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StuartM

Battery powered/Radio controlled locos

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Hi Corbs,

 

Excellent video!

 

That is a really neat installation. It looks good and it works very well!

 

Frank

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I've posted this elsewhere already but thought it was worth adding to the thread.

A video showing how my 009 Bachmann 'Skarloey' works, including charging and running.

 

 

 

What's the charge time?

Edited by billbedford

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I'm building this 7mm scale Bagnall with a Wrightlines body, and a scratch-built chassis. It has a 650mAh battery in the boiler, and of course Deltang Rx

 

http://youtu.be/-gmWJ7T4t88

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Nice video Corbs

 

How big is the battery in the loco?

 

I like the idea of using a USB power bank for the E-flite USB charger as it makes you independent of a leccy supply.

 

 

Hi Dave

 

Thanks! The battery in the loco was a small one I took out of a RC helicopter from John Lewis. It was a smaller size than the ones I got from Micron. The battery is in the cab, so it is roughly the same width as the footplate and the same height as the inside of the cab, but quite slender in terms of depth.

Usually I charge the batteries on my cutting board, or on the hot plates in the kitchen (when they are turned off). The USB battery is great for this, no chords anywhere. I guess it would be useful at exhibitions etc. as well if there were not many electrical supplies.

 

Hi Corbs,

 

Excellent video!

 

That is a really neat installation. It looks good and it works very well!

 

Frank

 

Cheers Frank! It's thanks to your information and projects that I was able to do this.

 

What's the charge time?

 

I need to do a test but need to run it down first! From memory it was not horrendously long. When Bachmann release a 'Rheneas' I'm planning to convert one as well.

Edited by Corbs

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What's the charge time?

Just did a test, it was about 30 mins to charge the battery.

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Your e-flite charger gives 300mA per hour so that suggests the battery is about 150mAh

 

A 150mAh lipo can supply 1 Amp for about 9 minutes so your 70 minute run time suggests the loco is drawing about 129mA

 

When the loco is switched on and not moving the battery will still run down as the receiver draws about 15mA when idle and after 1 hour of no movement it switches into 'sleep' mode which draws about 1mA. To exit sleep mode you have to switch off and on again. Sleep mode start time can be set up to 6 hours or never.

 

Surprisingly battery power and radio control could be a good solution for exhibition use especially with multiple larger locos. For example my larger diesels have run times of about 4 hours or more. They could be switched on, left for 6 hours and still have 3 hours run time left! Or with 'sleep' never you can have a 2 hour/12 hour combo.

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Thanks Corbs!

 

I have a demo of radio control that gets half a dozen exhibition outings a year. It includes a small 009 layout so people can try the locos out.

 

The locos typically need recharging after 4 to 6 hours, depending on how much running they get. I have several I could interchange, so I could get by without recharging any, but I like to keep them ready to run. This means usually I need a mains lead but I do have a battery unit like the one Corbs has in case there is no mains socket handy. It works fine.

 

There are a few 009 layouts about at exhibitions now that use radio control.

 

Frank

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I'm building this 7mm scale Bagnall with a Wrightlines body, and a scratch-built chassis. It has a 650mAh battery in the boiler, and of course Deltang Rx

 

http://youtu.be/-gmWJ7T4t88

Hi Giles,

 

That looks a very nice loco and runs very smoothly. Looking forward to seeing it develop.

 

Frank

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Your e-flite charger gives 300mA per hour so that suggests the battery is about 150mAh

Either "300mA"  or "300mAh per hour" please.

 

...R

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Took the plunge and a box of rc parts have arrived. For the track cleaning through the tunnel purpose I am now thinking of putting rc parts in a van or wagon and using the 33 with its body off, the rc power simply being supplied by removing the decoder plug from the 8 pin socket and plugging into the socket the rc supply

Edited by Butler Henderson

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I have made some inroads in BPRC. Initial trials are positive. Please see my Duchess thread, link below.

 

Best

Simon

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Hi folks

 

Sorry for jumping in here!

 

I am hoping that someone with more experience than me could offer some guidance..

 

Im building a 7mm 0-6-0 tender loco and id like to build it as battery RC.

 

Now I actually have RC cars and use lipos etc but in that world everything is marketed with accessibility in mind and knowing what works with what is much easier to understand etc..

 

It seems so far in the railway modelling world that volts, amps and watts is the language used, and this is where I'm stumbling a bit..

