A 5 volt Model Railway

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zebedeesknees
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A 5 volt Model Railway

Postby zebedeesknees » Thu Oct 29, 2020 7:50 pm

Those who think that CSBs are a step too far, may not expect to see any of this in the Snews...

It seems to me to be a logical progression from radio control and single battery cells, given the ubiquitousness of 5 volt USB chargers for smartphones, smartwatches, iPads, MP3/4 players, remote speakers and now even AA cells, that model railways could go to 5 volt supplies.

The Li-Po batteries in most of these desirables now have sophisticated control/protection circuits built in, so that without any more components they can be left on charge from a USB port overnight, or for even longer. Further, the item can be left 'on' indefinitely to the point that the control circuit shuts the supply down before the battery is damaged or the house burns down. They are available in a surprising range of sizes, both physical and capacity, to suit any tank, tender or fuel tank one may wish to fit.

The question that has been an issue for some time has been how to charge a battery that is inside a loco. Any method that involves handling the model is clearly inhibiting, so the advantage of the common and traditional pickups from the rails via the wheels is obvious. So I choose to keep them.

Traditionally, our tracks have a varying up to 12 volts DC across them according to the desired speed of the loco, the polarity reversing according to the desired direction of travel. The somewhat less traditional DCC system requires around 16 volts AC across the tracks constantly. Both rely on a consistent quality of current collection to maintain smooth running, or extra components in each loco to compensate for interruptions in the collection, but neither cope with short circuits across the tracks particularly successfully.

That is because until recent advances in technology, much more powerful magnets especially, DC motors could not be made small enough or sufficiently powerful at the size needed to fit inside our models if supplied at a lower pressure. The reason that DCC requires a higher voltage to drive 12 volt motors is because of losses in the rectification to DC and control systems used.

There's an old joke that ends with "Well, I wouldn't start from here!"

Starting with the Li-Po battery, a single cell - called 1S, has a nominal output voltage of 3.7 volts. This clearly requires a motor which provides sufficient torque at that voltage, to drive a loco in a manner similar to the 12 volt motors that we are used to. There is a large range of motors now available that are suitable.

So, a battery, the radio receiver - equivalent to a DCC chip - is all that is needed in the loco, or tender if it has one.

A minor difficulty here is that the USB supply is DC, and so is the battery and receiver, so the loco could only be run one way round, or the supply would need to be changed with a reversing DPDT switch. But that would only be required when the loco is on a charging track. The rest of the time, the loco would not need to pick up current as the battery supplies this, a sort of inverse of the 'stay alive' concept.

On the other hand, only one extra component - a bridge rectifier - would be needed in each loco to correct the polarity so that it wouldn't matter which way round either the loco or the track polarity was.

Pros:- Only charging tracks need be wired. These could be adjacent to water columns or in shed areas, or even either side of water troughs, how often do we see those modelled? Or more modern, by diesel fuelling points. Shades of getting it all right!

Pointwork need not be wired at all.

Running the wrong way into a point set against would not cause a short with a rectifier fitted to the loco, as this prevents current flowing from the pickups back to the track.

Stock works perfectly well on rusty sidings as the rails need not supply current. No more painful track cleaning except on the few, straight, charging tracks.

Cons:-

Existing locos with 12 volt motors can still be accommodated by adding just one more component, a voltage booster between the battery and the receiver. The Pololu U3V12F12 is tiny, costs around $4 U.S. and can supply over 1A. There are a number of alternatives, many of them with adjustable output voltages on eBay. These are a bit larger and the ones I have can supply up to 2A, though this is rarely needed in 4mm scale.

If the track is normally supplied with 12 volts DC or 16 volts AC, a couple more, still small, components may be required for radio control. After the rectifier,a voltage regulator, and there are now much smaller ones available than that I used in the 14xx, to provide 5 volts for a 1S battery, and then a booster if the motor is still a 12 volt one.

I currently have three locos running on USB supply, the Simplex in my S4-9? topic, the WD 2-8-0 that I demonstrated at CHEAG before the C19 interruption, and a Collett Goods with High Level running gear. The WD retains the Bachmann pickups and motor, but now has a new 850mAh battery in the tender. The Collett is pure 5 volt, with experimentally a pair of 200mAh batteries wired in parallel in the tender, and an FF-130 motor on a High Level 40:1 'box. Even with the added traction of a CSB chassis, it spins the wheels freely against the buffer stops. There will be a 30:1 'box in the next one.

