I have the QOLSYS original panel and am using the hardwire 16 to translate my original Honeywell hardwired sensors installed from ADT. The other day my system presented with a “low battery” from my front door sensor (which is not wireless). All sensors are working great and I have no other alerts. The system has been up and running for almost 2 years with only one wired sensor error in that time and it was an installation error.
If the sensor that is reporting a low battery is indeed wired into the Hardwire 16 (and not a wireless sensor), then the low battery report would refer to the backup battery plugged into the Hardwire 16.
Have you tested this battery with a multimeter? What is the battery marked as (Volts/Amps) and what does it test at?
i attempted to call qolsys and they stated that they cannot trouble shoot with homeowners 
How old is that battery?
Did you have any power outage before this occurred, did you perform any work on the system or power cycle it, or did the low battery come during otherwise normal operation?
Unplugged the HW translator and let the battery run down for a few hours. Ended up tripping a tamper on the translator and I don’t have a switch on the can. Tripped and in tripped the tamper manually and the tamper persisted. Ended up resetting the HW translator and re-programming it… so far it’s working with no trouble codes… wonder if I have a bad HW translator…
As clarification, deleting, resetting, and reprogramming the sensor would result in the panel assuming no trouble conditions, and conditions likely wouldn’t surface until supervision interval.
Check after 24 hours to see if any issue arise. If not the issue may have been caused during installation originally and is now resolved. Deleting and resetting the memory is a good troubleshooting step to resolve some issues.