jibs drivers are 1117 based LDO regulator. I believe it should have a MAX drop out of 1.5V...less at lower currents or something. for blu-ray its fine, for 445 its ok too. but for reds, being a linear regulator, two cells would = an excess of 4.5V or so, at 500mA thats over 2W of heat. im sure thats ok for this host. the groove is based off the same 1117 chip as well. I personally like to keep the voltage as close to the required as possible. two 3V batteries would be best. since their max charge would be 3.3... i believe Li-MnO2 cells are like that. Im not sure where you guys are located, but Fry's Electronics in my town has them for sale, as well as chargers. 2 rcr123 Li-MnO2 cells + 3v charger for 15 bucks. thats probably the best choice for reds....like i said you could use regular li-ions and Helios's host does have incredible driver heatsinking so its probably not that important, but im just presenting an alternative.