Railpro with battery

I bought some 3.7V 700mah LiPo's from an online vendor (5 batteries and a charger for $20), a Pololu voltage converter from Litchfield Station (convert 3.7V to 12V), and some 2-pin plugs from Evan Designs.  The batteries I bought could only fit in the fuel tank area, so I enrolled the help of a friend to mill all the metal out of the fuel tank of a Kato SD40-2.

I routed the wires through the frame, around the motor and then to the voltage converter.  I placed the 2-pin plug between the battery and the voltage converter.  In this picture you can see the wires coming up on the side of the motor:

Another view of the set-up.  The Pololu board is right in front of the Railpro module, mounted to the styrene board.

The plug is located right underneath the dynamic brake hatch, allowing me to easily pop the hatch off and unplug the battery.  This is also how it is charged....I plug the charger directly into this plug and let the battery trickle charge.

Because Railpro has direct radio control and only takes power from the rails, it makes it very easy to convert to full battery power if you want.  Railpro doesn't care where the power comes from, as long as it is of sufficient voltage (12V is plenty).  However, as a disclaimer, Ring Engineering doesn't recommend using LiPo batteries in model trains due to their inherent fire risk.  This is something I did on my own and am fully aware of any risks.

A short video explaining the above and demonstrating a bit of operation:

Cool but scary

That is an awesome ability and I would love to be able to use it. However, I just cannot bring myself to risk a fire that burns up a loco that I've put over 200 hours into...too scary. I hope to see more of your wonderful modeling soon Kevin!

Very good

Glad to,see you give this a try. It wouldn't be too much of a stretch to charge from the rail using a step down converter from Pololu and diodes to prevent sending power back to the rails. Personally I see this as the future of the hobby. I don't think there is a risk of fire anymore than my cell phone bursting into flames in my hands. 

I have a number of engines with different dead rail solutions - Tam Valley, NCE, CVP, and BlueRail boards. Each have advantages. 

The problem

I see is that batteries take up room that could be used for bigger speakers? I think the size and difficulty of wiring a layout would need to be balanced with the more difficulty and bulky battery installation. Getting unlimited power from a centralized source like rails or overhead wire  is a pretty elegant solution only used on the most important high traffic areas of the prototype so we are lucky to be able to have it so easily in model railroading :> ) .......DaveB

S-Cab has a similar set up,

S-Cab has a similar set up, but the battery charges automatically when the rails are powered. There is a battery disconnect option to save battery life when not in use. The Rail-Pro decoder would simply replace the decoder in the diagram below. S-Cab has other wiring options for use of battery power.

http://www.s-cab.com/

On batteries and Railpro

Analogbeatmaker - Yes, it's a risk, but as has been noted, most of our electronics run on some form of LiPo battery now.  Cell phones, tablets, laptops, etc.  The risk is relatively small.  However, I've considered getting one of the fire-proof bags that R/C guys use to be on the safe side during charging, etc.  Probably overkill, but it doesn't hurt to be safe.  

Neil - I'm not that familiar with Pololu's complete line of products so I'll have to look into them.  If they have other boards that are equally small that will allow charging from the rails, then it may be something I look into.  I'll also need to familiarize myself with how to wire that up so I don't cause any damage.

Dave - I've made the decision that all of my speaker installs will be a minimum of 2 "sugar cube" speakers.  My dual (and sometimes quad) speaker setup sounds way better to my ear than any other speaker I've ever installed.  And I've tried most every type of speaker in most configurations.  These dual speakers make the sound a little "fuller" and cut out a lot of the grating "tinny" sounds I typically hear from model railroad locomotives.  And the dual speakers centralize the sound right underneath the exhaust stack, which is exactly where I want it.  This locomotive was an experiment to see if I could build a loco that was completely independent of any rail power.  So far so good, though I still need to test how long the battery lasts.

