I have added two KA2 TCS Stay Alives to Loksound V4 decoders. One was a micro and the other was a standard size model.
The Loksound decoder requires CV113 to be set to its maximum (255). The KA2 S/A with 5 farads of capacitance on board, depending on motor current draw is suppose to keep your loco running for around ten seconds or something. This does not occur with the Loksound decoder though, as it seems ECU has limited (by way of decoder programming) stay alive capability to just under 5 seconds. No big deal though.
If you down load the loksound V4 manual from the ECU website, page 26 shows how to wire the stay alive (ECU calls it a power pack). You will notice there is a difference on how you wire the micro and the standard size decoder. I don't think you mentioned which one you were using?
Another slight difference you may notice is that the ESU Power Pack uses three wires. The third wire enables the decoder to control the charging rate. This is possibly why the ESU product is more expensive.
With the TCS stay alive, I simply used the two decoder pads depicted in the instructions for when using a capacitor. I have had no problems so far and highly recommend the TCS product. I just finished a Z13 class sound install and the KA2 is working very well. See my latest blog post if your interested.
If you can not access the the Loksound instructions PM me with your email and I will send it to you.
I am new to DCC so didn't jump in right away to answer however it seems your not getting very far with info.
Hope this helps,
Thanks for the info and the links.
Also thanks for being the only one so far that has answered the question that was asked.