# RC/battery... and track power!



## pcz (May 13, 2010)

Ciao from FRA&PIE route.

For my first experiments on FRA&PIE route, I have used locos (Bachman K-27, 2.8.0 Connie and Accucraft B4C) with a unique 24V = 4 A trafo connected to tracks and power line (under the main line connected each 4.00 meters to tracks) have the problem of line lenght with the usual problem of low voltage along the way. My idea was to separate the line in insulated parts with a trafo feeding each one.

With the idea to have a constant 24V= along the tracks, I need a remote control to "control" each locomotive... usual DCC are not ok because FRA&PIE route (when finished) will be more the 200 meters long in an area of 2,000 sqmeters. 

On may I bought from RCS/Beltrol my first RC for Bachman K-27 with Spektrum Dx5 radio control. 2.4gHz are ok for move trains in a large area.
My first idea, to cancel problems shown below, was to feed locos only with batteries; tracks and power line used to feed only all switch motors, lights (houses, stations, factories, etc...) and everything you'll find along the tracks... including coaches and cabooses lights.

Yesterday I activated my K-27 with remote control by Tony Walsham's RCS and battery back-up... and it's incredibly perfect and easy for my idea of leading a loco in my garden railway!
for me the only problem is: 14.4 volts from batteries in tender are not enough for a shining front light and if you think I used 2x6x1.2 volts 2400 mAh = 12 AA batteries I'm sure moving locos with this kind of power, batteries'll be very hot and low charged after a couple of minutes. 
Now I understand I have used a wrong type of batteries, the AA... I had to use C type with the same volts and power. But I think problem wil lbe the same, discharge will be not in minutes but in half an hour?

Now my question is: if I continue to feed locos with track power, aided by batteries in black out for dirty tracks, etc... the problem is only connected for 90% to dirty tracks because locos have an important weight and we are in Fn3, not in HO, loco weight helps to have a continuos feeding from tracks.
I have to create sections (neutral sections) along the railway line for a continuous and costant 24V= 4 A... I'll install more than one trafo, one for each part with same trafo, equal Volts, Amperes and +/- connection... with a neutral section in the middle.

I think yes, the neutral section must be longer than the longest train... In this sections lights doesn't work and if tracks lie in a climb zone, loco is not able to continue running.
And if neutral sections are feeded? In this way train and lights don't stop working... But I need to switch power from one trafo to the next one in each neutral section. 
My idea is to use reeds before arriving in the section and in the section, loco switchs power from one trafo to the next automatically...


TRAIN DIRECTION >> -- trafo1 ----(x1)----| |---------(y2)--- neutral ---(x2)---------| |------(y1)----trafo2 --


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## Steve Stockham (Jan 2, 2008)

I am not completely sure about your entire question but as to batteries, I think that you are significantly underestimating the running times you can get! Using three 7.2v NiMH batteries wired in series should net you 21.6v which I have found to be more than adequate to power an Accucraft C&S #60 (the B4C). The Bachmann K-27 and Connie (2-8-0) run on two 7.2v NiMH batteries and run times are roughly four hours for each between chargings which is more than enough for me. I understand that LiON batteries are giving runtimes of up to _seven_ hours (although I personally can not confirm this.) The trick is the capacity of the battery! The more milli-amps it is rated the longer the charge will last. This is a _very _simplistic explanation and I apologize that I am not more knowledgeable about this but I do have (or had) all three of these engines and I run RCS r/c with NiMH or NiCad batteries in all of my engines and this has been my experience.


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## lotsasteam (Jan 3, 2008)

I am running my Bmann K27 with lights and 2ah smoke unit on 2 x 6volts 5ah lead acid batteries and get 4hrs + running time,i also have 2x 18v 1,3 ah nicad batteries (18 volts 2.6 ah)which give me ca 2hrs runtime! keep in mind the smoke unit is on all the time(12volt 2ah Harbor Hobby ) 

Manfred Diel


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## pcz (May 13, 2010)

Ciao Steve, ciao Manfred...
Thank you for your quick reply.

Steve you are right: I'm afraid I'm not able to "play" with my loco for a entire evening... I' afraid about the long timing for recharge them...
But I'm afraid and I never tried effective running time for K-27 in battery mode.

Next saturday I'll have a full immersion on FRA&PIE route with K-27 and battery power only on my 3% main line with 4 coaches (brass) and I'll inform you about effective working time.

Next operation is on 2.8.0 Connie for RCS remote control and battery power/backup.

Thank you very much again.
A presto.
Pier


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## Richard Smith (Jan 2, 2008)

I'm using 12 AA cell, 1800mah 14.4v NiMH battery packs, although in smaller engines than you, and I get just at four hours run time. Note though that's not in continuous loop running but rather switching ops and movement on a point to point RR. The guy that put the packs together for me did carefully match the batteries as a single "low" performer will pull the whole pack down. After nearly six years all the packs are still going strong. My lokies have reversing headlights (all but one) and Phoenix Sound but no smoke. If smoke is not important to you then disconnecting the units can add significantly to run time. 

I'm not speaking as a battery "expert" but rather as a user just FYI. 

Also I charge my battery packs overnight on a slow trickle charge of 14-16 hours. My chargers shut off automatically. I run then until they poop out or every 3 months during the winter. They are set up for a quick and easy change of packs in the lokies if needed.


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## Greg Elmassian (Jan 3, 2008)

First, and I am not trying to change your mind, but you need to get your DCC information from someone else.

I run a DCC system that uses wireless throttles, and have have 31 wireless "base stations" which will support an area much larger than what you are talking about.

It also supports multiple power boosters, essentially unlimited numbers of them.

So your layout is easily doable in DCC with current production equipment.

And you can be standing anywhere on the layout and not necessary to be near the loco or accessory you are controlling 


To your questions:

there is no need for "neutral sections" but short ones cannot hurt I guess.

Use all the same type of power supply, and no sophisticated overcurrent circuits, only simple circuit breakers.

There is NO need to reverse the polarity of tracks, to get power from the rails, then power any "direction senstive" equipment from a full wave bridge rectifier from the rails.

This way, no matter what the orientation of the cars or locos on the track , you can have the same voltage polarity if you desire.

For reversing loops, there is a DC autoreverser made by Massoth.

(I cannot see all this effort to do it this way, either go all battery or go DCC is my opinion)

Regards, Greg


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## Totalwrecker (Feb 26, 2009)

Why not use both track and batteries? Since you'll have power on the rails anyway this set up will recharge your battries when track power is the stronger current and will seamlessly shift to battery when track power is weak or disconnected for reverse loops and wyes, run on battery until you get back on live track. 
Despite all those who tried to do it and couldn't and will say so, it has been done successfully. 
You can run any R/C this way.










http://iptrains.com/TrainUPS-Conversion-Kit-FBCK1.htm 

John


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## lownote (Jan 3, 2008)

Just fr information, not to persuade you of one form or another.

