Peter models S-scale and has now converted three of his locos to S-CAB radio control with battery power. He has meticulously documented these projects on his own website and I invited him to summarize his first installation, the NW2 switcher, as a guest blog. He agreed, and what follows is his description with some Stanton editing. My apologies for skipping several of Peter's detailed explanations. Please visit his website for complete documentation.
I have decided to convert this engine to use the S-CAB system, and to make it battery-powered. You can read about S-CAB in the article I wrote about it. The first step in any installation is to remove the body shell. I have a separate article on how to do that. After stripping all electronics, what remains is a motor, flywheels, truck drive shafts and wires for rail pickup. The first challenge is to determine locations for all S-CAB components and be able to replace the body shell with everything installed.
After studying the opening into the body, I realized that there is space above the motor mount and under the BPS circuit board. However, the heat-shrink wrap makes the combo too wide for the opening, although the circuit boards by themselves would fit. I eventually replaced the heat-shrink material with electrical tape, but first, I wanted to do a test install of the decoder/receiver and see if the system as it stands actually works.
And off to the layout I went. The track was not powered. I swiped the magnet wand over the sensor on the BPS board, turned on the S-CAB throttle, and moved the speed control. The chassis started running smoothly, in both directions.
Yippee! What a neat sight to see the engine running without rail power! I took a quick video and posted it on Vimeo (the chassis is running on my desk!!!) Next step, back to the work-bench.
Next, I connected the lights, snapped the cab back onto the body, put the engine on the track and tested it again paying attention to the LEDs. They looked good and they matched the engine's direction of travel.
At this point, everything was functional. However, there was one more part to install, the battery off switch.
I put the engine on the track and tested the final set-up. Everything worked great. I could turn on battery power by placing the magnet wand right behind the front exhaust pipe and operate the loco. When I am done running, I briefly insert my "exhaust pipe tool", and the battery is off! I love it! All with no external modifications to the engine.
I tweaked some decoder CVs and got the engine to run nice and slow, while keeping its top speed reasonable for a NW2. As a stress-test, I ran the engine back and forth on my layout, which has about a 20-foot mainline. The headlight was on, but it was not pulling any cars. It was tedious, but I wanted to find out just how long a battery charge would last. I let the battery charge overnight so I was sure that it was full. I turned off all rail power and ran the engine purely on battery power, back and forth. I varied speed every so many runs, including maximum speed sometimes. The engine shut down just a few minutes short of THREE HOURS! Wow! The goal of this system is to have HO-scale engines run for one hour. It is fantastic that I got 3 hours out of it with an S-scale loco.
My next test was to see how this engine behaved on our Digitrax-powered club layout (the Houston S Gaugers). We had a one-day show. As my S-CAB article mentions, Neil indicated that the engine's drain on the battery is faster than the battery can be recharged. However, I figured that with the layout providing power and my home layout test showing three hours, I might get at least four hours operation out the engine. I started it with a 15-car train when the show
opened at 10am. At 4:30pm when we started to take our layout down, I turned off my engine. It had run the entire day! It never stopped, and it kept on running at one point when a short on the layout shut down the Digitrax system.
These two test results were way better than I had expected. I would have been happy if I could get a one-hour ride out of the engine on my home layout and maybe a two- to three-hour run on the club layout. This was fantastic.