How do I select the parts?

Now that you’ve seen what a basic installation looks like, the next question is “how do I select the parts?”

The starting point for this is knowing the current and voltage that you want or need to handle.  Once you know those, you can start to narrow down the choice of controller. We’ve got some resources on this page that should help. If you are still thinking about what voltage to use, then we have this page that talks through the options [we usually recommend 24V wherever possible].

Once you’ve chosen the controller and have an idea of the maximum current, you can then decide on the size of the power cables and fuses. The cables must be able to carry the nominal maximum current that you expect, the fuse must withstand the likely stall current.

The throttle and direction controls are very much a personal choice depending on what you are building. You should think about safety, e.g. what happens if I drop the control box? Some applications are ok with a twisty knob, others require a deadmans handle arrangement. The Pro-100 / 160 / 360 models have a wide variety of input options.

Then comes the choice of batteries. How long do you need this to run? As a rule of thumb we’ve found that 0.5 x nominal maximum current x the desired run time [in hours] gives a very approximate capacity in ampere hours [Ah]. For maximum duration, LiFePo4 batteries will give double the usable capacity of lead-acid types, but at a significant cost. They are also lighter, which may not be a benefit in model locos which need the extra weight for traction. Properly managed, LiFePo4 batteries will last longer than lead-acid, but they do require certain precautions to be taken in their use – see this page for more details.