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Thread: Powering a camp lantern with a car battery?

  1. #1
    Unenlightened
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    Default Powering a camp lantern with a car battery?

    Hello,

    I'm an author, and am working on a book in which one of my characters needs to power a battery-powered camp lantern with a car or snow mobile battery. It could be an LED, fluorescent, of any kind of bulb, as long as it emits light. For that matter, it could even be a large flashlight. Would anyone be willing to tell me the specifics of how to accomplish this? I need to know the type of wiring, whether or not resistors are necessary, or anything else my character should know in order to not get eaten in the dark by cave monsters.

    If it matters, the resulting setup need not be portable. Once she gets some light, she'll stay put for a while.

    Thank you in advance!

  2. #2

    Default Re: Powering a camp lantern with a car battery?

    Well...if the age of the light isnt important, and older Coleman tent light that resembled a small bedroom style lamp could be used. https://i.ebayimg.com/images/g/lMIAA...nE/s-l1600.jpg

    These lights used a square 6 volt battery with spring terminals but the lamp socket was the same bayonet style that was common in automotive use in the 70s and 80s. The lamp came with it's own 6 volt rated incandescent lamp but you could easily swap out the original for a 12 volt single filament automotive lamp (seperate turn signal lamps or back-up lights) or even a 12 volt LED replacement and run at least 16 gauge wires to the contacts. The red and white sections unscrew to access the battery. Simple metal plates on the underside of the white section make contact with the battery spring terminals with the switch sliding to complete the circuit.

    Back in the eighties, 6 volt automotive lamps were still relatively easy to find compared to nowadays. The whole thing is plastic and worked surprisingly well. My family had one for camping when I was young.
    Last edited by lightfooted; 07-25-2020 at 05:21 PM.

  3. #3
    Flashaholic* RetroTechie's Avatar
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    Default Re: Powering a camp lantern with a car battery?

    Welcome here, farkuldi!

    Just cabling: 2-conductor wire from car battery (cigarette lighter) -> DC connector that plugs into 12V powered lamp. Such lamps are a dime a dozen exactly because the ability to power and/or charge from a car battery is a useful option. Many such lamps aren't much more than 12V DC input + series resistor + NiMH battery pack + LED + switch. The lamp doesn't care if 12V comes from a car battery or AC powered wall brick. If DC connector (example) is not available, one could partially disassemble a lantern & attach wires directly to the inside. Same for attaching to car battery. Materials useable for this purpose can be found everywhere. For example loudspeaker wire, AC mains cord, or even coax cable would do.

    Of course for dramatic effect, it's better to have stripped wire ends duct taped directly to the battery poles. Don't need any connectors or fuse in between!

    As long as lamp is low power (like a LED lamp of a few Watts max), a car battery has comparatively 'infinite' capacity. So how that is recharged, may not matter until many weeks into the situation.

  4. #4
    Flashaholic
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    Default Re: Powering a camp lantern with a car battery?

    Many of the older fluorescent lanterns, popular in the 1970s to the 1980s came complete with a 12 volt power lead to connect the lantern to a 12 volt cigar lighter outlet in a car.
    If the lantern used 8 cells (about 10 volts on load) then the resistance of the connecting lead was intended to drop a couple of volts.
    If the voltage difference was greater then the lantern incorporated a circuit to reduce the car battery voltage to that produced by the internal battery.

    Run time varied according to size and condition of car battery but was dozens of hours.

  5. #5
    Flashaholic
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    Default Re: Powering a camp lantern with a car battery?

