I have this headlamp. It has survived 3 cave trips now with no issues. The mAh claims are a lie and the lumens claims are a lie.... but I do love the headlamp.
Here it is for $16: http://www.amazon.com/Waterproof-Headli ... e+headlamp
- The batteries and charger are likely garbage. Plan to immediately deposit them in the garbage can where they belong, or if you can find the same light cheaper with no batteries, get that.
- The power switch is located on the back - maybe twice per cave trip, I hit it on the cave ceiling and it shuts off. Easy to turn back on, but annoying.
- I have very little confidence in the watertight seals. It does have gaskets in the battery compartment, but the charge port is just a little rubber plug. No idea how waterproof the lamp part is.
- This thing is crazy bright. Not 1800 lumens bright, but bright. Twice as bright as anyone else in the caving party, including some higher end lights.
- I get around 4 hours out of a good set of 18650 batteries before it dims and maybe 6-8 hours before it dies (I change them when it dims at all)
- Has a lower brightness setting that should squeeze more runtime out of your batteries
- Has held up to the caving abuse so far. Probably won't last forever, but for $16 I'm really not worried about it.
- Straps hold to my petzl helmet with no issues
I have a few tenergy protected cells for primary batteries and I carry a bunch of recycled laptop cells for emergency backups. I use a proper nitecore charger (get one, they're only $20) and try to follow appropriate safety measures when charging/discharging the batteries (especially the unprotected cells).
Anyways, just my two cents from a guy who has to cave on a tight budget.