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Discussion Starter · #1 ·
When I drive (which can be several hours a day) I charge my battery via the cigarette outlet. I bought a 10 foot extension on Amazon (with good reviews) to run it into the rear, not sure if the extension contributed. The battery draws about 120 watts, which I thought should be fine, since the fuse on the power outlet is 20 amp and the extension was suppose to have a 10amp fuse as well. Well, suddenly the battery stopped charging. Apparently too much heat and the contact point melted. I had to yank the thing out of the socket since it was melted into the socket. Apparently this also somehow cause the 20 amp fuse to blow. Replaced the 20 amp fuse and pulled out the socket. Cleaned it up a little and things seem to be working again (with a new extension cable). But the lesson is, be careful. Old timers will remember these power outlets used to be used to light up cigarettes. So I guess I shouldn't be too surprised that a constant 120 watt draw could heat things up too much and melt the cheap contact point metal.
 

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2016 136WB low roof diesel, converted to an RV by Sportsmobile, TX
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Lighter sockets are a terrible power interface. They were designed to get hot, not to deliver power. If you have loads that are over a few amps (and 120W is 10A at 12V), you REALLY want a different interface. I use Anderson PowerPoles for all my high current needs, but then again, I am an electrical engineer and a ham, so I am used to what it takes to use them.
 

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2019 118" Silver
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Power outlets in modern vehicles for the most part are not cigarette lighters anymore, that’s actually a special order item. I remember the old cigarette lighters in vehicles I used to have were heavy duty solid steel, not these flimsy imposters of today.
 

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2018 136" HR
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i thought the cigarette plug is 15A fuse?? I might be wrong but that is what i remember.
 

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Discussion Starter · #6 ·
Lighter sockets are a terrible power interface. They were designed to get hot, not to deliver power. If you have loads that are over a few amps (and 120W is 10A at 12V), you REALLY want a different interface. I use Anderson PowerPoles for all my high current needs, but then again, I am an electrical engineer and a ham, so I am used to what it takes to use them.
I might do something like this. When I yanked the socket it out it was some kind of 3 pin connector. So I just need to find a compatible connector and wire things up directly instead of thru the cigarette socket.
 

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2017 - 2500 159
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Also, good reviews on Amazon mean almost nothing. So many products are full of fake reviews and they can be pretty convincing.

I always try to buy from other retailers primarily because I assume most stuff in Amazon is crap. The good thing about Amazon is the return policy and usually quick shipping.
 

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Discussion Starter · #8 ·
Also, good reviews on Amazon mean almost nothing. So many products are full of fake reviews and they can be pretty convincing.

I always try to buy from other retailers primarily because I assume most stuff in Amazon is crap. The good thing about Amazon is the return policy and usually quick shipping.
definitely true...the amazon reviews (especially on the cheaper chinese stuff) is not very good indicator these days
 

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Also, good reviews on Amazon mean almost nothing. So many products are full of fake reviews and they can be pretty convincing.

I always try to buy from other retailers primarily because I assume most stuff in Amazon is crap. The good thing about Amazon is the return policy and usually quick shipping.
reviews are what u make of it

products are variable quality.....i have been mostly very happy with purchases....espically since
Nafta we have lost 40% population....retail has moved out except l_wes & Wally world
the Amazon choice product is very helpful and usually good price....socks....sandels....boots....crazy hardware products.....stain.....folding toilet .....bags for toilet...shovel....etc....

Rust retarded great stuff....u can find small liquid amounts at auto parts.....i like spray.....

Sent from my LG-H871 using Tapatalk
 

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2017 2500 HiTop 159 Cargo Van white.
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I might do something like this. When I yanked the socket it out it was some kind of 3 pin connector. So I just need to find a compatible connector and wire things up directly instead of thru the cigarette socket.
Go directly to the battery. Almost as easy to run directly from the battery with a fuse line than to fiddle with the existing cigarette feed.
 

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Most of the power plug ins and extensions like that on the market at 16 awg wire, a few are 14 awg.

I am speculating here but I wonder if you had a true current limiting device (charger) that actively limited the current to 10 amps, or have been relying on the resistance in that wire + modestly discharged battery when you measured 10 amps?

The reason I wonder is that normally a 20 amp fuse will actually support 20 - 25 amps for quite a long time before it trips, unless it gets very hot from something else. This "could" be an indication that the actual current somehow was more like 30 + amps for a while. Perhaps the battery that you were charging was more discharged than you typically have experienced in the past?

The power plugs in a vehicle are not perfect but if the current was really 10 amps and the connection was solid, then it seems like this should have worked. The core assumption though is that the device that you were powering is really actively limited to 10 amps draw max, not just a resistored down setup that is burning voltage drop in the wiring and turning it into heat.

