Battery heads up (and solution)

[Archer1440]

As many of you know, CR type batteries (coin cells) are increasingly being produced with "bitterant coatings" designed to prevent children from ingesting said batteries.

These coatings, particularly those on Duracells, can compromise continuity and decrease available voltage, sometimes causing the battery to read low, or causing contact issues in sights. This is particularly the case where battery contacts are not designed with sharp points that can cut through said coating.

The coating can be removed with isopropanol or can be scuffed with Scotchbrite or other abrasives to increase contact reliability.

It should be considered to be good policy going forward- along with testing such batteries on a load tester- to be sure to clean all batteries in this manner before any red-dot installations.

Note that many such batteries can also test low on battery testers that have rounded contact points, if the coating isn't removed.

[RoyGBiv]

Thanks!

I'll plan on tasting my coin cells going forward. /jk

Seriously... Good info. Thanks for sharing.

[SoCalDep]

Thank you for that and I’ll keep it in mind. That said, we use Duracell’s almost exclusively and have not experienced any issues with the new batteries.

When the initial concern was voiced about the bitter batteries we were in the process of conducting our own battery tests and I added the new bitter batteries to it. We found them to have comparable run time to the previous Duracell 2032s, which is to say substantially better than any of the other batteries tested.

This was in Aimpoint H-2 rifle optics, though I’ve not heard any complaints with RMRs, SROs, DPPs, or the new ACRO P-2. I can see how different contact types could have issues however.

[GJM]

Thank you for that and I’ll keep it in mind. That said, we use Duracell’s almost exclusively and have not experienced any issues with the new batteries.

When the initial concern was voiced about the bitter batteries we were in the process of conducting our own battery tests and I added the new bitter batteries to it. We found them to have comparable run time to the previous Duracell 2032s, which is to say substantially better than any of the other batteries tested.

This was in Aimpoint H-2 rifle optics, though I’ve not heard any complaints with RMRs, SROs, DPPs, or the new ACRO P-2. I can see how different contact types could have issues however.

Have you tested Renata 2032 batteries?

[SoCalDep]

Have you tested Renata 2032 batteries?

Yes. They were the 2nd place finisher and I think they are a quality option. Going by memory which may not be exact they went ~100 and ~175 days. The Duracells went 124, ~220, ~240, and around 1.5 years. I stopped the bitter battery Duracell testing when they were still going strong after 125 days - I needed the optics for other batteries and they beat out the weakest old-style Duracell so I consider that comparable.

Of course, all the batteries got dim in the last 3/4s (ish) of their life, but the Duracell’s maintained full power clearly longer than anything but the Renata and beat them out for overall lifespan.

[Archer1440]

10 mA load testing of several coin cells on a YT video - methodology seemed to be fair, using a calibrated load and timer to determine time to 2 v at something like a common ambient temperature.

[SoCalDep]

10 mA load testing of several coin cells on a YT video - methodology seemed to be fair, using a calibrated load and timer to determine time to 2 v at something like a common ambient temperature.

What YouTube video? How many samples? How does 10 mAh compare to common optic power draw?

The Duracell results don’t surprise me but I’d like to get more information to compare. I’d also like to know if 2v is arbitrary or based on a functional necessity.

[RJ]

What YouTube video? How many samples? How does 10 mAh compare to common optic power draw?

The Duracell results don’t surprise me but I’d like to get more information to compare. I’d also like to know if 2v is arbitrary or based on a functional necessity.

Some speculation from an EE: Energizer spec sheet says a CR1632 has about 130 mAh capacity.

https://data.energizer.com/pdfs/cr1632.pdf

Holosun claims 50k hours for their HS507c X2. I'd guess that is with some solar assist, though. I'm not really convinced an optic can be powered up for five years, so as an engineering estimate, I'd say two years, maybe?. Running 24 h per day, 365 days, times two, is 17,520 hours. Back to the battery: 130mAh is 0.130Ah, so dividing 0.130Ah by 17,520 h yields a current draw of about 7 uA.

10 mA would thus be a factor of 1000 higher than the optic draws, assuming these figures. The circuitry would not be complex, probably a single IC. Most of the current would be driving the emitter, I would guess.

As to the 2V, yeah, the circuit is likely built around some floor voltage, but not sure it'd be available online. I would guess 2V is just a convenient percentage (2/3 of Voltage) of nominal for the same of comparison.

[Archer1440]

What YouTube video? How many samples? How does 10 mAh compare to common optic power draw?

The Duracell results don’t surprise me but I’d like to get more information to compare. I’d also like to know if 2v is arbitrary or based on a functional necessity.

1. https://www.youtube.com/watch?v=vQwaV5IbZV0

2. Not enough for a definitive test by any means, but it does appear to match results from other tests as well as the manufacturer TDS.

3. 2v is where the typical Lithium chemistry coin battery is for all practical purposes considered dead. This is common across all vendors.

4. A huge difference from common optics power draw, which also introduces the question of how the relatively high draw affects development of internal resistance and related chemistry complications.

It's just a data point that I thought would be relevant to the discussion.

ETA: And no way am I going to buy generic Harbor Freight batteries for important applications- no way to tell anything about what's actually in those blister packs from month to month.

[vcdgrips]

Is there a school solution battery tester we like that covers coin style and AAA thru D cells and CR123s etc.z/