Found this in a different forum. For those who like to tinker.
http://www.members.optusnet.com.au/mainnorth/StayAlive2.htm
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
16,000 uf is a lot of capacitance, and it's going to be a fairly long short when voltage is initially applied to it. The little diodes in an HO decoder's bridge rectifier will get beat up with that kind of a load.
I strongly recommend putting at least 10 ohms in series with that much capacitance to limit the current during charge up of the caps.
DC
http://uphonation.com
You completely missed the point. That was just an experiment to see what would happen. It was not meant for normal operations. Look at the complete article again.
.Rich
Possibly a more realistic approach to the same concept ....
http://www.members.optusnet.com.au/mainnorth/alive.htm
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Notice both web links are the same guy, he was just goign to the extreme with experimenting with the 16,000 mfd. Next step woudl be a 1fd supercapacitor, except most of those are only rated at 5V and would not be usable.
Also notice that even in the 16,000mfd version there IS a resistor and diode. The whole purpose of that is to allow the cap to charge slowly instead of killing the recitfier and/or causing an inrush surge in the dcc system, and the diode lets the cap discharge as fast as needed to keep the decoder running. This is the bit that seems to be missing from QSI decoders and makes them have problems recovering from short circuits with some DCC systems.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Mark R.Possibly a more realistic approach to the same concept .... http://www.members.optusnet.com.au/mainnorth/alive.htm Mark.
That's a nice, thorough description of the R&C solution. Thanks for posting that.
The full throttle DC operations at my club is limited to 12v. Since my Radio Control receivers require 11.5v min to be reliable, the voltage drop across a Si diode was just a little too much for the filter to be effective against drop outs. A Ge diode would probably work, but finding one that can do 2 amps and fit in my HO loco has been a challenge in the past. Since I'm doing fine with just the R&C alone, I don't bother any more. At 14.3V peak, my train runs the best on the club's DCC power. If I only ran on the DCC power, the diode would be an advantage.
Here is a link to the same guy, Marcus. Lenz has had a product on the market for this same purpose. Marcus is very active in the Yahoo SoundTraxx Group.
http://www.members.optusnet.com.au/nswmn1/USP.htm