alarm system on a UPS

On a typical security system, say for example on an Elk, there is a battery so the system stays up and running during a power outage.

If there is a UPS already in-place near the alarm panel, any harm in plugging the alarm system AC adapter into the UPS? Hopefully extending the runtime a bit?

I assume the dedicated alarm system battery would kick in once the UPS goes dead.

Any comments? Good / bad / ugly?

Thanks!

It will work just fine, however your panel will not be able to tell that there is a power loss until the UPS battery is depleted.

That's what I was hoping, thanks.... in this situation the most important thing is extending battery life so that's acceptable.

Kazibole said:

It will work just fine, however your panel will not be able to tell that there is a power loss until the UPS battery is depleted.

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True. To work around this issue, I found a 6v relay at Radio shack I had in my junkbox. I also have a boatload of spare wall wart power supplies.
I simply put an unused Elk zone on the relay contacts, and plugged the wall wart into a non-protected power outlet.
Now I know when the power goes out, and back on by monitoring that zone.

If your goal is simply extending runtime of the panel I would think adding a second battery to the panel would be the easiest solution and all your power outage stuff works as normal.

Steve said:

If your goal is simply extending runtime of the panel I would think adding a second battery to the panel would be the easiest solution and all your power outage stuff works as normal.

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I would go this route first, increase the size of the panel's battery or install 2 in parallel, within spec of the panel.

You can run on a UPS, however unless the UPS is very significantly sized, your additional runtime would be trivial IMO, with the end result of delaying the ac loss report, if enabled and desired.

Thanks for the tips guys.

It's a huge waste going from 24VDC to 120VAC through an inverter, then back to 16VAC, then to whatever the panel uses, which I believe is 12VDC. You can skip all the hardware and get real efficiency gains by just adding more 12VDC power.

Work2Play said:

It's a huge waste going from 24VDC to 120VAC through an inverter, then back to 16VAC, then to whatever the panel uses, which I believe is 12VDC. You can skip all the hardware and get real efficiency gains by just adding more 12VDC power.

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Huh? Thought extending run time during a power outtage was the goal.

As a mention - alarm batteries can last pretty long. Last time I checked mine it was > 12 hours.

This might be of interest

The M1 can support up to an 18AH battery, which is pretty good sized. If longer standby time is desired, loadshedding to another power supply for the powered devices can increase the panel's standby time even further.

If you think about it a UPS makes sense. In my situation the alarm panel isn't the only thing of importance. There is a 48 Port switch, a router and the FIOS hardware to keep operational, too. Either way you look at it, you are going to be replacing a single large or multiple smaller batteries every so many years or some combination in between. Why not keep the system running 100% during a power failure.

In a case like your specific install, as a pro, I would not connect to it unless the UPS provides trouble contacts for AC loss and LB that could be supervised by the host panel. Preferably, on top of that, I would like the UPS to self test and/or do a dynamic load test automatically.

The UPS does me no good if it can be unplugged and/or the battery isn't up to snuff and not be supervised for such.

Just commissioned a 1500 door access control system where all the panels were tied to UPS' and the units we had in there had all those outputs and features as well as being tied to the host panel(s) in the closet.

I may be a stickler, but that's the way I'd want to fly and connect with a UPS to an alarm panel.

Monk said:

Huh? Thought extending run time during a power outtage was the goal.

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A UPS runs off 24VDC batteries and has to run through an inverter to get back to 120V where you have a transformer plugged in that drops back down to 16VAC to connect to the panel which then drops down to 12VDC I believe. All that extra hardware comes at a big waste expense. That's why I said if the goal is to extend run time, skip all that and just follow everyone else's recommendations to just use more/bigger batteries.

And yes - your cable modem and router and switch need power too - you know you can run them through a supervised battery setup as well.

Just think about it - that hardware, the beeper, the display, the inverter, the transformers - they're all wasting energy. They're not going to run for 12 hours - BUT, getting something like another DC power supply with charger and battery (elk makes some) and supervisory outputs, you'll get much better efficiency making it run much longer - easily 12-24 hours depending on how you set it up. I don't see a conventional UPS lasting more than 4 hours.

I there is a power outage for more than a few hours, that's when I switch on the generator. B)