Battery Powered Forney

BakerJohn

BakerJohn

Baker, Modeler, Flour Ambassador
After my initial planning of this loco with Phil's help we said that we would share all planning with the forum. Since the planning process itself would get confusing I decided I'd share a wiring diagram. I found that DigiKey has a free online program anyone can use that is very user friendly.
109319_6f4617dd538c5736c0738e71a42ad89d.png

Each section is (or will be) isolated with a set of in-line connectors. I couldn't find such things in the options available. The only exception here is the motor block; a small modification from the LGB plug, both wires come off their pins separately.
The RC Trains Rx pads A and C give 0v when activate, so the LEDs are wired backwards, each with a 160 ohm resistor in the positive lead. The lights are incredibly bright and I probably would use a slightly higher resistor were I to re-do this locomotive.
In addition, Phil suggested a 1K resistor in line each the smokestack and connection between the Rx and MLS Soundcard. I only have one button on my transmitter, so I can either set it to play the whistle or horn. At the moment it's connected s shown, but I may prefer the horn (bell, in my loco's case).
You will notice that the smokestack is on it's own switch. Since I certianly don't plan to use the smoke constantly Phil suggested that I isolate it completely.
My SPDT main power switch is an ON-ON so the engine is either set to RUN or CHARGE. Obviously without the charger plugged into the locomotive it creates an incomplete circuit.
Finally, an auto-reset fuse is recommended in-line with the battery to protect things further.

You know though, as I am writing this I feel I have few things backwards...
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
22,038
32
Tamworth, Staffs.
Very good Jon...
Errata:
The RC Trains Rx A and B give 0v when active..
There should NOT be a link between battery -ve and motor -ve in the middle of your drawing! :eek:;) - the feed to the 'smokestack' should be isolated from the M2 connections.
If I am being really finnicky, the A and C connections on your representation of the RCT-Rx65c are the wrong way round. :p;)

I (personally) would have used a 'buck' converter in the feed to the smoke-unit, rather than a resistor. The smoke-unit probably has black and white leads, so is a 5v unit..
A small regulator would allow you to 'tune' the supply to match the smoke-unit, and how much smoke you actually wanted.
 
BakerJohn

BakerJohn

Baker, Modeler, Flour Ambassador
Not sure how the B- and M- connected themselves... opss!
As for the Rx, I confused myself because mine is connected backwards. I connected the motor block so the train runs the right way in terms of the throttle, but it's the opposite of what the A & B pads expect. So, I had to connect them so the rear light mirrors the Tx when binding.

Edit: You missed one Phil, the front LED+ was connected to the Motor+ ...

109327_ba2980b6a9781da2206659b5c8edcc8a.png
 
Last edited:
JimmyB

MOTM

JimmyB

Learning; but slowly!
23 Feb 2018
1,198
12
64
Weston-super-Mare
John no expert on DCC or even electronics, however I notice the fuse on the negative side of the battery!
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
22,038
32
Tamworth, Staffs.
John no expert on DCC or even electronics, however I notice the fuse on the negative side of the battery!
It doesn't matter which side it goes in (in this application).. Not like a vehicle, where the whole of the vehicle is negative return, and not like domestic mains, where the live is a higher potential to ground than the neutral.

The most important thing, is it as close to the battery as possible, and that there is one!
 
BakerJohn

BakerJohn

Baker, Modeler, Flour Ambassador
I fixed the charging port wiring issue this morning. Perhaps a larger speaker in the future along with a voltage regulator instead of the resistor for the smokestack. But, for my first time doing this (or any wiring, for that matter) I am very happy with the results!
Thanks to everyone whom helped me with this project.

Up next... Bachmann's TTTE 'Toby' will be converted to battery R/C and get a fair amount of detail work done...