Power Cars - Evans Boxcar

by Paul Norton

INTRODUCTION

Aristo-Craft Plug and Play diesels have an MU plug on each end, and a switch to change between track power and battery power. This article details how to build an Evans power boxcar to take advantage of those plugs. A power car is simply a battery car with a receiver added for on-board radio control.

This power car utilizes two Aristo-Craft, lithium-ion battery packs and is designed to power and control big, modern diesels like a Dash 9 or SD-70 MAC.

As this is an enclosed car, the battery packs will be charged on-board using two-pin plugs that mate with the Aristo-Craft battery chargers. One charger could be used, but two are recommended so that charging can be completed within four hours.

Unlike Gel Cell, Ni-Cad or NiMH battery packs, Aristo-Craft lithium-ion packs must NOT be wired or charged in series. A standard, four-pole double-throw (4PDT) switch will be used to allow the packs to be connected in parallel to power the receiver, but charged separately.

The plug sets and switch are both available from All Electronics under catalog numbers CON-240 and STS-71 respectively.

OVGRS members can purchase the plug sets and 4PDT switch by contacting Paul Norton. See the Items For Sale Section for details.

An Aristo-Craft, 27 MHz Train Engineer (TE) set will be used to provide the radio control, as it can handle the power requirements of large diesels or multiple lash-ups. If your TE transmitter came with a short rubber antenna, call Aristo-Craft and request a replacement telescoping antenna. The chrome antenna will dramatically increase radio range.

Radio range can be further improved by replacing the long wire antenna on the receiver with an Azarr, micro-lite antenna. With the telescoping antenna on the transmitter and the micro-lite antenna on the receiver, reliable and responsive radio range of greater than 100 feet is possible.

The M-27-L antenna is available from E Cubed R/C.

OVGRS members can purchase the antenna by contacting Paul Norton. See the Items For Sale Section for details.

A boxcar is needed to provide the necessary height for the micro-lite antenna to function properly.

REMOVING THE CAR BODY

Remove the 6 screws indicated with yellow from the bottom of the car. Lift the car body from the frame. Fasten the screws back in the car body, so they do not get lost, and set it aside for now.

POWER CAR SWITCH

At the spot marked with the yellow X on the side of the frame WITHOUT the brake line, drill a hole with a 1/2 inch drill bit for the four-pole double-throw (4PDT) switch.

Install the power car switch so it toggles forward and rearward. Stick a Charge label on one side of the switch and a Run label on the other as shown.

Check to ensure the switch is in the center off position.

BATTERY PACK CHARGING PLUGS

CAUTION: The 2-pin plug sets sold by All Electronics are not always colour coded the same as Aristo-Craft plug sets. If the colour coding is not the same as on the lithium-ion battery pack and charger, just click on the following link to see how to change the AE Plug Set Wiring so that proper polarity is maintained.

The female half of an All Electronic plug set has the same connector as the Aristo-Craft, lithium-ion battery pack.

At the spots on the frame marked with the red Xs, drill two holes with a 5/16ths inch drill bit for the battery pack charging plugs. Drop the wires of a plug through one of the holes. The wings of the plug are spread out, and then the base is wiggled through the hole. The base is held with a spade terminal which is secured to the top of the floor with hot glue. Repeat the process for the other plug.

Cut the plug wires to a length that will easily reach the power car switch. Solder and shrink wrap a number 6 stud, loop terminal to the end of each wire.

The 4PDT switch has 12 screw terminals. To make the wiring easier to understand the terminals have been divided into three columns: the left for the charging plugs, the center for the battery packs, and the right for the TE receiver.

Fasten the charging plug loop terminals under screws in the LEFT COLUMN of switch terminals as shown in the following diagram. The colour coding of the wires from the center of the car to the edge should be: red, black, red, black.

That completes the installation and wiring of the lithium-ion battery pack charging plugs.

LITHIUM-ION BATTERY PACKS

Drill four holes, with a 3/16th inch drill bit, in rear of the frame as shown in the following picture. Pass long cable ties through the holes taking car not to damage the frame details.

