I replaced back-up battery in my GE simon 3 ( 4 hrs ago), however when I perform a system status check I still get the msg "low battery".

The Simon 3 supervises the panel battery and when it's bad or the a/c has been out for a long time..will likely have to charge the battery. A problem arises where the keypad unit will not acknowledge that the battery has been recharged/replaced without you doing a basic power cycle.
Whenever this panel battery is replaced in a Simon 3 (worn out or depleted from no A/C (power-outage)) you should disconnect the A/C adapter, install the new or recharged battery properly and hear the panel tell you it's ok..."..simon ???? is OK.." and THEN plug in the A/c adapter. Assuming the panel is not damaged..it will talk when a suitable battery is installed with the A/c out. If it doesn't talk..check the battery with a test meter. Voltage over 6 volts(approx) is required to make it talk.
Of course, after a total power cycle you will have to set the clock.

Remotes(key fobs) aren't usually supervised (as they are carried away from the site) so it's unlikely it's referring to a key fob low battery. Might you be talking about a remote keypad or device in another part of the house or garage that may have low batteries..finding it and checking the batteries will clear the second part of your beeping.

Call your Central Station and put your account on test if it is a monitored system.

Power down the system. Disconnect the battery, then the AC adapter. Then plug the battery in first, then the AC adapter. Plugging the AC adapter in first can cause the low battery message.

if that doesn't work, with the battery disconnected, measure the voltage of the battery with a multimeter. If it reads less than 5.4 volts, the battery is bad. Bad out of the box batteries are not too uncommon.

Next, check the charging voltage from the panel. Measure DC voltage from the leads that connect to the battery. They should read around 6 Volts DC. If the charging circuit is bad, it will cause a low battery trouble and the console will need to be repaired or replaced.

Hope this helps.

Did you run sensor test(drop down cover enter you code pess test button then done button. let run 5 min. close cover press status button If that fixes great. If not, you need multi meter. remove battery put metter on leeds coming off panel. You should see voltage there at least equal to the battery. If not then you may see the the red wire for battery has a lump in it about 1" long that is a fuse. remove wire from panel and meter for resistance/continuity/ohms what ever you want to call it. if there is no resistance or an open ckt then replace that wire.if you see resistance in wire then you have a bad panel. GL.

You cannot disable the low battery detection on the Simon 3. - AlarmProfessor.net

No it does not need a few days 12 hrs should have been enough. you will need a multi meter to check this. pull battery off panel after confirming leed where connected properly. meter battery. I believe its a 6v battery should read 6.25-6.5v approx. if so check volts on the leads should also read 6.25-6.5v appox. if so try running sensor test. open panel door look for red numbers enter your code then select sensor (test) then "done" wait 5 min then close panel door. Then press status button. if this does not solve problem. time for service call.

The 945T is an Ademco contact. It’s a hardwired alarm switch. No battery. I need moor information?

disconnect battery put dc meter on wires. should read over 6v if not need new panel. if over 6v put system in sensor test wait 5min then close cover hit status 2 times. if reset great. if not try another battery. repeat sensor test. if resets great if not need new panel. : (

Read the battery voltage with the system on but with the ac power disconnected. I always suspect the battery from experience. Battery needs to be replaced every few years normally(but can vary).

it should be a 6 volt, 1.3 amp hour battery. you can get them at batteries plus. best bet is to take the old one with you to the store to ensure that it fits.

Response 1 is correct. If you plugged the transformer into an outlet before connecting the battery the system wont see the battery and give you that error. Should be a simple fix however. Unplug the battery and then the transformer, then reverse the process. Plug in the battery and your Simon should power up, then plug in the transformer. If this doesn't help then you should replace the battery. Did you buy the system from a dealer and have it professionally installed or did you do-it-yourself? If it was professionally installed have your technician come back out to diagnose/replace the battery if needed. Good Luck.