Alan - I'm aware of the S-cab battery management board, but from what I remember it is rather large (1.5" long I believe).  Initially I didn't think I'd have room for anything else.  When all was said and done I ended up with some extra space in the shell I didn't count on, so I could've possibly fit one in there.  But I have to say I so far like the idea of being fully independent of any rail power.  I have removed the wires completely from the trucks, though I can add them back in the unlikely event that I want to go back to rail power.

-Kevin

S-Cab

"I'd love to see someone

    I considered it for my new layout but after thinking about it I decided I could just add feeder wires to the rails easier than installing the extra parts in my engines. The track feeders are a one time solution that take care of any new engines while the onboard batteries and related parts are a repetitive solution that never ends. My conclusion was battery power would be a last resort solution for outdoor layouts or those needing to run without access to wall power......DaveB

S-cab BPS and Railpro

Joe, I may try the BPS+Railpro out on the next locomotive that I build, but that will have to wait for ScaleTrains to deliver their SD40-2.  If I do, I may document and write up an article.

To be clear, with the installation I did above I did use a step-up converter because the battery was only 3.7V.  Most LiPo's I came across that would fit in our locomotives are 3.7V, so a converter is a necessity.  I chose the battery I did because it had much higher amerpage than other batteries that would fit in the shell.  I also planned my install so that the battery would never have to be removed for charging.  In this case, charging for me is as simple as popping the dynamic brake and plugging it in by my computer.  However, this really only works on hood units with a removable hatch....can't do this on GE's or something like the SD70 family.  In those cases a BPS board or plug in the fuel tank would be more reasonable.

If I can get 3-4 hours on one charge then that is more than enough for me.  I don't ever run for longer than that. 

-Kevin

Trickle charge is the key

The trickle charge feature of S-Cab is the key. With that, you can use smaller batteries with a lower total amp-hours of even 1 hour. The endless trickle charge keeps the batteries topped off, so you get effectively an infinite power source on powered rails.

It's almost the ultimate in keep-alive, where gaps in rail power just won't matter as long as the loco can get track power enough to keep the trickle charge ahead of the power drain.

As for 3-4 hours, do you run a single loco 3-4 hours? Bet not. More likely 1 hour max is a lot more common - and that's CONSTANTLY.

Dead Rail and Rail-Pro Charging

  I think Joe has hit the nail on the head.  We do not need 3-4 hours of running time on the batteries.  Picking up power from the rail with a keep-alive circuit will get the engine over dead frogs and reverse loop gaps.  Many of the current DCC keep-alive units can provide 7-8 seconds of power(un-controlled!).  If Rail-Pro were to include this as part of their line, or a 3rd party would offer a conversion kit - This would be enough.  Dead Rail sound inviting and 'sorta'  cool - but many of use want to use the track for signaling, and not all folks run back-woods lone wolf operations.  Rail Pro has addressed the MU/Consisting issue quite well, and seems to have a handle on on this stuff.  Most of the others seem to be 'one off' and most of the Blue Tooth systems do not address consisting or sound right now.  Until they can get together with a common standard to follow; they remind me of all the command control systems before DCC - incompatible with each other...

Jim

Railpro and keep-alive

Jim - There's a discussion on here somewhere regarding Railpro and keep-alives.  There is also a healthy discussion on the same subject over at the Railpro User Group ( http://rpug.pdc.ca/index.php).

Adding any of the keep-alives on the market already to Railpro is fairly straightforward.  Basically all that needs to be done is to solder a bridge rectifier before the keep-alive and Railpro module.  After that you are good to go.  Quite a few Railpro users have done this and have had great success with it.  I plan on doing the same to many of my locomotives.  Battery power works, but right now it is more of an experiment in proof-of-concept for me.  I will probably limit battery power to two locomotives and do some form of keep-alive on the rest.

I know Ring Engineering is working on making their own keep-alive solution, but I'm not sure how far along that process they are.  In the meantime, other manufacturer's keep-alives (TCS, Soundtraxx, etc) work just fine as long as a bridge rectifier is installed.

