Making your own keep/stay alive units.

[SlapheadPenguin]

I'm just venturing into this field and I am a complete novice at electronics.

 

I have been out and purchased capacitors, resistors & diodes to make my own stay alive units as buying them seperately & ready made is just cost prohibitive.

 

Diode SC07337 http://cpc.farnell.c...337?Ntt=SC07337

Resistor: RE04465 http://cpc.farnell.c...465?Ntt=RE04465

Capacitor: CA04933 http://cpc.farnell.c...933?Ntt=CA04933

 

Enough of each to do all of my loco's cost £20+P&P. A lot cheaper than buying branded ready made manufactured @ £17+ each.

 

Each stay alive unit will/has been made up as per: http://www.members.o...north/alive.htm

 

See heading: 'Using and Connecting a larger Stay Alive Capacitor' This is about 2/3rds the way down on this web page for product image.

 

They work just fine as stay/keep alives for lights and are dead easy to install as such.

 

I just cannot however work out how to connect them up to the decoders to keep the motors alive?

 

Any one able to advise please?

 

So far I have not burnt out any decoders experimenting but if I carry on trying to work this out I will!

[RedgateModels]

The big question:

 

Which decoders are you using?

[SlapheadPenguin]

The big question:

 

Which decoders are you using?

 

Yes, that might help!

 

I have fitted to my loco's: Gaugemaster DCC 25 & 26. Bachmann 36-554 & 36-553, Lenz mini silvers, TCS M4PUK & TCS MC4.

[RedgateModels]

Ah, sorry, can't help with any of those, I know where to solder the neg end of the capacitor to on a Lenz Standard+ though.

 

Basically you need a DC multimeter, positive to the blue wire then carefully probe around looking for the negative end of the bridge rectifier.You should get approx track voltage at the right point. It helps if you know what you're looking for, what a diode looks like etc.

 

Some of the decoders you mention are very small, you will have to have a tiny soldering iron and a very steady hand ......

[Nigelcliffe]

I doubt that 220uF is enough storage to make any appreciable difference to a motor.

 

I find that 1000uF is the minimum to make a meaningful difference to a motor, and that only removes microscopic stuttering in an otherwise superb running small 0-4-0. This does make a difference to quality of running, but its not going to magically carry a loco over a dead-frog turnout. 2000uF and upwards and one can start to see a few mm of wheel movement on loss of power, and noticeable improvements in perceived running quality, though again, it won't carry a loco over dead track.

 

Trying to squeeze in that much capacitance into a loco can be challenging in 4mm scale. So, I've ended up searching electronics suppliers and noting carefully the capacitance, diameter and length of components so I can pick those which will squeeze the most storage into the available space. Capacitors can be wired in parallel, and the energy storage will be added.

 

 

The big jump for "lenz power 1 module" running of perhaps a foot without power requires changing to "gold caps". Those bring a load of other issues around correct voltage (or use of voltage multipliers) and charging/discharging rates. I've never found any gold caps which will fit into my locos, so haven't tried to work out appropriate circuits.

 

 

- Nigel

[SlapheadPenguin]

Thank you for your reply. You lost me when you mentioned bridge rectifier. However good old google images has been able to show me what such looks like - just a case of working out wich circuit drives what now as per the diagrams: http://www.members.optusnet.com.au/mainnorth/alive.htm

 

I can check for continuity though! As said, I am a novice at electronics but we all started at the bottom with everything once!

 

On my multimetre, where do I put the +pos probe on the decoder, to look for a -neg feed?

 

To what position am I placing the dial?

 

On the LCD screen display; what am I looking at being displayed please?

 

This is the multimetre I own: http://gsmserver.com/shop/equipment/measuring_equipment/multimeter_mastech/mastech_ms8200g_digital_multimeter.php

and I use it to 99.9% check continuity and the other 0.01% the temperature with it!

