I had major issues with new SC12A (SC1200a) becoming totally useless as 5 out of my 7 DS10 door sensors reported "low batt in zones." I checked the batts and they read over 3.0v on all. I replaced a few batts with fresh new ones and no change.
So I decided to check it out in detail.......
I changed the zones to ones that did NOT report low batt and the problem followed the DS10's..... so it was not a SC12 problem....
I then put an adjustable power supply on a DS10 and starting at 3.00v I lowered, each time triggering the magnet so it sent data, until the SC12 reported "LOW batt;" consistently 2.70v (or lower) did it.
Raised volt back to 3.0 and guess what?? NO CHANGE - still low batt. triggered magnet multiple times, no change. still low batt. I had ASSumed that on the next report it would report healthy. Not so. I raised voltage to 4.5v - no change still lo batt....
Just for kicks, remembered that if you hold down test button on DS10 for a while it "resets" or something, I did. Now the DS10 is dead to the world..... clicked test button one more time and BINGO! I could tell low batt report went away as the zone number no longer flashed! Solid ON for open, solid OFF for closed. I found you do have to press clear on the SC12 to clear the low batt indicator also. Repeated this experiment a dozen times and got same results.
So I can report that my DS10 would send low batt indicator along with open or close sig when voltage goes below 2.70v.
I can report that my DS10 would clear low batt indicator along with open or close sig when voltage goes above 2.75v (after a reset/clear thing).
I can report that my DS10 will not clear a low batt indicator along with open or close sig when voltage goes back above 2.75v unless I press and hold TEST button down about 5 seconds: the red LED then flashes slowly 3 times to indicate it took whatever I just did. Then it does not send anything until I press TEST button quickly 1 more time (LED blinks fast about 10 times to show it liked this I assume). Then it is back on same code minus the low batt indicator.
So the moral of this story is two fold:
1) it appears even if you replace batts in a DS10 sensor, that alone may not solve a LOW BATT indicator on SC12.
2) X10 tech support showed again their total incompetence when I called them and they had no clue about how the DS10 functions and so decided I had bad SC12s that needed to be returned instead.
It seems sad that X10 does not tell folks that to reset their low batt alarm from DS10s to rest them with the test button. This should not be a secret.
Since I had the stuff on my workbench, I DID get out my grid dip meter and watch the relative signal strength as I had an idea that perhaps if 2 batteries are good, 3 may be better! Sure enough. I got a repeatable 5 units of rf on 310mhz with 3.00v and it went upto to 12 units at 4.5v! What does this mean? It means the DS10 is transmitting a tad over twice as much rf so it will work more consistently and further. The current draw went from about 1ma to 2.5ma - plenty acceptable in my book. Batt life will still be about the same as shelf life so no hard done. I am sure the small transistor amp in the DS10 doesn't care about the higher wattage either. I will be ebaying to see if any one sells lithium (2 or 3v) cells in AA size or if not, buying 10 single AA cell plastic batt holders. I will hot glue 1 to the side of each DS10 and add the 3rd batt in series with the other 2 for more robust signal.
I hope this is of some value to others.