We run a very simple medium sized layout (maybe 300 feet of track) on dcc. We have one base station and a wireless throttle, and power connected to the track at three places--not blocks or isolated sections, just 3 sets of two wires, connecting to the track at different places. From the track we run a number of lights and all the switches: the switches are remotely controlled from the wireless throttle. We could also turn lights on and off via the wireless throttle if we wanted to. 

Most of the lights powered from the track are LEDS, to reduce current draw. We have conventional incandescent low voltage DC lighting via a separate circuit made of commercial outdoor lighting--the brand here in the US is "Malibu."Track cleaning is no big deal for us, just run a track cleaning car around a few times. But if you want reliable electrical operation with track power you will eventually want to put clamps on the track joints 



DCC layouts can handle reverse loops automatically and very easily. Adding a reverse loop is on my list of things to do!


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## TonyWalsham (Jan 2, 2008)

The main problem Pier Carlo has with the K-27 is that the power supply to the PnP ESC is an either battery power OR track power via the loco switch. 
Also, the 14.4 volt batteries lose an extra 1.4 volts via the bridge rectifier on board the ESC. There is a way of rerouting the batteries and apply the voltage directly to the ESC via a plug in cable with a diode for protection. 
AA size cells are definitely not adequate for the load a K-27 will pull. Two x 7.2 volt sub C packs in series will work much better. Mainly because the C cells can handle a much bigger current draw than AA size cells can. 
As stated above run time is a function of battery capacity. The bigger the capacity as in mah, the longer the run time. 
The lights on the K-27 are voltage controlled LED's and are not very bright. More battery voltage will not make them brighter.


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## pcz (May 13, 2010)

Thanks to all for your reply!

From your reply I understand my idea is very complicated and all of you tells me to try only RC (or only DCC).

I understand I have not to invert polarity because trains with RCS moves in reverse mode with electronic command and not with changes on rails.

My first idea was to use track power and battery as backup recharged automatically.
Tony told me on K-27 rcs is not able to use track power as "main power" and to recharge batteries while loco is runnig, no problem.

For the moment I stop my experiments and in August, at home near FRA&PIE route, I'll try all possible versions (battery, track+battery, etc...) for having a clear idea about how to drive my trains.

I know the easiest way is the best, I suppose to run trains for hours... I hope.

In future, your suggestions will be appreciated.

My new experiments on http://www.zuccarello.com/fn3

Grazie a tutti per i consigli.
Pier


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## Totalwrecker (Feb 26, 2009)

I posted a link that will allow you to recharge from track power with on board batteries. It will work with RCS, it's just that Tony doesn't like the idea. Tony's RCS isn't set up for you to do that without an extra component... thus (I think) his negative comment. Vendors here tend to promote their way and to dismiss other ways. 

I use the floating battery supply... with limited track power; The loop is powered, but the wye and reverse loop are dead. While running on track power the batteries get a tickle charge and when on dead track the batteries powers the train. The power leads then go to what ever R/C wireless throttle you desire. I don't have a battery charger other than a section of live track. My power source is a 24v meanwel type regulated power supply. 

I asked about it when I joined this board and several said no way can't be done, then I talked with a fellow making the very item.... and saw proof it does work! The battery guys told me to make up my mind either track or battery. Oh yeah we sell chargers.... 

Power is power, your Rx doesn't care if it comes from track or batteries, as long as it's steady and the right voltage. Check the link I posted above. 

John


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## TonyWalsham (Jan 2, 2008)

John. 
I am well aware that what you say can be done. 
I have no philosophical objection to the method of recharging whilst running. 
In fact I was doing that 20 years ago. 
The problem with it is that batteries of various voltages and chemistries require different circuits and not just a simple resistor and diode. 
For example, how would you differentiate and control the charge rate and voltage monitoring of Li-Ion batteries when compared to, say, NiMH batteries? 
Unfortunately one size does not fit all. 

In future, I would respectfully suggest you leave my thinking to me.


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## K27_463 (Jan 2, 2008)

i am in with Tony on this. He and I had such discussions and tests in the early 90's. It is always great when someone new reinvents the wheel for somebody who was already there for 20 years or so, give or take. No one says this dual method does not work. Just not practical on many levels. The problem is not electronic. It is the combination of electronics and Physical issues. Batteries do not like intermittent charging. Does not contribute much to long life. The change in state between discharge and charge condition is not instantaneous.A chemical reaction inside the cell must take place. While it is fast on human time terms, it is not fast enough to be comfortable with rolling intermittent contact on a microscopic scale. Charging while stationary is generally fine. While rolling is another matter completely. in addition, how do you regulate current inrush at the start of a charge? Through your already pitted loco wheels? As Tony said, how do you detect battery chemistry? Brute force dumb charging of the sort advocated is simply not best when modern electronics allow smart charging at low cost. 
So , you get to purchase and maintain both battery AND track power systems, added complexity, with many factors such as state of charge an unknown. Charge your cells in a way not conducive to long life and top performance. It is a hobby and a choice , everyone gets to make the choices. 
I would also ask that I be allowed to think for myself and present my own ideas, rather than have some generalized derogatory statements made about the fact I sell smart chargers. 
Jonathan/EMw


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## Totalwrecker (Feb 26, 2009)

Batteries have come a long way from those days... it's not as tricky as implied. 

For a newcomer to repeat a false statement doesn't hold much water... 'Tony said it can't be done', not it might be tricky.... Tony this sounds like a 'no' to me... 

I think the Li-on example is kinda lame as you need a specific charger (and a fireproof container) for those...so that means you are aware of battery chemistry.. as are most battery users. 

The folks that designed the system get plenty of hours with their batteries... why are you guys so negative? 

The generalised charger remark wasn't derogatory as much as an explanation perhaps of your negativity towards the concept. 

I have no pitted wheels.. where did that come from? Scare factor? 

I wanted our newcomer to be able to think for himself as well, and I don't think Tony allowed that... sad that 20 year old ideas are acepted as fact 

That's why I spoke up. I hold both of you in high regard and rather than make it personal I used 'vendors' for the rest. Tony was named by the OP and I commented on that. 

I moved up from track power, so that was already there, I added batteries inside the boiler of my loco, too hard to get to for service or replace with fresh batteries. The loop track still has the non converted loco running on it, so it is maintained anyway. Only the reverse loop and wye are un powered and that's why I went to batteries... with on board charging there isn't anything to maintain there... so maybe my was is simpler! 

I use NiMH and they are no longer affected by memory... as was true 20 years ago. The onboard charger does not use brute force, it trickles, takes 5 hours the first time to charge on the track. 

