A new customer asked me to come up with a ready to go battery R/C and sound package to fit in a 120 mm x 70 mm x 45 mm space in the tender of his scratch built loco. Here is what I came up with.
The battery pack is 12 volts. 10 x 1.2 volt AA size ENELOOP hybrid Alkaline/NiMh cells. I have had great success with them in the last few years. Unlike regular NiMh cells, which self discharge in a few weeks, these are guaranteed to hold 85% of a charge for one year. I mounted the pack on a sheet of styrene with silicone adhesive. They are ideal for smallish low current draw locos. I do not recommend them for high current draw installations. The RCS-Beltrol ECL-3r is in two parts. The decoder part and Hobby King RX were mounted with silicone at one end. The actual Motor driver part was mounted along one edge. Beside that part was a MyLocosound sound system with the new version mechanical chuff timer. At the end is a row of 5 x 2 way terminals to take wires to various points. I have no idea how long the wires need to be for the chuff reed switch, speaker and charge port, so I left them long so the owner can shorten them to suit without having to do any soldering. The ON-OFF switch is on a remote lead and can be mounted anywhere convenient.