The nice thing about Railpro is their direct radio communications, making the system pretty much set up for keep-alive/deadrail function with minimal effort (which is basically adding a battery or keep-alive).  At no point will you loose control of a Railpro-equipped locomotive if it hits a dead spot once those are installed.  As long as you have power, you have complete and instant control.

-Kevin

 "At no point will you loose

I think the whole layout concept would need to be considered to make the railpro/battery decision. If just the turnout frogs are dead then a keep alive cap would suffice so one could keep DCC and it's advantages . If longer dead sections were desired then batteries and the railpro constant control would be more important. Advantages I see for DCC are much more choices of hardware and sound decoders while rail pro is easier to consist. The layout's environmental  conditions might influence the choice if they made it difficult to keep the track clean, also builder's experience and it's effect on ease of wiring and track maintenance.....DaveB 

@Dave

It's a give-and-take either way.  Positives to both systems, Railpro and DCC.  In any case, this thread was to show the possibilities of battery power with Railpro.  Bill Brillinger has another thread going discussing Railpro and keep-alive installation.  Both options are easily do-able with Railpro.  So if one wanted to go full dead-rail, then one way to do it would be Railpro.  If one wanted Railpro but also wanted to use keep-alives, that is entirely possible also.  

It's up to the user what system they feel most comfortable with, be it DCC, DC, Railpro, etc.  I ended up choosing Railpro for a variety of reasons and have been happy with my decision.

-Kevin

Tractive effort?

Has anyone measured tractive effort before and after solid engine weights are replace by a battery and the associated electronics?

Tractive effort

Don - I don't have numbers for you, but I suspect the tractive effort is lower now with the battery.  The removal of a significant portion of the frame weight had to be done in order to fit the battery.  The battery itself has some weight, but nothing like the frame itself was.  If I were to have installed a battery in the shell and left the frame alone, the tractive effort likely would have been increased.

I do have some extra room inside the shell and in the fuel tank, so I might throw some weights in there to improve traction.  But then again, the prototype #1778 has been coupled to sister unit #1999 for several years now and they always work in a pair....since I'm modeling the prototype I will follow suit.  When I finish the second unit there will always be two SD40-2's working together so tractive effort should be a non-issue.

-Kevin

Cool

I think this is the future of model railroading. You'll be able to buy a battery powered locomotive with sound and radio, no moding required.

Tractive effort

Doug --

Thanks for the quick response.  Tractive effort is important to me, as both my club (La Mesa) and home (SMR) layouts have grades that affect performance.  So much so that full length club trains require 18-24 driven axles and the SMR requires 12 axles.

That said, the installation you've created is really neat, especially for this stage of the game.  It will solve a lot of issues if the process can be brought into commercial engine production.  Thanks for posting your efforts for all to see.

 "When I finish the second

If the engine can do the job without more weight I view that as an advantage. Less weight puts less strain on everything, the wheels can slip easier so gears and motor are stressed less. I'd rather run two light engines than one heavy engine......DaveB

As Kevin said it is up to

As Kevin said it is up to each user which system he wants to use.

For Dead Rail speaks you save more than just the wiring. You save the constant cleaning you need for running DCC sound.

Regarding the risks of LiPo batteries: It can minimized by buying the right types. Avoid the batteries the R/C guys use, we don't need 20C or 45C discharge rates. These batteries were not good enough to make it into computers, smartphones etc. The R/C guys need the high discharge rates for cars or e-flight. And these batteries are the ones that can make problems.

Buy industry standard batteries with PCB/PCM protections. This will trip when charge or discharge are too high and if voltage gets too high or too low. These batteries are more expensive but quite save.

Even safer are LiFePO4 batteries.
Regards, Volker

Charger

Perfect

Would be interested myself to a similar setup 

Small battery, trickle charge

Small battery, trickle charge through the DCC-powered rails and a standard DCC decoder.

That would be my preferred approach. Small step-up converters are available. But I have not yet come across a small trickle charger that can be connected to DCC-powered rails.