# K27 battery conversion



## placitassteam (Jan 2, 2008)

I'm sure there are plenty of other threads on this topic but here goes anyway. I mostly run live steam but I wanted a K27 and the Accucraft live steamer is no longer available except used and the price is more than I feel like paying, therefore, the Bachmann. The first thing I did was take apart the loco and tender and trace out where all the wires went and what function they were associated with. After some discussion on this forum I decided to not use the built in chuff triggers in the cylinders, the smoke unit and the fan so all that wiring was discarded. The plug and play board in the tender was also discarded. I also got rid of the track power wiring but left the little board in the loco that the motor leads are attached to, it makes a convenient place to disconnect the top shell from the chassis. Next I played around with the Phoenix P8 sound board and speaker, the Rail Boss RC, the Specktrum reciever and the batteries to see how it would all fit in the tender. I ended up with the speaker in the supplied location but had to make a small adapter due to the speaker being 3 1/2 inches instead of 3. I also made up 3 packs of four 4/3A 3800Ma NMh bateries.










Those items are shown here as they are located in the tender.









Batteries and speaker installed









I made a plywood box to cover the speaker.









I mounted all the electronics on a Masonite board which is screwed to the mounts for the P&P board. The spade connectors (one is near the top center of the photo) make it easy to disconnect the tender from its chassis.









Here is everything from the other side. I ended up using only 6 wires between the tender and the loco, 2 for motor power, 2 for the headlight and 2 for power to the PC board that controls the marker lights, fire box flicker and cab light. I haven't tried it yet but I may only need one wire for for the head light as is seems to have a common connection with the marker lights.









This is what the tender looks like all assembled except for the coal load. The ON switch and the charge jack are in the water hatch and there is a fuse holder mounted through the coal door in front (barely visible).









Next up is the loco wiring.


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## jake3404 (Dec 3, 2010)

Looks good Wynn


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## placitassteam (Jan 2, 2008)

Here are some additional photos of the tender. A better shot of the fuse holder.









The power switch and charging jack. The switch is forward for RUN, center OFF and back for CHARGE.









The underside of the tender showing the chuff sensor and magnets, the volume control (green toggle to the upper right) and the connector for the loco plug (lower right).









I left all the PC boards in the loco but cut off the wires I wasn't using. Here ia the main board and fire box flicker unit.









The motor board, I left it in just to have a convenient place to disconnect the power leads coming from the ECS in the tender. All the chuff wires are removed. I also left in the switch board in the front of the smoke box to control the lights and fire box flicker. The smoke is disconnected.









Since my RR has 5 foot minimum radius curves I do not need the side to side motion of the drivers so I removed the springs on driver axles 1 and 4 and replaced them with spacers. The spacers were made from 9/64 brass tubing which was split on the side and cut to .150 inch length.









They were spread enough to fit around the axle and the squeezed back closed. One is just visible between the wheel and the frame.









I ran it on the RR yesterday and everything works well and the loco tracks very nicely. I did have to move the chuff sensor closer to the wheel and added a second magnet. Some chuff systems don't work very well when lots of input pulses (instead of chuffs you get a continuous hissing sound) but the P8 sounds great. So I added the second magnet on the tender wheel which now gives almost 4 chuffs for each driver revolution. Not really synchronized but close enough for me.


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## Del Tapparo (Jan 4, 2008)

Nice job Winn. I don't know why I didn't see your post sooner. Looks like you have it all under "control" now.


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