Scangauge II Monitor Battery Health?

I have a Scangauge II and was wondering if I can use it to tell if my battery will soon be failing. I monitor the voltage and it usually runs ~14 V when the engine is running. When I shut the engine off the gauge will drop to ~12.5 V and stay there until the gauge shuts off. Are there any symptoms of a failing battery that will show up on a Scangauge? Thanks

 

https://carbatteryworld.com/car-battery-voltage/

if it drops too low they yes

 

12.5 is pretty healthy. Mine is at 12.4v if the truck is off and I turn on the gauge. What is it reading if the truck is off for an hour or so then you turn on the gauge?
Best way to test a battery is a load test. Advance auto/auto zone do these for free.

 

I have not checked after having the car off for a while. I'm not too concerned now but last summer the battery just died with no warning and would not jump start (2 years in Texas on "8 year" battery). I'd rather be able to have some warning and then get a new battery or load test, rather than have it die on me (or get constant load tests). I bought the scangauge for a number of reasons but was hoping it would tell me when the battery may need attention. If I understand correctly, if voltage reads low (under 12V?) when not charging, then battery should be checked. I think I'll start checking voltage before I start the engine and monitor that way. Thanks knottyrope and doogz