View Full Version : Overheated Battery

05-30-2008, 01:12 PM
This past weekend I had the negative post on my battery get so hot that it melted. It melted plastic, lead post, and broke the terminal. I know that low amps can cause this heat, but I'm looking for some other suggestions.

I've since put a new battery in and it seems OK, but I was wondering what other things there are that should be checked to make sure there still isn't a problem out there. I'm not convinced that this was just a bad battery. This battery was only about a year old and was replaced b/c the other wouldn't keep a charge. I'm just wondering if there isn't another ground or short out there that will ruin this battery also.


05-30-2008, 01:24 PM
Tell us more about the events leading up to your experience with the melted negative post on your battery? Might help to figure out what went wrong...

For example a loose/corroded connection between the negative terminal and the post and a lot of continuous cranking of the starter could describe your situation.

Oh, and if you get a chance throw some pics at us too!

05-30-2008, 02:02 PM
I did have some problems with my starter acting like it was dragging. I thought maybe it was the problem. i changed the relay last year. Right before this happened my starting drug real bad almost like a low battery. Then I lost all power (dash, lights, etc...). I went straight to the battery to check the connections and noticed the negative cable sticking up in the air and then saw the post melted. Also, I normally run between 12 -13 volts with the engine running (even with this new battery). I actually used someone else's battery to crank it and then ran back to the dock with no battery at all. When I did, I was running 14 volts. That tells me that my altenator is OK right? But why would I run more volts with no battery at all than with one connected.

I would just like the piece of mind knowing the battery was the problem

Pics are coming in just a few minutes.

05-30-2008, 05:17 PM
Here's the pics.

05-30-2008, 05:44 PM
My buddy had the same thing happen a few years back. I believe that it was due to a loose connection on the negative terminal. The connection was not tight. That would be my two cents.

05-30-2008, 06:12 PM
It's low voltage that causes this. You need to look at the starter, solenoid, ground cable, positive cable to the solenoid and make sure all contact points are clean and tight. If you have cranked with a low battery charge a lot in the past, your starter is probably toast. The heat caused by the low battery has melted the enamel that coats the windings and caused a short, which killed the battery.

Loose connection will cause the same problem but it'll also kill a starter. Have it checked for current draw.

06-01-2008, 02:20 PM
I'm actually pulling my starter this weekend to have it checked and possibly re-built. It's starting to sound like this starter has been the culprit all along. Just not sure which caused the other...starter or battery. Thanks for all your help!

06-01-2008, 02:36 PM
Low battery charge level will take out a starter very fast. Replace the battery and it seems to take care of the problem for a while and then, it starts to crank hard again. The shorted windings in the starter cause the battery to dump a lot of current in a short time, which exceeds it's capability, damages the plates and leads, decreasing the current delivery capacity, making the starter crank slower, drawing more current,....

You can see where this goes. Also, since the alternator has to work harder when the battery is weak, you might want to take that in, too. Just to be safe and it will save you at least a trip, possibly a weekend of boating (or longer).

Oh, yeah- replace the battery cables.

06-01-2008, 03:49 PM
Here's the pics.Yikes! That is a picture I hope never to be able to take of MY boat.

06-01-2008, 07:34 PM
Alright...here's my list:
-Have starter checked (possibly re-built)
-Have altenator checked
-Replacing battery cables
-Battery already replaced.

Did I miss anything? Thanks a ton guys!!!

06-01-2008, 09:52 PM

And it better be GOOD beer!

06-01-2008, 11:29 PM
Here's the pics.

I would just recommend not using the stud and wing nut method to connect your cables to the battery. Personally I wouldn't want the Hundreds of amps running through that small of a connection. Switch the cables over to the traditional clamp style of connector for the most surface area between those parts.