Not only run times, but discharge rates are not going to be enough for most applications. The LEDs we use pull current at a fairly aggressive rate. If you have batteries that cannot handle it, you will either just pop the batteries or worse, depending on the specific chemical composition of your batteries. Most of our LEDs want to grab at least 1A from the battery (some more than that). If you have a battery rated at 1.5C discharge rate and it is a 300 mah cap then you'd have at most 450 (hypothetical number, the discharge rate is actually probably much less) which is totally insufficient for what our use is. Keep in mind, that 9Vs have been tried many a time with sabers and they stink. For the same reasons.