[RedgateModels]

Set your meter to DC voltage, between 9 and 20V will be fine for most DCC controllers on the market

 

positive probe to the blue decoder wire, negative probe to decoder pcb where you think the right point is. If you get it right you should see approx full track voltage on the meter.

 

As a final test once soldered up power up the decoder, and put the test leads across the capacitor. it should show that it's charged up to the same sort of voltage that you measured before. Now, cut the track feed and the voltage should rapidly decay indicating that the capacitor is discharging through the decoder. If it stays charged you're not going to get the effect desired .....

[SlapheadPenguin]

Positive probe to the blue decoder wire, negative probe to decoder pcb where you think the right point is. If you get it right you should see approx full track voltage on the meter.

 

Nigelcliffe 'I doubt that 220uF is enough storage to make any appreciable difference to a motor' I cannot fit a larger capacitor and even this one I don't know how I am going to get it in some of my locos's. I may have to undersling & paint them out black?

 

Thank you, this will be my evenings entertainment.

 

Just hope I get no expensive detonations. My working living experimental 'tried out on first' model Harry the hauler will be the first to work on & get this sorted as that is the easiest & has the most space available.

 

Probably a daft question? If I have a Lokprogrammer and decoder reader can I still do this on the test track that all this id connected to via my PC? Yup, I have all of that fancy gadgetry and use it to just (presently) to set CV's - I will be using these for their intended use at a later date though.

[SlapheadPenguin]

Decoder is a Bachmann 36-553. I have no idea to what circuit I have actually soldered this into (can any one tell me?) but I managed to get a working module put together today & with no detonations!

 

Albeit the capacitor has no direct affect on the motor it self as it is too small when you turn the power off.

 

It has however improved its crawl/minimum speed - so I know the stay alive side of things is working/doing something with the motor.

 

I looked at the other decoders as mentioned. They are simply just too small to work on; well for me anyways.

 

So, you ask yourself, 'he now knows how to solder together & wire up a resistor, a capacitor & a diode to make a stay alive unit that is functional'.

 

I know, I have no idea where I am going with this too!

 

But this is how i started with making and fitting lights. Now all of my loco's that did not have lights fitted, firebox flicker, Suethe smoke units etc., now have.

 

As said this Harry the hauler and its Bachmann 35-553 decoder are the crash test dummies of my modelling world and they gets everything tested out on them first - better than riking an expensive model/circuit board/decoder.

[Simond]

Please see posts 38 & 39 in my Porth Dinllaen thread (link below) for further investigations & links to DIY KA installations

 

Best

Simon

[Sir TophamHatt]

A mega bump to this topic but I'm interested in this.

 

Are there any recent guides on what I should be buying and how to fit them together?

[nick_bastable]

A mega bump to this topic but I'm interested in this.

 

Are there any recent guides on what I should be buying and how to fit them together?

this thread covers it pretty well

 

http://www.rmweb.co.uk/community/index.php?/topic/107235-2mm-coal-tank-test-build/page-6?hl=%2Bstay+%2Balive&do=findComment&comment=2770652

 

Nick

[Torper]

Are there any recent guides on what I should be buying and how to fit them together?

 

As to what you should be buying, the TCS KA series will give you the 6 - 15 seconds additional power that you want - http://tcsdcc.com/Customer_Content/Products/Keep-Alive/Keep-Alive.php .  They're not cheap, however, and are also pretty bulky.  Do note the advice from TCS that if you fit one of these you should ensure that you disable DC mode running in the decoder.

 

DT

[Sir TophamHatt]

Thanks for the pointers.

 

Is there a limit on voltage?

 

For example, these capacitors are 4700uF, which I guess will give me a good bit of running (how long/far?), but say 35v. The website I saw said Zimo recommend about 16v but I couldn't find any high capacity that has a low voltage.

However, re-reading, I guess the low voltage is a bad thing, as if I had a capacitor that rated at 2v, but gave it the full 16v track power, it'll kaboom - correct?

 

Sorry, my knowledge of basic electronics isn't great. Tried to learn through theory but couldn't, so learning through doing/making it.

