200 amp landing lights

Discussion in 'Maintenance Bay' started by RonP, Jan 5, 2021.

  1. RonP

    RonP Pre-Flight

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    Rather than hijack the thread titled “wing tip or landing light modifications” I am starting a new one regarding my question.

    In that thread it is stated the landing lights draw 200 amps. This was also confirmed by another person. 200 amps seems way too high of a current draw. Given the alternator or generator is typically anemic on the average GA airplane it seems hitting the electrical system with a 200 amp draw during landing would leave one with a dead or weak battery after landing given the time the 200 amp landing light is on. Since I am far removed from being an expert on aircraft electrical systems how can the charging system and battery maintain such a high draw in the 200 amp range without some penalty?
     
  2. Salty

    Salty Final Approach

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    Seemed odd to me also
     
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  3. pburger

    pburger Pre-takeoff checklist

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    I'm not even going to read the other thread, but I'm going out on a limb and saying they meant 200 watts, which would be 16.7A at 12V. A standard GE4509 is 100W, and draws 8.3A.
     
  4. LesGawlik

    LesGawlik Pre-Flight

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    I don't know how a landing light could draw more than the alternator output for any length of time.
     
  5. Greg Bockelman

    Greg Bockelman Touchdown! Greaser!

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    Yeah, that.
     
  6. benyflyguy

    benyflyguy En-Route

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    200amp is the service for most homes now.
     
  7. Bell206

    Bell206 En-Route

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    It can't. I believe a closer look at that particular model's wire diagram one will see that type landing light is powered through a 25A or 30A CB/fuse. For comparison most small aircraft starters barely draw 200A. I pretty sure the Grimes retractable light is rated at 200W or 250W....
     
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  8. schmookeeg

    schmookeeg Administrator Management Council Member

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  9. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    Which is enough to overwhelm the 15(???) amp generator added to a Cessna 120 and run down the battery if you leave it on while flying. Guess how I know.
     
  10. Sinistar

    Sinistar En-Route

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    I could see if it was a pulsed system and drew something like 30A (instantaneous) for very short durations.

    Its watts.
     
  11. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    Ampere, Watt, Volta, whatever. All three of them guys died like, 200 years ago.
     
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  12. Dan Thomas

    Dan Thomas Final Approach

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    Those lamps are rated at 13V, so the amperages are a little lower than that.

    A lot of older Cessnas used a single 4522, a 250-watt lamp that drew 19.2 amps on a 20-amp breaker. That breaker got pretty warm and its contacts would oxidize over time, building resistance that made the heating worse so it would pop at inconvenient times. A fix (minor mod) is to replace the breaker with a 25-amp unit and increase the wire size to 12 gauge, if I remember right.

    But, to address the OP's question, someone is confusing amps with watts. A 200-amp landing light would be 2600 watts at 13V or 5200 watts at 26V. You could almost start fires with light like that. Melt the ice on the runway, maybe, or burn the fog out of the way...:)
     
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  13. GeorgeC

    GeorgeC Administrator Management Council Member PoA Supporter

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    I want five megawatts by mid-May.
    popcorn.jpg
     
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  14. Daleandee

    Daleandee Line Up and Wait

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    200 amps is for the phaser array ...
     
  15. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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  16. RonP

    RonP Pre-Flight

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    My speculation when reading the other thread is that they meant 200 watts and not 200 amps. However another post on the other thread implied that high amperage, “enough to weld with”, is not uncommon on wing lighting on Alaskan bush planes. What is disconcerting is advice is being given out regarding the topic by people who may not know basic wiring with regards to voltage, current, wire size, circuit protection, etc. Hope the OP consults with people versed in these areas and not unknowledgeable posters claiming to be familiar with these areas.
     
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  17. Tom-D

    Tom-D Taxi to Parking

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    With an 35 AMP generator they won't. all three of my 170s would peg the amp meter when the landing light was on. 5 minutes was about all you expect before the battery was dead.
    When I converted to a 60 amp alternator and installed the LED bulbs, you wouldn't see the amp meter flicker.
     
  18. Tom-D

    Tom-D Taxi to Parking

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    The landing light in the 48 -170 has a fuse that controls the relay, not the light, it wired direct to the battery.
    This is why the wire was fried when I restored 23V.
     
  19. Tom-D

    Tom-D Taxi to Parking

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    The 120/140 original were a reflector and bulb. they were marked as 25 -? I can't make it out. I still have one (reflector and glass).
     
  20. Tom-D

    Tom-D Taxi to Parking

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  21. Salty

    Salty Final Approach

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    Watts the difference?

    I wanna see the cessna 150 powering a 200 amp 12 volt bulb off a 60 amp alternator. That would be a sight to see.
     
