Before you scrap your recorder, check the manual for "Recording Automatically" or perhaps "Auto Rec". Manufacturers use different terms for 'sound activated recording'. Generally posting, the recorder waits in standby mode and when a noise / sound is louder than your preset sound level, the recorder opens a new file and starts recording. Saves power and memory space. I don't think that you want countless hours of 'the sound of silence'
I have to make some guesses. You set up to hack the battery compartment or are using a power bank with USB cable. I have done both but prefer my power banks.
Olympus, Sony and others have made nice little voice recorders. One can view the user guides / manuals on line at B&H Photo Video to make comparisons before buying equipment. Reviewing the frequency response, battery types and memory capacity is vital. Go to the recorder manufacturer support page and find the list of 'supported media' that are approved. Many big name brands have models that are not approved.
TASCAM makes recorders like the DR-05X and DR-07X that do not break the bank. $79 and $119 respectively. They have "Recording Automatically" ( Auto Rec ). Operate on 2 AA batteries and USB power port. Max memory is 128GB microSDXC card. The sweet part is they are '20--20' recorders. The low performance setting ranges from 20Hz to 20kHz ( 20-20 ) and the max setting is 20Hz to 40kHz. Most voice recorders are limited to 40 to 50 Hz. Zoom rolls off really bad at about 30Hz and they are still popular.
I have Anker 20,100 mAh power banks that will drive a TASCAM DR-05X for days. I do not like to leave audio equipment out in the wild forest so I am in campsite mode.
Reviewing: reading manuals at B&H is time consuming and helpful even if a purchase is not made. Entering the brand names and models also shows what units are no longer available.
Good luck DarkEyes