are not fuses or breakers, just disconnects. 

If you make it a habit of turning it do disconnect the batteries, you don't have to worry about forgetting the turn the main power switch off, mice/rats chewing wires and shorting them, or as mentioned, a trim motor switches shorting. 

 

Me being a lazy butt by nature, I tend to be hit or miss with them.  About half my boats I've installed them and the others I never get that proverbial "round to-it" and they never got one.  My Javelin does not have one, a Stratos that stays at the lake does and I always turn it to disconnect. 

[Way2slow]

Tom, look at those broken strands like this. Your TM probably has a #8-10ga wire, which can handle 40 to 50 amps for very short runs with minimal loss from resistance and minimal heat caused by that resistance when running on max and say drawing 45 amps. Circuit breaker, motor, everything is happy and trucking right along with no problems Now, if you cut that #10 wire and placed a 1/2" long piece of 12ga wire in it, which can only handle about 30 amps for a short distance and you are running along at max and motor still trying to draw 45 amps. Circuit breaker or fuse is not going to know that 12ga wire is in there and it's a happy camper, motor is just going to slow down a little bit because the additional resistance that 12ga wire is causing, is also causing some voltage loss to the motor, but it's going to keep right on trucking along. However, that piece of 12ga wire is not going to be happy at all trying to pass 45 amps through it and will start smoking and melting before long from the heat the resistance it's causing. Other than that piece of wire, everything else thinks things are just as they should be so no fuse or circuit break will ever trip. I've seen those circuit breakers that mount on the battery have a bad connection that melted the battery terminal and plastic housing on them, but the bi-metal strip inside never heated enough to trip because there was never a current over load to cause it to.

[bass1980]

I just got more confused reading these replies haha. Actually really busy at work and just read a few sentences really quick. After work I'll read all the comments carefully and go take a look. Hoping to disconnect the cables without getting shocked. Then redo the power cable and hook it up to a new battery and lower the motor down. Going to winterize the boat this weekend.

Keep them coming, I'll learn something from these useful suggestions.

[bass1980]

As far as the boat goes it's an older boat, 89' Bass Tracker. Basically given to me from my brother. I have not look into the boat much as I just started using it this year. I know for sure the battery for the trolling motor has a fuse on the cable. Haven't check the battery for the trim/motor.

[Way2slow]

The battery is not going to shock you, not enough voltage. If you short it out, it can explode in your face or get what ever you shorted it with red hot but don't worry about getting electrocuted. At the most, if you ground a tender part of your skin, you can get a little stinging feel. However, you do want to be careful handling it, and wash your hands afterwards. If you spill the electrolyte in it on you cloths, you can throw them in the trash because every were it touches in going to be a hole when washed. The electrolyte is approximately 12% sulfuric acid so I can also cause skin burns if left of it very long.

Use baking soda if needed, to neutralize the electrolyte and then rinse everything off with water. Sprinkle baking soda, keeping it wet and rinse it off until there is no more foaming action when you add more.

[bass1980]

My trim motor maybe shot. When I hook up power all I hear is a light tick noise. Still not sure what caused the short. Look at the pics, hummmmmm.

[Way2slow]

Did you charge the battery, or have you left sitting a run down?

Since most likely you don't have a way of checking a sealed battery, you need to fully charge it and then take it to a parts store or some place that can check it with a Medtronics tester.   If it test ok, get you one of the marine adapters that will clamp onto the post and give you a stud terminal to reconnect you cables.  Also, pick up a couple connectors to go back on your wires.  The larger wire for the motor cable needs to be cut back to good insulation, and clean copper, cleaned and new end crimp on and soldered, because unless you have a very good crimper, you will not get a good crimp on it, and that can put you right back where you are at now when that bad crimp heats up.

 

That stud most likely melted out because the wires connected to it were not tight and they was a large, steady current on it.

 

One of the key causes of the melting of the positive stud is what you have on that negative stud.   Take those flipping wings nuts off and throw them as far as you can and get stainless steel hex nuts, and use a wrench to tighten them. 

 

It's also a good chance the trim motor is fried, but there are some checks you need to do before coming to that conclusion.  Once you have a known good, fully charged battery, before you hook it up, the first thing you want to do is take the cover off the motor an find the connecter for the trim motor and unplug it.  Look at the size wires at the trim motor and try to follow them up into the main wiring harness.  It will be about the only two/three wire connector in there with wires that large. 

Now, make sure the key switch and main power switch is off and  connect the battery and see if you still hear that click. If you still hear that click, one of the trim switches are most likely still stuck and you are hearing the relay energizing, so disconnect the battery.  There is a three pin connector on the motors main wiring harness for those also, if you can find it and disconnect it, or you are going to have to start disconnection switches. 

 

Since I don't know what kind of motor you have and everything is speculation right now, that's as far as I'm going until you can get the battery checked and installed.

[WRB]

The corroded or loose connection generated enough heat to melt the lead and battery insulation at the thread post. Check your battery warranty., it's possible the post is defective internally.

Get some anti corrosion sealant (Vaseline works) to coat the cleaned tightened connections.

Low DC voltage (12 volts) with high current requires good tight grounds and large enough wire reduce resistance and over heating the wiring or loose connections creating arcing

good luck, should be able to get this resolved.

[bass1980]

Sorry for the delay guy been tied up big time lately. Now thinking about it I bet it was because the wing nut was loose.

I got a new battery and cut the melted wire and redid the ends. Sonar still works, wheeeew. Trim motor doesn't and all I hear is a tick. When putting the power cable on which starts the motor I get lots of spark. This leads me to think there a short somewhere. I have not had time to completely redo the cables but that will be the next step. I just need to fire it up to winterize the boat. I can manually trim it and deal with that next year lol.

[Way2slow]

What I mentioned above should be done and check it, and I would not leave a battery connected until it's checked out, especially if it's making a click when connecting it. If everything is right, it ain't suppose to be doing that. You won't be real happy when the fire department shows up and tries to save what might be left of your boat if it does it again.