DCC Fridays Ep. #1 - Keep Alive Capacitors

I'm excited to announce that each Friday I'll be posting a ~5min length video where I'll discuss all kinds of useful hints, tips and products to help you with all aspects of using DCC with your model railway! Skip to the 10min mark to hear me chat a little more about what I'm hoping to achieve with this segment!
If you'd like to know more about what I covered in this episode or would like me to cover something else, let me know in the comments below or get in touch with me via email: [e-mail]
www.bmodeltrains.com

[@phillipg1588]

Hi Jarryd, I have read somewhere that a diode and resistor are also needed in the Stay Alive circuit. And the recommended cap voltage is 25v.

[@buckamboolmodeltrains]

Hi Phillip, yes when using a capacitor/s with considerable capacitance (uF) a diode and resistor are used as a charging circuit. I've found this is necessary when capacitance exceeds around 1000uF. When using 2 or 3x 220uF capacitors I have found that this is not necessary, however I do still use a diode in parallel with the capacitors, to prevent anything over 15V reaching the 16V capacitors. For HO scale people prefer 25V as it is safer, the disadvantage is that 25V capacitors are physically larger, which restricts their use in N scale applications. I've fitted well over 100 sound fitted N scale locomotives for customers with 3x 16V 220uF capacitors, and haven't had an issue since starting this procedure several years ago :)

[@EsotericArctos]

Tantalums are great, but have to watch running them at there limit as they do have a tendency to short circuit, where Electrolytics, although larger for the same capacitance, don't tend to do that. On DCC I would likely aim for caps rated above 20volts for HO/OO scale. Maybe for N Scale as well. If I recall my DCC Specs, the track is a square wave that swings from -15V to +15V for HO/OO scale (and I think N Scale also). Thanks for some more great information. The advantages of keep alive caps does make the little bit of fiddling worth while. I've subscribed (and liked) to keep watching this series. Australian channels for this hobby are a little rare

[@buckamboolmodeltrains]

Thanks Brendan! Yep absolutely, the N scale layouts I operate on tend to run at around 13.5V so the 16V tantalum’s I have sometimes used are quite effective in that case. I also always pair 16V tantalum’s with a 15V diode to ensure the voltage never manages to get over 16V for the capacitors. I have also recently switched to using Polymer tantalum type capacitors which are meant to be more stable than plain tantalum capacitors. Electrolytic capacitors are great where the sizing and pairing of them together works out well! Such as in the new ZIMO STACO1 product, which I didn’t get to talk about in this particular video, as it wasn’t yet released! Thanks again, I’ll be looking to sporadically be releasing more videos!

[@petereames3423]

thank for sharing that can you tell me the value of the cap as i am doing a n gauge set up a i find it hard to ckeep it that clean i am in s.a and looking to do my own keep alive.

[@buckamboolmodeltrains]

Hi Peter, Which capacitor in particular are you referring to? If you’re wanting to build your own stay alive for N scale I’d recommend using some of the tantalum capacitors that I have available…