 

So I thought it logical to start with the motor and I was advised a 2.5w 6v surplus maxon motor..

 

So I guess I'm looking for advice on what RC equipment/batteries are best for this motor and if there will be any performance limitations etc?

 

Im only going to be pulling a few wagons or 2/3 6-wheeled coaches..

 

Are there any practical guides to this?

 

Thanks for any info

Dale

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Now I actually have RC cars and use lipos etc but in that world everything is marketed with accessibility in mind and knowing what works with what is much easier to understand etc..

Will the RC equipment you are familiar with fit inside your locomotive, and if so, would you prefer to stick with the equipment you are familiar with?

 

If this was my project I think I would try a cheap motor with some AA cells to power it  directly to see if it provides enough power. Then you have not wasted much money if you find you need a more powerful motor.

 

You can't identify a suitable motor controller until you know the motor you are going to use and the voltage and current it requires. I would expect model cars for racing to need a lot more power than a model train so maybe the model car controller would be suitable, at least for testing.

 

...R

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Will the RC equipment you are familiar with fit inside your locomotive, and if so, would you prefer to stick with the equipment you are familiar with?

 

If this was my project I think I would try a cheap motor with some AA cells to power it  directly to see if it provides enough power. Then you have not wasted much money if you find you need a more powerful motor.

 

You can't identify a suitable motor controller until you know the motor you are going to use and the voltage and current it requires. I would expect model cars for racing to need a lot more power than a model train so maybe the model car controller would be suitable, at least for testing.

 

...R

 

Hi and thanks for your reply,

 

My car RC equipment is quite large compared to the current model rail equivalents, and the ESC and receiver are two separate items.  Even so they may be able to be squeezed in..

 

The motor I have in my RC car has a voltage range of 7.2-8.4v, My receiver is 2.4Ghz like the popular ones used in garden rail etc and rarely has any trouble when racing around large open car park spaces etc...  I guess it would be odd controlling a train with a stick type handset but if it keeps costs down then hey ho..

 

I was recommended the 6v motor from abc gears which is listed as suitable for battery controlled models etc.. surely this be good enough?

 

I guess I am perplexed as to why there's not just a standard way of doing this, when i was converting an older DC loco to DCC I could find 100s on pages of 'how to' examples etc Isn't there a general consensus as to what motor will work with an average O gauge loco?

 

Dale

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I guess it would be odd controlling a train with a stick type handset but if it keeps costs down then hey ho..

I have some friends who control garden railway locos (live steam and electric) with regular joystick controller. IMHO the questin of whether the hardware will fit in the train is the critical factor. If it won't then the Deltang RC equipment is probably the next easiest option. I have RC in 00 Gauge with an Arduino based system. And a while back I put battery powere RC into some N Gauge locos with Deltang receivers.

 

 

I guess I am perplexed as to why there's not just a standard way of doing this, when i was converting an older DC loco to DCC I could find 100s on pages of 'how to' examples etc Isn't there a general consensus as to what motor will work with an average O gauge loco?

I suspect it is not common enough. Obviously the motors that work in regular track-powered locos will also work for RC with a suitable battery. I have a collection of several DC motors in my it-may-come-in-useful drawer so I can try options for free.

 

I would start by considering the sort of motors in this Ebay link

 

Unless you plan for continuous operation as at Pendon I doubt if there is any value in choosing expensive motors.

 

...R

Edited by Robin2

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My dad runs lives steam on older frequencies. I've used RC n boats, aeroplanes, cars and its a little more plug and play. The biggest challenge is always batteries, power vs size vs safety.

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Hi Dale,

 

I have put battery powered radio control into a number of small scale locos, mainly 009 but also OO, O16.5, and 3mm. It is surprisingly straightforward.

 

The place to start is the motor. Ideally you need a motor that does not take a huge amout of current. Modern motors are very much more efficient than the ones from ten years ago or more and use much less current. Modern n gauge /009 locos will typically run on 100 mA or less and OO / O16.5 on not much more. Your 2.5w 6v motor will draw about 400 mA which is a lot. Mainly this will result in short run time or the need for a bigger battery.

 

A 6v motor is OK and will usually run quite happily with a 1S (single cell) LiPo to power it. A 12 v motor would probably need 2S (two cell) battery pack in O16.5, which make charging slightly more complicated. If you have space (maybe in the tender) you could use more conventional lithium or even NiCad cells which would be more flexible in terms of voltage and easier to manage for charging. If your motor draws say 100 mA then a 240 mAh battery will give you two hours continuous running, and longer if the loco does not run all the time.

