9 replies to this topic

[nostromo]

Hi Im about to install an ELK M1 in UK and have question about supply power.
. Have searched forum etc and found old post from Spanky
"...In reality you can power the M1 from a separate DC power supply. Run 13 to 14 volts DC into the battery leads. Run a +13 volt wire from the +Battery input to one of the AC inputs so that the M1 will startup when the power switch is turned on. "

My question is can the M1 take a direct DC input to the AC feed (so I can keep Battery backup). Have looked at the board and it appears to have a standard bridge recertifier to convert the AC input. So DC should go straight through - no?

Thanks for any advice
Jim

[DELInstallations]

I think there's a couple of issues with the M1 in the UK.

First, you're going to be installing a panel that is ungraded for EU installations, not including SSAIB or NACOSS install requirements. It's also not designed to meet any BS standards, so it's another issue. I doubt you'd be able to get ARC or a permitted installation (bells only) not to mention if your insurer will allow it.

Barring all of that, I'm sure you could connect it to DC. If your mains weren't 50hz, you'd be able to use an appropriate transformer to provide the 16.5 VAC/60hz to the panel.

[nostromo]

Yes, not too worried about BS standards

Was wondering if anyone had experience or guidance on PSU. I assume the board is actually 12v after the AC is rectified, so was wondering about the 14V mentioned. Will probably start with 12V and see how I get on.

is is possible to move post to other forum section - It may be more appropriate to have in automation section

[Lou Apo]

Yes, not too worried about BS standards

Was wondering if anyone had experience or guidance on PSU. I assume the board is actually 12v after the AC is rectified, so was wondering about the 14V mentioned. Will probably start with 12V and see how I get on.

is is possible to move post to other forum section - It may be more appropriate to have in automation section

You would really need to talk to Elk tech service to get for sure answers.

However, the Elk runs right about 13.8v. Which makes sense if you consider it inputs 16vac and uses a bridge rectifier which kills a couple volts. If indeed it is a bridge rectifier, then running DC into it would pass it through, but you would still lose a couple volts unless you jumpered it out. You only need 12v for the system to function properly, but it won't be able to charge the battery.

However, I would expect 16vac at 50hz would be fine. If indeed it is using a bridge rectifier, the Hz rate will get smoothed out and almost dissapear (assuming it uses some capacitors). So the system probably won't care.

Edited by Lou Apo, 13 February 2012 - 02:19 PM.

[DELInstallations]

I believe, as per some prior experience with DSC and watching their clocks drift, that the mains HZ will become a problem with the time drifting significantly on the unit.

The M1's data bus runs best at higher than 12V, more along 12.5V (memory from a particular install). A host of other issues will arise, but that's up to you to decide if it's worth it.

[Lou Apo]

I think your best bet is to ask Elk if 16vac 50hz is a problem. I assume that 240vac to 16vac transormers can be picked up at th local electonic store, but what do I know, I don't live there. I doubt 50 hz will be a problem, but if the DSC clock somehow uses the hz rate as its clock, then maybe Elk does too. Seems like a crappy way to keep time when you could put a quartz crystal in there for like 5 cents and keep much better time. Also, Elk's xep unit has NTP querrying built in so it would correct once per day. But I don't know how much drift you are talking about. If it is a few seconds per day or a half hour.

[nostromo]

Thanks for replies. I Believe the M1 has a separate timekeeping processor with a small backup battery in the case of total power failure (guess it would not make sense to have AC based time keeping with the primary power backup being 12v DC battery). Good suggestion on the NTP sync - will implement this when up and running
Have purchased a 14V DC supply to run the unit. Will post how I get on (and any problems I encounter).
Planning to integrate with Lutron Grafikeye's (CE models) and heatmiser stats (European network stats) and also with quite a lot of custom Arduino microcontrollers - so lots of work ahead

Edited by nostromo, 15 February 2012 - 04:58 AM.

[Spanky]

You can put DC directly into the AC input terminals on the M1. The voltage regulator is set for 13.9 volts so you need at least 4 volts above that voltage to properly recharge a sealed lead acid battery. Remember you have a 1.2 volt drop across the AC bridge rectifier and need around 3 volts for regulation. The real time clock is referenced from a crystal rather than the power line. If you are using the M1XEP Ethernet module you can connect to a time server which will update the time once a day.

There is a selection of countries in ELKRP to electronically match the telephone circuit to the appropriate country.

There will be a new software upgrade for the M1 coming out in the next few weeks.

[nostromo]

Thanks Spanky, appreciate the info.
Will start with 16V supply and measure output to check its within these sorts of ranges.

[leo_bsb]

You can put DC directly into the AC input terminals on the M1. The voltage regulator is set for 13.9 volts so you need at least 4 volts above that voltage to properly recharge a sealed lead acid battery. Remember you have a 1.2 volt drop across the AC bridge rectifier and need around 3 volts for regulation. The real time clock is referenced from a crystal rather than the power line. If you are using the M1XEP Ethernet module you can connect to a time server which will update the time once a day.

There is a selection of countries in ELKRP to electronically match the telephone circuit to the appropriate country.

There will be a new software upgrade for the M1 coming out in the next few weeks.

sorry to use this old thread, but I need to know from Spanky about a safe voltage on a AC transformer I need to buy for my M1 Gold.
My city runs on 220V 60Hz. I am having a hard time trying to find a 16.5V transformer with 3A. Is it OK to use a 18V 2.5A? What is the highest voltage to use?