Gerber Infinity Ultra-M Runtime Test Results

Ok, so I really like the IU for there long run times. The are advertised and sold as being able to run for 100 hours on a standard AA alkaline battery. It isn't really bright, but in pitch black darkness, it could save the day. It is pretty indestructible as well.

So I was curious as to if the claimed runtime was really true. I decided to do a runtime test of my own.

I opened a fresh Energizer Lithium AA battery (you know, the silver colored ones that are suppose to run like 7 or 8 times longer than a standard AA Alkaline battery) and put it into a Gerber Infinity Ultra-M. I noted the date at time I turned on the flashlight. I put it on top of a shelf shining at a nearby wall in an unused room in my house. It was fairly cool in that room due to the air conditioning.

I checked on the light 13 hours later, and it was still running. That was not surprising to me as I was expecting the light to AT LEAST go over 4 days. After all, it is advertised and sold as being about to go that long on an alkaline AA, so it's possible (I was thinking) that it could go maybe even as much as a month due to the lithium AA's having 7 or 8 times the power.

After 24 hours, I checked on the light.... and, wait for it..... big disappointment to me. The light was dead, black, out, off, not shinning. It had been less than 25% of the advertised run time, and on a lithium at that!!! I took the battery out and put it back in and it glowed very, very dimly for about 2 more minutes, but then it went out again.

This was a brand new Energizer Lithium AA battery fresh out of the package. What a big disappointment. I thought it would at least go the 4 days.

I'm not sure when exactly it went out, but it was between 13 and 24 hours of runtime.

What does everyone make of this? What went wrong? Was I just naive to believe the 100 hour claim?

It's still a good light... just not as great as I thought it was.

I have heard that they do not run as long on lithium batts, they seem to run brighter, but poop out sooner.
This was the same owith my CMG IU as well.
I don't know why this is.
I have never tested mine in a constant run mode, however with intermittant use daily I have had the same battery in mine over a month and it is as bright as ever. I am using LSD NiMH .
I believe that intermittant use , giving the battery time to recover and alkaline batteries is probably the key to the longest runtime in total.

I have also read somewhere that the IU doesn't run as long on lithiums and the 100 hr runtime is claimed on alkalines only.

sabre7 said:

I have also read somewhere that the IU doesn't run as long on lithiums and the 100 hr runtime is claimed on alkalines only.

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Time for another test?

Well, alright then. I'll repeat the test, but this time with a standard AA battery. I'm not sure exactly how new this battery is, but it's definitely not expired. I think alkaline batteries self-discharge a bit over months right?

I'll post again here after the runtime test with a standard AA is done... hopefully it lasts days this time.

For comparison I'll also do a runtime test with my Infinity Ultra, the standard non-'M' version, white led.

I got the light new several months ago so I assume its the latest model. The package also quotes 100 hour battery life.

I wouldn't be a bit surprised if using the IU intermittently rather than continuously does yield a longer total runtime, but that test would be a PITA.

hi guys, i did a partial runtime test on alkaline batts some weeks back. i highly doubt its bright enough after 15 hours (mine's Gerber Infinity Ultra, non-M). i notice a visible drop in output after 8 hours.

with initial output on the dim side from start, i do not think the reminding 80hrs will put out enough light for tasks beyond arm's reach. :shakehead


just my opinion.

FWIW... I did some crude run time tests on the smaller Gerber Tempo (1AAA, Nichia emitter), and I found the box advertised run time of 3.5 hours pretty spot-on, with Energizer alkalines. If anything it was a little conservative, as I definitely got useable light for a good 6-7 hours. I found it really hard to evaluate the 50% drop with such a low 7 lumen starting point.

Ok, 24 hours into the run on alkaline the IU is really dim. Its at about 5% of its starting output.

The voltage was down to 0.86 but it was rebounding as I was taking the reading.

I'll leave it running and check it every twelve hours or so.

I bought a CMG IU some years ago, and IIRC, it claimed a runtime of 26 hours, and mine managed 25+ on a fresh Lithium cell.

Karl

I wonder how an oxyride would fare? I have a lot of them an own about 4 IU's!!:twothumbs

Mike

I carried my own run-time test, and the results were visible dimming at around 7 -8 hours and no output at all in less than 24 hours. That was on a freshly charged battery. 100 hours run time, no way.

The Auditor said:

I carried my own run-time test, and the results were visible dimming at around 7 -8 hours and no output at all in less than 24 hours. That was on a freshly charged battery. 100 hours run time, no way.

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Out of curiosity, what was the MAH rating of the battery used ?
This could be helpful in calculating continuous runtimes with other MAH values.

My 2nd run-time test is still running. It's been over 55 hours on a generic alkaline battery, and it's still going.

With that said, it is really really dim. I think LED indicator lights on electronics equipment (you know, like the power on light) are brighter than what it is currently.

I'll check it again tonight.

I'll keep this thread updated as to the results.

It just strikes me as weird that the crappy no-name alkaline has gone over twice as long as the Energizer Lithium "8x the power" cell. I guess I understand the rationale, but still, that seems backwards.

yalskey said:

My 2nd run-time test is still running. It's been over 55 hours on a generic alkaline battery, and it's still going.

With that said, it is really really dim.

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I'm at the 60 hour mark on my runtime test and I agree, the led is very, very dim.

Its still bright enough to navigate around a darkened house at night or to read by at a distance of a foot or two.

Interesting...

What is the current draw? Is it possible energizer lithiums are not optimal with such low current draw? Is it possible you got a dud-cell? Your findings are completely backwards from what the streamlight microstream users are reporting.

Many manufacturers dont use the "50% rule" when publishing run time specs. To them .01 Lumens for 3 hours is still considered run time.

:thumbsup:

kramer5150 said:

Interesting...

What is the current draw? Is it possible energizer lithiums are not optimal with such low current draw? Is it possible you got a dud-cell? Your findings are completely backwards from what the streamlight microstream users are reporting.
:thumbsup:

Click to expand...

It's possible that the cell was a dud, but not probable. It's also possible that my light itself is somehow defective, but not probable. The reason it's not probable is that other on this thread have reported supporting facts and similar result.

I agree it seems backwards, but I don't know enough to explain why that is.

Actually, that is exactly what I would expect. Same with a NiMH, as both types of cells put out pretty constant current/voltage right up to the bitter end, then taper off fairly rapidly. There were a couple of alkaline tests of CMG and Gerber IU's a few years ago, and about 120 hours is the norm, but it is mostly in that looong tail of the curve where the batteries voltage has dropped off, and likewise the current that the circuit can draw. Once it is pulling only a few milliamps, the remaining energy in the battery takes forever to drain, and this light's circuit will fire on almost nothing, which is great. I must admit, it is pretty dim after the first 20 hours or so, but as an emergency backup in a cave, 4-5 days of enough light to see what is in front of me is WAY better than nothing. Another interesting test recently was an intermitent runtime on alkaline, can't remember what light though. Bottom line, with something like 15 min. on, 2hrs rest, and pasting the curves together over a continuous discharge curve, you do get a lot more bang for your buck that way than what the continuous curve would suggest. And of course that is the way we most often use our lights.

I got my non-M version Gerber IU about a month ago, it came with Energizer alkaline AA, and package claims "battery life: up to 100 hrs." Would it make a difference whether it was an Energizer, Duracell, or generic alkaline?

Old but interesting thread: https://www.candlepowerforums.com/threads/125921