I'm getting used to being put down every time I bring this up... thanks so much. 

John


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## East Broad Top (Dec 29, 2007)

I think the Li-on example is kinda lame as you need a specific charger (and a fireproof container) for those... 
You do need a specific charger for LiIon batteries. You do NOT need a fireproof container. I've got Li-Ion batteries in things all around the house that charge quite safely on their dedicated chargers without any precautions of any sort. My train batteries are no exception to this. I'm not denying Li-Ion batteries haven't failed in spectacular fashion as evidenced by the myriad YouTube videos. I'm balancing that with the overwhelming lack of fires caused by the--literally--millions of Li-Ion batteries charging safely in our cell phones, laptops, digital cameras, bluetooth headsets, etc. every day. If the batteries are handled correctly--not overcharged, over-discharged, damaged, etc., they'll charge very safely when charged with an appropriate charger. The R/C plane guys usually chuck their Li-Ion packs after a crash because of the potential for internal damage that can cause fires. 

Back to the subject at hand... In my opinion, you can do it, but why would you want to? By charging batteries via the track, you're inherently limiting yourself to a battery chemistry that can support such charging, so the weight/space saving Li-Ion technology is not an option. Granted you don't need hours of battery capacity since you're only using the battery for short periods of time, but you're still looking at AAA-sized batteries at the smallest (at 700 - 1000 mAh), which for any kind of voltage (14.4 volts as a practical minimum), you're using a fairly sizable chunk of real estate--larger than Li-Ion packs at 3 times the capacity. In something like the K-27, space isn't a concern. But that locomotive is very much the exception. You're also exposing yourself to the need to maintain proper electrical continuity through the railroad. You're pulling from the worst of both worlds--the need for lots of battery space _and_ the need for good electrical conductivity. It doesn't make sense why you would subject yourself to the extra work. 

More than that, though, you're still going to have to charge the batteries offline. NiCad and NiMH batteries are not known for their ability to hold a charge long-term. Gel Cells do better, but they're ridiculously heavy for the power they supply. So the likelihood of having fully-charged batteries (without pre-charging or keeping them on a trickle charge while in storage) is pretty limited. If you're only trickle charging the batteries while on the track, you're most likely not charging at a rate sufficient to offset the power lost by the train running over the dead sections. So even with a charge, you're operating at a net power loss, so eventually you'll still be stuck with dead batteries on dead track. If you're in a situation where you need to charge the batteries prior to running, why not go with batteries that pack much more power in a smaller space and not worry about keeping electrons flowing through the rails? Or just power all the sections of the railroad, use the modern circuitry that controls wyes and reverse loops, and just not worry about batteries. 

Later, 

K


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## TonyWalsham (Jan 2, 2008)

......so if you want longer run times simply wire the charge jack to do two things. Accept a charge or use as a port for plugging in auxiliary batteries in a trail car. 

JohnJ. 
If you can show me where in my two previous posts in this thread I have used the words *"it can't be done"* I will give you a free system. In fact I have agreed it can be done. 
I do not do it for any number of reasons, mainly because I have discovered during the 25 years of experience, experience that you seem to want to unceremoniously discount, I have been making ESC's for battery R/C locos, that there are far simpler ways of gaining extra run time than adding the complication of wiring from track power as well and using that track power to also charge the batteries. 
Kevin has adequately covered the various scenarios above. 
Let me stress that I have no vested interest in batteries or smart chargers. I do make a NiCd only trickle charger and I do sell smart chargers in Australia.


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## Totalwrecker (Feb 26, 2009)

"My first idea was to use track power and battery as backup recharged automatically. 
Tony told me on K-27 rcs is not able to use track power as "main power" and to recharge batteries while loco is runnig, no problem" .......From OP"s 3rd post 

Tony, the above is where I got the impression that you might have said that. Do I win? I ask with a smile. 

I regret making 'the Charger' statement, it isn't my focus, but has become one during this thread. Stress away! lol 

KS... consider this... parked in a car barn, the trickle charge tops off the batteries, ready to go at a moments notice. Plenty of battery for the dead sections (only 1 /3 of layout) and depending on the train speed there is plenty of juice for the recharging while running under power. 24v on the rails. My other loco isn't converted yet so it runs off track power and can't traverse the expansion...yet. The car barn will be isolated for charging 24 hours a day or less could be on a timer....oh that's the part you discounted Yet it will be online. 
In the 2 - 3 hours I don't drain the batteries, slow speeds, no smoke and no lighted cars 'cept a caboose which will be converted to LEDs and an under car battery. Anyway for a single old man it works for me. I also only run one train at a time so I can park the bat loco on a section of live track while I run the other from a rheostat/ throttle. 
An Aristo C-16 w/ 14 bats in the boiler left plenty of room in the tender for electronics. I haven't noticed an decrease in the pulling power required for the short trains I run up and down hills. (I did add lead shot in many places) The electronics come pre-assembled, collecting the leads from track pickups is simple and so are the leads from the battery wire them in and take power from the 'out' side to brains and then to motor etc... 
I started with track power, I use AC's SS and used longer allen wrenches to set the SS screws, that was 5 years ago and it still maintains conductitvity. I only used clamps where I cut rail or the holes were off for screws, 1 example of that. It's not like track power is costing me more or more headaches, one pass with the AC track cleaning car and I'm ready to run. I already had that. 

All I know about Li-On I read here and at another G ga. site and there were some strong warnings... 

In a nut shell; the less I need to open (and break something!) the better, so recharging onboard was a must. I don't really have a weather secure place for recharging outside via a charger, it's far simpler to weather proof a box for the power supply. Nor would I trust much wiring outside in my climate and with my critters, they all love to chew on wires. There is only one connection to the oval and one will be in the car barn. That's pretty simple wiring. Very easy to trace as well, both are short runs. Power for building lights can be drawn from track power too. 

I'm using Tenergy 2300mAh bats. They seem to act as required and do hold a charge longer than I've been led to believe. Maybe they have gotten better in 20 years. I know they don't have that memory problem of yesterday, ie; no need to drain completely before recharging. 

At some point I had to trust the designers more than the nay sayers.. and did and am happy. That's the point of my post. 

There is a Principal that will keep man in everlasting ignorance and that is; Contempt prior to investigation. (I don't remember the author nor the exact wording). 
I kept an open mind and looked at what is available. Found what suited my needs and went for it. I repeat I am happy with my choice, therfore don't understand the passionate denials... 

