Wait, if these are for lower voltage, then what's best for, say, a KGO? While not a HV device, it's unregulated 3.6-4.2, so a fresh charge could easily create the heat required for a burnt taste. On a side note, I've had two just decide to randomly leak all of their juice out, no clue why, but the shame was the flavor on the ones that leaked was amazing prior to the gasket spilling out gobs of liquid.
Please note that I just summerized what I was reading and as I mentioned there were several that it worked well up to 4.2v... still everyone's preferences will differ so really you won't know until you try it if it is for you or not...