LIon vs primarys Spark ST5

I Have a Spark st5 125ow and use both primarys and lithiun ion batteries. The Primarys seem to be brighter? Anyone know why? It's very hard to compare the two with only one light, but the primarys are brighter!

I remember hearing that before (but have never tried it myself). I think it has something to do with the circuit; it's able to boost current from a single AA primary, but has to go into a less efficient mode to handle the higher voltage of of the Li ion battery. Or something like that.

Ted

Drivers that are able to handle a wider range of voltages are inherently less efficient than those that are designed for a narrower voltage range. Look at the new ZL's and you'll see what I mean; they're very efficient and designed only to work in the 1v - 2v range.

I bought a 125OW from SBflashlights, but the unit was defective (as was Ted's) and I had to send it back. I noticed some particularly peculiar behavior with the light using a 14500 compared to a primary or a nimh. The low and high modes were the same on both cell types, but on 14500 the medium setting was almost indistinguishable from the high setting.

The new ones are supposed to be getting XML's and I'm supposed to receive one of the new ones as soon as they become available. If there are no issues with it, and the beam is even floodier than before because of the XML, I may have a new favorite headlamp.