Respectfully, 
John


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## East Broad Top (Dec 29, 2007)

John, I can easily see how your system evolved to what you're doing, and it most definitely works well for you. My comments weren't intended to criticize your operations specifically as they've evolved over time. My apologies if you construed them as such. Certainly anyone who started out with track power and is now looking to convert to battery has _already_ invested in the infrastructure needed for a system that recharges while running, so why not take advantage of it if it works. For someone just starting out fresh, it's a lot of extra work and expense. It's not that I'm arguing it wouldn't work--clearly it does. But what's the actual return on the investment? Is it _worth_ the time and expense up front if you're coming to it without any existing infrastructure? I just don't see where you gain anything from it. 

When I look at how you operate your railroad, there are striking similarities to how I operate mine--to the point of being virtually identical--one locomotive at a time, slow speeds, reverse loops, 2 - 3 hour operating sessions. Really the only difference in terms of operations is your preference for on-board (non-removable) batteries where I effort to make mine removable. Because of the similarities of our situations, (and having used 2300 mAh NiMH batteries prior to converting to Li-Ion) I can say with a fairly high degree of certainty that you could chop the wires to your mainline, run entirely off the batteries and never notice any difference in a typical operating session. Based on what you describe compared to what I'm doing under nearly identical circumstances, I really don't think you're getting anything in return for charging your batteries on the main. I'd be able to do the same thing with the same batteries and no track power at all. Maybe you're getting a few extra minutes' worth of power via the recharging, but if you're shutting things down within the timespan where the batteries would last without any recharging, what's the point of charging them? You're not benefiting from the extra charging at all, you're merely charging them for the sake of charging them. 

Keeping the batteries charged while in storage is certainly has merit, and using an energized track to charge them works. That way you know you always have a full charge when pulling out for an operating session. With the NiMH batteries, that's a good thing. I'm certainly not criticizing that aspect of the installation. 

At some point I had to trust the designers more than the nay sayers.. 
Aye, but keep in mind that some of the nay sayers _are_ designers. I've been working with batteries and battery power for a long time, including looking at ways to do exactly what you're doing. For my purposes, the benefits never outweighed the work involved; the alternatives were always easier and just as effective. Yeah, you can do it, and it works. In my opinion, it's simply not worth the bother. 

Later, 

K


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## Totalwrecker (Feb 26, 2009)

Hi Kevin, 
Thanks for the reply. 
As my G $cale experience grew and evolved I realised I would never compete with the big boys and their expensive toys. I'm semi retired, tho I worked for a co. for 24 years, there's no pension or health plan... with the $melt down my work hours hit a wall from 40 to 14 and all my handy man jobs disappeared. 
Simple R/C w/ 2 stick controllers fit my budget and canned sound... I can solder a neat joint, but have very little understanding of how it works. 
Presently my great nephews prefer running Jupiter around the loop on track power, I think they'll want to join me on the "foggy side" and run on the new track w/ R/C. I plan on keeping that option alive with her and have bashed a tank car for batteries and electronics. 

Sayers of nay.... I read most of the threads and have seen designers disagree.... just as there are many opinions.... but my only reason for writing was to say I'm doing it and it does work, for me, it's just what I wanted. For that I get essays why I'm .... 

It's hard and awkward for me to carry the locos in and out to run, the less I need to handle them the longer the details last... 

I am very sorry for any negativity my participation might have caused. 

Tony I don't really think I won your jest Too easy to limit it to the posts that didn't say that.... I ain't no hick at the country fair! lol 

Be Well, 
John


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## pcz (May 13, 2010)

"My first idea was to use track power and battery as backup recharged automatically. 
Tony told me on K-27 rcs is not able to use track power as "main power" and to recharge batteries while loco is runnig, no problem"

Tony told me it's not possible because system I bought from him doesn't support (...it was not created to...) recharging batteries form tracks while train is runnig... He never told me it's not possible because the idea doesn't work!

Tony: I'm sorry for problems I gave you with this my topic. From today I'll read arguments as guest but I'll write on this no more.

Pier


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## Totalwrecker (Feb 26, 2009)

Pier, 
Please don't let our little tug of war deter you from posting. I apologise for my part and am sorry it was on your thread. 
Had you looked at the link I posted you could have done it with Tony's system and caused it no harm. 
I look forward to your posts, please don't hide. 

Your Friend, 
John


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## TonyWalsham (Jan 2, 2008)

JohnJ. 
If you are familiar with the Bachmann K-27 you would know that, unlike the AristoCraft socket wiring, it has an either or Track - Battery switch. 
The installation of the ESC is Plug'n'Play. 
If you would care to suggest a method of wiring the battery back up and provide an understandable wiring diagram that does not involve cutting any track pick up wires or tracks on the circuit pcb, I am sure Pier Carlo would be well pleased.


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## lownote (Jan 3, 2008)

I've also done this--my layout runs on DCC, but I have a few locos running on the old aristocraft 75 mhz. train engineer. I keep these around for kids. One of them is a 0-4-0 diesel that sits on a siding with track that does not get cleaned that often, and so I put a battery in it. The battery charges from the track, using the IP trains circuit, and the loco seamlessly switches to battery power if the track power is spotty. It works well for me, since the loco is stored outside, on the track, I don't have to fiddle with chargers or removable batteries. 

As Kevin mentioned, it made sense in this particular situation--I was already set up for track power, and just wanted to make the operation of a small loco with limited power pickup more reliable. This rig would work well with the aristo REVO, or with QSI/Gwire or Airwire using constant voltage DC.


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## Totalwrecker (Feb 26, 2009)

Tony, 
(I'm John not JohnJ)








I've never touched a Bachmann K let alone seen inside one, other than pics online. 

I did post a link (UPS) that does allow that operation. They have the circuitry, far beyond my skills. 

Please see Mr. Lownote's post, maybe you'll see I'm not a complete idiot.









Could a DPDT switch be incorporated after B'mann's switch? If so track power could be routed to the motor or the UPS. On my installation I gutted the board, as per this group's general recommendation, so those considerations didn't occur to me. I would think that you could figure it out far better than I!

Initially I tried to send the link directly, as I knew 'the firestorm a comin' , but his settings prevented that, so.... 

Can somebody please convince Pier to return and accept my apology for this mess? 

Sincerely, 
John


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## TonyWalsham (Jan 2, 2008)

Thanks for the correction John. 

As you have no knowledge of the Bachmann K-27 wiring, perhaps you will believe me when I tell you that what you are suggesting is not possible with a stock K-27 installation. 
It may be possible with gutting and rewiring, but that is not an option. 
Whilst your pet method is possible with some locos it is not really practical with the K-27.


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## pcz (May 13, 2010)

John, Tony,

I opened this subject not to create problems.