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  22. Tarheelpilot

    Tarheelpilot En-Route

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    On the spray planes the night lights for night spraying are two 650 watt two 850 watt and one that is 300ish. When they are all on the amp draw goes from 12 ish to about 90 according to the little gauge on the screen. I don’t see how 200amps is accurate. But who knows. Perhaps it’s a really big light. Lol
     
  23. Cap'n Jack

    Cap'n Jack Final Approach

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    I fell for a similar trap in a photography forum. Someone said his power supply drew 10 watts but delivered 20 watts output. I questioned it until it came out that there was a battery in the power supply. It could deliver the higher power until the battery needed recharged. Yeah, the bulb can theoretically draw 200 amps, but not for long.
     
  24. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    Wow......watts meet amps. Lol o_O
     
  25. Salty

    Salty Final Approach

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    Yeah, if the wiring doesn’t melt first, maybe for 5 minutes.
     
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  26. timrb

    timrb Pre-takeoff checklist

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    Oh no! You mean I'm the one who you think has confirmed the 200A statement? That was meant to be a joke.

    Tim
     
  27. Dana

    Dana Pattern Altitude

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    You could probably see it from orbit!
     
  28. texasclouds

    texasclouds Cleared for Takeoff

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    Yea 200...201, whatever it takes.
     
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  29. RonP

    RonP Pre-Flight

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    Tim,

    My apologies for misinterpreting your ”weld” comment as a joke. I was taking the thread and the content as informative. Didn’t see a joke coming. Will be wiser and more open in the future.
     
  30. GRG55

    GRG55 Final Approach

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    Amazing what you can carbonize with green power...
     
  31. timrb

    timrb Pre-takeoff checklist

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    No apology necessary--I guess it wasn't much of a joke. I thought it was fairly plain that the poster meant watts, or at least not 200 amps. I pictured some guy with a Cub out in the middle of nowhere trying to weld a busted frame back together by shining his landing light on it.

    Tim
     
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  32. Tom-D

    Tom-D Taxi to Parking

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    My TIG is often less than 20 AMPS.
     
  33. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    That is better accomplished with the battery, jumper cables, and coat hanger wire.
     
  34. Cap'n Jack

    Cap'n Jack Final Approach

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    Yeah, Six, watts. My statement still holds. The unit of watts quantifies a rate of energy transfer.

    The point is that when you can store energy from a continuous supply, you can draw, for a limited time, more power than the continuous supply delivers, until the storage device is "empty". The storage could be a battery, capacitor, a water tower, dam, or a compressed air tank. I can deliver amps or volts as needed (which is why I used watts) until I run the storage dry, then it needs to recharge.
     
  35. Dan Thomas

    Dan Thomas Final Approach

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    Type-certified airplanes are required to have power generation sufficient to power all continuous electrical loads simultaneously. In the old days, generators couldn't do that. Alternators changed everything. A generator regulator had a current-limiter function to prevent generator burnout from overloading; alternators don't have that and are big enough to cover the whole constant load. A landing light is a constant load. A flap motor is an intermittent load.

    FAR 23:

    §23.2525 System power generation, storage, and distribution.
    The power generation, storage, and distribution for any system must be designed and installed to—

    (a) Supply the power required for operation of connected loads during all intended operating conditions;

    (b) Ensure no single failure or malfunction of any one power supply, distribution system, or other utilization system will prevent the system from supplying the essential loads required for continued safe flight and landing; and

    (c) Have enough capacity, if the primary source fails, to supply essential loads, including non-continuous essential loads for the time needed to complete the function required for continued safe flight and landing.

    A 200-amp landing light would put the system far outside the capacity of a 60-amp alternator and would be illegal.
     
  36. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    in the bidness....we call that ...."in-rush" current...which is the momentary spike (impulse) as the device is starting.
     
  37. Tom-D

    Tom-D Taxi to Parking

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    Scratch all that, and install in accordance with the STC or field approval..
     
  38. bnt83

    bnt83 Final Approach

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    Landing and taxi lights are not tabulated as a continuous load under OEM data, see 177 service manual: (I know its not the same model aircraft in this thread)
    upload_2021-1-6_10-2-14.png
    upload_2021-1-6_10-3-27.png


    Where can a guy buy a 200 amp light?

    200 watt sure, 200 amp, no.

    1969 thu 1976 172
    upload_2021-1-6_10-26-34.png
    upload_2021-1-6_10-26-10.png

    I'd bet with all lights on, pitot heat, radio equipment and moving the electric landing gear on a Beech/Mooney/Piper/Cessna the demand is significantly over 100% of charging capacity.
     
    Last edited: Jan 6, 2021
  39. Salty

    Salty Final Approach

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    You ain’t getting a field approval for a 200 amp light in a c150.
     
  40. weilke

    weilke Touchdown! Greaser!

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    Watts, Amps, it's all the same, right ?