So I wanted to do a follow up for potential interested parties. So I ordered an RC controller from Locoremote in the UK. I will give an update on this later when I get it and can do a proper review. But for now the subject had come up on how to protect this remote and still provide enough power to run my locos at a speed I will be happy with. On another post here many people said I just won’t be happy with 12v, and I know what 14v looks like and acts like with our trains. I really wanted to get at least 14v if not 14.5v if I could do so and protect it.
The remote is rated at absolutely no more than 15v peak. Its operating voltage is 12V but after talking to Chris at loco remote he said it should work just fine at 14.5v as long as I NEVER spike it past 15v. His concern with 14.8 (14.4v) lithium ion batteries is that they charge beyond 15v initially. He was worried that I would deliver a spike of higher voltage and fry the board. So I posed the question on here and it was suggested to try a buck convertor which in layman’s terms a voltage regulator. It will give a set output regardless of the higher input. Not to be confused with a buck/boost converter which will increase a lower voltage to the same working voltage.
So I purchased These which are a buck convertor. They have an operating input voltage of 3-40v and a regulated output voltage of 1.5 to 35v @ 3A. The controller I am getting has a 2A rating so this covers it.
Now right off there is a built in inefficiency in them. No matter what the input voltage is the output voltage will be 1.5V less. So you need to make sure your battery is providing at least 1.5v more than the desired output. Since I want to run at 14.5V that means I needed at least 16V input. Now this did somewhat defeat my initial purpose of wanting to stick with 14.8v lithium Ion batteries that I already have. So I plan to switch to 18.5v batteries (5 - 3.7v cells). This should give me the 14.5V I want all the time.
So with that said I received one of these in the mail. I soldered the type of plugs I use on the input side and a pair of bare leads that will go to the motor. I hooked the input up to my bench top variable power supply and the output to my multi-meter. Right off the bat the 1.5v drop was spot on. It dropped exactly 1.5v (with some fluctuation but never more than a couple tenths of a volt). You adjust the output voltage with a little flat head slotted screw knob on top of one of the gizmos. Its the only thing you can turn so its not hard to figure out. Turning it clockwise increased voltage turning it counter clockwise decreased it. All with the input voltage remaining steady. Once I set it at 14.5v on the multi-meter with the input at around 25v I started decreasing the input voltage. It remained at 14.5v output until I reached 16v input and then at that point the output voltage decreased at 1.5v below the input voltage. Just as advertised. The final test was to shock it by rapidly turning up the voltage in my feeble attempt to create a voltage spike. I certainly could not turn my supply up fast enough to cause event he slightest bit of spike through the convertor.
So the long and short of it is that these little buck converters, at A $1.50 a piece are great for controlling voltage. Knowing I can plug in anything from a 14.8V battery to clear beyond 20+v batteries and get a constant output is pretty cool. Now I will have to buy 18.5v batteries if I want to get the 14.5v but at this point that is not a tragedy. I think I only have one 14.8V pack left after destroying one and giving one up for my nephews train. I will use the one I have left to run a critter or some smaller thing that I don’t need speed out of. I will wire a polyswitch in between the buck convertor and the controller just in case something goes bad on the converter and it wants to send a larger voltage through. I don’t even know if this is a thing but it will make me feel better having it in there.