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hermes

Radio control for small locos

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I am using Tam Valley Depot equipment to radio control locos on an 00 gauge garden railway which is proving very successful. It's easy to fit the batteries into larger diesels  or tender locos but l am running into problems with small tank or diesel shunters because of battery size. Can anyone suggest smaller size batteries that will have sufficient oomph in them to be any good and suppliers please. If offering technical advise please treat me like an idiot as l am an electrical dimbo on these thing !

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I get the impression that garden railways are big and use the larger track gauges. What is your understanding of a small locomotive I wonder, mine is a 4mm Sentinel (!). Not being facetious (sorry), but it is important to battery size. 

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Hermes, how big is the Tam Valley equipment itself? I have done some small scale installs using Deltang equipment which is quite small, but only with 3.7v single cell batteries.

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Also, a basic question, what voltage does the Tam Valley equipment need?

 

Micron Is a good supplier in the UK and has a range of batteries that is pretty representative of what is available. Their single cell range is here:

 

http://www.micronradiocontrol.co.uk/lipo_1s.html

 

You can get multiple cell packs for higher voltages.

 

Do you know what current the batteries will have to supply?  Or what sort of loco have you in mind?

 

Frank

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TV DRS is designed to be used in conjunction with standard DCC decoders, so you need to provide enough juice to fire up the logic circuits. Sounds adds a further power requirement, and most DCC sound decoders require 7v-8v to get started on D.C.

You will need either 2 or preferably 3 batteries in series, or a step-up booster. You may be able to get a high density 14500 sized cell into a loco boiler, with the other components in the tanks, for small steam locos. Tender locos and diesels present more space, unless the modern practice of a very large metal frame has been followed.

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On 22/04/2020 at 10:25, PenrithBeacon said:

I get the impression that garden railways are big and use the larger track gauges. What is your understanding of a small locomotive I wonder, mine is a 4mm Sentinel (!). Not being facetious (sorry), but it is important to battery size. 

00 gauge garden railways are quite a common idea now as cheaper alternitive to O gauge. What l'm looking for is something that is small enough to fit into a tank engine bunker (Jinty, M7) . The alternitive is the battery fitted into a wagon or van and connected to the loco.

  • Agree 1

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On 22/04/2020 at 10:41, Corbs said:

Hermes, how big is the Tam Valley equipment itself? I have done some small scale installs using Deltang equipment which is quite small, but only with 3.7v single cell batteries.

With a bit of fettling it fits flat in say a class 47 or 40 quite easily or loco tender. Tam Valley suggest a 11.1 volt battery but some say a 7.5 or even 3.7 volt will work but with loss of speed/power. Not a problem as my M7 does not need to do 125mph!

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The reason l chose to go with the Tam Valley system was that l could continue to use my existing DCC controller (Bachman) . Both Deltang , Micron and Protocab use there own hand held control units and l'm think they only run DC but am happy to be corrected there, although l do have some DC locos which l might wish to convert as well.

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Posted (edited)
4 hours ago, hermes said:

With a bit of fettling it fits flat in say a class 47 or 40 quite easily or loco tender. Tam Valley suggest a 11.1 volt battery but some say a 7.5 or even 3.7 volt will work but with loss of speed/power. Not a problem as my M7 does not need to do 125mph!

I have found that the physical size of the battery is important for 4mm tank engines, just to get it in. I have also found that the power requirements of RTR model's motors are incompatible with those batteries assuming that you want a reasonable period in between charges. My solution has been to bin the RTR motors and replace with smaller motors but that has meantreplacing chassis too. The Bachmann Jinty is a case in point as is the Hornby Sentinel, which I came to the conclusion isn't convertible to BPRC unless I scratch build  a chassis. The existing chassis won't do. One thing leads to another.

Matching the motor's power needs to the battery is important I think unless you want to be constantly charging. There is more to this then met my eye when I started with BPRC last October!

Cheers

Edited by PenrithBeacon

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Many thanks for that, will have to do some research before l go further. 

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Here's some clips to show the speed of 3.7v on locos fitted with standard 12v motors.

 

In this one you can see how far I turn the speed control

 

 

 

In this one the big tank loco is going flat out! The banker has slightly larger wheels and is being held back a bit to avoid too much slipping.

 

 

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Corbs, can l ask what sort type of battery you use and where you fit it?

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Depends on the space available, I usually buy from Micron:

http://www.micronradiocontrol.co.uk/lipo_1s.html

 

Sometimes I chop down the weights inside the locos. On the Hunslet 48150 conversion I did recently, I was able to remove the pickup plate and fit a battery in its place quite neatly.

