Mark R. The TCS KA1 stay alive module has a capacitance of 200,000 uf. It uses five 1 farad capacitors wired in series. Most commercial modules with multiple super-caps are usually about the same value. Mark.
The TCS KA1 stay alive module has a capacitance of 200,000 uf. It uses five 1 farad capacitors wired in series. Most commercial modules with multiple super-caps are usually about the same value.
Mark.
Thanks. I ordered a couple of KA1s today, $23 with shipping each. They will be hugely more than the 1000uF I used in the GP9, so I figured if going to the effort, the 1000 would be a marginal stab at what might help, so a KA1 will be my next move. I'll defer tinkering with the tender wheels until adding the KA1. I'll have to solder to one corner of the Select micro decoder but that looks do-able, a bit smaller than the Select Direct in the GP9.
Paul
Modeling HO with a transition era UP bent
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Well you could use metal axle wheelsets with one side insulates, and make wipers that rub on the axles, so one truck picks up from the right side and one from the left (depends on which side you put the insulated wheel), or you could add wipers that rub on the backs of the existing wheels and get full 8 wheel pickup from the tender, both trucks, both sides.
You'd have to order from some place other than Radio Shack, but a 25V capacitor is a high enough rating and may be slightly smaller for the same capacitance value as a 35V version. I don't think I'd try a 16V capacitor as that is cutting it rather close and if you ever run the engine on someone else's layout it may go over 16V.
I've rarely built anything that needed such high protection voltage, so maybe a 1N40007 is no bigger than say the 1N4001, but the 4001 is rated for 50V PIV, the 4002 is 100V, the 4007 is all the way up at 1000V, way overkill. ALl are the same 1 amp current rating. I think they are all the same physical size though so you might not save any room there.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks for pointing out the important electronics specifics. On my GP9 I was guided by the LokSound Select manual details; i.e., with a 2200 microfarad (25v) capacitor, a 100ohm (1/4 watt) resistor and a 1N4007 diode. I varied only the capacitor "capacity", trying less than 1000microF unsuccessfully, using the 1000 successfully and stopping there, since the 2000microF (non-supercap) would not fit. These two Radio Shack items are 35V rated.
I haven't had a chance to check but I'll probably add the 2200 if it fits, if not, buy another 1000 and try it. Or just decide to order some less expensive Keep Alives. (I have not come across the capacitance ratings for the Keep Alives or Current Keepers, but being supercaps I presume they are far more effective than the non-supercap types.) I haven't looked at their instructions but assume they connect to the Select decoder at the same two spots? EDIT: I need a bit of time to digest the good references that Rich has provided! I've only glanced at them and want to absorb the good info there.
I'd also be interested to understand exactly how to add pickups to the tender. I think the original wheelsets are metal wheeled with plastic axles so need replacement with metal wheels and axles, one wheel insulated. How do I choose them? I think I can find a thread on adding the wipers (e.g., Kadee springs) and pickup wires.
Since I rarely expect to re-load the sound file (e.g., for a FT version) I think I'll just use a small pin connector to allow unplugging one side of the capacitor for LokProgrammer loading.
You really need to pay attention to the voltage rating of the caps - regardless which kind you use. I once built my own using a single 16 volt capacitor (don't remember the uf value, but not important) , after placing it on the rails for about two minutes, the capacitor blew up with a loud BANG and spewed yellow shmutz all over the inside.
After cleaning up the mess, I rebuilt it using a 25 volt cap and three years later, it's still working just fine.
My track voltage is set to 13.8 volts, so I "assumed" (never do that !) that a 16 volt cap would be fine. Must have been voltage spikes or something that stressed it.
Actually quite easy. If you do it with just a cap, you need a 100 ohm resistor and diode. Those are in the super cap modules. I did that some years ago.
http://wayback.archive.org/web/20120729061658/http:/www.members.optusnet.com.au/mainnorth/alive.htm
http://www.members.optusnet.com.au/mainnorth/alive.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.
For my next bit of advice - if you are going to have to put the stay alive module in the tender anyway, I'd add some wipers, perhaps with the Kadee #5 spring method, to the tender trucks and get additional pickup to go with the stay alive. Should result in an unstoppable loco (well, due to any power issues anyway).
Good advice. I'll get one of the commercial ones.
Thanks.
Hi Paul:
I have to agree with Mark. I have spent a long time searching for the magic 'supercap' - you know the one - tiny, powerful, proper voltage, but so far I have come up blank. As Mark says, you have to gang a whole bunch of them together to give you enough power to keep your locomotive running. The cost quickly rises to that for the manufactured keep alives.
Having said that, one advantage to building the keep alive yourself is that you don't have to have all the capacitors in the same place. If space is at a premium you can fit individual caps wherever they will go and wire them in series to give you the power needed. Recently there was mention on the forums of one modeler who was successfully installing keep alives in N scale locomotives. Mind you, that would be pretty fussy work! You would need to be pretty good at keeping your wiring sorted out.
Mark points out one potential problem with DIY keep alives, and that is having them interfere with programming. I'm working on a railtruck that I want to put a DIY keep alive into. To solve the programming problem I am simply going to install a micro slide switch in the floor which will disconnect the keep alive whenever I need to do programming.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
You can build your own super-cap stay alive module, but it still end up being the same physical size as the TCS version.
Super-caps don't come in high voltage values like a standard capacitor. Standard voltage values for super-caps are usually around 3 to 5 volts. You need multiples of them in series in order to attain an operating voltage that won't blow them up ! Wired in series, the rated voltage will be the sum of all the rated voltages of the single super-caps you are using.
By the time you buy all the components and put it all together, you might just be further ahead to buy a commercial version and be done with it.
The ESU version contains additional circuitry that senses when the engine is being programmed and takes the stay alive capacitor out of the circuit. Programming with the stay alive module connected can sometimes create problems when trying to program.
I just completed converting an acquired Proto 2000 HO 0-8-0 to LokSound Select with sound (dual sugarcube speakers). My first impression is it will have too many brief pickup interruptions to be pleasing. The 8 loco wheels pick up but the tender wheels are not wired to supplement the loco pickups. I presume I could convert the tender to pickup wheels, axles, wipers.
I'm inclined to address the issue with a capacitor addition. The LokSound Select manual shows how to hook up a (2200 microfarad or their PowerPack module) capacitor to the decoder. I used the former option to upgrade my only troublesome prior loco, a Genesis GP9, adding a 1000 microfarad capacitor and associated diode and resistor. The capacitor was a typical Radio Shack (25v or so) one, the largest that would fit the short hood. Luckily, that was all that was needed (smaller ones did not help enough).
So, with my 0-8-0, I could just add a similar 1000 microfarad cap and see if that's adequate. A cnventional 2200 microfarad also might fit. Of course, I could add the more space efficient "supercapacitors" that are used in the Soundtraxx Current Keeper, TCS KeepAlive, or ESU PowerPack. The latter one is 1000 times more capacitance (1 farad), but cost $50. Seems like overkill. The Soundtraxx and TCS are about half that amount; don't know their capacitance but they must be supercaps to provide over 1 sec power).
I'm mainly interested in two options as I think I need just moderate improvement (for slight interruptions, not horribly dirty track):
a) put in a 1000 or 2200 microfarad as I did the GP9
b) similarly wire a higher capacity / more space efficient but cheap supercap that might be obtained from a supplier like DigiKey, but I have no idea what to buy. It would still be a cheap upgrade if the right types are available. I don't think I need the 1 farad capacity, 1000 times more than what did the job for the GP9.
Has anyone added their own decoder supplemental supercaps other than the decoder company offerings?
Thanks, as always, for any help.