I just want to share that Energizer lithium batteries seem to make my headlight and two rear light (mars 3.0 and viewpoint ultra) brighter. They are more than regular batteries but it seems to be worth it.

They have a higher voltage than alkaline batteries, that's why your light is brighter.

Thats good to know. I was amazed at the difference. IMO worth the extra few bucks.

And I believe these two lights are not meant to run on Lion batteries. The higher voltage will shorten their life span. Read you manual on either light, if it says to use Nimh batteries, the alkalines are going to fry the lights eventually.

I think he meant lithium primaries, not lithium-ion rechargables. Besides having a higher voltage, they also maintain a pretty consistent voltage until they're nearly dead, instead of drifting down with age. And they work at extremely low temperatures too.

There are 1.5V lithium batteries, such as Energizer Ultimate Lithium AA and AAA batteries. These can provide significantly longer life as well as offer other benefits:

https://www.energizer.com/products/li...batteries.aspx

https://data.energizer.com/PDFs/l91.pdf

https://data.energizer.com/PDFs/lithiuml91l92_appman.pdf

Aren't lithium primaries the same voltage as alkaline (1.5V)? Agreed about the voltage staying more constant vs lifespan and the better cold weather performance.

NiMh is lower and I've been burned by this in the past as I had several digital cameras that required the 1.5V batteries. My latest camera runs fine with NiMh and it's a big benefit to me. Glad someone finally decided to make that arrangement work.

No, not neccessarily. Some Li primaries have an initial voltage of 1.8v. If you have 4 of these in series in a device, it will driven by 7.2v initially, vs 6.0v from alkaline cells with initial 1.5V, or as low as 4.8V from depleted NiMHs at 1.2V.

Some devices will be damaged by operating at 7.2V instead of the intended 6.0V. I burned out a Petzl headlamp with Li primaries. I was aware of the situation but didn't worry because it was an old headlamp anyway, pretty dim compared to current headlamps. It did not die right away, but rather took 10s of hours, and it didn't completely die, but it burns very dim now on any cells.

As mechBgon stated, Li primaries do have a flatter discharge and work in cold weather when alkalines and NiMHs may not. Also, Li primaries are significantly lighter in weight (14g vs 22g in the AA size). They are ideal for lightweight backpacking purposes, provided the device has an adequate voltage range to use them without damage. Many newer devices have now evolved to accept Li primaries, so the device makers are catching up with the cell makers.

I've considered getting lithium-ion rechargables to use in blinkies, nominal 3.7 volts, but use just one Li-ion and one dummy cell (a piece of stainless-steel tube or whatever). That would be an interesting way to overdrive standard blinkies and have rechargable capability at the same time.

@mechBgon:

Any dummy cell you can dream up, someone has probably already made it, and probably sales it somewhere.

CPF is full of discussion of DIY dummy cells and the Marketplace sells them too.

I don't know what size cell you need, but you can fabricate them yourself with common tools using Al tubing or rod from Lowes / HD. Al is easy to cut, file and sand.

One the most important aspects of Lithium primary cells is their extremely low self discharge rates. This characteristic makes them the perfect choice for your emergency back up light that may not be used frequently. I use Lithium primary cells in my "emergency" household flashlights as well.

In contrast NiMH are best used directly after charging. The only real "issue" with alkaline cells is their loss of resistance and subsequent "runaway" heating when used continuously. In a blinky light, or low current circuit -this is not as issue.

Don't get me started- I keep going and going and going and going ........

Sanyo Eneloops are also LSD cells, just like Li in this respect. Good cells for emergency devices, especially the many that take AAs.

I've tested Eneloops: charged to a fresh 1.31v , set back for 12 months, dropped to only 1.28v. I get more drop than that from conventional NiMHs in a few days.