Use Velcro dots to fasten the lithium-ion battery packs between the four holes as shown. Secure the packs using the cable ties.

CAUTION: Take care when handling the battery pack wires to ensure they do not touch each other, or both make contact with any metal object such as a wire cutter, stripper or screwdriver. DO NOT CUT BOTH BATTERY PACK WIRES AT THE SAME TIME.

Cut the red wire of a battery pack about 1/4 inch from its plastic connector. Solder and shrink wrap a number 6 stud, loop terminal to the wire. Repeat the process for each of the other three battery packs wires one at a time.

Fasten the battery pack loop terminals under the screws in the CENTER COLUMN of switch terminals as shown in the following diagram. The colour coding of the wires from the center of the car to the edge should be: red, black, red, black.

That completes the installation and wiring of the lithium-ion battery packs.

27 MHZ RECEIVER

Turn the case of the 27 MHz receiver over and remove the four screws at the corners. Open the case and remove the circuit board. If it sticks, remove the fuse. Put the case back together, install the four screws, and put it back in the box it came in.

Place the circuit board or a TE template on the front end of the frame against the posts as shown. Drill 3/32 inch holes in the floor using the holes in the corners of the receiver or template as a guide. Tap the holes with a 4-40 screw.

Turn the receiver over and glue a 1/4 inch long spacer around the hole at each corner. The nylon spacers are available from All Electronics under catalog # SP-42. OVGRS members can purchase the spacers by contacting Paul Norton. See the Items For Sale Section for details.

Unsolder the long wire antenna from the circuit board, and replace it with an M-27-L micro-lite antenna.

Fasten the receiver to the floor of the car with 1/2 inch 4-40 screws. Shape the micro-lite antenna so it will follow the roof line on the inside of the boxcar.

If you did not purchase a micro-lite antenna, fasten the Aristo-Craft wire antenna around the outside of the six floor posts with hot glue as close to the top as possible.

Cut the heavy, red and black, power input wires of the receiver to a length that will easily reach the power car switch. Solder and shrink wrap a number 6 stud, loop terminal to the black wire only.

Cut a piece about two inches long from the extra red and black wires cut from the receiver. Split the red and black wires apart, and set the small piece of red wire aside for now. Solder and shrink wrap a number 6 stud, loop terminal on each end of the black wire. This wire will act as jumper between two screw terminals on the switch.

Place the loop terminal on the black wire from the receiver and one of the loop terminals on the black jumper wire flat against each other. Fasten the loops under the screw in the RIGHT COLUMN of switch terminals as shown in the following diagram. Fasten the loop terminal on the other end of the black jumper wire to the another switch terminal as shown. The switch can be moved 1/8 of a turn to access the screw behind the plastic post on the floor of the car.

Bend the terminals slightly outward so the black jumper and negative wire of the receiver are about 30 degrees away from the switch. This will make it easier to install the diodes in the next step.

Two, 3 amp, 40 volt, Schottky diodes are a safety device to block power from passing from one battery pack to another. The power can only flow from battery packs through the diodes to the receiver. The diodes are polarity sensitive and have a band around the end with the negative lead. The diodes are available from All Electronics under catalog # 1N5822S.

OVGRS members can purchase the diodes by contacting Paul Norton. See the Items For Sale Section for details.

Straighten the positive leads of the two diodes. Strip a length of insulation off the small piece of red wire split from the black jumper. Cut two pieces exactly 7/16ths long from the insulation. Slip a piece of the insulation on the positive lead of each of the diodes.

Slip a number 6 stud, loop terminal over the end of the positive lead of each the diode and solder them in place.

Fasten the loop terminals under the screws of the terminals in the RIGHT COLUMN of switch terminals so the negative leads of the diodes overlap as shown in the following diagram. The switch can be moved 1/8 of a turn to access the screw behind the plastic post on the floor of the car. Solder the red wire from receiver to the overlapping leads.

If you have a piece of insulation wide enough, cut a slot in it and press it over the top of the diodes and the receiver input positive wire. Alternatively, vinyl electrical tape could be used to cover the bare leads.