DSCF0007.JPG


This is the Collett tender chassis. Pickups are 33swg p/b, arranged as stylus at the ends as I find that this keeps the wheel treads clean. A bridge rectifier is fitted to the small piece of stripboard. The receiver is slotted into a piece of unshrunk shrink-wrap glued to the lead weight.

Ted.
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Horsetan
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Re: A 5 volt Model Railway

Postby Horsetan » Thu Oct 29, 2020 11:32 pm

I remember that 5v was the supply for TTL logic circuits....
That would be an ecumenical matter.

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zebedeesknees
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Re: A 5 volt Model Railway

Postby zebedeesknees » Fri Oct 30, 2020 12:30 pm

Horsetan wrote:I remember that 5v was the supply for TTL logic circuits....

Now why would you remember that Ivan? (rhet) You are right of course, and thanks for the idea. The original TTL was going out of fashion when I joined that industry, trouble shooting it was a pain as a faulty input could pull down a correct logical 'high' output. When I started in 1979 my employers had already moved into 4000 series CMOS at (ironically!) 12 volts. Much lower current, huge fan-out, but very static-sensitive. Now the later TTLS (Transistor-Transistor Logic Schottky) gives the best of both at 5 volts. Hmmmm, I wonder how I could use that in models... The Schottky part is key to the 5 volt railway though, but in the bridge rectifier. There is a small CIG on emails who are aware of this already, along with a lot of other R&D concerning batteries, receivers and motors, but there seems little point in sharing it on here, boring and frightening members, halloween notwithstanding!

Ted.
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JackBlack
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Re: A 5 volt Model Railway

Postby JackBlack » Fri Oct 30, 2020 3:47 pm

Excellent work Ted! You might even have persuaded me to consider fitting pick-ups, since you what you've developed requires neither charging socket or switch.

Where can I get some of those tiny bridge rectifiers from?

Lots to think about..


Nick Allport
CLAG


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zebedeesknees
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Re: A 5 volt Model Railway

Postby zebedeesknees » Fri Oct 30, 2020 4:39 pm

JackBlack wrote:Excellent work Ted! You might even have persuaded me to consider fitting pick-ups, since you what you've developed requires neither charging socket or switch.

Where can I get some of those tiny bridge rectifiers from?

Lots to think about..

Thanks Nick, I found the Schottky bridge rectifiers on eBay UK after trying to get them from RS Comp, who wanted me to order at least 50, but then didn't have them in stock for two consecutive months! They are 'Comchip CDBHD140L-G Schottky Diode 1A 40V TO-269AA 5 Pieces OMB1-16' They came from a dealer called 'breconjess' in Wales at £3.99 for five. And free delivery from Caerphilly. I ordered 30, which brought the price down to £3.39 for five.... They are marked 'MDS14L'.

Importantly, they are quoted as having a forward volt drop of 0.45v or thereabouts, but in testing it has been more like 0.3v. The point here is that the Li-Po batteries need at least 4.3v to charge fully, and non-Schottky bridges drop over one volt forward, so will not charge the battery properly if at all from a 5 volt USB supply.

Cheers!
Ted.
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JackBlack
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Re: A 5 volt Model Railway

Postby JackBlack » Fri Oct 30, 2020 5:35 pm

Great, thank you! I've ordered 10. I'll be in touch on how to fit them...

Cheers, Nick


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zebedeesknees
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Re: A 5 volt Model Railway

Postby zebedeesknees » Fri Oct 30, 2020 5:40 pm

JackBlack wrote: You might even have persuaded me to consider fitting pick-ups, since you what you've developed requires neither charging socket or switch.


More pros, the pickups won't need to be ultra-reliable like 'live' ones, just one wheel each side will do. It would be preferable in this case to be able to monitor the charge current with an ammeter between the USB supply and the charging track. This will only need to be on the ! Amp setting with the batteries I have tested, the 850mAh one in the WD drawing only 360mA peak from fully discharged. That dropped to 240mA after around a minute.