 

Alternatively, what are the details from commercial versions?

 

I don't mind buying one, but this is also an opportunity to learn.

[RedgateModels]

Spot on, higher voltage than your DCC track voltage is fine, it's just you will find that they are larger physically than lower voltage types

[smokebox]

Deleted. I was repeating what had already been said.

[Sir TophamHatt]

So, the shopping list so far then is:

 

4700uf 35v - I'll be daisy chaining a few of these together.  Or maybe even a couple of these 6800uF at 25v would be fine?

 

100ohm resistor - not sure if this is the correct sort?

 

A Diode - again, not sure if this is the sort of thing I would need?

 

Do these seem okay?

[JohnGi]

So, the shopping list so far then is:

 

4700uf 35v - I'll be daisy chaining a few of these together.  Or maybe even a couple of these 6800uF at 25v would be fine?

 

100ohm resistor - not sure if this is the correct sort?

 

A Diode - again, not sure if this is the sort of thing I would need?

 

Do these seem okay?

 

Hi,

 

You've obviously got the basic hang of things but for some parts you could use more common (standard) ones.

 

You won't need a 3 Watt resistor, get a 0.25 Watt one, it will be smaller. The diode you've picked is a specialised one. Choose a 1N4001 instead, it will be smaller and cheaper.

 

For the capacitors you say "daisy chaining" together which is a bit ambiguous. Connect your capacitors in parallel to increase capacitance. (the individual capacitance values will add together). Be aware that this type of capacitor is polarised so they need to be connected the right way round. They will be marked on the package so you can see which terminal is which.

 

John

[Sir TophamHatt]

Okay, so, the kit is bought.

 

Now it's just a case of connecting the right components in the right order.

 

Is 4700uf smaller or bigger than 47f? I have a feeling the uf is smaller?

 

I might end up sending the capacitors I bought back as they're pretty big in size so difficult to hide.

[Crosland]

Is 4700uf smaller or bigger than 47f? I have a feeling the uf is smaller?

 

u stands in for a greek mu and means micro or 1/1000000. So 4700uf is 0.004700f and is 10000 smaller than 47f.

 

If you have really bough 47f the CHECK THE VOLTAGE RATING. They will be a few V at best and you must connect in series until the total voltage exceeds what you require. Unfortunately doing so reduces the effective capacitance. Four in series would be 1/4  or about 12f

[Simond]

Which would still be enormous, and keep your loco going for more than a second or two

 

Best

Simon

[Sir TophamHatt]

If you have really bough 47f the CHECK THE VOLTAGE RATING. They will be a few V at best and you must connect in series until the total voltage exceeds what you require. Unfortunately doing so reduces the effective capacitance. Four in series would be 1/4  or about 12f

 

And for a model railway, that means over the 16v supplied to the track, correct?

 

I bought the 4700uF originally, but they're pretty big so hiding them will be a challenge.  The 47 means more power but does also mean I have to use more of them to get over the 16v.

 

Why does connecting them in series reduce the overall power outage?

[RedgateModels]

 

Why does connecting them in series reduce the overall power outage?

 

Think of them like batteries, if you want to get 4.5v from 1.5v AA's then you connect 3 up in series

[Sir TophamHatt]

Think of them like batteries, if you want to get 4.5v from 1.5v AA's then you connect 3 up in series

 

But I thought adding them in a series would reduce the overall output?

 

What happens if I connect just two or three, so it's under the 16v track supply?

 

I can't see how commercial makers produce large capacities of power while having just 5 or 6 capacitors.

[RedgateModels]

 

What happens if I connect just two or three, so it's under the 16v track supply?

 

 

if the total of the combined max voltages is less than your track voltage then expect a loud bang and magic smoke

 

the way capacitors work is that connecting them in series allows you to have a greater voltage across them but the capacitance decreases (it's a fairly complicated bit of algebra to work out what you get if you are combining more than two....)