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I model mostly in 009 but I have a OO Bachmann Ivatt  2-6-2 T that I converted to radio control and it works fine.  It uses a Deltang receiver and runs off two 150 mAh LiPo batteries in series giving 7.4 v nominal which gives it a realistic speed.  It will run for a couple of hours continuous running although the top speed does drop a little towards the end of that period.

 

The batteries are in the side tanks, one each side.  I had to cut away a block of the solid metal chassis to make space but this was not a problem.   The chassis is not the current one, it it the older split chassis one and I had to do a bit of grinding where the chassis contacted the motor connections to isolate the chassis from the motor.

 

Overall though it was not a difficult job to do.  The "issues" were modelling ones not electronics.

 

I have had to replace motors to get radio control to give reasonable speed but this is generally with old, and often worn, motors.  Newer/modern ones seem much less of a problem.   Most motors are nominally 12v but how often do you run the loco flat out?   And if you do, does it look realistic?

 

Frank

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Most of the hobby power cells are designed for model aircraft, and are capable of very high discharge rates which we don’t need. They are also as light as possible.

How much impact does that have on the size/capacity of the cell? If designed with our needs in mind, with much lower discharge rates and extra mass (increased density) being a good thing, could the cells be smaller, or maybe have greater capacity in the same space?
Just asking about the technology/chemistry behind this.

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Posted (edited)

Hi....i 've got a 'toy' 2.4 Gig transmitter, with a useful range of about as far as I can throw the thing, so if I had a live steam loco, I'd be tempted to have a go at the conversion!

I was (off-topic!) contemplating modding an old loco to r/c for a garden railway that never got built, using some micro gear. Put 16v ac onto the track, and a rectifier, receiver and speed controller into the loco. It hasn't got past the thinking about it stage yet.

 

prototype pcb

Edited by TorrinFu

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14 minutes ago, TorrinFu said:

I was (off-topic!) contemplating modding an old loco to r/c for a garden railway that never got built, using some micro gear. Put 16v ac onto the track, and a rectifier, receiver and speed controller into the loco. It hasn't got past the thinking about it stage yet.

A garden railway seems the ideal candidate for battery power as it removes the need for track cleaning. Indeed dirty track will aid adhesion.

 

...R

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On ‎25‎/‎04‎/‎2020 at 06:08, hermes said:

...Not a problem as my M7 does not need to do 125mph!

But what is a problem is the balance of its wheel configuration. If it is intended to run with a pull-push set, thenit will thank you for putting the batteries in the coaches

33 minutes ago, Robin2 said:

A garden railway seems the ideal candidate for battery power as it removes the need for track cleaning. Indeed dirty track will aid adhesion.

Certainly doesn't in OO. You have to go around the track before running to clean off what nature randomly deposits, and I can promise you that the likes of bird droppings, snail goo and the like do nothing for adhesion whatsoever.

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1 hour ago, 34theletterbetweenB&D said:

Certainly doesn't in OO. You have to go around the track before running to clean off what nature randomly deposits, and I can promise you that the likes of bird droppings, snail goo and the like do nothing for adhesion whatsoever.

I stand corrected and I can see that a big lump of bird sh*t or twig could cause a derailment. But the cleaning would surely not need to be as meticulous with battery power as with track power?

 

...R

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What to do if a bird sh!ts on your garden railway?

Don’t invite her round again.

 

Eye thank you... where’s me coat?

  • Funny 3

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1 hour ago, Robin2 said:

I stand corrected and I can see that a big lump of bird sh*t or twig could cause a derailment. But the cleaning would surely not need to be as meticulous with battery power as with track power?...

A part of the 'secret' of the railway is the really smooth rail top. This is part of what enables relatively modest power outputs to move large loads. Small scale models cannot simply crush flat a deposit causing a less than smooth surface, they rock about on it and loose adhesion, and  worse yet the train wheels incur incremental drag. Ok if the train is short and light, but if going outside to run full length main line trains as I did, the effect is noticeable. (Then there's head winds, passing showers and frost. Battery power might do well on the last as being insulated from the rail doesn't matter, but there is still an adhesion problem.)

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I go round with a small garden blower which clears most of the debris off. Adhesion does not seem to be a problem and l have an up and over incline to contend with. Removing  the loco weights to fit the battery in could cause problems on smaller vehicles l suppose but so far l have only converted main line locos which seen fine so l will have to see.

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