And.. with USB chargers all over the place, each individual, unconnected charging track could have a separate supply, handy if there is a mains socket nearby. It wouldn't even matter which way round the polarity was wired with those Schottky rectifiers installed.

Yet another pro, the chassis can be connected to one side of the circuit in the loco, saving on wires inside, especially where features from the receiver like directional llighting are installed. Since only the circuit between the receiver and the motor are bi-directional, two locos touching wouild not cause a short unless they were on the same charging track and wired opposite poles to the chassis.

I'm sure there's more...

Ted.
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Will L
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Re: A 5 volt Model Railway

Postby Will L » Fri Oct 30, 2020 7:34 pm

If only we could all start again, given where electronics has gone, I'm sure 5 volt battery powered radio control would just be the natural way to go. If Only.

I've thought for a while that charging through the wheels on dedicated section of track made most seance than all those plugs and switched. I do wonder why you've moved away from wireless charging?

I suspect that when a loco is on a charging point it should show its status, e.g. a red LED if its changing and an yellow if the battery is full? For steam outline you could put it in the firebox!

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Re: A 5 volt Model Railway

Postby Horsetan » Sat Oct 31, 2020 5:05 pm

Will L wrote:....I suspect that when a loco is on a charging point it should show its status, e.g. a red LED if its changing and an yellow if the battery is full?....


You've reminded me of the Drumm battery railcars that saw service on the Dublin & South Eastern route
That would be an ecumenical matter.

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Re: A 5 volt Model Railway

Postby zebedeesknees » Sat Oct 31, 2020 6:01 pm

Will L wrote:If only we could all start again, given where electronics has gone, I'm sure 5 volt battery powered radio control would just be the natural way to go. If Only.

But Will, surely the same could have been said - and was on E4um - about CSBs a decade ago! (Don't mention the editor, Basil..) And the same with EM and 18.83 around a half century ago. But there is a difference between them, the gauge wars were about 'instead of' whereas CSBs are 'as well as'. The transition can be as piecemeal as the modeller desires.

The same applies here with 5 volt railways; I have been playing around with radio control for years, initially picking up 12 volts from the track and driving 12 volt motors. I found that a big capacitor after the rectifier helped, but still not reliable enough. Nor is there enough space for a really big 16 volt Cap. Then I tried batteries, in series, with a special multiple charging circuit board. Only enough space for those in a big diesel with the weight mostly cut away and Penbits bogies to maintain the drawbar pull. Then I discovered boosters. Now I could do away with pickups, and charge a single Li-Po battery from an induction coil in the track. There was still the need of space for the induction coil and associated pcb, plus a battery controller pcb, and the booster, but space was less tight, so I might even get all that lot into a tender! But a 14xx...Nah. Or alternatively keep the pickups, fit a rectifier and 5 volt regulator to charge the battery that way.

It is the progress of battery development that has brought the biggest change. That tiny battery in the pic of my Simplex has the control and protection circuits inside the battery case! Plus it gives full current at 60mA for an hour. Other battery sizes and capacities are available - see https://www.aliexpress.com/store/3567048 and hover over 'batteries' on the banner and click on 'lithium battery' on the column that appears. You may have to scroll down to get the images to appear. There are 7 pages, 234 items, surely a size to suit you Sir! Other sources are available...

Back to the point - if you are running a traditional layout, with 12 volt locos and a 12 volt reversible controller, you can only run one loco at a time on the track you are driving, (yeah, there's double heading) and only in one direction at a time. But, with a radio controlled loco as well, wired with options above, that one can be driven independently in either direction on the same track, as a banker for example. And for the modeller, the start of the learning curve.

Or if you have DCC, you already have those options, but perhaps given the investment you will be more reluctant to consider an alternative.

There is currently a minor problem with DT receivers that need more than 6 volts; details here:- http://www.micronradiocontrol.co.uk/rc_rail_status.html I'm not sure if the Protocab receivers use the same chip, but they are in stock according to their website. They have an on-board 12v booster which my be helpful to those keeping their 12 volt motors.
I've thought for a while that charging through the wheels on dedicated section of track made most seance than all those plugs and switched. I do wonder why you've moved away from wireless charging?

