Compatible and Incompatible Power sources and associated queries.

[96RAF]

This thread is for members to post any queries they may have about methods of powering their HM7000 decoders, either through the HM DCC app, using a DCC controller or by way of a DC Power Supply..

Note should be taken of the official information published in the documentation download area. Subject to over-ruling promulgation of advice from Hornby about which power sources can be used with the HM DCC app to operate HM7000 Bluetooth decoders, please note the following:

1. The Track output of any DCC controller that is NMRA compliant can be used.
2. The output from an HM6000 power module can be used (operated from the HM DC app) providing the speed slider in use is set to max and the PWM frequency is set to highest setting I.E. 7811.92Hz. There is no control for this module in the HM DCC app.
3. Any mains power supply unit (PSU) with a DC output of up to 20volts (12-15 volts recommended - see linked to list) can be used when connected directly to the track, usually by way of an adapter cable. A Hornby PSU is recommended as overload and short circuit protection is assured. Users of other make PSUs must assure themselves that these provide adequate protection. Hornby will not take responsibility for damage due to use of unsuitable power supplies.
4. The use of any DC controller Track output at high power setting to power decoders for use by the app is not currently recommended at this time regardless of make or model unless listed in the linked document. This list may change as devices are tested and cleared for use. Users should therefore disregard previous reference to the use of other make analogue DC controllers as a track power source and refer to the linked list for Hornby and any other approved controllers.
5. Tri-Mode on the packaging refers to use either on DCC under DCC control, operation under control of the HM DCC app or by way of a suitable DC controller. This has been further clarified by Hornby in the linked list.
6. Mode change is by way of selection in CV12. DC operation was only ever intended for running in purposes at moderate voltages as described in the decoder manual.

This post and the linked to list may be updated without notice to reflect any change in policy.

Any queries or suggestions should be posted in the new sticky topic.

Linked to list - https://d63oxfkn1m8sf.cloudfront.net/3216/8717/6518/HM7000-TXS_TRI-MODE_-_Compatible_Controllers_and_Power_Supplies.pdf

[NyGaugeGuy]

I've successfully powered an HM7000 8-pin decoder using a 3S 11.1V / 1100mAH LiPo battery. See video on YouTube when it was at 'proof of concept' stage:

The loco is an old Hornby Class 37 with a Ringfield motor.

I've disconnected the track pick-up competely and the only power to the decoder is the battery (black & red wires). The decoder is wired to the motor (orange & grey wires) and the control is via Bluetooth.

I get about 3 hours continuous running from the fully charged battery. I find that the decoder shuts down (elegantly - loco stops and then engine sound closes down!) when the battery voltage drops to about 9.5V but I still think that it's very impressive.

I have now fitted a charging socket & an on-off switch and I'm working on fitting running lights. I'll post an additional video once I've got those sorted.

A viewer suggested charging from the tracks but the battery is 3 cells and therefore needs a 3S balanced charger which won't fit in the loco (it's pretty full already).

Hope this is of interest.

Martin

[AndrewBiro]

Thnak you! I am about to try the same sort of thing. Be great if it all works.

Andrew

[GMD]

That’s superb. Well done. I asked Simon about this a few weeks ago in a YouTube interview, and although he’s not the technical guy, we agreed that someone somewhere was bound to give it a try!

Edit: just realised I’d already commented on YouTube! It’s old age you know….

[Fishmanoz]

What is it again?

[Anthony-355891]

So the information given says that my Hornby Select can be used to power a HM7000 decoder fitted loco. My query is can I run a DCC fitted loco using the Select at the same time as running a HM7000 decoder loco using a Bluetooth device with both locos running on the same track loop. Thanks.

[96RAF]

So the information given says that my Hornby Select can be used to power a HM7000 decoder fitted loco. My query is can I run a DCC fitted loco using the Select at the same time as running a HM7000 decoder loco using a Bluetooth device with both locos running on the same track loop. Thanks.

 

 

Yes and yes.

The Select puts DCC power to the track so you can run a regular decoder or Bluetooth decoder equipped loco from the Select (given their addresses are within range 1-59) and the app can run the Bluetooth decoder equipped loco. You can flip between the app and Select control on the fly.

[Anthony-355891]

Many thanks for your help.

[ExarKun42]

I just tested mine with a Railpower 1370 analog controller, and that works without issue.

[Paul K]

Hello!

It looks like there's at least one precedent for this, but I have a pile of 3S LiPo batteries from other hobbies, which seems like it should work to supply clean 12.6v DC to track. With the <1 amp draw of modern locos, there is potentially hours of running time per battery charge in even a modest-sized lipo battery designed for RC use.

A couple of potential concerns to mitigate, this is really where I'm wondering if others have already tread this path:

1. Short protection: LiPo batteries (and all others too, really) really don't appreciate dead shorts, and tend to react *violently* when one is encountered. I have no desire to burn my house down playing trains, so short/overcurrent protection is a must in my mind. There's the old taillight trick, but not sure if that's sufficient in this use case.
2. Am I risking the HM7000 decoder? We've seen the changing recommendations NOT to use standard DC power packs to supply track voltage for HM7000. From what I gather that's due to spiky/inconsistent DC waveform which I don't believe should be the case with a battery supply. But I recognize this is not an officially endorsed power source.

Just to clarify, I'm looking to use the battery to supply track power, I'm not thinking of trains carrying batteries running on dead rail (yet). I'm in TT:120 and there just isn't the room that I can see.

