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🛡Home Security => Problems and Troubleshooting => Topic started by: mike on November 06, 2011, 04:04:05 PM

Post by: mike on November 06, 2011, 04:04:05 PM
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.  

Post by: dhouston on November 06, 2011, 04:40:14 PM
I don't recall what batteries the DS10 uses but BR type batteries have a very flat discharge curve, holding their rated charge until shortly before end-of-life, so you really will need new ones at the point they drop below 2.7V. They also have greater amp-hours than similar sized alkaline batteries and, IIRC, have a slightly higher initial voltage. The downside is that they are not rechargeable.
PS: I may be misremembering details but I think they also do better at low temperatures but you should check the datasheets rather than trust my ancient brain cells.
Post by: Brian H on November 06, 2011, 04:51:42 PM
Two AA cells.
Post by: mike on November 08, 2011, 07:43:28 AM
so we had 2 nites now of alarm set ok w/o lo batt alarms, after 2 week of alarms.... I replaced no batteries, just held down test button 5 sec til 3 blinks then clicked once more for 10 rapid blinks and complete reset of alarm, so this must work.  checked DS10 instruction sheet and it says nothing of this.

On another note, 2 of the 4 working SC12a's  (1 w/antenna wire out) consistently catch open DS10's;  other 2 don't - even ones 40' away thru 1 wall.  Seems like maybe x10 factory does not even tune them?  Has anyone ever tuned one?  results?  These puppies need the antenna wire slid out of the case to get any range.  But before I pull those antenna's out, I want to test adding the 3rd AA batt to the sensors to see if the higher output power gains the distance.....
Post by: mike on November 21, 2011, 12:14:26 PM
15 days and counting..... no more low batt alerts on SC1200's after simply resetting the DS10's as stated below (not documented by X10) so am convinced they can get into fake 'lo batt' announcement state and stay there stuck until this is done.

I ordered single AA batt holders to add a 3rd batt per below to almost double the power output of the DS10 for potential added range.  They came in, I tested.  Holding DS10 in hand with and without the 3rd battery had almost no effect on range!  I still assume it may provide more reliable reporting in a situation where range is near the limit tho;  I have not made the time to test this theory tho.  To do so would be mount a DS10 at near range limit such that it reports missing 4 hour report once or twice a day then clears itself up other times....  THEN add 3rd batt to same setup and see if the 2x per day reports stop....  may do this in the next week if anyone cares...  at this point my DS12 replacement of DS7000 has been rock solid with my present DS10s so I cannot test this w/o adding a new one...
Post by: dhouston on November 21, 2011, 01:01:55 PM
I doubt that increasing the supply voltage will do much for range. Adding a passive radiator has been measured to give a 10dB increase.
Post by: mike on November 21, 2011, 01:54:00 PM
ya, my 10watt 146mhz 2meter has similar range to my 25watt one and my 50w one is a tad noticably more range... mostly they fill in the weak spots within the normal coverage area as I said below....  my 150w to 2kw on KWM-2 makes a difference tho :)  My doubling power is only 3db as measured with grid dip meter from 3 to 4.5v.  Wish I could get 10db on any antenna design by simply setting a passive element like a director or reflector next to the driven element!  I'd be rich!  Think we'd be in trouble with the FCC or law if we sold 18" coat hangers as 10db gain antennas for x10?   :'