John, I visited your link because you suggested me a site exactly for my idea: I thank you for this.
I've studied the electrical diagram and texts but I'm not able to understand how it works in moment in which track power is low or zero and it backs-up motor with batteries.
And also, if the problem is: for batteries is not good a uncontinuous recharging, where is the electronic circuit able to recharge only when loco is stopped with a constant voltage?
I have only found 2 diodes, 1 resistor and 1 bridge rectifier... but where is the logical part to choose when batteries will be recharged or used as back-up? 

I understand uncontinuous chargement doesn't explode batteries or others, batteries will not good for 500+ recharging times, I'll have to change them before.

I'm the last arrived and I don 't want to create problems.
Ops... Sorry for my English, I don't want my Italic-English writing mode creates misunderstanding in people reading my posts.

Ciao a tutti.
Pier

P.S.: this week end, temperature was near 40°C (104°F) with a sunny day and 90% humidity... And it's not usual in North-West Italy: for my tests, I'll wait a cold day and I'll inform you about my tests.


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## Totalwrecker (Feb 26, 2009)

Pier. 
First I'm glad you didn't take Tony and my 'spat' personal. 

The system works by taking power from the stronger source, my track has 24v and my batteries are 16.8v. So while running on live track the power comes from the rails. Where I have 'dead' track the batteries take over. When running on track power the left over voltage supports recharging. You don't chose when, the system does, by the highest power available. The R/C controls the motor, so when stopped on live track, the batteries get charged from the track power.

On the matter of recharging cycles, since the batteries are never drained and recharged, rather are kept topped off or near full, they don't go through normal cycles. '500' times isn't necessarily an accurate way to measure this use. I think my suppliers have comparrable lifetimes with their batteries. Maybe longer as the running charge is but a fraction of a whole cycle. I wonder if an electrical engineer can comment on this? Because we (I) use track power our batteries sleep more than drain, thus increasing the lifetime in hours/days/years, not necessarily cycles. 

You are welcome here and you are in no way responsible for my 'contribution'. 
On my loco I was advised to gut the electronics, Tony pointed out that your loco doesn't require that and the Track/battery switch would need rewiring or something... while you wish to keep it stock (as bought). 

I'm glad you posted again, boys will be boys and we are passionate about our toys! 

John


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## TonyWalsham (Jan 2, 2008)

So John. 

If I may ask the following questions, would you kindly enlighten us as to: 

Are you saying you never ever need to clean the track? 
If no, how long does it take for the track to tarnish such that it will never ever be able to power the loco meaning the loco will only be running on battery power anyway? 
If yes, how often and how long does it take you to do so? 

Do you ever need to work on the track joints to maintain track conductivity throughout the track? 

How does the "system" cope with different battery chemistries such as Li-Ion when compared to the easy to monitor batteries such as NiCd? 
In other words, how does the "system" handle the requirement to monitor each Li-Ion cell in a pack? 

Does the maker provide loco and battery specific installation instructions?


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## East Broad Top (Dec 29, 2007)

Tony, I'm not going to speak for John, but in reading his responses to my posts, I think the answers to some of your questions can be extrapolated. 

In terms of track cleaning, he doesn't specifically answer that. From his description of his operating scheme, he may very well not be getting any kind of charge on the mainline, and may simply not know it just due to to the fact that his ops sessions are within the charge capacities of the full-charged Ni-MH batteries he's using. Having said that, he has other specifically track-powered loops, so I would expect track cleaning to be a periodic part of his periodic railroad maintenance anyway. If you have to do it for part of the railroad anyway, doing it for the rest isn't too big of an issue. You'll get no argument from _me_ that track cleaning is a hassle, but there are still many who enjoy such tortures.  (Or at least for whom it is an acceptable evil for the given return.) 

As for battery technology, that's a point I made early on, to which he merely responded that he didn't run Li-Ion. I can't speak to the specific products he's using, and whether they're able to take that into account. There are chargers on the market that can charge across technologies. The electronics to do so would have to be on-board, though, taking up space. I believe Rick Izzard (Cordless Renovations) makes a universal smart charger that's built into one of his battery-car boards. He'd have to speak to whether it's practical to operate that in an environment such as is being discussed here. Since I'm in the "why would you bother?" camp, it's not something I worry about. 

Later, 

K


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## lownote (Jan 3, 2008)

This is getting silly. For the system John is describing, and which I use in one loco, the track must be clean enough somewhere, and part of the time, for the battery to charge. But when the train with said charged battery is run over a section of track which has no power, the battery instantly kicks in. For example, one might have a track powered layout, but also have a section with no power--a reverse loop or wye, for example. In that case, rather than wiring relays or switches to manage the track polarity, one would simply let the loco run on batteries in that portion of the layout. 

The advantages? The advantages of track power, which in this case one already has, plus a simple way to manage a reverse loop or wye. It's not complicated to understand at all. And it does work. A second advantage would be if one had a layout where there were sometimes dirty track patches, as in, say, under a tree prone to shedding sap, the battery would also kick in, then cut out when normal track power resumes. 

Whether or not you or I think this is a good idea is another story. I can only say that it works as advertised. I won't be using it in the future, because I've gone to DCC.


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## East Broad Top (Dec 29, 2007)

A thought occurred to me while running errands today... For those of you running this system, do you match the track voltage to the battery voltage? I would think you'd have to lest you have a distinct jump in the locomotive's speed from when it enters and leaves the "dead" sections. For instance, if you've got 14.4 volts of batteries, and are running at 2/3 throttle, you're getting around 9 volts to the motor (or the PWM equivalent thereof). When you jump to powered track with something like 24 volts, you're now feeding 16 volts to the motor. That's a pretty substantial jump in speed. 

Later, 

K


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## lownote (Jan 3, 2008)

I have a 75 mhz TE decoder in the one I have set up this way, and it stays at whatever speed I set the TE to


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## Greg Elmassian (Jan 3, 2008)

Kevin: 

You apply "charging" power to the batteries, not the motor! 

Raising the charge level does not automatically bypass your motor control electronics! 

Otherwise all battery operated locos would run at full tilt all the time! 

To repeat: you would feed constant "charging voltage" to the batteries, irrespective of what speed you were running. 

Since the track voltage would be held constant, there would be no jumping! 

I'm not sure you got this idea, maybe you were thinking that the rails go directly to the battery? 

For this to work well, you need some kind of "charging circuit" to make this work well, if it's nothing but a regulator. (I'd balk at just a current limiting resistor, but it has been done). 

For example: 

You pick your battery packs so that they will just go to trickle charge at X volts... 
then you set up a regulator to supply that voltage... 
now you supply enough voltage on the rails for the regulator to operate, usually 2 to 4 volts above the regulated voltage. 

This can work. 

Does it give you optimal battery life... not really, but realize that by supplementing the battery with track power, you will also have fewer charge/discharge cycles, so the battery will last longer in that respect. 