    Quote Originally Posted by farkuldi View Post
    Hello, I'm an author, and am working on a book in which one of my characters needs to power a battery-powered camp lantern with a car or snow mobile battery. It could be an LED, fluorescent, of any kind of bulb, as long as it emits light. For that matter, it could even be a large flashlight. Would anyone be willing to tell me the specifics of how to accomplish this? I need to know the type of wiring, whether or not resistors are necessary, or anything else my character should know in order to not get eaten in the dark by cave monsters. If it matters, the resulting setup need not be portable. Once she gets some light, she'll stay put for a while. Thank you in advance!
    These days, some LED flashlights and small lanterns can be powered from USB (5v dc) which can be powered from an ac adapter, but also easily from a 12v adapter which plugs into the vehicle lighter socket. These devices are all over the place, even in dollar stores. It's usually connected using a standard USB cable (also widely available and cheap). If there's no lighter socket, direct wiring from adapter to battery can be done with a couple of wires. Dave

  6. #6

    Default Re: Powering a camp lantern with a car battery?

    If you want something a little rougher, it would be perfectly possible to take the battery out of the vehicle, rip out a marker light or headlight with some of the wiring attached*, sit the battery in the cave, strip some insulation off the end of either wire (that can be done with fingernails or teeth, or by dragging it over an edge of rock) wrap one piece of wire around each terminal, and it would be ugly, but it would run until the battery died. A headlight would probably only run overnight, a running light much longer.

    *the wiring will be two wires.

  7. #7
    *Flashaholic* Poppy's Avatar
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    Default Re: Powering a camp lantern with a car battery?

    Quote Originally Posted by Ken_McE View Post
    If you want something a little rougher, it would be perfectly possible to take the battery out of the vehicle, rip out a marker light or headlight with some of the wiring attached*, sit the battery in the cave, strip some insulation off the end of either wire (that can be done with fingernails or teeth, or by dragging it over an edge of rock) wrap one piece of wire around each terminal, and it would be ugly, but it would run until the battery died. A headlight would probably only run overnight, a running light much longer.

    *the wiring will be two wires.
    Ken,
    I like this.
    I imagine that the OP is looking for the character to MacGyver something together.

    If she happens to have a cigar lighter to USB adapter in her car, she might use it to power a 5-6 volt lantern.
    This picture depicts how I connected one with alligator clips to an 18V tool battery. Those little gadgets will work with anything from 12V to 24V and drop it down to 5V.



    Then a USB charging cable and be stripped and the ends jammed into the battery box of a 6V lantern (and held into place with the batteries, between the end of the battery and the terminal of the light).

    Here is a picture of a 6V lantern that I soldered a charging cable into it so that it could be run from a battery bank, but with the above set up it could run from a car battery.

    My Grand Kids call me Poppy

  8. #8
    Flashaholic
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    Default Re: Powering a camp lantern with a car battery?

    Quote Originally Posted by Poppy View Post
    Ken, I like this. I imagine that the OP is looking for the character to MacGyver something together. If she happens to have a cigar lighter to USB adapter in her car, she might use it to power a 5-6 volt lantern. This picture depicts how I connected one with alligator clips to an 18V tool battery. Those little gadgets will work with anything from 12V to 24V and drop it down to 5V. Then a USB charging cable and be stripped and the ends jammed into the battery box of a 6V lantern (and held into place with the batteries, between the end of the battery and the terminal of the light). Here is a picture of a 6V lantern that I soldered a charging cable into it so that it could be run from a battery bank, but with the above set up it could run from a car battery.
    Majority of lighter-plug USB adapters should work up to 24v or higher, but not all. I have some older ones which are marked only 12v (one shows 12v+/- 10% which does not make total sense with automotive battery voltage). If in doubt, read fine print on the label. I've taken several of these apart (a bit out of scope for this discussion) to see what's inside: chip type and voltage/current capability. Some cheaper adapters claim to be good to 1A output. Judging from how hot the chip gets with this load, I'd recommend limiting these to 1/2A, keeping in mind load current of the lamp/lantern. Others rated at 2A/2.1A output should be fine. In any case, 12v-only USB adapter will work on any 12v battery. A 5v USB manual hookup will work on 3-cell or 4-cell lamp though the latter may be a bit less bright than with fresh cells, should be fine. For direct battery connect, cable with alligator clamps for battery on one end, and lighter plug socket other end, is available from hardware and automotive stores.

    Dave
    Last edited by Dave_H; 08-24-2020 at 08:05 AM.

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