So I'm considering a thermal purchase and the device I am looking at uses CR123A batteries.

I have a few stocked up, but I wanted to ask what you guys use? Thoughts on rechargeables?

I have had great luck with these.
The blue ones where crap but theses are great.
In my TLR1 they last about 45min compared to the disposable so plan accordingly.
My go bags have standard batteries which last about 1.2 hours.

From what I've been warned, the rechargeables can get hot and could explode.   No practical experience though

Slightly off topic, but this review was very helpful, I decided to switch to the "off brand" because it's better and cheaper
http://www.candlepowerforums.com/vb/showthread.php?362052-Selfbuilt-s-CR123A-Battery-Comparison-2013

They also start out at a higher voltage.  I know they have burned out my surefire e2d head and had to have it warrantied (they told me that was the cause) YMMV.

Have not heard of that, hard to believe
53 of them for $50 with free shipping, 5/5 with 93 reviews.
http://m.batteryjunction.com/tpen-tcr123a-.html

Regarding rechargeable CR123A's:

Most important is does the maker of the thermal allow the use of rechargeables in the device you intend on buying? Not all makers of thermal allow rechargeables.   Rechargeable CR123A's (aka RCR123A's), upon being freshly charged, will have a voltage of around 3.8 volts vs the 3.26 or so volts in a fresh CR123A.  If the unit can't handle that high of voltage, it could be damaged.  Even if rechargeables are allowed, let them sit about an hour before being used following the recharge process.  The voltage will drop a little and will stabilize.

My thermal allows rechargeables.  The rechargeables I use (Tenergy) are 900mAh.  My thermal uses 2 of them.  They last about 1 1/2 hours with the screen brightness on medium.  When I use 1400mAh Titanium (Chinese) non rechargeable, my thermal runs about 4 hours.  When I use Panasonic 1550mAh non rechargeable, my thermal runs about 4 1/2 hours.  I buy from Battery Junction in bulk.

Call me a liar then,  this is what surefire told me when my light stopped working and I had it sent to em...they said my led is burned out and they ask what batteries I am using.   They said we cover it anyways but stop using rcr123.  Been using Panasonic, streamlight and surefire 123 ever since (in all my gear).

Sorry! I thought you were talking about the Titanium Innovations CR123A's I posted the link to... Yeah, rechargeables have different chemistries compared to alkaline and lithium, so the voltages will be different.

We had a guy at work that used yhem in a handheld flir.  He actually mixed regular cr123 and rechargable.  It caught on fire and sorta blew up. Not an explosion but ruined the tam.

Aha! So after reading this I dug a bit deeper. I'm actually looking at the Pulsar Apex XD50A. It does mention an external battery!

Thanks!

No rechargables in my gear that is not explicitly approved for them.  Contact your manufacturers for their position.  Rechargable batteries have caused grief on some systems in the past.  The juice on the savings isn't worth the squeeze to me.

Same with me, only use rechargeables in LED lights since they can handle the various voltages most of the time.