Where these left in the head torch for any amount of time before you found them dead? I bet it was a parasitic drain that has run them down to zero. This could happen relative quickly especially if the batteries where near flat when you put them away.
YOU can bring them back, but whether you SHOULD is a whole other story. You may of even gone into negative charge if they were in series.
- there are reports that switches are falling out, or rather are falling in (the enclosure).
The driver seems to be less than perfect, with the main light dimming when you ignite the two other leds.
- IF the issue is the driver or other internal electronics, it can wear out the batteries, even when sitting on a shelf.
A protected battery stops at 2.8-3.0V, an unprotected battery stops when it is completely drained/dead.
A protected battery can be charged as usual, an unprotected battery can (sometimes) be revived.
- The OPUS is an analysing charger and has more possibilities and options than any of my XTAR chargers. But it does not revive a Li-Ion battery that is drained to a voltage just above that of a NiMH battery.
What I normally do I leave them in the head torch.
Approximately every two weeks when I have night shift work I charge them while driving to work
Last week while I was driving to the work night shift I used USB cable supplied with head light and I drove for about 2 hours (means batteries on charge for 2 hours)
while I was at work I tried to use the head light nothing tuned on !!!! hooked head torch with USB cable there is light once I unplugged no light!!! same happened before two months with different set of battries
When I came home and used my USB Nitecore UM20 charger and charger read zero means batteries not getting charged
Regards
Zillah,
I very highly suspect the Boruit... I bought one on eBay, was happy initially then after several weeks the electronic power switch had intermittent and eventually fatal failures. I felt cheated.
Could be as it is ebay stuff ,for the head light I don't mind to buy a quality one
I want to cross check if the batteries were gone and can't be used any more