UPS, large batteries, generator. . and the Elk M1-G


Active Member
I've searched and read about this in other threads (for instance, here, here, and here), but I have a slightly different scenario. .
The house is under construction. I have three large batteries: Marathon 155AH Absorbed Glass Mat (type of lead acid). Each weighs a good 120lbs or so. I also have three commercial-type UPS's (pics attached, I believe they are ferro-resonant type, 600 or 700W capacity each). This hardware came from Craigslist when a local outfit disassembled a cellphone tower and its equipment room. Plans for the house do include a stand-by generator.

Any recommendations on how best to address the following issues:
1. ?plug the Elk power supplies into one of the UPS's?

2. ?use one of the 155AH batteries directly wired to the Elk instead of using it as a battery for a UPS. Dunno if the Elk can charge these things, but they are 12V DC batteries. Perhaps another power supply like the P624 would be able to charge them.

3. I think I can get at the transfer switch and install relays that could be used as input zones on the Elk to notify it about the state of the generator, i.e. if gen is running, if load has transferred to the generator. Can the Elk really know the state of the AC / DC power states using these batteries and/or UPS's? I would ideally be able to send notifications or voice announcements when AC fails, when gen takes over, etc. So I can think of several "states" for the house: normal / AC power on, AC power off / running on battery, AC power off / running on generator.

I realize these batteries are prob overkill, but I have them and they were a great deal. They have all been load tested and should last another 7 years based on their specifications and manufacture date. It should also be mentioned that the UPS's have dry contacts on the back for "alarm" that I could likely use directly into an Elk zone.


  • CIMG0300.JPG
    163.6 KB · Views: 23
  • CIMG0299.JPG
    177 KB · Views: 21
  • CIMG0308.JPG
    152.3 KB · Views: 22
My "big battery" solution is in this thread:

Some weeks ago, a hurrican-leftover of Ike run -with his former eye- directly over my farm (5 driving hours north of Houston). Causing a lot of powerdamage at all of my neigbors for a few days. During this time I'm in Germany. So I could give my generator to neigbors, because my ELK-system has a real longterm powersupply. With a 55 Ah carbattery. I was able to call and control the system at any time. Sure the normal 8 Ah ELK-battery wouldn't be enough in this case.

Sorry, I can't say how long the power on my farm failed, because I havn't programmed this case. Anyway, in less than a month I'm back in Texas and then I can see it in the loglile.

With your big backup-power, I would plug the ELK powersupply into a UPS. This way you are also save from spikes via the powerline. And any contakt of any relay at your powerline is telling any zone if there is powertrouble.