[Slats]

Hi

wondering if you can wire directly the Hornby 15v 4 Amp unit to the track? That is not use the R8241 Digital Power Track. Asking as I want to install short protection between the power supply and the track and create 2 power districts. I also don't like the look of this track. Thanks

[P-Henny]

@Slats

This is a recurring question that typically asks if there is a product that can connect the 2 pin track connector plug to general wires instead of the Hornby track power connector.

The answer is always the same. As no specific compatible connector is made, do not cut off the 2 pin plug to expose bare wires.

Instead use a 2 way Nylon screwdown strip terminal as an interface between the connector lead and wires (industry standard electrical wire termination strip that can be cut to the number of ways required).

If an appropriately sized Nylon terminal strip is used (3Amp?), the screwdown holes match the pitch of the 2 pins of the Hornby connector. This means that the Hornby 2 pin plug can be inserted and screwed down on one side of the Nylon strip and wires inserted and screwed down on the other side. Then the wires can be used to make any custom connectivity you want.

This method maintains the integrity of the Hornby HM7020 connection lead and therefore its Warranty status.

[Slats]

@P-Henny

thank you very much - great information.

Much appreciate it.

John

[LTSR_NSE]

Hornby list of approved controllers & PSUs:

HM7000-TXS_TRI-MODE_-_Compatible_Controllers_and_Power_Supplies.pdf

[Fishmanoz]

I notice there are two unanswered posts from page 1 of this thread and quite old:

• EX - re your analog controller - it may appear to work but don’t. You risk damaging your decoder and invalidating the warranty
• Paul K - it is impractical to expect you will never get a short on your track so would be good to include a circuit breaker to protect the batteries and your house.

[teiger]

Can someone please explain to a non electrical/electronics wizard (me) why it is not possible to cut the plug off the Hornby controller to make the connection.

Alternatively I would be happy to see a photograph of the proposed connecter mentioned here.

[P-Henny]

If you want to completely eliminate its second hand value and invalidate the Warranty, then by all means cut off the plug. It also removes any chance of reverting the lead back to factory condition if you wanted to reinstate the offical Hornby power track / track power connector. The use of a simple Nylon strip connector keeps all your options open. That's all there is to the forum recomendations. At the end of the day it is your choice and your rules that need apply.

The following online image show complete strips, these are easily cut to any length i.e 2 way to suit. Note that the link is only an example to show you what the Nylon Strip connector style looks like, as these Nylon strips are sold all over the place and available over the counter. Retailers like B&Q, Screwfix & Toolstation for example:

https://www.ebay.co.uk/itm/295674909612

I would suggest that either the 3 or 5 Amp (probably 3 Amp) would be the most appropriate size.

[BritInVanCA]

On 28/09/2023 at 16:11, LTSR_NSE said:

Hornby list of approved controllers & PSUs:

HM7000-TXS_TRI-MODE_-_Compatible_Controllers_and_Power_Supplies.pdf 2.88 MB · 11 downloads

So am I correct in saying that every approved unit is Hornby so if you use anything else and have a problem (i.e. decoder failure) Hornby will say repair/replacement is not covered by warranty? This is the feeling I got when Gaugemaster users started seeing decoder burnout but I was wondering if anything has changed. I have an Atlas DC railroad controller that is within the required specifications but I haven't used it with HM7000 up to now because of the warranty issue. I have had a decoder "burnout" with my Select so nothing is foolproof!

[Fishmanoz]

There’s a lot more than Hornby in Rob’s OP at the start of this thread. So not correct. 

[LTSR_NSE]

@BritInVanCA - the issues identified with DC controllers/PSUs are:
• non-smoothed output (e.g. clipper/duette) - produce voltage spikes that are over double the max rating that HM7k decoders can tolerate.
• even smoothed output controllers (e.g. gaugemaster) - can produce/result in transient voltage spikes during a short-circuit event (e.g. derailment.)
• not containing short-circuit & overload protection - in addition to being a fire hazard, can also cook sensitive electronics like decoders.

A DC PSU can be confirmed to be compatible by checking that the manufacturer specs include short-circuit & overload protection.

However the only way to be sure a DC controller is safe to use, would be to record oscilloscope readings (since transient spikes may be faster than human eye can detect) - this is obviously impractical for most people, hence Hornby just recommends not using DC controllers.

[BritInVanCA]

12 hours ago, Fishmanoz said:

There’s a lot more than Hornby in Rob’s OP at the start of this thread. So not correct. 

More than Hornby power supplies maybe but only Hornby controllers

[BritInVanCA]

5 hours ago, LTSR_NSE said:

@BritInVanCA - the issues identified with DC controllers/PSUs are:
• non-smoothed output (e.g. clipper/duette) - produce voltage spikes that are over double the max rating that HM7k decoders can tolerate.
• even smoothed output controllers (e.g. gaugemaster) - can produce/result in transient voltage spikes during a short-circuit event (e.g. derailment.)
• not containing short-circuit & overload protection - in addition to being a fire hazard, can also cook sensitive electronics like decoders.

A DC PSU can be confirmed to be compatible by checking that the manufacturer specs include short-circuit & overload protection.

However the only way to be sure a DC controller is safe to use, would be to record oscilloscope readings (since transient spikes may be faster than human eye can detect) - this is obviously impractical for most people, hence Hornby just recommends not using DC controllers.

Thanks. The only specs I have for the controller is what is listed on the back which only details input/output voltage (no specs on the internet) and I know it has short-circuit/overload protection from the many years I have used it for my DC layout. However considering there is no guarantee and it is a fairly old controller I've come to the conclusion it's not worth the risk. Trying to save $70 dollars and possibly fry a $120 decoder seems like a risk not worth taking. 

[Fishmanoz]

I can’t see how the track output of any NMRA compliant DCC controller can be construed as limited to Hornby?