Recharging batteries in place

Discussion in 'FAQs' started by mhdishere, Mar 23, 2004.

  1. Fred_M

    Fred_M Guest

    Upon looking at it more it seems to me that a few LEDs could be ran directly off the transistor output so we could loose the relay and its power drain? What you think? FRED
  2. Pitchwife

    Pitchwife Dreamer

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    I'd say it would be worth a try as long as the 4069 will supply enough current. Anything that will make it simpler.
  3. ezdays

    ezdays Out AZ way

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    Got lots of good ideas and opinions here. I still think it's a waste to have rail power available and not use it. a zener diode to limit the voltage to the LEDs and a large capacitor (or battery) to keep it there while the train is stopped should d nicely. Don't know how long a time they would stay on, that depends on the number of LED's and the capacitor or battery size.

    Just another thought on the magnetic reed switch, (or latching relay). How about placing a magnet a bit before a tunnel to turn the lights on when approaching and another one as it exits to turn it off? Just playing around with thoughts until I can get back to working on my layout. :rolleyes: :rolleyes:
  4. krokodil

    krokodil Member

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    In case of tunnel it is probably easier to use a photoresistor to switch the LEDs (like you garden or gate lamp).

    :thumb:
  5. Fred_M

    Fred_M Guest

    Don, I agree about the rail power if it wasn't so dang hard to build reliable pickups cheaply. Does anyone sell premade pickup trucks in what would be on passenger cars and cabeese? Esp. the cabeese as I don't run passange trains. And instead of a zener use a 78xx series voltage regulator to charge batteries. FRED
  6. ezdays

    ezdays Out AZ way

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    Fred,

    Yeah, the mechanics of it is a problem, but one also has to consider the reverse polarity as well. A bridge rectifier will handle that, and a 78L05 would work and is about as cheap as a zener.
  7. Pitchwife

    Pitchwife Dreamer

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    originally posted by Don


    The problem that I see with using a capacitor is the physical size. It would be fine in a baggage car or something like it, but with a coach or other car with windows running the length of the car it would be difficult, especially if you are detailing the interior. The advantage with going solid state is that a PC board can be mounted to the ceiling where it wouldn't be noticed.
  8. ezdays

    ezdays Out AZ way

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    Clark,

    A capacitor sized to do this would be rather large, I agree, but so would a battery. There are still two elements missing here, # of LEDs (current draw) and the "backup" time required to keep the lights on without raill power. Once we have this, we can then calculate what it will take to provide the power to do it.

    I gotta admit that a battery is going to be a lot smaller and a whole bunch cheaper though (small, high value, low voltage caps are way up there in price). :) :)
  9. Pitchwife

    Pitchwife Dreamer

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    The only battery solution I can think of off hand are the "button" batteries such as are used in watches etc. If used in conjunction with track power, a number of them in series could power the lights when the train is stopped. Still, there is the problem of price. I know that they aren't cheap.
  10. ezdays

    ezdays Out AZ way

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    Clark,

    Button batteries like that are not rechargable and are designed for very low current for a long period of time. Best bet would be a NiMH. They are available in AAA. A 650 mAh runs under $3.00. A pair of these would run three or four LEDs for an entire session without recharging. Gee, now we're back to the original problems and previously discussed solutions.:rolleyes: :rolleyes:
  11. Fred_M

    Fred_M Guest

    Some of the new "memory" caps are about 1/2 the size of a AAA and store 1 farad @ 5.5 volts which should last a few second depending on load. But, we get to much complexity and cost. I again say 4 AAA NIMH will run 2- 20ma leds for 7 to 10 days per charge. No fancy switches, fancy mechanics, or fancy electronics needed. Of course if you like electronics there is nothing wrong with making something fancy either. If you don't like electronics (or are just cheap and lazy like me) do it with 4 batteries:D . FRED
  12. mhdishere

    mhdishere Member

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    For the record, my MDC Harriman cars will take a pair of AAA's side by side in the roof without showing thru the windows, and I could probably hide two side-by-side pairs, one at each end. AA's are a tighter fit and they'd hang down a bit, and the holders couldn't go on the sides of the batteries, so I'd go with AAA's.

    I wanted to turn them on and off because I didn't want the lights on, say, while they're sitting in the coach yard with no engine. On the other hand, I do want them lit while sitting at the depot loading passengers, so the lights would have to stay on for a few minutes without track power.

    I've also wondered if I could cut out part of the floor and hide the batteries there, to keep the cars from being top-heavy. I'll have a look at that this weekend.

    The cars will have at least some detail in the interior, seats and people. I don't see any sense to lighting the interiors without enough detail inside to make it look real.

    I'm going to hang onto this thread, there are some good ideas, and when I'm ready to get into lighting my cars I'll have a good start.
  13. Pitchwife

    Pitchwife Dreamer

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    What we need is for someone to invent a flat rectangular battery that will fit in a coach. :D :D :D :D
  14. Fred_M

    Fred_M Guest

    Do harrimans have roof details like vents that can be used for simple ON_OFF switches like my crude doodling? FRED

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  15. krokodil

    krokodil Member

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    If you are not limited by budget there are excellent flat batteries used in different small Walkmen, Discmen and MP3 players.


    :D :D :D
  16. Pitchwife

    Pitchwife Dreamer

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    Firstly: how big are they?
    Secondly: are they rechargable?
    Thirdly: where do you find them?
    and Forthly: what kind of budget are we talking about?
    You miight be on to something. :) :) :)
  17. Ray Marinaccio

    Ray Marinaccio Active Member

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    Those little matchbox car size RC cars use small rechargable batteries inside the car. You might check to see if replacement batteries are available for those. The whole car, recharger and controller only cost between $10-$15.

    I like your switch Idea Fred, Good thinking.:thumb:
  18. Fred_M

    Fred_M Guest

    THX, but it wasn't an original thought, it was how the old Estes rocket launcher interlock keys worked. They are easy to make from brass strips and metal roof vent details. FRED
  19. Fred_M

    Fred_M Guest

    Here's some NICADs I salvaged from a battery pack from a Motorola StarTac phone that I picked up at a flea market for a buck. They are 3/16 X 5/8 X 1 3/4 and are 1.4 volt at 1000mAH. There were 5 in the pack all good. Shown with a AAA. FRED

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  20. mhdishere

    mhdishere Member

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    Dash,
    I LIKE that idea, and never thought of it. Perhaps even a small push-button SPST switch attached to a vent, push, lights go on, push again, lights go off. Kinda like the button on top of a pen. Since, given my layout plan, I'd sometimes have to reach a bit to get to a car, it's best not to have something I could pull all the way out by mistake and then have to try to get back in.

    If we keep discussing this I'm just gonna HAVE to put some other projects aside and get to work on this!