Sorry - didn’t intend to make more work for you 
Dear mike,
If your passenger car is all LED, forget the pickups, just go ordinary alkaline battery. No flicker, lights still on while stopped at the station.
Watching for off-brand sales I have bought 32 packs of AA alkalines in for as little as $4 (13 cents each.)
At least 3 alkaline batteries in series (3x1.5V=4.5V) are needed for enough forward voltage to turn on the LEDs.
You will have to find battery holders/boxes for 3 or 4 AA cells, though.
Choosing series resistors for each LED depends on the LED’s forward voltage and how bright you want them.
What are the values for your present (20 volt track power) series resistors?
Sincerely,
Joe Satnik
Edit: added battery holder sentence.
Joe has a good idea. Batteries will be a lot cheaper than ball bearing wheels. Using rechargeables will eliminate having to open teh car and change the batteries. If your cars have the bathroom, that is a perfect place to hide batteries and charging electronics. Just cover over the window from the inside so you can’t see the batteries. Mine have the brass wipers. Very noisy and add a lot of drag too.
Dear Jon,
Why mess with the track pickups? If rechargeables, just install a recharging socket and plug into it while on a siding. If you want power from the track for re-charging, make a cable with a recharging plug on one end and alligator clips on the other end to clip on the rails. Another idea; retractable pickups for the wheels, or retractable pickups touching the rails.
Hope this helps.
Sincerely,
Joe Satnik
Thanks Joe and John. I thought about batteries. These were old cars and had the 9 volt battery box attached. But we run on constant track power with remote, so the track is always at 20 volts and we never change polarity. I just dislike buying batteries and changing them and worrying about whether or not they are switched off. We store our cars outside in a car barn, where they just roll out onto the track, and so I’d always have to be taking the battery packs out and moving them to wherever I keep the charger, watching for declining performance etc. Also I never have gotten a clear sense of how much battery time you get out of 5 leds and three AAs.
Putting a big capacitor in the circuit completely removes flicker–I just bought two of the biggest caps radio shack has, I forget the value–2000 uf? That eliminates all the flicker. Someday, when the incandescents in my aristo heavy weights go, I’ll put leds in there the same way. It’s great to not have to worry about whether or not I have a spare set of batteries in the house, or a charged pack
But yes, ball bearing wheels are expensive. One alternative would be to drill out the sideframes and insert brass bushings, then solder power pickup wires to the bushings. I did that with a hartland mini caboose–it works well, better than plungers. But it’s hard to find the bushings. I’m assuming–maybe this is wrong–that as the plungers wear down they’ll exert less pressure on the sides of the wheels
I have a 270 ohm resistor running 4 leds, and a 1 kohm resistor running a single led for the drumhead. I forget what I used for two leds in the Combine car–I think a 470
Mike,
Sounds like a good system with your constant track power.
AA alkaline cells test out at about 2 Amp-hours capacity with current draws around 100 mA, as in your case. My guess (a few assumptions thrown in there) is you are drawing about 15 mA for the drumhead, and about 25 mA each for the rest of the LEDs.
4 x 25mA + 15mA = 115 mA.
2 Ah / 115mA = about 17 hours for the observation car.
2 x 25mA = 50 mA.
2 Ah / 50 mA = 40 hours for the combine.
Hope this helps.
Sincerely,
Joe Satnik
3 battery system cost per hour:
3 x cost (13 cents in my case) = 39 cents
39 cents / 17 hours = 2.3 cents/hour observation
39 cents / 40 hours = 1 cent/hour combine.
4 battery system calculations:
3 cents/hour obs,
1.3 cents/hour combine
How much did you say for those ball bearning pickups?
Joe I can see your case for battery being cheaper, even if you figure BB wheels over the life of the railway. Two sets of BB wheels would be 60 bucks, and it would take me a good long while to spend $60 bucks on AAs. Thanks also for the figures on battery life. That’s very helpful.
I just don’t like batteries all that much. My wife is a bug about not throwing them away, and we have a big jar full of dead batteries which we take to the county disposal site once a year or so. In our house, somebody, especially the teenager, is always asking for batteries and taking them from wherever I put them and then I’m out when I need them. Also it’s just one more variable. We like to run them at dusk a lot. My wife will say “let’s run the train tonight” and I go out and oops I need new batteries, hold on a sec. “honey what happened to those double a’s that were in the drawer?”
I wonder though, how much more time I might get out of Lithium AAs, and if they would be worth it. We use them in our digital camera even though they cost a lot more, because they last much much longer. I suspect they are cheaper in the long run though I haven’t sat down to figure it out.
Last post on this, an experiment in an old trick the animated gif
(http://www.lscdata.com/users/lownote/_forumfiles/greenmov.gif)
