The voltage selection on the BO products is now very clear thanks to the posts on the issue. I am still bothered by the power choice for the BO products. Based on real world user feedback, the run time using CR123 disposable batteries is short (more like 2-2.5 hours depending on several factors such as battery condition and temperature), a hassle to keep changing, and expensive, over time.
Rechargeable CR123 batteries, can be used, but may void your warranty.
Rechargeable 16650 batteries can be used, but there are 3 types: flat top, button top, and protected button top. The flat top is not likely to work, the button top probably will, but the voltage may vary and again damage the unit and void your warranty. The protected button top is likely the best choice as high quality batteries are available in that style, but the protection features inside it make it slightly longer, and for some reason, BO likely made the factory battery extender too short to use them.
Of course, there is always the option of the external battery pack mounted in a pouch or on a picatinny rail. Even a small battery pack like the Anker is 6.5-7.0 ounces, so the "real" weight of say a 21 ounce optic is more 27 or 28 ounces. At that point, (using with a battery pack)the difference in weight might not be that far from say a 2.2# optic which although heavier still, possibly with an even better run time. It is, of course, very difficult to determine the truth on the weights as all the manufacturers post them differently, with or without mount with or without battery. Most reviews just repeat the specs given by the manufacturers. I haven't seen any that verify run time, weight or even length. Most try to make their units seem shorter by removing the rubber eyepiece. They should post both.