Large Scale Central

SD-45 battery R/C updated

G’day fellow LS’ers. I have recently installed RCS battery R/C in a new SD-45. I changed the way I did the installation compared to the old article. I have re-used some of the 2005 pics as I still cannot get the hang of my new Canon Digital camera. Sometimes it takes great shots and other times they come out grainy. This SD-45 doesn’t have sound yet but it may in the future. Removing the body shell is a snap on the AC SD-45 compared to most USAT locos. There are less screws and they are all easily accessible. The hardest part was removing the three weights in the fuel tank so I could install the two 9.6 volt 2400 mah SCR battery packs.

The glue just will not soften so I had to smash them off with a couple of heavy raps with a claw hammer. Once I had removed the weights I located the AC battery plug wiring at the rear end.

I cut the wires shorter so I could re-use them to power the AC electronics with the traction batteries via a small relay.

Once the AC battery plugs had been removed from either end I temporarily removed the two small pcb’s and cleaned up the backs of them by shortening the solder legs and insulated them with tape. They had shorted out on an earlier installation and the fault took some finding.

The RCS BIK-U6 charge jack was mounted in the rear panel.

I stuck the three wires to the underside of the chassis with super glue gel. I fed the wires along the side and up through the floor where they are hidden by the fuel tank.

The SD-45 has a steel U channel running the length of the chassis. It provides very good stiffness to the plastic frame and is great for hiding some of the wiring.

I installed the wiring underneath a styrene shelf before I stuck the styrene to the channel with silicone adhesive. Next I turned my attention to the battery packs. Fortunately the tank is big enough to take both 9.6 volt SubC niCd packs. Just. They snap in and would be impossible to get out without glueing straps to them BEFORE placing in the tank.

Once the glue was dry the battery packs were installed in the tank with tabs poking up that you pull on to remove the batteries if necessary.

The Y-CABLE was connected to the battery packs and the tank re-installed in the frame. The picture also shows where the three wires from the charge jack go up through the chassis.

Next I turned my attention to the RX-8 and AZARR antenna placement. Originally I mounted the RX-8 and antenna along one side just under the long hood. This is not the optimum way of doing it because of the interference created by the smoke and lights PWM generator on the switches pcb. This interference can severely reduce range. I thought it was time to try something different. So I located where the antenna wire would come through the cab wall and drilled a small hole. I fed the antenna wire through the wall and then mounted the RX-8 on the back of the cab wall. The AZARR antenna was mounted vertically up one corner. The excess wire was strung around the underside of the cab roof and tacked in place with dabs of silicone adhesive.

View of the RX-8 mounted on the back of the cab.

The BASIC-6 Motor Driver was stuck to the styrene sheet with Silicone as was the front RF-CHK pcb that suppresses the front motor block. Hanging down is the BIK-U6 switch assembly which easily mounts in the body shell in the space just in front of the AC switches. If sound is ever fitted I will also install a sound system volume control alongside.

At the rear I mounted the other RF-CHK pcb and the small 1 amp MOD-RELAY that is used to control the polarity of the battery voltage going to the AC electronics. I much prefer doing it this way as it completely removes the need to rewire the loco. The lights automatically reverse and are constant brightness. The smoke unit is powered if necessary. With the revised RX-8 and AZARR antenna mounting the the range has proven to be a spectacular 300’. I did try the set up without any motor noise suppression but, unlike the RS-3 version I did, the suppression fitted by AC to the trucks is not adequate for the four motored SD-45. The suppression is perfectly good for the two axle motor blocks.

Nice install and easy to follow article. Thanks Tony


Very nicely done, Tony. Thanks for sharing.

Nice article. Just curious, how well do these R/C things work in tunnels?

Ray Dunakin said:
Nice article. Just curious, how well do these R/C things work in tunnels?
Depends on what you mean by tunnel, how long it is and what you mean by "work"

Unless you are using a type of digital proportional control where the receiver has to “see” the signal all the time, going into a tunnel will have no effect on what the loco is doing. All the proprietary systems are memory types. They remember what they are doing until told to do something else.

Although metal lined tunnels are likely to prevent a signal getting through, with RCS you can always control the loco for sure, as in stop, start and reverse, as long as the TX handpiece is held close to the track outside of the tunnel.
Plastic lined tunnels should be OK. Cale Nelson seems to have good luck anyway.

Ok, that’s what I needed to know. Thanks!