Stay Alives

[itydog]

Hi folks,I am interested to hear your thoughts and experiences with stay alives.

Thanks in advance Mistydog

[JJ73]

What on earth is "stay alives"??? Never heard of it!!! 🤔🚂🚂🚂

[Jupiter 1707822591]

Does the job !

[The son of Triangman]

First thing is there is no such thing as a "stay alive". It's just some standard electronic components that can be found from any of the electronic suppliers that supply public and trade. These parts are often put in a bag and sold as a "stay alive" kit, usually at an inflated price in a model shop or on the likes of ebay. There are usually one or two common to find electrolytic capacitors in the kits, these build up a charge which they release when the power supply is lost. They have a few diodes to protect them against reverse voltage as the capacitors are polarised, and a few resistors. All very simple, but effective. You can make basic "stay alive" units for less than a £1, and there are good articles on the web, the Brian Lambert site is a good source of information.

[37lover]

JJ,

Over 2000 posts and you haven't heard of Stay Alives! There's a story there.

SoT,

I think that's a bit harsh to state there's no such thing as a "Stay Alive! Of course there is, there are several threads on this forum discussing them. However, your following text is a very good explanation that there is no need to fork out for inflated "proprietary" Stay Alives when, with a little bit of DIY skill. it is possible to buy the components and fabricate your own for a fraction of the price.

I have fitted several to coach lighting but so far none to locos. I understand the "time" benefit with locos can be quite limited unless you use supercapacitors but even so fitting a Stay Alive can help overcome some short duration interruptions of power. Chrisaff will probably be along to give some technical advice.

[Chrissaf]

Stay Alives and/or Keep Alives are primarily used on Digital DCC decoders. Commercial "off the shelf" versions can not be used on Analogue DC locomotives as the voltage to the motor is reversed to make the loco go in the other direction and the Electrolytic capacitor circuits used in commercial units are voltage polarity sensitive. For DC Analogue, you would need non-polarised capacitors. These when of a usable uF value would be physically too large to fit in a 00 loco. There has been a circuit published where smaller Electrolytic capacitors have been used in a DC locomotive, but this would have to be built as a custom circuit using individually purchased components. The success or not of this published custom circuit may be why it does not seem to be manufactured as a commercial unit for Analogue locomotives.

This description of Analogue post is placed in this thread, because you posted this question in the forum used for Analogue DC control and not the Hornby DCC forum.

EDIT : Written and posted before I saw the post by 37L.

[96RAF]

Certain of these device names, such a stay-alive, keep-alive, current-keeper, etc are registered trademarks but stay alive is used as a generic much as hoover is used to describe a vacuum cleaner.

[ColinB]

I have used them, as others have mentioned they are a capacitor circuit that is used along with a DCC decoder. The plus point is they are really good with 0-6-0 tank locos on points where the loco may not pick up the power properly because it is sitting on the frog, so it keeps the power on the decoder long enough for it to reach the next part of the track where there is a better connection. The down side to them is that they make reprogramming DCC decoders difficult, because the programming voltage is not on the rails long enough to charge the capacitor. I use the YouChoos special circuit, which I am sure I could probably make but it is a small pcb that is easy to fit.