I have the same concern. If the XP-E is getting hit with 1A or more of current from the 10440 I'd be worried. I believe the XP-E is only rated for 700mAH max? I'll probably stick to an eneloop or lithium primary.
It might be fun to try a 10440, but I would only do it for a brief time.
Hopefully 10440 users will continue to update us about their experiences. Has anyone run their Maratac AAA on a 10440 at the max setting for any length of time? 😛
Only several extended bursts of 90-120 seconds which is already well beyond the 30 seconds I would normally run the 10440 at. The little 10440 can't maintain 1A so the LED isn't seeing that sustained. Again, the 10440 battery itself is the weak link and the highest stressed piece of the package.
Phaserburn
Over 3C! Yikes! Unsafe discharge level for the cell.
Yeah, it's way above the "safe"
continuous discharge but I think the key parameter here is duration, duration, duration. Li-ion seems to be very resilient when it comes to spiking discharge rates as long as they're not held there for too long. Just as other hobbyists, as in the case of RC, sometimes push their batteries, so too do 10440 users in lights such as these. Obviously medium and low don't push any of the components so the only time the battery is under stress is on high. As long as people are aware that they're "hot-rodding" the cell and thus reducing it's life a bit then I don't see what we're doing as being any different from other high performance applications.
I also fly RC aircraft, mostly electric now, and use set-ups as large as 6S 6000mAh. The discharge rates are different from li-ion cylindrical cells but the principle is still the same. A battery may have a safe continuous discharge rating of 30C but can be discharged in bursts of 60C or even higher, as long as the duration is kept short.
Any 10440 user who is occasionally using high mode in these lights should monitor the charging process carefully while keeping the rate of charge around 150-200mA. It's always important to check that the finished voltage doesn't exceed 4.2V so use your DIMMs folks.
We're always going to have two different crowds here when it comes to the operation of batteries. There are the letter of the law people who believe it's wisest to take zero risk, and there are some willing to push their equipment a bit more even if it means they wear it out a little more quickly. Neither camp is "wrong" and I respect both sides.
To put things in perspective, I mentioned earlier that I still own the first 4 10440 Ultrafire cells that I purchased nearly three years ago. I've been using them in the fashion stated above for this entire time and they're still performing admirable. I don't know of any instances of 10440 cells venting here in the CPF community and unless improper chargers are used, I don't see why that would change.