battery life question (for the electrical geeks:)

[ST911]

Anecdote on batteries... Earlier this year I was cleaning out some storage and found a camera and lithium 123 batts that had been there for 10-12 years. I pulled the batts and ran them in a 6P for quite awhile, seemingly only slightly less time than I would've gotten from a new set. I believe they were Duracells.

Buying quality batteries makes a lot of difference. I've had bulk-orders of imported economy 123's that didn't go half as long as the set above. $0.99 Rayovacs at the Walmart, and their button-cell equivalents, are junk in my experience.

One of my colleagues recently acquired an Eotech, and has replaced his (AA) batteries twice in a terribly short interval. Most recently, he put some lithium AAs in, so we'll see. I prefer lithium, especially in stuff that counts.

I'm also of the opinion that batteries should be replaced periodically in stuff that counts to hedge the bet. My device might go umpteen thousand hours, but I feel better if I know the battery in it is no older than X amount of time.

[Pat_Rogers]

From the head tech guy;

Shelf life:
Lithium= 10 yrs
Alkaline= 8 yrs

An Aimpoint with ACET (M3, ML3, M4, T1) w/ 2 moa dot at med setting will draw less then the battery packaged on the shelf.

Poster stated that curve changes as you use them. Correct, and generally i will destroy/ damage items long before it becomes an issue.
Another factor is that new technology is fast moving, and what was great yesterday is mediocre today.

I replace Aimpoint batteries on my hard use guns 1x yearly. However, on the student guns 1 will replace at 3 years or as needed.

On my EOtechs i replace batteries constantly...

Hope that helps....

[ZGXtreme]

Here is a rule of thumb for Ops from a technical point of view. If you use the batteries on an op, chuck them immediately when you get back. Always go out with fresh batteries and extras.

Thats a great habit Sidewinder that I also adhere to. If I use my X200 on my pistol quite a bit over a few shifts then I replace them with new and toss the old batteries in a bag for training.

If you save them for training then you don't have to worry about wasting batteries and if they go dead, well it just makes you improvise during your training so you can adapt to good ole' Murphy!

[Rob96]

Rob- that is partial information, and without knowing specifics, is not too viable.

For example- which Aimpoint. The M68 covers the Comp M2, M3, and M4. All have different electronics, and different battery life estimates.

However, the big fly in the ointment is batteries. Not all batteries are the same. Certainly Lithium is the better choice, and what i use.
However, this may not always be possible.
I have tested brand new batteries just off the shelf that were non functional.
It is a common problem.

I did take an AA out of an EO that was "dead" and place it in an M4 and it worked. It is a little over a month now, and still functional.

Pat, I realized that after I typed it. Still lends credence to "if you have a battery powered optic, have spares on hand".

[Pat_Rogers]

I agree about spares (for anything) 110%.
Aimpoint failures are generally rare, and most Aimpoint problems are battery related. Having said that, older models will puke more often then newer models.
Not having spare batteries is dumb.

[toddackerman]

I agree about spares (for anything) 110%.
Aimpoint failures are generally rare, and most Aimpoint problems are battery related. Having said that, older models will puke more often then newer models.
Not having spare batteries is dumb.

Amen to that Pat!

I just got an M3 from Grant, (stated 50,000 hours, or over 5 years run time on the middle setting), and without even thinking about it, I included a spare battery with the order.

I have been in "Hi Tech" for most of my life and have worked with some pretty significant battery backed up systems. Especially in Life Sustaining Medical Equipment. I have seen for myself everything that has been posted here 1st hand. Hence, I immediately test all new Lithium Batteries for serious applications BEFORE I shelve them to make sure they weren't rejects out of the box, and then I only keep them for 1/2 of the shelf life date code before moving them to non-serious applications like the remote for the TV, or General Purpose Flashlights.

I plan on replacing the Aimpoint battery at 2 years Max.

Tack

[twl]

A pic of the prototype for one of my solutions.
Eotech with "on-board" unbreakable solar charging for the AA models.

[UVvis]

A pic of the prototype for one of my solutions.
Eotech with "on-board" unbreakable solar charging for the AA models.

That is really neat.

If I may ask:

What type of what chemistry and how many cells is this using? Where are the charger electronics, is it a smart charger? Solar cells embedded in epoxy? Any thought to adding a plug and putting a larger solar rack in something like a hand guard cover?

[twl]

That is really neat.

If I may ask:

What type of what chemistry and how many cells is this using? Where are the charger electronics, is it a smart charger? Solar cells embedded in epoxy? Any thought to adding a plug and putting a larger solar rack in something like a hand guard cover?

This is a 2 AA cell unit.
I use NiMh chemistry to eliminate the charge "memory", for this use, because I felt it was a better fit for the application.
It is "self-regulating" by design, so no worries about overcharge. Very simple circuit design.

The solar cells are the amorphous type on a flexible substrate that is about the thickness of a couple of sheets of typing paper. They're unbreakable. No glass anywhere in this charging system. In this application I used the existing protective arch on the Eotech as the framework.
It's not totally indestructible, but drops and such are no problem. Some reasonable care should be taken to not scrape the solar panel with any undue force, and keep volatile chemicals off of it, which could cloud the polymer protective layer.

I also make a battery-charging buttstock based on the Crane/LMT type stock with the battery tubes, so they can charge while in the battery tubes of the stock. One model that I sent to Crane NSWC for evaluation also had a plug on it for detonating Claymores, and thus reducing the need for the "clacker".
I could also make specialty units that could go on the handguard covers as well. I've considered this for a possible future project.
Charging capacity is limited by the amount of available surface area.

I've been doing stuff like this for a number of years now, on a limited custom basis for individuals who had some special needs.
I showed it to L3 at last year's SHOT Show. I don't know whether they are interested in buying this design, or not.
They seemed very excited about it, but nobody from L3 ever called me about it.

[UVvis]

Very nice!

I'm also wondering, what is the approximate rating of those solar cells?