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20A Cigarette Lighter socket

Discussion in 'Mobile Radio Systems' started by KC3U, Oct 3, 2013.

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  1. KK6GMN

    KK6GMN Ham Member QRZ Page

    Well, I went ahead anyway. Practical beats theory most of the time.

    I purchased an 18AH sealed battery. I am using a Kenwood d710a. I have the 18AH battery connected to the cig lighter through an EZGate to limit current to the battery. I also installed a dash voltage monitor so I can see the status of the radio battery. The radio spec notes 13.8vdc with a 15% margin. I figure I can run the radio safely down to 12vdc. I have tried the radio in high, medium and low power and see very little voltage droop with transmit. Sometimes .1v drop, most times none. The battery appears to hold at a voltage of around 12.4-12.6 most of the time when in use and comes back up to ~12.8v after charging with no load for a while.

    So, it appears to work for my needs at this point. YMMV. Flame suit is on.

  2. KH6AQ

    KH6AQ Ham Member QRZ Page

    From the description it looks like the EZ-Gate is a Schottky diode and a 3 ohm resistor. With the automobile engine ON (13.8 V) and the radio DC input at 12 V the EZ-Gate will supply only 0.5 A. With the D710A drawing 1.2 amps in receive it will discharge the battery faster than the EZ-Gate can charge it. I'd remove the EZ-Gate.
  3. KK6GMN

    KK6GMN Ham Member QRZ Page

    Understood. The EZgate is used to just top up the battery some while in use and while not in use. Since it will not be runnign 24/7 it should recharge fine. Time will tell. Main reason for the EZgate was I just wanted to be sure the draw through the cig plug would not exceed 2A. My fear was that if I connected the battery directly to the cig, it would possibly draw more then the 2A. May not even be necessary, but wanted to be sure. I did NOT want to run wires directly to the auto battery, so this seemed like a reasonable compromise.
  4. M0GVZ

    M0GVZ Ham Member QRZ Page

    Oh jesus here we go again.....

    Why do you continue to post this? For the uninitiated this is a picture Alan constantly posts to try and prove his point. Allegedly it was caused by a 5W HT powered by a cigarette lighter socket and there was no fault with the adapter or the radio.

    Basic electronics instantly proves the claim is a load of rubbish and the only way it could've occurred is with a fault, not by a 1-2A maximum drain.
  5. KH6AQ

    KH6AQ Ham Member QRZ Page

    The picture of the burned car that keeps appearing in this thread is an example of two logical fallacies: Appeal to Fear and Misleading Vividness. If you saw a picture of one of the 26,100 U.S. house electrical fires that occur every year would you have an electrician hard wire all your appliances? No, it's a small risk that we live with. Automobile cigarette sockets and plugs meet SAE and UL standards and are considered safe.
  6. KF5FEI

    KF5FEI Ham Member QRZ Page

    Until Bubba blows the fuse with his 100-watt export radio or million candlepower deer spotlight and replaces it with a 30a fuse.
  7. K0BG

    K0BG Ham Member QRZ Page

    It was not caused by an HT. It was a result of a laptop charger. According to the Fire Marshall, the socket overheated, and caught some insulation on fire. The end results are what you see. The original photo was dated 1999, and I believe it is a GM X car of some description.

    I have several others I can't publish, as I haven't been able to procure permission. One of them, directly from GM, is of a 2011 Caddy Escalade with basically the same issue except it was a rear socket.

    Anyone can wire their mobile any which way they want, including you Conor. You may think it is rubbish, but you won't if it happens to you!
  8. KK6GMN

    KK6GMN Ham Member QRZ Page

    Seems like if the vehicles fuses did not protect the user from using a commercial plug in a provided socket, there is a lawsuit somewhere that could be brought.
  9. KF7VXA

    KF7VXA Ham Member QRZ Page

    MFJ has a deal that uses capacitors, charges them when the need for amperage is not too high and discharges on transmit to add additional amperage. I don't know that I would trust it though, I have not tried one and know of no one who has.
    Much better to just get battery terminals that allow wire hook up, run 8 ga wire through the firewall, you can always get it through with other wires. Run it inside to a powerpole connector. Be sure to fuse both the positive and negative wires at the battery. I have done this with my vehicles and it does not hurt anything and is easy to remove for sale of the vehicle with no damage at all. I tried 10 ga, but got too much voltage drop, so I went to the 8 ga.
    Much better. You are asking for major trouble using the cigarette lighter, don't do it.

    73's John KF7VXA
  10. N7WR

    N7WR Subscriber QRZ Page

    Gordo is a showman/pitchman. He is not necessarily a top technical type. To the OP, you have had some very knowledgeable folks on here give you some very good advice. K0BG's expertise is widely known and STH has done land mobile radio stuff for years. You are risking way too much to use any cig lighter or "power point" outlet. Running two adequate gauge wires, properly fused, directly to the battery is the only safe way to go. You asked and the people that KNOW have given you advice. If it were me, I'd take the advice and not try to justify what seems to be a faulty plan that you are set on pursuing
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