I haven't, they have moved away from me! Actually, I have more than enough transmitters and receivers in stock, and found out when CLAG was contacted by a modeller in the States for purchase details that they are no longer available. The page has been withdrawn from eBay, and I couldn't find an alternative small enough to fit between the rails. Another issue that draws me to the pickup method is the space required for the induction pcb, and then the current supplied when the coils are as close as is reasonable, is not more than 150mA. This is fine for a battery of 60mAh, but the 850mAh one draws 200mA continuously for a couple of hours, so it would either damage the induction receiver pcb or take days to charge. It's fine for the Husky, as that has a small battery and the wheels are too exposed for pickups not to be obvious. Split axles definitely not an option.
I suspect that when a loco is on a charging point it should show its status, e.g. a red LED if its changing and an yellow if the battery is full?

I've been down that road Will. There are 3 or 4 different versions of chargers that do this on my bench. The smallest is 18mm diameter and 2mm thick, needing soldered connections. Those with USB sockets have a profile similar to the entire Simplex and are half as thick as the loco. Fitting one of any kind to a loco needs the space and is unnecessary, when one fitted to the supply to the charging track will do the same job for all, but - they are really designed for 'bare cells', which are not for us. As I mentioned earlier, an ammeter will show when a battery is drawing current, or has ceased drawing current from the charging track, and it is useful for other things. Another point, the battery rarely needs to be full. A feature of these batteries is that they provide sufficient current to run a loco normally until the minute they turn off. A quick top-up at the water crane, or a visit to the shed will keep them running for longer than the distance between fiddle yards. All the straight track can be left live at 5 volts if such a thing is a concern.

The USB supply to the track, each loco with a basic pickup arrangement, Schottky rectifier, a 1S battery, receiver and a 6 volt motor coincides with a philosophy I like. That is, getting it to work then throwing away all the bits not really needed.
For steam outline you could put it in the firebox!

If there's room for the charger pcb, and the LED can be lined up, yes. Or an optical fibre between the LED and the firebox door.. The LEDs on the pcbs are so small there's no chance of getting one off with the pcb or even the LED still working afterwards. The DT receivers however do have a status LED, and an output for a remote repeater of it. This can be any colour of our choice, and is on steady while the receiver is connected to the Transmitter. It gives single flashes if no Tx is active, double ones if one is active but driving another loco, and a five flash sequence if it detects a low voltage in the supply. Trickier wiring if the receiver is in the tender of course.

Ted.
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Re: A 5 volt Model Railway

Postby zebedeesknees » Wed Nov 04, 2020 11:09 am

Horsetan wrote:I remember that 5v was the supply for TTL logic circuits....

Another thought on that subject - turntables. There are a number of 5 volt motors with gearboxes on eBay, and the control logic of those with pushbuttons could be effected with 5 volt TTLS logic chips. Alternatively, a radio receiver could be fitted to drive the 'table manually. Another advantage with radio controlled locos is that the track on the 'table wouldn't need to be powered at all, solving a somewhat tricky problem there.
Thanks again Ivan!

Ted.
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Re: A 5 volt Model Railway

Postby hollybeau » Mon Nov 08, 2021 6:45 pm

I realise that it has been a year since the last post on here but I have only just discovered it so apologies. I hope someone is still monitoring.
I have been tasked with investigating, on behalf of my local club, the possibilities of "converting" conventional analogue (12 volt motored) locos to radio control. If successful there will be around 20 locos to convert but the first one will of course be the one where most lessons will be learnt. To appeal to other club members it needs to be simple, quick and cheap. While changing the motor for a 4volt or thereabouts modern efficient equivalent may be the way for some locos in the future for now I think my best bet, if I am to convert the sceptics in the club, is to keep the existing "hardware" and just add in some new software. That would appear to mean incorporating a voltage booster module.
I realise that using 12 volts in this way is at odds with the topic title of a "5 volt model railway" but my question, when I get round to it, concerns picking up from the track, as outlined in these posts. I understand the scenario outlined by Ted where locos pick up the 5 volts for charging purposes from dedicated tracks but is it possible to pick up from the "normal" 0 to 12 volts that is present in our existing tracks. Doing it this way, in a club setting, would avoid having to do anything at all to the existing layout and electrics: all the "special bits" being in the loco. (What I have in mind is placing the loco in a siding and turning on the power from the normal controller to do the charging).
I understand the role of the bridge rectifier in always ensuring correct polarity for charging but could that be combined with some other electronics that would ensure that if there was more than 5 volts in the track it would prevent that passing into the charging circuit?
I realise that this is adding yet more "bits" into what must be a crowded loco body but if Ted can get a radio controlled Simplex working then surely something could be achieved.
I am fairly clueless when it come to electronics so if there is a solution I would be grateful if you could post any reply in simple English with maybe a parts number and a wiring diagram (don't want much do I!)
Its all about spreading the word.
Thanks in anticipation.