I would think using all the same packs and getting pretty accurate on the terminal charging voltage required, and using only nicads, you could make this work pretty well. 

You can't use a "smart charger" pretty much because the microprocessor will reset with each power interruption. 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

Lownote. 
Unless there is some super smart electronics in the charge circuit the track voltage *MUST* be higher than the battery voltage otherwise the battery will not charge. 
That is the whole point. 
There will be a (lower) speed differential when battery power kicks in over track power. There has to be although it may only be slight. 
The trick is on how the charge voltage is actually regulated. There is no one size fits all. Some batteries such as Li-Ion require very sophisticated circuits to control the charge of each individual cell. All of which must be carried on board the loco. 

I keep saying, Yes I know it can be done. Just that the basic circuit touted will not provide adequate control over batteries other than what the particular values are set for in a given loco. Batteries with different voltages and chemistry will require specific values and circuitry. Something I have yet to see addressed by John. 

My guess is that you do not see any change in the loco speed because the loco never actually drops into battery only. This is likely as the track is constantly powered and clean for your track powered DCC control system.


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## East Broad Top (Dec 29, 2007)

To repeat: you would feed constant "charging voltage" to the batteries, irrespective of what speed you were running. Since the track voltage would be held constant, there would be no jumping! I'm not sure you got this idea, maybe you were thinking that the rails go directly to the battery? 

For this to work well, you need some kind of "charging circuit" to make this work well, if it's nothing but a regulator. (I'd balk at just a current limiting resistor, but it has been done). 


Greg, you're misunderstanding my question. I know you would limit the voltage going to the batteries via some sort of charging circuit. My question is what happens when you "switch off the mains, and go to battery?" If your live track is at 24 volts, your ESC is getting 24 volts. The voltage available to the motor runs from 0 to 24 volts. When you lose contact with the track power and run off of batteries, your maximum voltage available to the ESC drops to whatever your batteries can deliver. Consequently, the speed at which the train is running will drop proportionally to the difference between the track and battery voltages. The greater the difference, the greater the resulting change in speed. 

Hence my questions as to whether those who run with this kind of system need to match the track voltage to the battery voltage. Not running in this environment, I don't know how noticeable the difference would be on something like moderately dirty track where power is lost just periodically or even momentarily. Perhaps it's not all that noticeable. On the other hand, if you're running in an environment such as John's where you've got long stretches of "dead" track, I would think if the voltage feeding from the rails is substantially higher than the voltage coming from the batteries, you'll definitely notice a change in speed as it transitions from one to the other. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

You have dropped the statement: 

" For instance, if you've got 14.4 volts of batteries, and are running at 2/3 throttle, you're getting around 9 volts to the motor (or the PWM equivalent thereof). When you jump to powered track with something like 24 volts, you're now feeding 16 volts to the motor. That's a pretty substantial jump in speed. " 

That was kind of "whacked out" because it assumed you fed power directly from the rails to the battery and also the ESC with no control on the voltage which would be ridiculous. Kind of like plugging your loco batteries into the wall outlet.


OK, I'm making the assumption that you do not have 24 volts charging an 18 volt battery, for example. 

(you could do this, but then it would obviously give you very inconsistent operation... so I discounted that right off the bat... maybe this is the situation you are asking about... I think it's unacceptable... and that's probably why many people don't like this idea) 


My opinion is that I would not want a system that had huge differences in voltage from the batteries vs. the track powered areas. You could to this to try to increase the recharging rate, but then you need a bigger difference between the track power and the battery, and more difficult, a charger that can handle this and not freak out (read: microprocessor reset) if power is interrupted. Really, not practical in my experience.


So, proceeding from here, assume that your charging voltage should be only slightly greater than the voltage from the batteries to make this relatively seamless... 

That also affects how fast you can charge to a degree... but the idea was to extend run time and handle brief interruptions, so the idea holds water. 

The bottom line here what are you asking for? 

If you look at it in terms of percentages, like the loco can get track power 80% of the time, I think it will work reasonably well. 

If you get down to 1/2 the time, than the track power is just helping extend the battery life, and it's likely that no significant charging will occur. 

Bottom line, it seems like a lot of work to go through to get not a lot back in performance. 

So, professionals like Tony will say, forget it. I understand that and respect it from the point of view that a person who runs a business needs to focus on things that work well and universally for people. 

Can an individual make this work... sure... how effectively? That depends on the "Tuning" of voltages, battery packs, percentage of "live" track, type of "Charging circuit" etc. 

I'm not trying to talk anyone out of it, but to me, it seems like too little in return for the effort expended unless you only had a few locos and closely matched batteries and controllers. 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

Don't get me wrong. 
I am not saying it cannot be done. 
From my testing 20 years ago using the system I discovered that there needed to be at least 4 volts overhead to get about 100 ma charge current into Sub C NiCd's. 
Greg's estimate of around 80% charge time is pretty accurate. After that as Greg says , all you are doing is extending a battery run time. To achieve that you end up with a much more complicated installation. 
Given the specifics are correct for the particular loco, battery and track voltage then it will work. More or less. 
There are much simpler ways of extending battery run times. 

Unfortunately one size does not fit all. 
What we are not getting from the supporters of this system are specifics on how it will work in certain, and increasingly popular, installations such as Li-Ion.


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## TonyWalsham (Jan 2, 2008)

Sorry about the double post.
I have no idea how I did that.


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## Greg Elmassian (Jan 3, 2008)

Trying this technique in li-ion would worry me, because of the very rudimentary charging systems typically used. 

Li-ions need a microprocessor controlled charger. Constantly resetting the charger could easily lead to overcharging (it takes a while for the charger to determine the needed charging rate and condition of charge). 

I would not recommend li-ions in this application, only nicads and perhaps lead acid. 

Regards, Greg


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## East Broad Top (Dec 29, 2007)

You have dropped the statement: 
" For instance, if you've got 14.4 volts of batteries, and are running at 2/3 throttle, you're getting around 9 volts to the motor (or the PWM equivalent thereof). When you jump to powered track with something like 24 volts, you're now feeding 16 volts to the motor. That's a pretty substantial jump in speed. " That was kind of "whacked out" because it assumed you fed power directly from the rails to the battery and also the ESC with no control on the voltage which would be ridiculous. Kind of like plugging your loco batteries into the wall outlet. 
I'm not addressing the circuit charging the battery at all. I'm presuming the electronics involved in charging the batteries would be kosher, and not fry them in the process. I'm talking specifically about the voltage going to the ESC. If you have an ESC being fed with 24 volts, then all of a sudden switch the supply voltage to 14 volts, the train's gonna slow down. My question to the two gentlemen in this discussion who are actually using such a hybrid system is relative to how they deal with that. Are they required to closely match the two voltages, so that there's enough power to charge the battery, but keep the speeds fairly constant when going between "live" and "dead" track; or is the difference in speed in reality not all that noticeable to where you can have a modest difference in voltage between the two sources without ill effects? 

