Motion Sensor (2842-222) Low Battery Confusion

[Wingsy]

The low-battery event for the motion sensor has me baffled. First, I somehow got a status for 1 of my motion sensors stuck on low-battery (observed from the Admin Console). Strange, since there isn't anything but fresh batteries all around me. Anyway, I tried to get rid of it by removing the battery for a minute then reinstalling it, thinking that its battery status would update. No. The only way I could get it to not show "ON" for the low battery status was to remove it from my system and add it back. Then I did some testing...

I connected a 9v power supply in place of the battery and then slowly took the voltage down by 0.2v at a time, waiting for 5 minutes between each step. At 7.2v all was well; at 7.0v I got a low battery status after about 30 seconds. (I continued taking it down. At 4.0v it started acting flaky, giving an ON condition for motion a second or 2 after giving an OFF condition. At 4.5v it worked normally.) Then I wrote a short program to turn on an on/off module when triggered by the low battery event (If low-battery status=ON then On/Off Module = ON). All other programs were disabled. I disconnected power for a couple of minutes then re-applied 9v. Status at the console is still stuck at ON for low battery and it won't go away, and the program I wrote never fired when the voltage was taken down as far as 6v. I was thinking that maybe there is no OFF status ever sent for low battery, only an ON, and that's why the console could only show nothing or ON.

And now I see on my other sensor that the battery status for it is showing OFF (not low), whereas before it was a blank field.

I wish the software guy would chime in and say a few words about the low battery logic, or if anyone else has done further testing on these things.

[Teken]

I am assuming this is seen in the ISY UI?

[Wingsy]

I am assuming this is seen in the ISY UI?

If you mean the Admin Console, yes.

[Teken]

If you mean the Admin Console, yes.

There are several things at play here so bare with me. First if you're not using the latest 4.2.21 firmware release some of this will not be possible. There are several instances where the field will be blank and the common reason is that the ISY has been rebooted which loses its state of on / off. Battery devices can not be queried prior to activation.

With the advent of 4.2.21 you can now push auto updates to a MS sensor with out touching the set button. Simply walk by the sensor and it will update any programming is queued.

This seems to work on other battery operated devices too. The ISY will queue up the updates in order of FIFO and those that require activation can be done so with any press of the button besides using the set button now.

If you remove and replace the MS with a new battery and press the set button it will refresh the new low battery to off.

[Wingsy]

"If you remove and replace the MS with a new battery and press the set button it will refresh the new low battery to off."

That's what I assumed it would do, but it doesn't. I also read somewhere that pressing SET 7 times would update the day/night sensor, which it does. But not the battery sensor. And I have 4.2.18 which is the current s/w. 4.2.21 is still beta and I'm not sure I want to experiment with that, but when it becomes final I definitely will give it a go.

[Teken]

I believe you will find 4.2.21 to be very solid and does offer you a few extra features that might prove great to have.

[Wingsy]

Some more tidbits to add...

At 9v, the idle current is 36uA. When the motion sensor is triggered it draws 6ma, with a couple of short peaks to 12ma (estimate about .5sec each), and after about 3 seconds the current drops to idle level. During the timeout phase this 36uA fluctuates slightly as motion occurs in front of the sensor, rising to around 80uA with lots of motion. When the MS is again triggered due to timeout the current again rises to 6-12ma for a few seconds then goes back to idle level. Thought some of you would like to know.

Also, since the low-battery level is around 7v, using a rechargeable 9v lithium may or may not work well. Most, if not all, 9v lithiums are 8.4v fully charged and are 7.2v during the middle of their discharge, with 7.0v occurring long before they reach a near discharged state (which is 6 to 6.6v, depending on your point of view). They may possibly work well enough for our use if all MS have the same threshold as the one I measured. I'll be testing this but it will be some time before I report back.

[Teken]

This is great reference data to see even if its specific to your own environment. None the less it provides insight for those curious about the same.