LED Headlamps and Lithium Batteries

Yup. Energizer Li batts are abt 1.6V, so a set of three will yield 4.8V, not the 4.5V the circuit expects. You can always email PT for a definitive answer. Most manuf. have taken note of Energizer batts (lightweight, longer lasting, and excellent cold-weather use) and are specificall listing (or delisting) Li batts.

Note that there are Li-Ion rechargeable batts in AA and AAA format (as well as CR123A format) that are even higher voltage; these should never be used in traditional headlamps/flashlights.

Lithium batteries are great B/C they are lighter and last longer than alkaline and work much better in cold weather. But they are pricier.

Many PETZEL headlamps will burn out with the use of lithium batteries. I think PETZEL has finally addressed this "burning issue".

Also Princeton Tec is among the few headlamp makers who uses specal circuitry in their larger headlamps to give you VERY little decrease in battery life until the last 10 minutes, when it drops off quickly. My Black Diamond headlamp does not have this so the light dims at a constant rate as the batteries lose power.

If you are fascinated by high tech flashlights like the pricey SureFire ones be sure you get this advanced circuitry in it.

Yes, I heard that lithiums could provide too much juice. But the lack of specific warning in the instructions or on the PT website confused me. I will contact PT to get the definitive answer like you said.

So there are practical issues with using lithiums in headlamps not specifically designated for lithium batteries? Like overheating or damage to cicuitry?

I do also have a PT EOS that is regulated. I want to try out the PT Fuel because it is lighter and less bulky.

I have used Lithium batteries in my Princeton Tec Fuel with no problem. The batteries are getting close to end of life so I have another set ready when I decide it's too dim.

Of course, I like them because they're lighter and last longer.

I have a Petzl Tikka (or something like that) that warned about using Lithiums, but I did it anyway without problem. I think there is a chance, at some point, of an LED burning out.

I have an older Princeton Tec that's hard to get the batteries in and out of, which set me on the path of using Lithiums to reduce number of batter exchanges.

I have used lithiums in both Petzl and Princeton tec headlamps with no problems whatsoever.

It sounds like there is a potential for a problem but not necessarily a problem. Good to know.

IIRC, the Petzl "squared" series (e.g., Tikka XP^2) are all compatible with lithium batteries…

It's not a good idea to use lithium batteries in the original Petzl Tikka XP model. It will still light up and you will be able to use it but the battery drains very quickly and as lithium batteries are expensive this not ideal.

Also there is a real risk of damaging the circuits and this too is not ideal. A friend of mine frizzled her Tikka using lithium batteries.

This is not a helpful development when you're out in the bush, especially considering it is strapped around your noggin, and this region of the body should not be exposed to any type of frizzle related events.

I called Princeton Tec, but I ended up talking to someone who put me on hold a couple times to get more info. In other words I got customer service not the tech department.

They said they don't recommend the lithiums for unregulated lights such as the Fuel because too much voltage goes to the LEDs and they can burn out or something like that.

So there you go, that's what I thought they would say. But as some folks have posted above, it seems in the field there may not be any problem. Hmmmm.

But, it's a porobalistic thing

If there's a small chance the LEDs burn out when I put in Lithiums, then I'll probably be okay

If Princeton Tec has a many customers trying Lithiums and a few burn out their LEDs, then they'll have a bunch of unhappy customers

Better for Princeton Tec to just recommend not using Lithiums

Maybe unwise of me to use Lithiums if there's even just a small chance of LED burning out when I'm on a trip and need it to work

Most likely to burn out when I first put in batteries when voltage is highest? So maybe after new Lithiums, use it a little before going off into the wilderness?

OK, folks, here comes the second-rate gear experiment geek again. Hide the children and small pets.

During the rather cold Boulder, CO winter of 2004 I decided to once and for all figure out the relative efficiencies of flashlights/headlamps, various batteries, and temperatures. I tested 9 or 10 different Princeton Tec lights, 4 different bulb types (LED, xenon, halogen, and basic krypton), and 3 battery types (NiMH, alkaline and lithium). I loaded the lights with the batteries, and then turned them on and let them run until they ran out of power. I did this at room temperature (~70*F), ~32*F on the patio, and ~0*F on the patio. I recorded everything on a spreadsheet.

The results were about what one would expect:

Alkaline batteries don't function very well below 32*F, and they become nearly useless at 0*F. NiMH cells do better in the cold than alkalines, and a whole lot better at temperatures nearing 0*F. Both of these battery types will regain some efficiency when rewarmed (such as inside your pocket). Lithiums, of course, remain stellar until the very end, regardless of ambient temperatures.

Now, the bulbs. I only blew 3 bulbs–one halogen with alkaline cells at 70*F for 3 hours; one krypton with lithium batteries at 70*F for 2.5 hours, and one xenon with lithiums at 70*F for just an hour. There was no problem with any of the LEDs. My theory (completely unscientific, purely anecdotal) is that the bulbs (but just a few) became overheated and blew when exposed to 1-3 hours of steady use at 70*F. There were no issues when the lights were used at lower temperatures. I should also note that the vast majority of the tests at 70*F produced no problems, even with run times of 5-6 hours utilizing lithium cells. There certainly are a few unknowns involved here, including perhaps the consistant quality of the bulbs themselves.

Now, I don't think any of these lights employed regulated circuits, as the concept probably hadn't been used as of 2004. Anyway, I myself have used lithium batteries in all my lights since then, even in my xenon flashlights. I've not had a problem, ever. Your experiences will probably vary.

But whatever we do, lets not frizzle our tikkas…

…to drop the voltage on the lithium batteries before using them in devices that can't handle the higher voltage. Use the batteries for a bit in an old fashion flashlight, or radio, etc. This will drop the voltage down from the 1.6-1.7V to about 1.5V. Then the older headlights, or unregulated lights, or older Garmin GPS units, can use them.

You can always test the voltage with a multimeter (very cheap at radio shack).

Steve

Some great info and insights!