Ice storm today with many outages and resultant surges. My security system console is showing a low battery indicator. There is a 9v transistor battery in there to hold the zones and detector info.
When I replaced the battery the low battery status light does not go out, so I am beginning to wonder whether the leads have detached inside the console or worse, that part of the electronics got fried.
Is there a way I can use a multimeter to touch the battery contacts that would attach to the 9v battery to know if things are o.k.? Am I looking for continuity? And, do I test with the AC power on or off to the console?
The first thing you might want to do is to find and read the documentation that came with the security system. There is usually a troubleshooting guide which might help you solve your problem, talk intelligently with a tech rep on the phone or, worst case, give them the information they need to be able to get you up and going with only one service call.
It's likely there's a gel cell or small lead-acid 12V DC battery which provides backup power to your security system, and that is likely the cause of your LOBATT indicator. You might want to look around for that battery (usually it's in the console cabinet). If you replace that, it just possibly might solve your problem.
The thing is, you may need to reset some parameters once you've changed the 9V memory backup battery, and you'll probably need the manual to go through with that.
To answer your immediate question, your 9V transistor battery is used for memory backup. You can set your multimeter on the 20V DC Volts range and measure the battery voltage. It should be around or close to
9V DC with AC power on or off. If it reads less than 8.5V DC in either case, the battery is probably worn out.
To check the 12V gel cell battery, put your DMM on the 20VDC range, and measure -- both with power on and with power off. If the battery voltage doesn't start to charge up when power is restored, or if the battery voltage collapses (meaning going below 11V after a period of recharging), it's probably bad. You can find suitable replacement gel cells and small lead-acid batteries at industrial supply houses.
Good luck with your troubles. Unfortunately, there are such a wide variety of security systems taht I don't think anyone on this forum is going to be able to provide you with specific advice unless they happen to have or be familiar with the system you're using.
To be more specific, this is a little wireless security unit and the 9v battery is all there is. The system is back to working fine except for the low battery indicator which is lit whether or not there is a battery in there. What I would like to do is check the circuit without the 9v attached and determine if there is a short or problem with the harness from the 9v. Not sure how to do this with the meter. Shouldn't touching the empty +/- contacts show me something at the right setting on the multimeter?
Measure the voltage across the battery with your DMM while the battery is installed. With a new 9V battery, it should read 9 volts. If it reads low, get a brand new battery and measure the battery *before* you install it. Then, measure it again while installed. If the readings don't match, you have a problem in the unit.
There is a chance that you need to disconnect both the battery and the AC power for a few minutes, then reinstall the battery and after that turn the AC supply on or plug it in. That might reset the indicator.
Measured 9.5v at the battery, then attached it to the unit, touched both sides of the connection cap and got 9.5v. Does this indicate a complete circuit and therefore something else is wrong? thx
No - all it indicates is that the battery is good and is not being shorted by the device.
To see if the device is drawing current, you could try connecting the battery to only one side of the snap on connector. Connect your volt meter across a 1 meg resistor. Then connect the resistor between the other terminal on the battery and the unconnected snap on the battery connector. If you get a reading, it means the device is drawing current from the battery. Without knowing the specifics of your device, it is impossible to say how much voltage you should see. But if you do get any voltage reading, it means the wires from the battery connector to the device's circuit board are still attached. If you get no reading, it may be worth disassembling the device to visually inspect that the wires are connected.
This sounds like an X10 or similar alarm controller.
It may require a full "Edison reset" (remove the AC adapter and the backup battery). You will have to reprogram the controller (re-install all the sensors and remote control units, put in the phone numbers to be called, re-record the announcement).
I've had to do this once in two years of using an X10 alarm system - when the power was off long enough for the backup battery voltage to drop too far.
Left the battery out and the X10 Protector Plus console unplugged for an hour. Unfortunately, as soon as I brought it back online, it stopped recognizing the 9v battery. Guess I'll have to tear it apart to review the battery harness connections.
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