# Installing the RCS PnP-3 battery R/C into the K-27.



## TonyWalsham (Jan 2, 2008)

Here is how I have done the basic battery R/C installation using the new RCS PnP-3, but no sounds.


As the K-27 operates at a very realistic top speed on about 14 volts, I chose to use 2 x 2,400 mah 7.2 volt SubC NiCd packs wired in series to give 14.4 volts.


First of all I mounted a 3" 1 watt speaker in the tender even though I will not be installing sound just yet.








Next I glued the two battery packs to the uprights and part of the speaker frame.  They lean inwards slightly but that is not a problem.
The two battery packs are put in series with an RCS # Y-CABLE set.
Sorry about the picture quality.  I still can't master this Cannon camera. 








The next K-27 I do will have an oval speaker.  That way I can mount the batteries on the tender floor.
I mounted the RCS TX-8 receiver up under the rear of the tender shell.
The BIK-U3 charge jack was mounted in the water hatch.  This required trimming out a small amount of the support web to clear the jack.








I tacked the Azarra antenna into place with dabs of silicone glue along the inside top edge of the tender shell.  Even though the suplied RCS antenna gives adequate range when strung out straight I always use an Azarr in tightish situations.








The BIK-U3 switch pcb was mounted right behind the battery packs.  The switch is readily accessible by reaching under the tender.  It is easy to flip the switch ON - OFF with one finger.
This pic also shows how neat the basic wiring can be.  There will be plenty of room for the Phoenix P5 + P5T sound system I will be adding at a later date.  The PnP-3 simply plugs into the socket in place of the supplied dummy pcb.








The 3 x wire Red/Black/White wires are the cabling for the charge jack mounted in the water hatch. 








The installation from the front.








The installation from the rear.








The plug in PnP-3 shown is a prototype.  It has a heatsink on the H bridge motor driver for maximum current capability.
Production PnP-3's will be available mid March.  As well as this RCS version, there will also be an EVO PnP-3 for those that use regular low cost 2 stick Digital Proportional R/C.
The installation provides a fused battery supply and the PnP-3 has inbuilt motor "noise" suppression.
Performance is flawless.
I have not had it outside to check range but I would expect at least 100'.
I will run such a test in the next few days and report back.

Here is how I did the Phoenix P5 + P5T sound system.
There are just 3 x solder joints.
Two wires for the speaker and one wire from the PnP-3 chuff connection to the P5.
TherE are screw terminAls on the BIK-U3.  All other wiring connections are plug and socket.
Nice and simple.








The # Plus-3 provides an extra 3 functions with the P5 + P5T.

Most of the wiring is excess with the Phoenix sound.  Their plug and socket leads cannot be shortened.









The onboard electronics works for me.

To date I believe this is the only truly PnP installation with sound anyone has achieved.  
i.e. *Absolutely no modifications or additions* to the Bachmann electronics.

The chuff works just like I expected it to.  The chuff beats seem to be pretty even to me.

There have been just four hidden holes drilled in the bodywork.
Two in the water hatch for the battery charge jack and the Phoenix programming jack.
Two in the floor for the ON - OFF switch and Volume control.

I will get the outdoor testing done as soon as I can.

The next loco I do will show how to install Sierra sound and then how to install Dallee sound.


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## Dougald (Jan 2, 2008)

Tony 

A nice neat installation. Am looking forward to your install of sound presumably replacing the supplied chuff sensor with a more appropriate one to give the correct chuff.   Were you able to make the tender top watertight?

Also, the range test is of interest though I have never had problems with RCS range. 

Regards ... Doug


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## TonyWalsham (Jan 2, 2008)

Hi Doug.

The whole point of this exercise is to achieve a plug in battery R/C installation in the K-27 without making any changes to the Bachmann wiring at all.  
If that is possible of course.
If it isn't possible, rest assured you will hear about it from me.

The PnP-3 has an inversion transistor built in for the chuff. 
Whether the chuff works properly or not remains to be seen. I am still waiting for the Phoenix P5 + P5T sound system to arrive.


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## TonyWalsham (Jan 2, 2008)

I have now installed the Phoenix P5 + P5T in the K-27.
It all works just fine *without any additions* or modifications to the Bachmann electronics.

Pix now added to the install above.


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## Dougald (Jan 2, 2008)

Thx Tony ... the install tutorial is very much appreciated. 

Regards ... Doug


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## jimtyp (Jan 2, 2008)

Nice P-n-P installation! I like how it makes thing easy and clean. 

I did have a question on the P5 installation. Did you use the optical chuff that comes with the loco or magnets? I'm using the optical chuff but notice that at about 40% of throttle the chuff on the P5 starts cutting out. I was wondering if you noticed this as well?


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## Greg Elmassian (Jan 3, 2008)

There's apparently 2 theories on this.


One is that there is nothing wrong with the K, but you need to put a .1 capacitor across the chuff output (to ground) since many decoders see chuffs coming too fast as noise.


The other is that the ground between the K and your sound card is not well defined, and at higher chuff rates, the chuff output, with respect to the sound card ground, does not move "enough" to positive and ground that the card detects the transitions.


I won't tell you whose theories these are, but try the cap first, since it's easy to find a .1 mfd disc cap... radio shack... 

Fixing the ground problem is beyond the scope of anything that can be communicated in layman's terms.


Regards, Greg


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## TonyWalsham (Jan 2, 2008)

Jim,
I used the optical chuff fitted by Bachmann as is.

There are components built into the RCS PnP-3 pcb that eliminates the problem you describe.
Apart from the battery components, ON-OFF switch, charge jack and sound, there are no additions or alterations to the K-27 electronics whatsoever.

Because of the very high 14.5:1 gearing in the K-27, the top speed at 14.4 volts is almost enough to blend in the chuffs.  Higher voltages will almost certainly cause the chuffs to blend into one long hiss.


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## SlateCreek (Jan 2, 2008)

Tony, 

Curious ... how come the charge jack is in the water hatch instead of the rear beam, for trail cars, etc? 

Also ... with this installation, how do the headlights and marker lights work? If the headlights are now directional, is that a function of replacing the dummy plug, or are they being powered by your throttle? 

Finally, there was some discussion of a conflict between the smoke unit and the optical chuff light source, that for track power users would deplete the battery if the smoke were not shut down. Does your installation solve this issue as well? 

Matthew (OV)


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## TonyWalsham (Jan 2, 2008)

Posted By SlateCreek on 02/19/2008 5:12 PM
Tony, 

Curious ... how come the charge jack is in the water hatch instead of the rear beam, for trail cars, etc? 

Also ... with this installation, how do the headlights and marker lights work? If the headlights are now directional, is that a function of replacing the dummy plug, or are they being powered by your throttle? 

Finally, there was some discussion of a conflict between the smoke unit and the optical chuff light source, that for track power users would deplete the battery if the smoke were not shut down. Does your installation solve this issue as well? 

Matthew (OV)


Hi Matthew.
The owner didn't want any modifications to the body that would be obvious.  
You could still have aux batts in a trail car.  They would plug into the water hatch instead.

The headlights are powered by the Bachmann electronics with polarised voltage from the PnP-3.  They are controlled by two transistors in the PnP-3.  Just like they would be if the PnP-3 was a DCC decoder instead.
The marker (classification) lights are powered by the Bachmann electronics just like they always have been.

The smoke unit control is separate from the chuff control.  There are two wires on a plug coming from the PnP-3.  One is the chuff signal the other is for the smoke unit.
I could have quite easily hooked up the smoke unit to turn it ON - OFF with an RCS function.


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