Later, 

K


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## lownote (Jan 3, 2008)

I'm not "a supporter" of this system. I just tried it in one loco that runs in an unusual place on our layout. It has the battery I got from IP Trains--I forget what kind of battery it is. I've done no investigation of whether other types of battery would work, especially since the battery replaces the weight in this little 0-4-0 and I don't want a light battery. The loco has a decoder in it. I rarely if ever have the thing running at full speed--it'd fly off the rails--and so when it switches from track power (21 volts) to battery I don't see any speed difference. If I was running a long train full out yes, I'd see a difference. 

I'm not really interested in efficient battery management for this application, since the battery is rarely called into use. It's mostly used to smooth operation on a siding that rarely gets used, except when kids come by. The way I use it it functions like a UPS system for electrical power, or like a bank of capacitors. Since the layout is DCC, and the battery backup won't work on DCC, it's of limited utility and I have not investigated it further


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## Greg Elmassian (Jan 3, 2008)

You really don't get it or don't want to.

THE POWER FROM THE TRACK WOULD NEVER BE DIRECTLY CONNECTED TO THE BATTERY, SO WHAT YOU ARE SAYING ABOUT JUMPING IN VOLTAGE WOULD NOT HAPPEN. THE DIFFERENCE IN VOLTAGE TO THE ESC WOULD BE BETWEEN THE BATTERY VOLTAGE AND THE CHARGING VOLTAGE.


I've been talking about how to do it that could work, and the limitations. You can try all kinds of tricks, but you cannot get away from the fact that you cannot fast charge the batteries without making the charge voltage much higher than the battery voltage, and then get different voltages that would affect running. I already stated that I ignored that situation because it would not work well. See below.


This is what you apparently did not read (again):

OK, I'm making the assumption that you do not have 24 volts charging an 18 volt battery, for example. 

(you could do this, but then it would obviously give you very inconsistent operation... so I discounted that right off the bat... maybe this is the situation you are asking about... I think it's unacceptable... and that's probably why many people don't like this idea) 


I already said it was a bad idea... you apparently want to keep asking about it... forget it... it's a bad idea... please read this sentence over and over and stop asking about a situation that does not work well. If someone wants to use it that way, and they are happy with how it operates, then leave them alone.

To be clear... keep the charging voltage close to the battery voltage for consistent operation, which has the downside of slow charging. Then there is very little difference to the voltage supplied to the ESC, and thus very little effect on the speed as you go from live to dead track and vice versa.


Greg


Posted By East Broad Top on 02 Aug 2010 11:25 PM 
You have dropped the statement: 
" For instance, if you've got 14.4 volts of batteries, and are running at 2/3 throttle, you're getting around 9 volts to the motor (or the PWM equivalent thereof). When you jump to powered track with something like 24 volts, you're now feeding 16 volts to the motor. That's a pretty substantial jump in speed. " That was kind of "whacked out" because it assumed you fed power directly from the rails to the battery and also the ESC with no control on the voltage which would be ridiculous. Kind of like plugging your loco batteries into the wall outlet. 
I'm not addressing the circuit charging the battery at all. I'm presuming the electronics involved in charging the batteries would be kosher, and not fry them in the process. I'm talking specifically about the voltage going to the ESC. If you have an ESC being fed with 24 volts, then all of a sudden switch the supply voltage to 14 volts, the train's gonna slow down. My question to the two gentlemen in this discussion who are actually using such a hybrid system is relative to how they deal with that. Are they required to closely match the two voltages, so that there's enough power to charge the battery, but keep the speeds fairly constant when going between "live" and "dead" track; or is the difference in speed in reality not all that noticeable to where you can have a modest difference in voltage between the two sources without ill effects? 

Later, 

K


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## Totalwrecker (Feb 26, 2009)

Posted By TonyWalsham on 02 Aug 2010 07:05 AM 
So John. 

If I may ask the following questions, would you kindly enlighten us as to: 

Are you saying you never ever need to clean the track? 
If no, how long does it take for the track to tarnish such that it will never ever be able to power the loco meaning the loco will only be running on battery power anyway? 
If yes, how often and how long does it take you to do so? 

Do you ever need to work on the track joints to maintain track conductivity throughout the track? 

How does the "system" cope with different battery chemistries such as Li-Ion when compared to the easy to monitor batteries such as NiCd? 
In other words, how does the "system" handle the requirement to monitor each Li-Ion cell in a pack? 

Does the maker provide loco and battery specific installation instructions? 

---------------------------------------------------------------------------------------------------------------------


Sorry had to work yesterday and didn't get back to answer.
1. I run on Stainless and only run the AC cleaner car once around to remove bumps, grit, no tarnish ever! That's pre-run maintenance done no matter what power is used. I also clean switch frogs and clearances.


2. I torqued the screws in the track joiners down real tight 4-5 years ago and have no conductivity problems since.

3. I don't have a clue about other chemistries as I use what was sold with the circuit. What Li-Ons? I don't need a more expensive battery with super run times, as I never drain my batteries.


4. No specfics at the time of purchase. That was before plug n play became reliable (I think).

K; Does a RSC deliver a ratio of available power or a voltage? You wat it to be a ratio, I think, where as from operation it appears to send a voltage. I hope this clears that up.

Facts; 2/3 of track is live. The other 1/3 does not see 1/3 of train time.
I use 16.8 NiMh AAA rechargables.
Track is 24v. Power is rectified for polarity. System needed; 24v on rails and 16.8 in batteries.

I am only a consumer, I gave the link. I offered an option, never intended a war of words.. I certainly didn't expect it to be taken personally. It could be done in a K, but not with added on restrictions and insulting examples based on those... yeah I read. And you really don't need Li-Ons so why bring those up? The batteries cover the gaps and are NOT the main source, so they can be somewhat ordinary. 

Or are you looking for ways to defeat it? 

It sure is silly. why should I need defend it? I just am happy using it.

OK?

John


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## Totalwrecker (Feb 26, 2009)

"How does the "system" cope with different battery chemistries such as Li-Ion when compared to the easy to monitor batteries such as NiCd? 
In other words, how does the "system" handle the requirement to monitor each Li-Ion cell in a pack?? 

Gentlemen. To grasp this idea you need to change your thinking from Pure battery to track power w/augmentation. You seem to be more concerned with run times and newer chemistries as befits the Dark side, here on my island, it's the Foggy side! I take advantage of the best of both worlds. (best to me is cheap and good enough). No need to monitor... KISS..keep it simple sonny/sister... It works fine as is, designed for the chemistry it uses. 

