All of my locos use batteries. In a way this makes life easier -in the fact that I pick one off the shelf and run it. However, this does involve some design constraints when you design your loco. When I built my first loco I went for the then high tech NiMH battery. Modern NiMH batteries are far superior but at the time it was a case of having to take them out of the loco charge them in cool environment and then replace them. As at that time the only chargers available were slightly modified NiCd chargers -it could take 36 hours until all the AA batteries for my loco were charged...

For my second loco I tried a cheap Sealed Lead Acid gel cell (SLA). I have never looked back. They are heavy, blocky and very dependable -plus I can charge a 4.5Ah one in around 90 minutes!!!

Certain considerations have to made though -the SLA must be charged in an upright position, the one I like can easily be dropped into a firebox housing and forgotten about.

The first drawing shows the general arrangement of a Radio Controlled loco. The SLA feeds via a slow blow fuse to a double pole single way switch thence to an Electronic Speed Controller. The 5V take off BEC feeds the Receiver and the Receiver send data pulses back via the white cable (I assume FUTABA coding). It is important to completely isolate the battery from the rest of the loco when not in use. This prevents the so called 'Black wire corrosion' or to use the correct term Electrophoretic Attack. Positively charged ions and particles are attracted to the negatively charged loco and eat through bits of your wiring....

The second drawing shows the isolation arrangement of the motor. The motor kicks out quite lot of electrical noise that interferes with your Receiver. To reduce this you need to arrange three capacitors in the above drawing. One between the power lines, one from each power line to the motor casing, and then you "Earth" the motor casing to the negative supply line.