Smaller Power Bank

[Graham in the USA]

I have started installing HM7000 decoders in all my steam locos. Works greatgrinning

For my Wishlist I would ask for a mini power bank. 0-6-0 tanks need the stay alive most, however they have the least room. I cannot fit the HM7070 due to its size. The existing stay alive lasts for some time (sound only for about 30secs). My most important need of the stay alive is for 1-2 secs whilst crossing points or bad spot on track. A stay alive 1/3 the size, or extra slim (3mm) to fit inside the tanks of a small loco, would be useful.

[LTSR_NSE]

Totally agree @Graham - unfortunately at present the size is dictated by the need for adequate voltage to power both decoder & loco (the generous runtime is merely a happy by-product.)

Hopefully in the future, adequate voltage will be available from smaller components.

[96RAF]

Depending upon the decoder type some pin configurations have a C+/C- pad that can be used to solder on a stay alive. As the decoder manual says though these pads are for future Hornby use and their use with third party devices may not work, may damage the decor and may invalidate any warranty. Could be worth a punt.

[ColinB]

Actually LT&SR_NSE it isn't, LaisDCC do one that is substantially smaller. They are the components Hornby chose to use. Thank you for the information 96RAF, trouble is not knowing what is driving these pads and a device at £60.00 plus, it is probably not worth experimenting. I did find with one loco, using surface mount tantalum capacitors in parallel was much easier to fit in a small space but that only works with a Zimo decoder where you just add a capacitor.

[96RAF]

@colin

The decoder manual states that the decoder has some charging components on-board so a regular 2-wire stay alive should work, but Hornby will not validate the fit for obvious reasons. Their power bank has extra components to sense and regulate when charging should occur, stationary or moving. I would guess the switching is done in the decoder MCU via the sound profile so any direct attach stay alive would by-pass that power bank logic and charge immediately upon power up.

[RDS]

0-6-0 tanks need the stay alive most, however they have the least room. I cannot fit the HM7070 due to its size.

 

 

Your USA versions will of course be different but I have 3 Class 08 UK Loco's fitted with Sound and Power Bank.

I had to remove the detailing from the cab but to be able to use the Loco's reliably was far more important for me. I do agree that the length of time they run for on the Power Bank could be reduced but I would not want that to impact on how good they are.

[ColinB]

I have done a lot of tests on different types of "stay alive". The original ones I used gave me the issue that I couldn't read parameters in programming mode. After I found out that others didn't suffer from the same fault especially after testing the one in my Accurascale class 37, I figured that there must be different types of "stay alive" and what circuitry they use around the capacitors. The LaisDCC stand alone pack achieves this really well, as does the Hornby one. I could also list the ones I have tried that work as "stay alive" but are useless in programming mode. So be careful what you fit.

[LTSR_NSE]

Actually LT&SR_NSE it isn't, LaisDCC do one that is substantially smaller. They are the components Hornby chose to use.

 

 

@ColinB - please cease & desist telling others they are wrong, when you simply want to make an alternative point (and are not actually correcting anything!) Such behaviour is obnoxious, rude and extremely tiresome.

You are perfectly correct that size is dictated by component choice. I was providing one of the major reasons for Hornby’s choice (naturally there are others e.g. cost & availability of components etc.)

You state that other manufacturers’ alternative products are smaller, whilst also admitting that they include different components & function in a different way - therefore are not a direct comparison.

Nothing in your post is inaccurate, but neither is anything in mine! They are both providing useful, but different, information.

[LTSR_NSE]

…I figured that there must be different types of "stay alive" and what circuitry they use around the capacitors. The LaisDCC stand alone pack achieves this really well…

 

 

Extremely useful information - have you tested whether it provides all of the functionality of the Power Bank if fitted to an HM7000 decoder?

[96RAF]

The issue of programming with a stay alive installed has been discussed time after time on here.

In essence if your controller has a separate programming output then the service track will only see a short lower power programming signal per NMRA advice, which a stay alive will likely swamp. If your controller only has a track output then effectively it programs on the main (PoM) at full potential, hence a stay alive will already be charged and not act as a damper to programming signals.

Some PoM controllers do offer an internal programming switch which may mean that the programming signal is again a short low power burst.

The Hornby power bank has direct control from the decoder that delays charging by a couple of seconds so that when programming it is as if a power bank is not installed.

[ColinB]

Look LT&SR_NSE, I am sorry I upset you all I was doing was pointing out that there are other products available which a quick search of EBay would highlight. This is am information forum so I am sharing the information I gained when I tried fitting "stay alive" to many of my locos. To be honest I got most of the information off Digitrains when I just asked them if there was a "stay alive" that didn't mess up programming on DCC. If you think I am wrong you are quite welcome to criticise me, in my field of engineering that is how we learn. Incidentally all I said is that there are other smaller packages which there are, LaisDCC do two that are much smaller. I needed one to fit into a Bachmann diesel shunter.

As to 96RAF I know we have discussed this over and over again, it seems to be if the "stay alive" has some more elaborate electronics the issue of it interfering with programming is no longer an issue. I assume they must use a combination of zener diodes and transistors to delay the charging of the "stay alive" capacitors which when I looked at the circuitry on the LaisDCC and Train O matic ones, seem to back this up. A lot of the others don't seem to have this. Hornby get round this I assume by controlling it via the micro which is what I suspect Zimo do on their sound decoders. I just wish someone had pointed all this out when I started fitting "stay alive" to my locos. Last time I asked the question on this forum and others I just told to remove it when programming. When I get the time I will work out what the circuit is, my analogue electronics is a bit rusty but I will get there in the end.

As to adding a LaisDCC "stay alive" to a HM7000, it would have to be done at the 21 pin socket end by soldering to the correct pins, that way there is no way it would invalidate the warranty of the HM7000. As to whether it would work, I suspect it should as people are using HM7000s in their Accurascale locos which have "stay alive" prefitted, so it obviously doesn't harm it.

I forgot to add, yes the LaisDCC "stay alive" works just like the Hornby Powerbank. Admittedly the LaisDCC is fitted to my Hornby 4P locos and my Hornby 0-6-0 ones whereas the Powerbank is fitted in my Sir Nigel Gresley and P2. It works exactly the same. I did find the time period it lasts, was longer on a Zimo decoder as opposed to a Train O Matic one but that is probably dependant on the hardware design of the decoder.

[96RAF]

You are right Colin in that the Hornby charging delay is triggered by the decoder main MCU. As such information comes to light we post it for the information of all.

[Xsaraman]

Just found that the stay alive doesn’t fit a Class 08 - the sound is fantastic but points etc - please Hornby mini/micro needed.

[SteveM6]

Just found that the stay alive doesn’t fit a Class 08 - the sound is fantastic but points etc - please Hornby mini/micro needed.

 

 

OO or TT?

In OO it fits in the cab after a small amount of surgery.

Smaller stay alives are possible but only if more expensive components are used.

[Brew Man]

Yes, I fitted decode, speaker and power pack into my OO gauge Class 08 no problem. As Steve says, a bit of surgery required on the under side of the cab to thread the PP wires through.

[Fishmanoz]

I think you mean PB wires BM?

[Brew Man]

@Fishy

Yes, PB. I was thinking Power Pack.

[Rallymatt]

Not sure if you guys have seen some of the work by Richard at This Way Works. He has fitted to quite a few now, TT:120 08s an HM DCC Bluetooth decoder, speaker, Power Bank, cab crew and an array of lights. A fair bit of ‘jiggling and fettling’ but it can be done.