EOTechs and cold temperatures

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[ARCHIVED THREAD] - EOTechs and cold temperatures

Posted: 2/8/2021 2:43:52 PM EDT

I'm planning on doing a stand hunt in a couple weeks that may have me sitting out in temps in the 20s and teens if not lower for 8+ hours. I did this last year and had some electronics fail from the cold. I plan on keeping stuff inside my coat this year, but I just had the thought that I'm going to be using an EXPS3-0 on my rifle and obviously I can't keep that in my coat. This will be the first time I'll have been on a hunt in cold weather with an electronic sight.

So my question, anyone know if these sights have any problems in extended periods of freezing temps? Given they're a tactical sight I'd expect they'd be built to handle it, but at least one item I had fail last year I'd have expected could handle it too, and it failed.

Posted: 2/8/2021 3:06:36 PM EDT

[#1]

Quoted:
I'm planning on doing a stand hunt in a couple weeks that may have me sitting out in temps in the 20s and teens if not lower for 8+ hours. I did this last year and had some electronics fail from the cold. I plan on keeping stuff inside my coat this year, but I just had the thought that I'm going to be using an EXPS3-0 on my rifle and obviously I can't keep that in my coat. This will be the first time I'll have been on a hunt in cold weather with an electronic sight.

So my question, anyone know if these sights have any problems in extended periods of freezing temps? Given they're a tactical sight I'd expect they'd be built to handle it, but at least one item I had fail last year I'd have expected could handle it too, and it failed.

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No problems with my XPS-2. Not mid summer in FL or winter in NC.

Actually shipped it once from FL to NC mid winter through a 60 degree temp difference 80's to the 20's. Perfectly fine including the battery.

Posted: 2/8/2021 3:53:58 PM EDT

[#2]

Tested my EXP 3 yesterday in -2 degrees. Worked fine but my gloves sucked so I was only out for an hour.

Posted: 2/8/2021 9:46:27 PM EDT

[#3]

Quote History

Quoted:

No problems with my XPS-2. Not mid summer in FL or winter in NC.

Actually shipped it once from FL to NC mid winter through a 60 degree temp difference 80's to the 20's. Perfectly fine including the battery.

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Not so much concerned about lasting issues as much as just losing function while I'm out there. First time I'm going to be out hunting where my only useful aiming device is electronic.

Posted: 2/8/2021 9:48:29 PM EDT

[#4]

Quote History

Quoted:
Tested my EXP 3 yesterday in -2 degrees. Worked fine but my gloves sucked so I was only out for an hour.

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That's a pretty good bit of evidence, thanks. It's unlikely it'll be quite that cold, but I will be out there for way longer than an hour.

Last year I had things fail. When I quit around 3am, I turned on white light and realized everything I had out there was covered in frost.

Posted: 2/8/2021 11:40:46 PM EDT

[#5]

Batteries don't do well in the cold. As they cool, output current can drop. If the electrolyte actually freezes, they stop functioning altogether. Frozen batteries can even crack open/burst.

Low drain devices like an Aimpoint may work until the battery freezes.

One trick is to keep spare batteries inside your coat and periodically swap them with what was in the optic. Put the swapped batteries inside your coat to re-warm them. That should restore their function.

You did not mentioned what failed last time. Did the function recover when warmed with a new battery?

Posted: 2/11/2021 11:37:58 AM EDT

[#6]

Quote History

Quoted:
Batteries don't do well in the cold. As they cool, output current can drop. If the electrolyte actually freezes, they stop functioning altogether. Frozen batteries can even crack open/burst.

Low drain devices like an Aimpoint may work until the battery freezes.

One trick is to keep spare batteries inside your coat and periodically swap them with what was in the optic. Put the swapped batteries inside your coat to re-warm them. That should restore their function.

You did not mentioned what failed last time. Did the function recover when warmed with a new battery?

View Quote

Do people actually use alkaline batteries in $500 optics?

I only use lithium in anything that cost over $50 or anything I actually might need to depend on.

To answer your question, OP, I've used my 512s and 516s down to 14 degrees and never had any issues.

Posted: 2/11/2021 12:33:09 PM EDT

[#7]

Quote History

Quoted:

Do people actually use alkaline batteries in $500 optics?

I only use lithium in anything that cost over $50 or anything I actually might need to depend on.

To answer your question, OP, I've used my 512s and 516s down to 14 degrees and never had any issues.

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Who knows? OP never answered the questions.

Posted: 2/11/2021 12:43:50 PM EDT

[#8]

Quote History

Quoted:

Do people actually use alkaline batteries in $500 optics?

I only use lithium in anything that cost over $50 or anything I actually might need to depend on.

View Quote

I consistently run across people who do. And not just gun related shit either.

Posted: 2/11/2021 1:16:55 PM EDT

[#9]

Quote History

Quoted:

Do people actually use alkaline batteries in $500 optics?

I only use lithium in anything that cost over $50 or anything I actually might need to depend on.

To answer your question, OP, I've used my 512s and 516s down to 14 degrees and never had any issues.

View Quote

Yep, I use lithium in everything these days, even cheaper items.

Posted: 2/11/2021 1:21:37 PM EDT

[#10]

Quote History

Quoted:
Batteries don't do well in the cold. As they cool, output current can drop. If the electrolyte actually freezes, they stop functioning altogether. Frozen batteries can even crack open/burst.

Low drain devices like an Aimpoint may work until the battery freezes.

One trick is to keep spare batteries inside your coat and periodically swap them with what was in the optic. Put the swapped batteries inside your coat to re-warm them. That should restore their function.

You did not mentioned what failed last time. Did the function recover when warmed with a new battery?

View Quote

The item that failed that surprised me was my FLIR Breach. I was using Surefire brand batteries. After the device really got cold, I would toss in a brand new battery and it would die within a few seconds, literally. The batteries were fine though, and those same batteries were still operating my lights just fine by the end of the night.

I kept all those batteries and tested them, they were all good to go. I ran an experiment a day or so later, putting stuff in the freezer for a while, but unfortunately I don't remember the exact results of that. I just remember coming to the conclusion that the device was the issue and I should keep it in my coat next time when not in use.

Posted: 2/20/2021 5:26:22 AM EDT

[#11]

Two days in, no issues at all so far. Last night I was out about 6.5 hours. All my gear was covered in snow when I was done. It was just flurries and I couldn't really tell just how much it was snowing while out there. Temps were only in the high 20s though. Tonight I was out there around 5 hours, temps in the mid to low 20s. Again, covered in snow. Still no gear issues. I have the EOTech in NV mode the whole time though, I suppose that's a little easier on the battery.