Battery terminal post melted? Anyone seen this b4?

nicferrante · #1 (**permalink**) 07-10-2008

We have had consistent battery issues on our Islander28. We have a Yanmar engine and (we think)the original standard battery charger. We are on our second set of batteries, but the third time they have been depleted. This time the terminal posts melted. Has anyone seen anything like this? I am not sure where to start the investigations...the charger? Any insight would be appreciated.

sailingdog · #2 (**permalink**) 07-10-2008

If the terminal posts are melting, you either have a serious short someplace or some badly corroded battery cables, more likely than not. My bet would be the cables are badly corroded. A lot of boats used non-marine grade welding cable for the battery connections, and if you cut the ends off the cable and peel back the insulation, I am willing to bet that the copper there is badly corroded and black with it.

btrayfors · #3 (**permalink**) 07-10-2008

Nic,

Sounds very much like you have a serious problem, and one which could easily cause a fire.

I agree with dog, but think you need to look further than the cables as well. A looksee by a qualified marine electrician would be a good thing to do; well worth the cost.

I think you're looking at replacement of the batteries, the cabling, the battery charger and, possibly, the regulator for your alternator.

This is what I'd be thinking of doing if it were my boat. Piecemeal changes will almost certainly continue to give you grief. If you make the investment in correcting the whole system, you'll not have to worry for many years to come.

Bill

Maine Sail · #4 (**permalink**) 07-10-2008

First off there should be fuses at the battery terminals to prevent any sort of short melting the lead posts. Second melted battery posts are cause for concern!!

My guess is that you may have a ground short somewhere? Perhaps a pos cable is touching bilge water and has a cracked jacket or is worn through and barely arcing on the engine block..??

sailingdog · #5 (**permalink**) 07-10-2008

Btrayfors-

I'm not saying he shouldn't check further, but that the battery cables would be the first place I'd check.

hellosailor · #6 (**permalink**) 07-10-2008

Nic, it takes a lot of heat (extremely high amperage) to melt battery terminals. I don't know if an internal short in the battery could cause that, but then again, I wouldn't think the battery charger OR the alternator was capable of putting out that much power either, unless somehow you got 120VAC going into the battery.

Time to disconnect everything, and check each piece very carefully before theboat burns down. An Islander28 is an exceptionally well-mannered boat, it would be a shame to burn one up!

nicferrante · #7 (**permalink**) 07-10-2008

yes, we are very concerned and just realized that our steaming light is missing!!! Maybe those wires being exposed are causing it? I am not sure how long its been gone. We have been sailing about every other weekend, but we are on her every weekend just hanging out. We still are new to sailing and this boat so we are working thru all the kinks. I think we are going to call out an electrician and hope for the best! Thanks again for all the advice.

nicferrante · #8 (**permalink**) 07-10-2008

The last few times we left the boat in the slip we did not plug her in...we have had such problems with the batteries that we were trying to isolate it and see if there was an AC issue or battery charger issue. Before we arrived to the slip we had motored for 3.5 hours from Ventura to Santa Barbara because we had no wind, so the batteries should have been fully charged. We even docked at the accommodation dock and turned her off and then restarted her with no problem. Our bilge is hard wired to the batteries so we do not need to be plugged in for that to kick in.

sailingdog · #9 (**permalink**) 07-10-2008

The fact that the batteries are depleted indicates a short of some sort. Most battery cables should have a fuse between the battery and the main DC panel...but not all do. Obviously a fuse isn't involved, since it hasn't blown and unless the fuse is huge, any load that would melt the battery terminals should blow the fuse.

The amperage doesn't have to be that high if there is a high-resistance element involved, which is why I am leaning towards the battery cables being corroded. That would require less current to generate the same amount of heat.

Stillraining · #10 (**permalink**) 07-10-2008

Got to go with the dog in this one...We have a pretty large fleet of trucks and heavy equipment...I have personaly burned off a few battery posts...It's ALWAYS a connection at the battery..

When your charging what I do an hour and a whole crew will shut down you dont shut down to fix stuff like that you drive a nail between the post and the battery cable and keep going. Then fix it after hours..sometimes you forget and it stays that way for a while and works loose again then you hit the starter one time and up in smoke the post goes.

Never ever had a post burn off from over amped charging systems or shorts or any of that stuff in 30 years around heavy equipment and trucks.and believe me we have had every conceivable thing Short out ,burn up ,overamp you name it...Again its always a loose/bad connection at the battrie to take the post out.

Not trying to sound like a know it all... but I know this one..

You have more then one problum...you definitely have a draw somewhere to drain the batteries but thats not what fried your post...Clean both post and cable on the new one tell they shine..use a tool like below and actually take some oxidized lead off..get them good and tight and then grease them up..you wount loose another one..IF you do I'll buy it for you.