Hello this is my first post!

I haven't touched electronics for about 10 years since i was 16, but I'm starting to get into it again. I have really basic knowledge of electronics. not so good with logic in circuits though.

I'm wanting to build a circuit which intermittently checks the voltage of a battery (every 10 mins to an hour) and if it is below or above a certain value to sound a buzzer. I'd buy a device if i could find something that does this but it looks like ill have to make one.

the circuit discussed in this thread looks like it would be close -
Low Battery Voltage Alarm

but I need to alter it to be done intermittently so it doesn't drain the battery. would there be any other circuits here i could look at to connect the two together?

thanks for any help guys.

sealed lead acid. 4.2Ah 12v.
beacause i am doing careful measurement of its input/output, i was thinking of running the circuit on a seperate battery and using a relay to check the voltage on the test battery.