Bryan

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Re: A 5 volt Model Railway

Postby zebedeesknees » Tue Nov 09, 2021 4:48 pm

Hi Bryan, I am shocked to discover that my original post was over a year ago! Must be something to do with this infection thing...
I fear that it would take a long essay to do justice to your post, so a little at a time, and I hope, the most important first.

It is imperative for AG members who enjoy a specific layout that compatibilty is maintained with the minimum of disruption to the layout or individual stocks. This would have been true on Green Street at CLAG had Tony not moved before the radio concept began to mature. To this end, one of the first RTR models to be converted to radio control was the Bachmann WD 2-8-0 which had been re-wheeled by Prem Holdaway.

It retains the 12v Bachmann motor and the Bachmann pickups. These are separated from each other, and fed to the tender body where there is plenty of space available. The intention was to simply fit a radio receiver (Rx) between the wires in the tender, but the polarity from the pickups is reversible and therefore uncertain, while the Rx requires a definite + and - supply. So a bridge rectifier needed to be installed between the pickup supply and the Rx. No battery necessary, the loco worked normally provided that there was a full 12v DC (or even 16vAC) on the rails. But the supply to the motor relied on perfect pickup, as the Rx is very quickly sensitive to any dip in the supply voltage. A decent size of capacitor, as in DCC 'stay alive' circuits, between the bridge and the Rx does as expected...

Cost:- My preference was for the DT range, currently supplied by Micron Radio Control. A receiver for each loco costs around £30 for the low voltage (6v) version, with the higher voltage, 3 -13v version, currently discontinued and hopefully soon to be replaced by a Micron sourced range. I would expect these to cost no more than £40 each, but I have no control over that. In addition, a transmitter (Tx) will of course be required.

The train controller Tx on the Micron site is suffixed 22, the one I bought is the Tx22X which retails at £79. There is a kit version, though currently unavailable, for £38. Having built two of the earlier kit versions, which are still working, I felt that the price difference for a ready-made one to be worth it!

The first radio controlled loco conversion would therefore cost somewhere around £120, plus pennies for bridge rectifier and capacitor. Subsequent locos around £40 each, but we haven't got to batteries yet.

I should mention that the TX22 series can control up to 12 'active' locos at the same time. Each of these can be chosen with the 12-way 'Selecta' control switch on the Tx, once they have been configured to that number, 1 to 12. Any loco that has been set to run will continue unchanged if a different one is selected and driven - there are advantages, but obvious dangers there! Locos are 'active' while powered from track or battery, and have been previously selected and bound to a selecta switch position. If that loco is currently selected, the LED on the Rx will be on steady, if a different one is selected, then the LED on all that are not will give a 'double flash' indication to show that they are ready to go when selected.

This does not mean that only 12 locos can be controlled by the one Tx however, just that only 12 of those that are currently active can be; any number of others can be bound to the selecta switch, but only 12 at any one time.

I trust that to be enough for now, we'll get to the can o'worms that is batteries soon, and some more pictures and circuit examples too. In the meantime, any questions anyone?

Ted.
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hollybeau
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Re: A 5 volt Model Railway

Postby hollybeau » Tue Nov 09, 2021 7:40 pm

Thank you Ted: this is really most helpful- and not just to me personally but I suspect many who are reading this and are thinking of taking the plunge.

