Converting accessories from batteries

[Anonymous]

I have some accessories that run on 2 AA batteries. Can I convert these for my layout to run off a train transformer so I don't have to keep putting new batteries in?
Thanks, Bob

[brianel027]

Depends what kind of accessories Bob. Light bulbs are easy because they'll work off either AC or DC. LED's need a DC source. But I will assume you are using things that have small DC motors in them. The answer is yes, but if you use an AC power source you will need a full wave bridge rectifier between the AC source and your accessories. Also most train transformers start off with a higher voltage than you'll want. The older cheap little K-Line starter set transformer does start off at zero and has a smooth graduation of power. BUT probably the best thing would be to use one of those DC transformers that come with things like small tape players, answering machines, etc. Check with your local electronics store or Radio Shack. My local electronics shop has a whole bunch of these little wall pack power sources in an assortment of voltages and even some in AC too. There is an adjustable DC one made that has several voltage settings and a polarity adjustment - I've seen this type at K-Mart too. Keep in mind though that these little wall pack DC power sources hardly have any amperage, so you won't be able to power a ton of stuff off them. Although if your accessories are of a push button type that don't work constantly, you could wire up a few to the same source provided they're not all being used at once.
Good luck.
brianel, Agent 027

[Dr.Fu-Manchu]

Dr.Fu-Manchu The Train Guy Here: This is an Idea that may work: use a transformer for
HO trains! The voltage can be adjusted up or down as needed. I am not sure how many
items you can run off one, But if you use one of the bigger MPC transformers that might
handle your needs. Let me know if that works for you.

[brianel027]

Dr. Fu had a good suggestion, BUT I've done this and you NEED to use a better HO transformer. The small types that come with many HO sets (the little rectangular black one with the red handle) don't start off a 0 volts and don't have good voltage graduation... very uneven operation.
A friend just bought a LifeLike HO set for X-mas, and I'm impressed with the new style of power pack in that set. Very smooth operation with nice graduation of voltage... I'd look for one of those, or spend the extra money on a nice MRC power pack.
brianel, Agent 027

[Roger Bielen]

Bob, I've done this for a couple of battery powered items I picked up. One required 2 x AA, the other 3 X AA. I built small power packs using Radio Shack compopnents consisting of: full wave bridge rectifier (276-1146), and an adjustable voltage regulator (276-1778) with a couple of suitable resistors to get the voltage desired per the formula with the regulator. I connected the output to the battery holder for the LED device and it worked. [:D]

[Anonymous]

QUOTE: Originally posted by Roger Bielen

Bob, I've done this for a couple of battery powered items I picked up. One required 2 x AA, the other 3 X AA. I built small power packs using Radio Shack compopnents consisting of: full wave bridge rectifier (276-1146), and an adjustable voltage regulator (276-1778) with a couple of suitable resistors to get the voltage desired per the formula with the regulator. I connected the output to the battery holder for the LED device and it worked. [:D]

Thanks for the tip Roger. I'm off to Radio Shack today to buy the required parts. I am most interested in using parts in a circuit to power the horns on older Lionel Diesel engines which use a 1.5V D cell. I believe that you approach can be further improved by adding an electrolithic capacitor to filter and smooth out the DC.

[Big_Boy_4005]

QUOTE: Originally posted by dlagrua

QUOTE: Originally posted by Roger Bielen

Bob, I've done this for a couple of battery powered items I picked up. One required 2 x AA, the other 3 X AA. I built small power packs using Radio Shack compopnents consisting of: full wave bridge rectifier (276-1146), and an adjustable voltage regulator (276-1778) with a couple of suitable resistors to get the voltage desired per the formula with the regulator. I connected the output to the battery holder for the LED device and it worked. [:D]

Thanks for the tip Roger. I'm off to Radio Shack today to buy the required parts. I am most interested in using parts in a circuit to power the horns on older Lionel Diesel engines which use a 1.5V D cell. I believe that you approach can be further improved by adding an electrolithic capacitor to filter and smooth out the DC.

I've known about the electronics for a long time, but never thought to apply it to the old leaky battery problem. Think of all the trains that could have been saved if that technology had been available in the 50's.