Should Ma nature conspire and turn off the mains I'll still have plenty of power to run for cover! Park the trains and enjoy the show. 

John


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## East Broad Top (Dec 29, 2007)

Greg, somehow you seem to be completely misunderstanding my posts. First off, if you've read my earlier posts, you'd know I wholeheartedly agree with you that it's a not exactly my idea of a workable solution. I've thought that from the mid-80s when we were still using lead-acid motorcycle batteries to power our trains. Perhaps you missed my "you could, but why would you want to?" or "in my opinion, it's simply not worth the bother." Trust me, we're very much on the same page here. 

SO WHAT YOU ARE SAYING ABOUT JUMPING IN VOLTAGE WOULD NOT HAPPEN. THE DIFFERENCE IN VOLTAGE TO THE ESC WOULD BE BETWEEN THE BATTERY VOLTAGE AND THE CHARGING VOLTAGE. 
Okay, I see what you're saying. Everything would be in series; the track voltage input goes to the charging circuit _then_ to the ESC. The charging circuit plays the role of voltage regulator, eliminating the gap between track and battery voltages. That's one way to skin the proverbial cat. 

On the other hand, you could have a parallel circuit, where the track power goes to both the ESC and the battery charging circuit. Technically, the track power would be fed into a comparitor circuit along with the battery power, and the output of that comparitor would feed the ESC. In that scenario, you could have quite a discrepancy in the voltages. A circuit like this would isolate the charging circuit from needing to handle the high current the motor would draw. It would also allow for greater speeds under track power should the user desire. There are lots of reasons not to limit the power to the ESC, especially if this system is designed solely as a back-up for very intermittent power loss. 

I don't know specifically how the systems Mike or John use operate, hence my question to them as to whether this is an issue. If the electronics take care of things, then great. In either case, the "idea" solution seems to be to make sure your track voltage is close to your battery voltage by managing it at the source. Otherwise you're wasting a lot of energy through an on-board voltage regulator (lots of heat in an enclosed space), or dealing with the potential for speed shifts. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

Now you have it. Your "series" is what I have been saying, you would NEVER feed unconditioned track power into the battery, it has to be regulated somehow. 

(You could put 12 volts on the rails for a 18 volt battery, but then that would do nothing to charge the battery, and you would get radical speed variations when running from live to dead, another unacceptable solution in my opinion) 

The "parallel" idea "comparitor" or not would be just as above... you could just use a couple of diodes to isolate the battery from the track, but now you are switching voltages AND not charging the battery. That's from bad to worse. 

When you start looking at this idea closely, it has a number of limitations, as I see you comprehend. 

If I was to do this, what I would do is build a custom charger, a microprocessor controlled charger, but add in code (programming) to allow it to "remember" the charging rate and setup, and be able to "resume" and "interrupt" charging. Then I'd run the rails at a voltage (and obviously current) high enough to do fast charging. Then you could use smaller batteries and charge the **** out of them when there is track power. 

You would then have a nice setup, but I have not seen anyone develop such a charger. A charger like this would probably sell for $150 each if they were made in reasonable quantities. The Maha is $100 and they have sold millions. 

Gets impractical pretty quickly. 

I'd go track power if you need the running time/capacity. Making a reliable track powered layout is not impossible. If you don't need track power, a good battery installation with quality components will serve you, and maybe you can make it easy to swap packs. 

This hybrid approach is "tweaky". 

Greg


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## TonyWalsham (Jan 2, 2008)

My experience, for what it is worth, after testing these ideas over 20 years ago is this: 

At about 4 volts over the nominal battery voltage the charge rate is around 100 ma. Barely enough to make a dent on any battery. Any greater voltage and the transition "jump" is more plainly obvious. 

I discovered that it takes about 80% of continuous power to keep a NiCd battery pack charged using track voltage. You might as well simply have track power with the effort, or cost in terms of Stainless Steel track, that is required to maintain that much conductivity. 
Any less % and the exercise becomes pointless. 

It would be much simpler to have just a back up battery to take over when dirty track is encountered. 
Charging that back up battery is where the whole idea becomes "iffy". It does work for particular batteries at particular voltages. 
NiCd's should be OK as they can handle high voltages as long as the current is limited. 
Lead Acid batteries require regulated current as well as voltage, so in my opinion they are out. 
NiMh do not like overcharging even when being trickle charged, so there would have to be some sort of charge limiter kick in when the battery was "full" . 
Like wise Li-Ion must have individual cell monitoring so they are out too. 
That leaves NiCd and they will be banned sooner rather than later anyway. 
Like it or not. Li-Ion (or perhaps Li-Pol) will be the battery of choice eventually.

The simplest, and by far the least expensive, way to to extend run times is a simple circuit that allows the charge jack to do two things. 
1. Charge the batteries. 
2. Double as an access port for extra auxiliary batteries carried in a trail car.


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## Greg Elmassian (Jan 3, 2008)

I have a lot of rechargeable batteries. Nicads are 1.2 volts nominal, I charged them at 1.4 each and got a fairly quick charge to 80-90% capacity. 

For 12 cells, 14.4 volts, then I would charge at 16.8 and get plenty of current IF the batteries are depleted. 

So I have not found I need 4 volts but more like 2.4 volts... that's more manageable, so it CAN work if you tune everything well. 

so a difference of 2.5 volts between "dead" and "live" track would not make the speed of the loco jump too bad. 

Now you need to add the voltage drop of a full wave bridge from the track inputs, and then some regulation, and it would have to be exact and tuned to that battery pack to work. Over time, the terminal voltage on nicads changes (for full charge), so that would have to be accounted for. 

To do it cheaply you would need a regulator settable to about 0.01 volts precision and then "calibrate" it to the particular battery pack. 

I've done this over the years, with the terminal charge voltage on a sticker on each battery pack. It works, but if you are off, then you can seriously overcharge the battery, just off by a few hundredths of a volt. 

So, it's not easy, and you get right back to what Tony said, if you have 80% track power, why not complete the other 20% or just use more/bigger batteries. 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

High Greg. 

The 4 volts overhead was required because of the bridge rectifier and steering diodes needed to isolate the batteries from the track voltage. I was using regular silicone diodes but Schottky diodes would of course reduce the voltage overhead needed.


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## Greg Elmassian (Jan 3, 2008)

Got it, sorry I misunderstood. 

Interestingly, there was a move to Schottky diodes in decoders and then back away. In some decoders the extra resistance of the normal silicon diodes was preferable because it limited the inrush to the "hold up" capacitors on sound boards. Early DCC would trip on the momentary surge of charging these capacitors on sound decoders. (most people don't worry about hold-up on motor only ones). (except the revulsion system, it needs a whole bank). 

Regards, Greg


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