Perhaps if I say more on the particular circumstances that have led to this decision at my club: largely because I suspect that there are many in the same situation.
The club is small, at tops six members. Our "clubroom/layout room" is a large (36' by 12') permanently-sited caravan situated in the grounds of a children's camp in a remote rural location. The layout is in 00 (and yes this is a Scalefour Forum but I model in S4 and what I learn from this may be transferred to my own models, and in any case radio control is surely universal and not scale/gauge dependent so I offer no apologies for posting on here). The layout occupies the whole of the caravan and is basically a four track roundy-roundy (but including a near scale model of Quorn station on the G.C.R.) We tend to meet once a fortnight say for around three hours max. What tends to happen is that each meeting we must spend at least half our time cleaning track or fixing electrical problems. That leaves little time left for actual construction or playing trains. We returned a month ago after the 18 months Covid layoff. The layout had not suffered as badly as I thought it might but we have as yet only got two of the four lines running all the way round. There may be many reading this who are nodding and identifying with this scenario. It is this above all else that is driving the need to find a way to drive trains that simply work without the chore that is track and wheel cleaning.

Having read more about radio control I am beginning to revise my view on re-motoring. All the locos (the majority of which are from the steam era) have been given to us. We have a nearly new Hornby Peckett but the newest behind that are Bachmann or Hornby models that are at least 10 years old. At the other end of the extreme are Triang models from the 60's and even a Hornby Dublo ex 3 rail N2 with ringfield motor. Most of these mechanisms have done many miles and need a lot of TLC. Moreover the motors tend to be inefficient amp-guzzlers, which I suspect will quickly drain any Lipo batteries with their voltage upscalers if we went down that route. Accordingly the sort of motors that "Jack Black" espouses on this forum (with the simpler electronics that goes with them) may be the better bet. I will investigate further, but in the meantime look forward to Ted's further treatise, particularly on the matter of charging from a variable 12 volt supply.

Bryan

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zebedeesknees
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Re: A 5 volt Model Railway

Postby zebedeesknees » Wed Nov 10, 2021 5:41 pm

A picture of a Tenshodo unit prepared for radio, to be fitted under a Nu-Cast Partners Sentinel kit.The connecting strip between the pickups and the motor has been cut both sides with a carborundum disc, and the red wires each side fitted with a socket and the black wires to a matching plug. A plug inside the body connects the socket to the Rx via a rectifier, and a socket in the body from the Rx output connects to the black motor wires via the plug.
When they are joined, the unit runs as normal RTR, but for the S4 gauged 9.5mm diameter P87 wheels, insulated one side.
Though a 12v motor, it runs at a bit over scale speed on 4 volts!

Ted.
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Re: A 5 volt Model Railway

Postby zebedeesknees » Wed Nov 10, 2021 6:44 pm

hollybeau wrote:Thank you Ted: this is really most helpful- and not just to me personally but I suspect many who are reading this and are thinking of taking the plunge.

I am aware of a few who are - more than care to admit it on here.

Perhaps if I say more on the particular circumstances that have led to this decision at my club: largely because I suspect that there are many in the same situation.
The club is small, at tops six members. Our "clubroom/layout room" is a large (36' by 12') permanently-sited caravan situated in the grounds of a children's camp in a remote rural location. The layout is in 00 (and yes this is a Scalefour Forum but I model in S4 and what I learn from this may be transferred to my own models, and in any case radio control is surely universal and not scale/gauge dependent so I offer no apologies for posting on here).

Agreed - I was led this way by a 2mm scale modeller. And if it can be done in 2mm...

It is this above all else that is driving the need to find a way to drive trains that simply work without the chore that is track and wheel cleaning.

And grassy sidings with rusty rails can be modelled and driven along. 3D printed ones even..

Having read more about radio control I am beginning to revise my view on re-motoring. All the locos (the majority of which are from the steam era) have been given to us. We have a nearly new Hornby Peckett but the newest behind that are Bachmann or Hornby models that are at least 10 years old. At the other end of the extreme are Triang models from the 60's and even a Hornby Dublo ex 3 rail N2 with ringfield motor. Most of these mechanisms have done many miles and need a lot of TLC. Moreover the motors tend to be inefficient amp-guzzlers, which I suspect will quickly drain any Lipo batteries with their voltage upscalers if we went down that route.

