has anyone seen this with headlamp batteries?

“I must say I’m kind of shocked with how many non-rechargeable headlamps there still are on the market, but that is a topic for another thread.”

True, but there’s still a place for replaceable batteries, especially among adventure racers, fastpackers, hunters, and people who must plan on the potential of pushing well into the darkness.  Lithium is still the lightest/most powerful option if you’re pulling an all-nighter and need to carry spares…something I know Mike considers.

^ true that :)

also I was under the impression that Lithium primaries outclassed other batteries (rechargeable or else wise) in the cold

You could have two USB rechargeable headlamps.  When one dies, switch to the other.  Then recharge the first one.

The Iota runs maybe 2 hours on high, 8 hours on low (although they say it runs 20 hours on low).  Hmmm… they don’t seem to sell that anymore.

I do have a battery tester with a digital voltmeter in it, but it is of limited use with Lithiums. That applies even with pulse testing, where you draw something like 200 mA briefly. I KNOW that, so as long as the voltage is high enough, I keep using the battery.

As a matter of policy, all my gear uses AA Lithiums these days. On longer trips, given the light weight of the Lithiums, I carry a spare AA cell.

Cheers

A “USB rechargeable headlight” without user replaceable batteries is kinda limiting.  Gotta bring a power brick if you risk running out of power?  Much lighter to bring a spare battery if your headlight can accept it.

For those of you who would have a power brick no matter what, there are AA rechargeable batteries that can be recharged via USB (by Fenix).  And Olight has a RCR123 (16340) that can be recharged via USB.  Great options that open up great lights by Zebralight, Olight, etc.

I just received the ZTS MTB-1 tester that has both lithium AAA primary and alkaline AAA test posts- big difference when I measure what were once thought of as “good” batteries when measuring them on the alkaline post of my ZTS Mini tester.  Batteries that were showing 80+% on the alkaline post, show 20-40% on the lithium post.

Appears mystery solved :)

I have an interesting graphic which shows two differences between alaklines and lithiums.

The biggest difference is in the Service Hours scales. They are very different.
A less obvious difference but one which is very important is the amount of sag in the curves. The Lithium curve is a lot flatter until in nose-dives, while the alkaline sags steadily all the way down. This is why a battery tester calibrated for alkalines is really not all that useful on Lithiums.

Cheers