calculating the load on my M1G

So I am calculating the load on my M1G and had a question on the speakers. It came with the 73 but no load is shown in cut sheet. I will also have at least 3 SP12F speakers. The load on the SP12s is 5mA, each.

Is speaker load added to the max M1G load? or should it not be included.

So you should not need additional power supply as long as your total devices, including M1G and keypads and M1XIN expanders is under 1amp?

Thanks.

Speakers are not included. One amp is the maximum. Are you aware that there is an Excel spreadsheet provided by ELK? Look for it under support tools.

Yes. thanks. I have been playing with it, but developed my own spreadsheet to add up all my components, that adds more information such as the cable number (I labeled all my cablers with individual numbers), room, and type... Then i manually input the total into the ELK spreadsheet.

I will take out the speakers then. that should help a little.

What the spreadsheet does not tell you is if you add additional power supply, what battery would be required for both M1G and power supply. If you install power supply in can, you would have two batteries right?

Yes a separate power supply needs it's own battery. Battery size is not just based on load but also runtime. Calculating it based on the documentation is not going to be reliable, you're best bet is to test runtime by pulling the plug and seeing how long it lasts.

The only problem is that there are many scenarios under which the alarm would be working under. So you would need to test it when the alarm is going off, or certain devices are under max load, no? Or am i over complicating this....

Does the Elk allow you to test this without sitting next to it for hours? I am looking to have an additional power supply at M1g, plus a separate can in garage (total of three batteries, and two additional power supplies).

I would put one appropriately rated battery in the enclosure and use a diode to prevent the auxiliary supply from charging the battery.

Also size your extra batteries to outlast the primary; when expanders and accessories start dropping off, the system goes kinda crazy.

jpmargis said:

Speakers are not included. One amp is the maximum. Are you aware that there is an Excel spreadsheet provided by ELK? Look for it under support tools.

Click to expand...

Actually, I never received any definitive answer about this but have seen posts by Spanky stating how a 4 ohm load on output 1 can really tax the system. It also seems the system is capable of drawing somewhere around 2A total when in alarm, but only 1A from accessory power.

wuench said:

Yes a separate power supply needs it's own battery. Battery size is not just based on load but also runtime. Calculating it based on the documentation is not going to be reliable, you're best bet is to test runtime by pulling the plug and seeing how long it lasts.

Click to expand...

Nope. Not true, that method is a good way to plan on system failure and not performing to spec.

Calculation for runtime is going to be figured out on total load with all the devices in alarm state. Plug in some numbers, then figure on the current draw. I'd work up the values and multipliers, but I'm working on another problem elsewhere. Also, as the batteries age, temperature and cyclic use, a lot of times you're not going to see the rated output of the battery at the panel.

The best way to go about it, even with multiple supplies, is to treat each item as their own entity and NOT install a massive 55 aH battery and hope for the best, spread across 2 or 3 separate supplies and the panel itself. Good way to burn equipment up and have long charge times after a power loss/draw down. If you were going this route, you might as well install a large UPS and then 7aH batteries to take up the slack on the UPS and act as a buffer on the panel for overload.

Size each supply's battery appropriately with the panel having the longest standby. Also plan on using 0V loss power supplies for expanders, as Elk isn't too tolerant if the voltage starts to drift below 12, modules start to reboot. Many power supplies don't advertise the voltage loss when running on DC only, typically a volt or even more, from the battery voltage.