The 60's ones were high current, but even those are not as draining of the batteries as one might think. Li-Po performance is very different to that of the batteries that we are used to. The motors do not slow down and lose power at the linear rate that our old battery powered toys did; the performance at 3.2 volts is hardly distinguishable from the performance at 4.2 volts, especially if that is boosted.
For example, A modern RTR 12 volt motor draws around 300mA at full soeed, an oldie perhaps twice that. An 8x25x40mm Li-Po can supply 850mA for an hour via a booster. For how long do you wish to run the roundy-round at max speed? And that's without picking up from the track, which could be wired on the straights only, avoiding pointwork electrickery!

Accordingly the sort of motors that "Jack Black" espouses on this forum (with the simpler electronics that goes with them) may be the better bet.

Certainly for new build, and many of those mentioned by JackBlack are direct replacements for the much missed Mashimas. They are - for the time being - relatively inexpensive and extraordinarily torquey on 3.7 volts. There are coreless ones too, as in my 14xx on the CLAG site, which draw even less current for the torque.

I will investigate further, but in the meantime look forward to Ted's further treatise, particularly on the matter of charging from a variable 12 volt supply.
Bryan

A teaser - there are good small inexpensive voltage regulators available that will take 12 volts from the track, and convert it to 5 volts for battery and drive motor. There are larger and pricier ones that can provide 5 volts at 2 Amps from over 30 volts input. But we're heading for complications, my treatise on batteries next, I think..

Ted.
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ACJ
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Re: A 5 volt Model Railway

Postby ACJ » Thu Nov 11, 2021 9:33 am

Fascinating. What about sound systems?
Andrew

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Re: A 5 volt Model Railway

Postby zebedeesknees » Thu Nov 11, 2021 2:21 pm

ACJ wrote:Fascinating. What about sound systems?

Not on my horizon, I have no idea how they work. If, as I would guess, they change frequency according to the voltage supplied to the motor, then that could be picked up between the Rx and the motor input. But for a small tank engine, finding space for battery, Rx, and any other bits like regulators rectifiers and boosters is tricky enough, without speakers and driver circuits. It should be possible in locos with large tenders and diesels on bogies though, and I would be interested to hear (!) from a person with expertese in the subject. There are facilities on the Txs and Rxs to switch accessories like lights and uncouplers, so the controls could well be there already.

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Re: A 5 volt Model Railway

Postby jim s-w » Sat Nov 13, 2021 6:21 pm

It strikes me that the sometimes quoted idea of charging from the track at specific places is missing a trick.

You see if you don’t need to clean the track to run trains then you will have the issue of the wheels on the whole train getting very dirty and transferring all that crud onto your charging track. Plus you still have to arrange pickups so you still have to do most of the running maintenance each time anyway.

However if you had 2 extra charging rails (or just wires) that touch against wipers under the loco you basically eliminate all of the problems. No crud from the running rails and no need to arrange pick ups between the motor and the wheels.

Just a thought
Last edited by jim s-w on Sun Nov 14, 2021 11:27 am, edited 1 time in total.
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Re: A 5 volt Model Railway

Postby Winander » Sat Nov 13, 2021 10:05 pm

ACJ wrote:Fascinating. What about sound systems?


I think the developers of radio control systems are not focussed on sound and perhaps rightly so. They perhaps think that they will address it in due course but I believe they are missing a trick. They could leverage existing DCC functionality and sound decoders by using RC to send DCC commands, particularly now that voltage converters appear to be better. Another thing to cram into a loco but a lot of re-inventing of the wheel avoided. I seriously considered RC but didn't choose it because I wanted DCC functionality and motor control and probably sound.
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Re: A 5 volt Model Railway

Postby nigelcliffe » Sun Nov 14, 2021 9:37 am

Winander wrote:
ACJ wrote:Fascinating. What about sound systems?


I think the developers of radio control systems are not focussed on sound and perhaps rightly so. They perhaps think that they will address it in due course but I believe they are missing a trick. They could leverage existing DCC functionality and sound decoders by using RC to send DCC commands, particularly now that voltage converters appear to be better. Another thing to cram into a loco but a lot of re-inventing of the wheel avoided. I seriously considered RC but didn't choose it because I wanted DCC functionality and motor control and probably sound.


There are US companies offering bits to do this. They come-and-go a bit in product availability. Remains a problem of packing it all into a loco.


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