I have a Riva 901, and a GLV Mini and they work fine for me until the voltage starts to drop off. I usually change out the batts when they are at about 3.7-3.8v's. I use 2Ω cartos. So it seems to me, I need something that is regulated to 4v's. What is out there that doesn't cost an arm and a leg? Would something like this be better with a high drain batt rather than just a regular batt? Thanks.