jacktheclipper, I really appreciate your positive feedback.
Here are some updates to complement my review.
This is a link to the Ultrafire headband sold by Kaidomain. I believe this is the one which comes on Ultrafire’s “H” series Zebralight knock-offs. I don’t think Kaidomain knows what they have. If you search “headband”, nothing comes up. It’s sold as “Ultrafire Elastic Belt”, item number S009709. If you search either of those terms, it does come up. Amazingly low price: $3.54/free, and that price has not gone up since I bought in 2012.
http://www.kaidomain.com/product/details.S009709
It is in my opinion a very nice upgrade, better than “re-threading” your current Zebralight headband through the flashlight holes. One of those rare occasions where the cheap knock-off rivals the expensive original. If you’ve never found your Zebralight headband a little tight or overly curved though, you probably don’t need it. But it can be used on a variety of other lights, including the Trustfire right-angles which never came with a headband. Rubber is extremely soft, like the Zebralight one, and the headband softer, more easily stretched, and therefore more comfortable, but likely not as durable.
I have ordered the “Genuine Sanyo UR14500P 14500 840mAh Li-ion Battery (2-Pack)” from FastTech (currently $9.94/free). The UR14500P is probably the highest quality 14500 cell in existence (and what is inside Zebralight’s ZL584 14500 battery). However, this lot from FastTech appears to be old (January 2003 according to a comment there), just bare unprotected red Sanyo cells, hence the low price, I guess. I actually wanted unprotected in this case, to try for better fit in the H502, but I’m worried about age’s impact on capacity. I don’t have equipment to properly measure capacity. If they are at or near rated capacity, they’d be an outstanding value. Intl-Outdoor sells a 2-pack of new, protected UR14500P, but they’re pricey at around $17.50.
http://www.fasttech.com/products/0/10002603/1287511-genuine-sanyo-ur14500p-14500-840mah-li-ion-battery
I’ve read the Nitecore NL147 cell (14500, protected) is a bit thick, and though I didn’t order it, I believe it would probably not be too thick for the H502, as my Trustfire flames have a little wiggle room to shake inside the tube. Length is another matter. FastTech has the best price I’ve found. This is a slightly lower capacity Sanyo cell. I have not found a discharge graph to compare to the UR14500P.
http://www.fasttech.com/products/0/10001848/1134000-nitecore-nl147-14500-750mah-37v-rechargeable-lithi
There is a good discussion of the best 14500 at:
thread title: “14500 battery from Fasttech-which one for SK68 clone”.
I’m now measuring from 3.6V and up on Trustfire flames. So far, it looks fairly well regulated to 1 amp on High. I’ll update when I’m finished charging.