I didn't try them but did ask if its ok to use them as I here they can at full charge be as high as 1.85V and the whites E-series can handle up to 15V, if you don't have a newer machine you should probably check first. I have the MXT and when I get down to 10V at start up I can hear a noticeable difference in the start up beep so at that point I'm afraid that I would be missing those deep whisper targets, thats why the regular AA rechargeables don't appeal to me as they are only 1.2V at full charge. When its at 10V at start up its probably much lower after you have been detecting for a little bit, most batteries will show more charge than they really have till a little drain is on them. If you end up getting some post back at how they work out for you, some people say they don't last any longer but that doesn't bother me as long as I'm getting better voltage the whole time. I usually change my batteries when they get to 10V so the regular batteries at 1.2V is only 9.6 all together, that just won't cut it for me. HH