12 Volt Meltdown and Malfunctioning Inverter

[off-the-grid]

One of the original 12 volt sockets on my boat went on me, and I replaced it with a new one, just a few months ago. Now, the new one already died. Looks like it heated up enough that over time from forcing the inverter in there (it's a tight fit) the end bulged out, so the tip of the inverter doesn't make contact anymore.

It appears that maybe it's the inverter that's overheating. I put in a new socket, once again (actually swapped it with the one from the other side of the boat). Occasionally, the led will go red (indicating over/under voltage, or over heating), and the inverter switches off. This seems to happen mainly in the middle of the afternoon, when the voltage on house bank gets above 14volts, and the solar controller switches to trickle mode.

It's just a tiny little 100 watt inverter, that I'm using mainly with my laptop, and for charging small devices.

Any ideas?

Other than maybe I'm spending too much time on the computer, for someone who's sitting on the hook.

[David M]

Is this in an enclosed space where the air is getting too hot?

I use a 12 volt 120 mm computer fan in a couple enclosed spaces with electronics on my boat.

[sailvayu]

I would check the wire size and condition to the plug. 100 Watts is not much but poor connections or small wires result in heat. Maybe upgrade to a real plug not one of those cig lighter plugs those things are bad for good connections. Or better yet hard wire the inverter on a fused supply.

[Tellie]

I agree, I hate those sockets on a boat, but if your plug in is heating up there's an issue somewhere that should be hunted down. 100Watts shouldn't be a big deal.

[donradcliffe]

a 100 watt inverter can draw up to 10 amps, and that's too much for the cigarette lighter sockets. Just cut the plug off the end of the inverter and hard wire it--that's the instructions that my oldest inverter 150 watt (still going strong after 17 years) came with Just be sure to get the polarity right.

[off-the-grid]

Originally Posted by David M

Is this in an enclosed space where the air is getting too hot?

Nope, it's right in the main cabin.

Originally Posted by sailvayu

I would check the wire size and condition to the plug. 100 Watts is not much but poor connections or small wires result in heat. Maybe upgrade to a real plug not one of those cig lighter plugs those things are bad for good connections. Or better yet hard wire the inverter on a fused supply.

Yeah, I wouldn't put it past PCI to use undersized wiring. Real plug, as in fire up the big inverter, and just turn on the main AC?

Originally Posted by donradcliffe

Just cut the plug off the end of the inverter and hard wire it--that's the instructions that my oldest inverter 150 watt (still going strong after 17 years) came with Just be sure to get the polarity right.

Kind of hard to do that on a tiny 100 watt unit, that's just a single molded piece. I have a larger one too, I think 400 watt, that I could hardware, but I got the little one, with the idea that it will draw much less, if I'm just running the laptop or a charger. Guess that doesn't really help, if the thing heats up and dies on me, though...or worse.

[familycruisers]

Personally, I would do away with the inverter and get the 12v dc adapter for your laptop. Less watts used to invert to AC just to convert back to dc.

[sailvayu]

"Yeah, I wouldn't put it past PCI to use undersized wiring. Real plug, as in fire up the big inverter, and just turn on the main AC?"

I was referring to a bayonet type plug like perko makes. to plug the inverter into. The thing is to have a good power supply to the inverter using properly sized wire with good connections. 100 wats @120 Volts equals about 8 AMPs at 12 volts but this will go up if there is a voltage drop to the inverter.

[Ex-Calif]

Are you guys doing the math right?

100w/120v=0.8a

It sounds like the inverter is too small for the charge load. I have a 400w inverter. It draws 3.3a at max load. I guarantee it is not drawing 33+ amps.

I do agree it should be hard wired and fused.

[barnakiel]

Originally Posted by Ex-Calif

Are you guys doing the math right?

100w/120v=0.8a

It sounds like the inverter is too small for the charge load. I have a 400w inverter. It draws 3.3a at max load. I guarantee it is not drawing 33+ amps.

I do agree it should be hard wired and fused.

Hey Boss,

But is the 400W not 40A on 10V side?

The 3.3 A you quote seems to be what your inverter DELIVERS. To make the same 400 out of 12 you suck in 400/12 = 33.3.

Just asking as we have a small 150 (peak) inverter here and I am dead convinced it takes out well in excess of 10A from our 12V system when under full continuous load!

???

A small inverter does not have to be hard wire but a big heavy unit in the seaway better be!

b.

[jdoe71]

I have a 100 watt inverter that I run a 22" LCD TV off of, it draws 6 amps. The TV is rated on the case as drawing 75 watts, therefore, the 6 amps is exactly what I would expect to see. 6 amps X 12 volts = 72 watts.

It makes the plug receptacle damn warm, if it had a marginal connection I think it would get hot enough to melt plastic.

[cal40john]

I'm pretty sure he's talking about one of these. Gonna be a mess hardwiring this.

John


Original Power 90306 75/100 Watt Mobile Inverter Power Equipment

[alti804]

These cigar lighter plugs will only handle a small amount of current, they will heat up causing the end of the plug to carbon up (be careful as it will cause severe burns if you touch). The carbon will cause more resistance and more heat, eventually causing failure and is a dangerous fire hazard. Most manufactures will tell you (if you call their customer support) that this can happen and they recommend using the alternate power supply cord that will connect directly to the battery. I also recommend either connecting direct with an inline fuse (or panel circuit breaker) or a better quality type plug. Stay away from auto style cigar lighter plugs. The higher resistance on the DC power connection at the plug can cause degraded performance and sometimes complete failure of the AC output.

[Florida Mike]

You could go to a junkyard and pull a metal cigarette lighter/power plug from a car and install that. You can also go to hell supply house and get the same thing. You might try to increase the wire size. If you decide to put in all metal receptacle you need to coat it with a non-conductive grease ( I can’t remember the name of the grease off hand). FYI the plastic plugs are very flimsy. Just my two cents, Mike.

[mitiempo]

I install this one from Blue Seas often. The socket is rated at 15 amps but I would keep any load under 10 amps as that is all the plugs are rated for. They sell for $6 or $7.