Check to ensure ALL the wires on the switch from the center of the car to the edge are colour coded: red, black, red, black.

That completes the wiring of the power car switch.

PROGRAMMING THE 27 MHZ RECEIVER

The receiver has a small power switch next to the fuse. Turn it on by sliding it toward the heat sink. Slide the small switch on the back of the circuit board toward the red LED, its linear power position. If this switch is left in the PWC position, the momentum and soft reverse features will not work.

Programming momentum prevents sudden starts or stops which could damage the gears in a heavy diesel, especially if it is hauling a long train. The soft reverse feature can be used when switching cars. When the reverse button is pushed the diesel will slow to a stop, pause while a car is coupled or uncoupled, change directions, and gradually resume speed in the other direction.

When the power car switch on the bottom of the frame is toggled rearward, the battery packs are connected in parallel through the diodes and jumper wire to power the receiver.

The red LED on the back of the receiver should light up and stay on. If the red LED goes on and then fades out, return the lithium-ion battery packs to Aristo-Craft for a replacement.

Link and program the transmitter and receiver as detailed in the manual that came with them. If the transmitter is used with other receivers, using the first last digits of the power car road number to program the frequency and channel numbers is an easy way to remember them.

After programming the TE, leave the small TE power switch on, but return the power car switch on the bottom of the frame to the center off position. The red LED on the back of the receiver board should go out.

CHARGING THE BATTERY PACKS

If the battery packs have not been charged, with the power car switch in the center off position, plug in each of the battery chargers. Plug the chargers into a wall outlet and toggle the switch forward. When the switch is toggled forward, each of the battery packs is connected independently to its charger.

The chargers will take about four hours to charge the lithium-ion battery packs completely. When complete, toggle the switch to the center off position and remove the chargers.

POWER CAR PLUG

Drill a 1/8th inch hole in the center of the front end of the car body between the first two bottom ribs. The front end of the car has no brake wheel. Slide a 1/2 inch length of shrink wrap down the wires of the female half of an AE plug set until it is against the connector. Slip the wires through the hole and pull them until the shrink wrap and connector are snug.

About 2 inches inside from the car wall, hold the wires together and place a glob of hot glue on them. This will act as stress relief should the power car and locomotive become uncoupled during operation. Two inches of slack in the plug wires however, does make it easier to connect the plug before the power car and diesel are coupled together. The excess wire can be pushed back into the power car after coupling.

Some owners also remove the locking tab from the connectors on their locomotives. If the power car and locomotive become uncoupled during operation, the connectors will slip apart and the locomotive will stop. Alternatively, the ridge on the power car connector could be filed flat and the expensive locomotive connectors left untouched.

Solder and shrink wrap a length of wire to each of the plug wires. The wires should be long enough to pass under the receiver and easily reach the output screws on the receiver when the car body is set beside the frame.

Set the car body beside the frame. Slip the wires of the power car plug under the circuit board. Solder and shrink wrap a number 6 stud, loop terminal to the end of each of the wires. Fasten the loop terminals under the output screws on the receiver. This is the one time that polarity does not matter as it will change with each change of direction.

That completes the wiring of the power car.

REASSEMBLING THE CAR

Remove the six screws from the car body. Tuck any excess power plug wiring under the receiver and place the car body back on the frame. Take care not to disturb the antenna which should follow the roof of the car about 4 inches off the floor. Do not insert the screws yet.

CAUTION: Always ensure the power car switch is in the CENTER OFF position before connecting or unplugging a diesel. It is not unusual for a diesel to jump slightly when the power car switch is toggled to power the receiver.

Connect a Plug and Play diesel to the power car. Toggle the power car switch rearward, and test the power car for function and range.

If you have a transmitter that has a dedicated button for each direction, you may find the arrows on the buttons and the direction of the diesel are mismatched. If so, just reverse the positions of the power car plug wires under the output screws of the receiver.

If everything functions properly, toggle the power car switch to the center off position, unplug the diesel, and fasten the car body to the frame with the six screws.

CONGRATULATIONS! You now have an Evans power boxcar that lets you battery power and radio control a diesel or two. ENJOY!