I'm considering purchasing a clip on thermal. Does anyone have any experience with these? I'm a northern Yankee so battery life in the cold is a real concern for me. Any thoughts? Thanks

Several thoughts.

First, you don't save much in the way of money with clip on thermals.

Second, people think clip-on thermals will turn their day rifle into a night rifle and it will, but it doesn't make your rifle a jack of all trades as there are some tradeoffs. One major tradeoff is a loss of FOV. Also, most clip-ons are 1x which means you are looking through your magnified daylight optic at a 1x image. You zoom your day optic to 3x, do not give you a 3x image but a 1x image magnified 3 times...sort of like holding up a magnifying lens to the TV.

Third, a lot of people who buy clip-on thermals end up buying dedicated thermal rifle scopes because they find the clip-on adaptation to not be the experience they want.

Fourth, while clip-ons are supposed to have great return-to-zero (RTZ) capability, I have seen numerous hunts ruined when the clip-on somehow isn't aligned perfectly and the shooter can't hit squat. If you use a clip-on and don't verify with a shot on target that your scope is indeed where it should be, sooner or later, it will cause you a problem. The key here is to trust, but verify.

Fifth, adding a clip-on to your day scope puts a goodly amount of weight on the muzzle end of the rifle. So you have a rifle weighted down by two optics and one of them was way forward which many people finds upsets the "balance" of the rifle. I actually like the additional muzzle end weight because it helps moderate muzzle rise on recoil, but if you are shooting offhand, holding a muzzle heavy gun gets tiresome very quickly.

Six, because the optic is positioned at the far end of your day optic, making any adjustments to the clip-on thermal can be quite a reach, depending on the day optic you use, rifle, and the length of your arms. Often, the experience ranges from inconvenient to quite difficult.

Seventh, you don't see a lot of people using clip-ons for the reasons noted (and probably some others)

Eighth, a few people out there really like them, in part because they can more readily move them between various rifles without removing their day optics that may not have RTZ mounts.

If you are dead set on getting a clip-on thermal, if you can't borrow one from somebody to test out extensively, I would suggest you buy a clip-on digital NV optic for a few hundred bucks and learn the ins and outs of clip-ons before you spend a few thousand bucks on a clip-on thermal.

Your response is the reason that I was asking. I never would have thought about half of the things you brought up. Thank you for your detailed response. I guess I'll just save up for a true thermal. THANKS AGAIN!

You are welcome. Those are my observations and opinions. I am not a big fan of clip-ons (you can infer that I am BIASED). I was sort of hoping somebody would post some counter arguments or at list least why they DO like their clip-on. They certainly have their place and utility, but I did not find them the best match for me and my needs.

I got counter arguments but none that would sway it one way or another .

A clip on is technically more versatile than a dedicated optic.

This added versatility brings along with it added complexity and need for the user to adapt themselves to the process of use and troubleshooting when things don’t work right.

Someday I’ll add counter points but that’s the gist

I've had an ATN clip on for about a decade now, and I absolutely love it! I like that I can switch the clip-on between several different rifles without investing in multiple thermals. I use it on several ARs with the rails without having to alter anything. I use it on one of my R700s in .308. I added a McCann rail to the R700, and other than it being somewhat awkward when using a sling over my shoulder, it doesn't alter the operations one bit.

I use a hand held thermal for scanning, so battery life isn't an issue.

Most thermal scopes have multiple zero files so you can easily switch from one gun to another. For a couple years I ran a day scope and thermal scope on the same rifle, both with quality quick release mounts and never sighted them back in. I also use my thermal scope as a scanner until I’m ready to shoot then clip it on the gun.