Power supply recommendation for older M1s

[Paul]

what is the current recommendation for DC power supply to replace a original 17 VAC power supply on an older M1 Gold units.  (not talking new M1 units that will likely be built for DC now I assume)

i see notes from the chief stating in subsequent firmware updates years ago that 17-20V DC supply support was added and a conflicting post here saying 2.0.

Also what amperage would be ideal/minimum?

I’ve been recommended the use of a 24V DC power supply which I feel is a little high.

 

[Brad Weeks]

You should use the ELK TRG1640 Transformer to power the ELK M1 Gold.

[Paul]

Hi Brad,

Sorry, I meant DC only not AC.

We can’t source AC units in Australia for the M1Gs anymore due to the MEPS standard.

Hence needing to know the max DC voltage and recommended DC voltage, and recommend current.

 

 

[Brad Weeks]

16-18VDC connected to the AC Terminals.

[Paul]

Chief engineer (aka spanky) previously posted that battery float needs to be 4V above the 13.9V delivered to the bus. There is about a 1.2V drop across the rectifier, so that means a minimum of 17.9V coming in. Even if you bypass the rectifier it still would need min 16.7 so a 16VDC won’t even start or run an older M1G assuming I understood the engineers numbers right?

Ness confirms older panels need higher voltage to address power stability issues.  The debate is on what voltage is best, but its got to be above 17VDC as that’s the current “replacement” supply that isn’t working on older panels reliability even if the rectifier is bypassed.

AC to DC conversion is not 1 to 1 depending on whether the AC value is peak or RMS. Exactly what the DC equivalent of the original M1G power supply is unclear but its not likely 16-18VDC. Note if I convert based on peak, then 1.4 x 17VAC gives the magic 24VDC number Ness has quoted.

Older panels were not all manufactured the same, so won’t be as efficient as new AC/DC units. I’m talking 10-20 year old units where components are aged and might have been manufactured in different plants (as Ness has hinted at)

 

[Brad Weeks]

{Unfortunately not able to paste into the forum} Feb 23, 2009 M1 Firmware (4.5.14 and 5.1.14) Note: 14 Added ability to power the M1 Board from a 16 to 18 VDC power supply in lieu of an AC Transformer. NOT AVAILABLE FOR M1EZ8! On the M1, simply connect 16-18 VDC to AC input terminals, no polarity need be observed. The DC voltage MUST be a minimum of 16 Volts in order for switching power supply to work properly. This capability was added as a result of some areas of the world outlawing AC transformers due to their inefficiency.

I suspect the version of M1 board will need to be Rev M to support this feature. The Rev of M1 board can be found in the upper left hand corner right above Zn1

 

[Paul]

I am also having trouble posting links into this forum, my two last posts with further details never posted.

One was about that firmware update, but its an old 2009 release before the new energy standards came into effect and subsequently there was a mention from David that he was adding changes to at least the Ness firmware to take support it up to 20V (I assume he meant DC).  I have been unable to get a hold of any M1 firmware notes from Ness so cannot verify if this voltage support ever got released.  Also not seeing any Rev M markings above zone 1.

Great we agree 16VDC will not cut it.  I’ve been discussing with another installer we both believe the advise from the local support technicians to use 24VDC is likely very bad advise, and from past experience we have found the local distributor not to be willing to replace hardware when their recommendations cause damage so unless we can find firmware release notes or some proof of 24VDC being supported by the M1 its probably too risky to try their advise.

I might hunt around a bit more to see a an AC power pack can be sourced via some off market channel or order a custom built transformer, failing that will try a 18VDC 3amp pack but it would be great if we could come to a definitive answer.

Next worry is with M1G’s tend to fail at the worst time if something is wrong such as inadequate power. We may hookup a new supply and find they work ok for weeks until an alarm event occurs, high power event or minor power brownout then their internal circuitry forces an immediate restart essentially meaning they are unstable and very difficult to identify what causes it.  Another reason I’m trying to avoid determining the DC power supply sizing by trial and error.

[Author]

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