Even a mediocre AGM battery can draw 50 amps of charging current when it is in bulk mode and the lifelines that I use can easily accept 75 in bulk mode. (100 amp-hr @12 volt type)

Are you essentially trying to do a battery to battery charger arrangement with a direct connection to the house battery via the 12 volt power plug and a 16 awg wire?
 

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Discussion Starter · #13 ·
Most of the power plug ins and extensions like that on the market at 16 awg wire, a few are 14 awg.

I am speculating here but I wonder if you had a true current limiting device (charger) that actively limited the current to 10 amps, or have been relying on the resistance in that wire + modestly discharged battery when you measured 10 amps?

The reason I wonder is that normally a 20 amp fuse will actually support 20 - 25 amps for quite a long time before it trips, unless it gets very hot from something else. This "could" be an indication that the actual current somehow was more like 30 + amps for a while. Perhaps the battery that you were charging was more discharged than you typically have experienced in the past?

The power plugs in a vehicle are not perfect but if the current was really 10 amps and the connection was solid, then it seems like this should have worked. The core assumption though is that the device that you were powering is really actively limited to 10 amps draw max, not just a resistored down setup that is burning voltage drop in the wiring and turning it into heat.

Even a mediocre AGM battery can draw 50 amps of charging current when it is in bulk mode and the lifelines that I use can easily accept 75 in bulk mode. (100 amp-hr @12 volt type)

Are you essentially trying to do a battery to battery charger arrangement with a direct connection to the house battery via the 12 volt power plug and a 16 awg wire?
I'm running an ecoflow (similar to a jackery or goal zero). If I recall the specs says the cigarette charger is 12v at 10amp. And when it's charging the display says about 120 watts. When I run it via the extension it reads about 110 watts, and I assume the dropoff is due to the length of the extension cable. So I do think the ecoflow does limit the draw to 10amps. My only other guess is that I was in the desert heat, and maybe the direct sunlight heated open the charge point? I mean sitting in direct sunlight in the desert can get things pretty hot. So between the electrical heat and the sun heat maybe it caused the cheap metal of the extension to melt?
 

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Discussion Starter · #14 ·
FWIW, I've been running this setup for almost a year now. The only thing different was this time I was in the desert heat???
 

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Thank you for the insight and explanation. I am very curious about common electrical components that fail during real world use, especially if it is potentially due to an edge case (high / low temperatures, vibration, special end use case, etc).

I am especially curious about your set up because I build what you might call a "Ruggedized version of those power stations on steroids".

Usually it is used with ~ 600 watts of solar and the solar charging is (sometimes) supplemented with ~ 600 watts of alternator supplied power, and can also charge from 120 vac - also at 600 watts when available.

I have recently added a 10 amp / 120 watt charger capability supplemental use with a 12 volt automotive power socket. The reason for the feature was to help customers who didn't want to add a 600 watt / 12 volt connection that switches on / off with the ignition, but still wanted "some" alternator charging.

I have tested it quite a bit, but as you have observed, things can work for many months and then fail under more extreme conditions or an unanticipated use case.

Obviously I want to prevent field problems, so your field failure "event" is very interesting.
 

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The historical use case of these small power systems was for tail gate parties at college games. At that time, people would charge them up at home and use them for powering music, lighting and phone charging.

Later they started to be used at camp outs along with a small solar panel for similar things, and were colloquially called "solar generators".

As a supplemental / trickle charging method, 12 volt socket charging was added by most companies.

To be honest, it never occurred to me that an end user would use this tertiary / modest 12 volt socket connection as the primary / only charging method, (even though I have tested it this way) so your use case is sort of two edge events:
  • Somewhat unexpected use case
  • Hot conditions

The hot conditions I have anticipated, but only to the extent that the supplied wire / socket is used directly into the switched van power outlet. I had not anticipated the use of a 12 volt extension cord purchased off of amazon.
 

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Was the failure point at the interface of:
  • the vehicle 12 volt port / extension cable?
  • The extension cable / power system cable?
 

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Here are some examples of 12 volt sockets that are available:


In the marine world, there is a lot more vibration than in a vehicle, so sometimes people will use a "twist lock" type 12 volt socket.

The good news is that it is really held together very well.

The more challenging side of this story is that the push in / rotation forces are fairly high. When mounted on stainless or Al plates they work great.

When mounted on a polymer / plastic surface, it is very difficult to prevent the entire socket from rotating under the required forces.

In my case I had to use the appropriate plastic solvent / glue to literally bond it all together to prevent rotation.

The Perko connector is also quite good.

Marinco is owned by the same company as bluesea but a different brand.
 

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Go directly to the battery. Almost as easy to run directly from the battery with a fuse line than to fiddle with the existing cigarette feed.
He is taking advantage of the ignition on / off capability as well.

Do you have a suggestion for how to do this part?

If so I can see that as very useful.
 
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