Hi. I've been on a long sabbatical from the hobby due to general burnout. Bad news is I'm back ! Anyway, unless it's already an option with say, Bachmann, Riv, Atlas, etal, I'd think, just as Kadee couplers have become commonplace, why isn't Keep Alive common yet, as an option on locos now; where the box would now say: "DCC/Sound/Keep Alive/on board". I too realise battery power is developing more and more. But why go battery if 'KA' can prevent stall outs ? After all isn't that the No.1 feature of battery=dead rail, other than no more wiring (except for accessories/signals ? For me stall outs are the no.1 pet peeve; that sinking feeling you get having to 0-5-0 push the train. Of course, with either KA or Batt, a stallout will be 97% a physical fault (caught in frog/guardrail/de-rail, and easy to remedy). Am I out of touch ? Where is KA in the industry now, other than self-installation ? Why/why not ? .....M
ADDENDUM to my post above : Who out there has several locos with keep alive ? How much more $ is this per engine ? My guess is $25. No ? How easy or diff is it to install ? Are you happy you did it ?
I have been putting keep-alive into all my ESU LokSound installs. Not enough for significant "off rail" running, but enough to buffer drop outs in sound and power (across dead frogs, etc). This is typically 450uF (3 20V 150uF Ta caps, wired in parallel). Total cost = $6.45 (plus snips of wire). For a true KeepAlive circuit, I've used ESU mini-PowerPak in some steam - $40 -- but this is a "smart" unit that can be programmed in conjunction with the decoder. The more typical "dumb" keep alive circuits run in the $20-$25 range
Hey ! My first price guess was exact; $25 for the dumbest type ! But, what is 'off rail' running ? What other running does a train do than on the rails ? Anyway, all I'd ever ask for is no stall outs. That would be heaven. Thanks, M
The bigger packs can literally keep the motor or sound going even if you lift the unit off the rails! I built a couple of sound cars for a member, and installed the Soundtraxx CurrentKeeper for him. Those cars continued to make sound for upwards of 10 seconds after removal from power. For simple stalling, the 400 to 700uF range of DIY capacitor array is cheaper.
I install Keep Alive in all my N scale DCC and sound equipped locomotives. I use banks of 330uF capacitors. In my SD60, for example, I have 2,310uF of capacitance I it. It all depends on the space. Some I can cram 4 310uF capacitors in there, others I have gotten eight in there (SD26).
You can try DigiKey. They have 150uF 20V (p/n 399-4794-1-ND) and 220uF 16V (p/n 399-10429-1-ND) in stock. Mouser will be getting 200 uF 25V Ta capacitors back into stock by middle of January (p/n 581-TCN4227M025R0100) The capacitors can be seen at the front of these to chassis (on the right)
The positive is to the blue wire, the negative to the decoder ground. Capacitors are in parallel, which adds the capacitance.
Thanks for responses/explanations. Just like knuckle couplers and DCC itself are commonplace now, I bet keep alive will be next in commonality within 2-4 years. Package will state "DCC/sound/keep alive/on board ". With mass production I see no reason for the price tag to be above $15 more per loco. If an Atlas diesel, normally about $140, were now $155, in the great realm of things it would be well worth it for those like me who care not to get involved with electronic modifications. 2 questions: Do I gather that KA (keep alive) is solely the addition of capacitors before the motor ? Or are there other components needed ? Also, does KA affect the slowing or stopping of a train, outside the normal throttle Aps ? Ex: A head-on is about to occur (DCC). Will the red panic button override the KA ? Or will train not make a full stop due to this added capacitance ? Thanks, M
The capacitors don't go "before the motor". They aren't connected to the motor drive wires. Read the manufacturer's instructions to see where to make the connections. It's typically to the blue wire used for the function outputs and a ground on the decoder. ESU suggests adding a resistor and diode to the circuit. There is a diagram in their installation documentation. The resistor limits the charging current and the diode bypasses the resistor when the capacitor is supplying power. Basically this prevents the capacitor from causing a current overload while charging but allows the decoder to draw power when needed.
