12v Receptacle Melting Stuff

[labatt]

Hello All -

So I have a 12v receptacle at our nav station. It connects back to a breaker on our 12v distribution panel.

Connected to the 12v receptacle is a splitter from Radio Shack. I have a laptop power adapter and a charger base for a handheld VHF connected to it. There's a little green light on the splitter that lets you know if it's receiving power.

So the other day I was working on my laptop when I noticed that it stopped charging. I looked at the splitter, and the green light was off. I pulled the splitter apart and looked at the fuse. The fuse LOOKED OK, but who knows. I then plugged my laptop charger directly into the 12v receptacle and continued to work. About 10 minutes later, I noticed that, once again, the laptop wasn't charging. I pulled the charger out of the receptacle and noticed that the end of the receptacle had melted slightly and the metal contact (tip) was askew, embedded into the melted plastic.

All of my 12v books are on our boat, 2.5 hours away, and I don't know much about 12v electrics (yet). Any suggestions on what might be going on?

Thanks!

[PBzeer]

First thing to check for is a fault in the wiring, creating a short.

[sailingdog]

You've probably got a short someplace....that's what is generating the heat to melt the plastic. BTW, I would highly recommend wiring the VHF handheld charging base directly into the boat, rather than bothering using a 12 VDC receptacle on it.

[RickLaPaz]

The cheap 12 volt plug-ins and receptacles are exactly that--cheap. And as you can now see, potentially dangerous.

In the future-(when you sort out the problem and replace the burnt stuff) always start off with low amperage fuses. If it has a 5 AGC, start with a 2, etc. Under fused is ALWAYS better than over fused. For proof, just look for pics of old VW bugs with tin foil replacement fusies.........

[k1vsk]

uhhhhhhhhh - check the voltage

[hellosailor]

Melting=overheating.

Could be from the combination of loads pulling too much power (amperage) for too long. Fuses will generally NOT BLOW for a long time unless there is a large overload (i.e. 2x-10x) on them. And then again, Rat Shack is not known for quality parts, they could melt just for the heck of it.

With a multimeter you could check the current that each device draws, check the voltage, try to find out exactly what is or isn't working as rated. About $25 at Target or WalMart, for one with a 10-amp range on it.

Could be your voltage is too low from the battery--so the devices are trying to compensate by pulling too much amperage.

"tin foil replacement fusies........." We used to use the tin foil wrappers from chewing gum. (Which was used to fix other things.)

But that's to get home--not to fix it really.

[SEMIJim]

Sounds to me like either a defective receptacle at the nav station or the 12v adapter for your laptop is toast.

Jim

[labatt]

The 12v adapter came to me with the boat so I don't know much about it. It damaged both the Radio Shack splitter AND the laptop charger. The 8D batteries are fully charged and so have a voltage in the 13.x+ range. Most adapters I plug in (and I'd have to check the laptop adapter) usually allow for a variation on input voltage to account for this. I was surprised that the breaker on the distribution panel didn't trip. I need to look into what causes it to trip. Does anyone have a recommendation on where I can get a "high quality" 12v receptacle? I'm thinking I'll just replace this one

Now that I think of it, the gauge of the wire back to the distribution panel might be too small. The laptop can draw 7Amps-9Amps when charging. I have no idea what the wire gauge is. What gauge would you use for this load? It's not high, but it seems like it might be a high load for a 12v receptacle.

[Valiente]

Labatt, you are probably onto something. Laptops are "non-trivial" draws in my experience, and 7-9 amps on my boat would call for a 12 gauge wire run. You probably have 18 gauge. I have 12 gauge to spreader lights and 14 gauge to the masttop lights, and when I put these gauges in, the difference was dramatic.

I am also interested in a "best quality" 12 V receptacle, as I currently have none aboard and wish to remedy this for plug-in lights, charging, etc. I'll need both standard and a couple of "marine" ones so I can run a handheld GPS on deck without eating two AAs every 90 minutes. (also a deck spotlight or a Davis Megalight or "mood lighting" for fair weather would be welcome on deck, and for this I need decent, weatherproof receptacles.

[sailingdog]

Valiente-

What I've used on deck and in the cockpit for 12VDC receptacles are the waterproof, twist lock type trolling motor receptacles. They have three wires, which was important for what I'm using it for, since I'm cheating and using one wire as the output lead for the solar panels which can also plug into the receptacle, and the other two pins are 12VDC and Ground.

You can see them here.