If the batteries in your metal detector have been discharged and the device refuses to work, a simple flashlight will get several hours of useful life out of these ones – checked on the Garrett ACE 250, Garrett AT PRO and Minelab X-Terra 705.
I’ve provided myself with a box to collect batteries that aren’t already working in the detector. I’ve also bought the simplest flashlights with 1 AA battery – a few of them. And uplighting in my life is for free ))