 

If you can fit them in then your current system will be OK but if not then the Deltang system is the usual one people use, it is designed for railways and the receivers in particular are very small. There are two basic variants, the Rx4 series runs up to six volts so is OK for a 1S battey and the Rx6 series runs happily at higher voltages and you will need it for a 2S battery. Deltang uses the DSM2/DSMX system which is compatible with some but not all aircraft systems, so you might be able to use you existing transmitter although the Deltang transmitters are much less expensive than aircraft ones.

 

The reason there is no standard way of doing this at present is that the locos vary so much in size and available space, and most people start off by fitting radio control to a kit built or RTR loco that already comes with a motor, so they use that one or change the supplied motor for a more efficient one that will fit the space. Its not like radio controlled cars where there is a standard "space" left for the motor that most motors will fit.

 

Hope this helps

 

Frank

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Thank you to all three of you for the info.. I'll take the advice given and see what a bit of experimentation brings with lower priced motors. Once I've got something substantial built I think it'll be easier to assess things..

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Thank you to all three of you for the info.. I'll take the advice given and see what a bit of experimentation brings with lower priced motors. Once I've got something substantial built I think it'll be easier to assess things..

Appropriate low stall/low amp high efficiency motors are the way to go, there are some cost effective ones out there. Also helical type gears (high efficiency gearboxes) as opposed to inefficient worm drives help with power delivery and power/energy saving. Edited by CME and Bottlewasher

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Yes, but, no, but...

 

Firstly, you need a motor that will give the performance you require. There’s no point in having Big Emma tractive effort in a Listowell & Ballybunnion 1-1-0, nor something suitable for an N Gauge Terrier in a gauge 1 Beyer Garratt. Not only the loco, but the territory too. My Duchess being a case in point. It needs to pull at least 8 bogie coaches up a 1 in 100 bank, and as most will be aware, it’s 0 gauge.

 

Most modern motors, coupled with a helical gearbox, will do everything that is needed in this department, and perhaps more, so for a light railway, or shunting, a small motor may be sufficient.

 

There was a trend towards coreless motors some years back, Portescap being the big name, though there are others. These motors offer high torque for a relatively low current, and are therefore ideal for R.C., but, like everything, come at a price.

 

DC Permanent motor physics: for a given motor, the torque is proportional to the current, and inversely proportional to the speed.

 

This means that the heavier your train or the steeper your gradient, the more current your motor will pull, until it stalls (or you get wheelslip, which is kinder to everything - so do not overweight your locos)

 

Then, there’s the question of battery capacity. Batteries are supplied in various chemistries, typically for model use, dry cells (zinc carbon, or alkaline), Nickel Metal Hydride (NiMH) and Lithium (ion or polymer, different packaging, more or less same chemistry).

 

Nobody will use dry cells as they are not rechargeable, though their capacity is similar or slightly more than an equivalent NiMH.

 

NiMH have a nominal voltage of 1.2V, and are available in standard consumer sizes, with, and without solder tags. AAA ~ 800mAh, AA ~ 1500mAh, and larger sizes.

 

Lithium are available as pouch cells (so called LiPo) and cylindrical ( Li Ion, no, not “iron”, though just to confuse there is a lithium iron phosphate chemistry). The cylindrical cells are not consumer sizes, the most common standard is 18650, being 18mm in diameter and 65 mm long, with positive at the tip, again, available as tagged cells too. Lithium cells have a nominal 3.7V, but will be 4.2V or thereabouts when fully charged, and 2.5 - 2.9V when discharged. It’s very important not to allow them to become over-discharged; you should never attempt to charge a cell that has been discharged below the Vmin that is specified by the manufacturer. They don’t like getting hot either. 50C max, preferably much less. Don’t try to use or charge them below zero C either. They’re moodier than a moody film star.

 

Lithium cells are available in a huge range of capacities, from a few 10’s of mAh to thousands of Ah. A typical 18650 will be 3000mAh = 3Ah.

 

Estimating the capacity you need would be easy, if you had good data.

Multiply the voltage of the motor by the average current, and allow something, say 20%, for the inefficiencies in voltage converters and receivers and ESCs, and you’ll get a number of Watts.

