Leadlight 105/110 Modification Stages1,2

[Athoul]

In some cases it takes about 2.6V or so for the pump diode to lase properly. In the case of NiMH, the 2.4V is sometimes not enough, or if it is, there is sometimes a noticable difference in output. You should find that Lithium (Energizer e2's) will work just as well as Alkalines and will last longer (though more expensive).