1.7v lithium or 3.0v lithium aa's?

[wvaltakis2]

I just picked up a 2xaa tube for my HDS to keep in my B.O.B. and I was wondering which would be better to keep in it, 2 E2's or a split CRV3 (already figured out 2x14500 wont work)? Common sense would say the 3 volts but I could be wrong so I thought I'd ask.

Thanks,

~Chip

 

[wvaltakis2]

Anybody?

 

[Curious_character]

Don't know anything about the HDS, but the two cells in a CRV3 are 14500 primary cells, with open circuit voltage when fresh of about 3.5 volts and dropping rapidly to about 3.0 volts under load. If your HDS will tolerate two lithium primaries in series (briefly as high as about 7.0 volts), CRV3 cells should be ok. Otherwise use the L91 cells.

Two L91s have very nearly the same total amount of energy as the two cells in a CRV3.


c_c

 

[wvaltakis2]

The HDS will take up to 7.13v if I remember right so the voltage is fine, but basically what you're saying is I'd get about the same runtime from either ?

Thanks,
~Chip

 

[Curious_character]

Actually, probably not. Chances are that the light has a buck regulator. So when using the two higher voltage cells, it would be regulated clear until the cells are fully discharged. But when running from the lower voltage cells, it will probably function pretty much like direct drive. If that's the case, you'd probably get a somewhat longer run time, but at lower and decreasing light level, from the L91 cells. Because of the possible variations of regulator design, though, I'd hesitate to put any money on it -- you'd have to run some tests to tell for sure.

c_c