And even the Duratrax one you have to watch out for, or else it'll bring them down to 0V anyway.. it's just 'indicates' they're done.
There must be some low-voltage relays that will cut off at .9 or lower.. I'm going to play with some 6V ones to discharge a 4-cell pack down to 3.6V, as my regular 12V relay only does the 6-cell packs.