I have been using a bit of 12 v dc lately. Had some problems with a couple of my leads. The ones that plug into the socket (Cig style) and then into the appliance.
The plugs have a fuse in the tip to protect it and I have found recently 3 times that the fuse, although appearing to be good is actually not letting very much current through. Just enough to light the LED indicator but failing when a load is put on. Bloody nuisance and cured by fitting a good fuse. The things must be just pressed in to make contact and corrode after a while.
Just a heads up for people to check more than the apperance of the fuse. More crap from over there !
Are yes the old cig lighter problem, Have seen many people complain about the erratic operation of their 12 Volt television or 12 Volt fridge while using this type of plug socket. Some people even tryed to claim to claim a warrentee !!! . Turned out to be the cheap cig plug that was used with this type of equipment. Even the one that are supplyed by the manufactures have problems.
Have seen the plugs melt to the point that the plug is near just imposable to remove from the socket due to heat caused by the poor conections, and have been amazed that a fire had not started. LCD televisions and 12 Volt compessor fridges can draw about 5 Amps and the internal spring inside of the plug looses tention due to current that passes through the spring, and this over a period of time the problem becomes even more of a problem.
My main fix is to change over to the european style Merrit plug and socket, these are rated at 20 Amps @ 12 Volts. I have used them on all of my 12 Volt Equipment and have never had a problem.
The cigarette lighter sockets were designed to provide power to a heater. The poor contact with the lighter (heater) was part of the heat produced for lighting cigarette heaters. The problem with using these sockets is they still have this potentially poor contact. The centre contact is hard to keep clean. Most plugs have a wiping action on the male contact from the female contact when you mate the connectors. The cigarette lighter connectors lack this basic feature. As a result the innards of the connectors are likely to heat up when you are using them for more than an amp or so current draw. This heat affects any fuse that is mounted close to the positive connector.
The best way to circumvent your problem is to install Merritt sockets in your vehicle and change the higher current devices plugs to Merritt plugs. If that is not practical then swap the cigarette lighter plug for one without a fuse.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Off subject a little.. I have replaced the fridge fuse with circuit breaker .. I'll be upgrading the terminals as they show signs of high resistance .. 3 way fridge .. Don't use it too often as DC is not very efficient ...
More crap from over there !