Multiply this by the length of time you want it to run for, and you have Watt hours.

Divide this by the nominal voltage of your cell (or cells if in series) and you’ll get a number of Amp hours or milliAmp hours which is

the battery capacity you need.

 

Eg, 12V motor. Pulling train, current = 400mA. Nominal power = 4800mW or 4.8W.

 

Add 20% for inefficiencies 4.8 x 1.2 = 5.8Wh

 

Target run time = 2 hours

 

Required capacity = 2 x 5.8 = 11.6Wh

 

Using a single lithium cell, V= 3.7 x 3Ah gives capacity 11.1Wh.

 

This is probably good enough, or I could double up, by having two cells in series, or two in parallel.

 

From a capacity point-of-view, this is identical, but there are other considerations:

 

if I have two lithium cells in parallel, I can charge them as one cell, but if they are in series, they have to be balanced every time they are charged, so I either need to arrange a balancing charger that plugs in (it will have three wires for two cells) or take the cells out for charging, which is generally not convenient in a model loco.

 

Conversely, if I have a single cell, or cells in parallel, I will only have 3.7 V and will need to convert this up to 12V, this means that the current my cell will need to provide approximately 12 / 3.7 x 0.4 x 1.2 = 1.6A to drive my loco & train, which is fine, unless my loco draws perhaps twice the normal running current when starting. 3.2 A will not trouble an 18650 lithium cell at all, but the voltage converter may struggle a bit. If you connect the cells in series, the current is going to be half this.

 

You can of course go further and have three cells in series, thus one third of the current, and three times the capacity. Scale runs from KGX to Haymarket might be possible!

 

But of course, you don’t have good data, unless you’ve spent a lot of time measuring voltage and current on locos, with your preferred motor & gearbox, under typical loads, on the track you want to run on. So we’re back to estimates, mainly for current consumption. Older motors would have stall currents of a couple of amps, and maybe draw an amp when running. More modern motors are probably half this for the same torque due to better magnets. Coreless motors might be even half again, though I guess not quite this much better. Then add a bit for starting and climbing hills, and take a bit off for coasting and stops, and then guess...

 

I’d suggest my original 400mA would be the upper end of an average for an express loco hammering away for lap after lap, and a light railway or shunting loco might need half this, or even less.

 

 

Hoping this helps

Simon

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I found with extensive testing of my 00 scale locos (I have converted almost 50 of them) that the conversion efficiency of a step up voltage regulator falls below 80% if the loco is drawing more than about 300mA. This is with a single lipo delivering a nominal 3.7V and a 9V regulator. For locos over 300mA or with a 12V regulator I use 2 batteries in series giving much better conversion efficiency.

 

To calculate the loco power requirement I run  an endurance test on a circuit of track with the loco pulling its normal load at the scale speed I require. for a pacific loco this would be 12 coaches at scale 60mph. If it was a pacific I would use 2 fully charged 100mAh batteries in series. Set it running and time how long it takes for the receiver (my Deltangs have low battery safety cut off built in) to cut the power, 6 volts for 2 cells or 3V per cell. Those cells can deliver 1 amp for about 12 minutes so you can calculate how many milliamps the loco is drawing. Scale up the run time for larger capacity batteries to suit your requirements. For example my requirement is 30 minutes run time in a 3 hour operating session. That pacific loco draws 400mA per hour so it will need 200mAh from the batteries. The receiver and regulator draw 20mA per hour when the motor is not running so 2.5 hours needs 50mA  - minimum battery requirement = 250mAh. Add a comfortable reserve and a pair of 160mAh or 180mAh should be OK. I also use a pair of 250mAh giving 500mAh which should be plenty.

 

I remove all my batteries to charge them and have modified the tender internals to make it easy to just pop the top off. Same for the diesels. With spare charged batteries this means I can 'recharge' a loco in less than a minute.

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Following the success of the Mechanical Horse, I remotored the RC Bagnall with the same tiny gearmotor. It performs beautifully, even with the heavy white-metal body.

The motor is 6mm x 8mm x 15mm with planetary gearbox added. Slow speed shunting is what I need, and this gives me about 8mph scale

 

47035484781_ddb87a816f_b.jpg

2019-02-09_10-53-59 by giles favell, on Flickr

 

40064717003_66232a6c9e_b.jpg

2019-02-08_07-14-46 by giles favell, on Flickr

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