I am still on my first set, (of 4), 18650 batteries from Solarforce, bought in August 2011.
After a failed attempt to replace a driver board. the emitter barely lit and the battery gave off a strong metallic smell, and no longer gave a reading on my ancient multi-meter. The other 3 batteries weren't used, so were unaffected.
I have just noticed my other batteries starting to have that same smell.
Is it solvent like? Like gasoline or nail varnish remover?
Metallic smells make me worry - is it like being near a photocopier which is working hard?
Is it acrid? Does it make you cough?
If the latter - dispose of the cells safely as a matter of urgency - it could be hydrofluoric acid which is exceedingly nasty stuff.
Can you lay your hands on a latex surgical glove? It must be latex - silicone rubber won't work for this. Leave the cells in the glove for a day or so. If the glove crumbles to dust when you touch it, you have some seriously hazardous waste on your hands.
7. If finding exceptional conditions, such as terrible odor, leakage, cracks and deformation on the battery crust, please stop using the battery immediately.
Immediately discontinue use of the battery if the battery emits an unusual smell, feels hot, changes colour, changes shape or appears abnormal in any way.
Analog MM will work fine. Check voltage by applying the negative (usually black) wire to negative end of battery, red to positive. I don't know if these were protected cells, but voltage should be somewhere between 2.75 up to 4.2v. I'm just suggesting to see if they have tripped the protection circuit. Follow Don's advice and be careful with those suckers, try not to breath the vapor if you can. Put them in a steel bucket in the back yard until you are sure.
I would think SF would replace if you've only had them since August.
If it is below 3V they are hazardous waste assuming they were put away charged. If not, then if they are below 2V don't even think about trying to charge them - the result will be very bad.
I cannot overstate how nasty lithium ion cells going bad can be.
Get them out of your house to somewhere where you don't care about damage.
Not knowing any better, I had already put two batteries in the charger. 1 smells a bit 1 doesn't.
They are protected cells, and I removed them as soon as you recommended. The one that smells a bit wasn't fully charged yet but does show just over 4 volts on the multimeter, as a matter of fact both batteries test just over 4 volts.
When the first battery failed about 6 weeks ago, I just though it was my tough luck.
How long should a 18650 Lith-ion battery last?
I carry and use 1 light maybe a hour or 2 a week, and recharge Friday or Saturday, the other 2 lights are mostly back-ups.
I was looking into buying some more batteries, but wasn't sure what to buy, if they weren't going to last more than 5 or 6 months.
Could you suggest a reliable, moderately priced, lith-ion battery, that is worth the asking price?
Thanks again, I really appreciate the resource of this forum!
Callie's are great, but I wouldn't classify them as moderately priced... Regarding your question on life - properly cared for Li-ion cells should last for several years and handle many charge cycles. I still have my first set of 18650s from 2 years ago and they are doing just fine. There is a natural loss of capacity with time, but it's not that much, on the order of 1-6% per year. They should be stored cool, at less than full capacity (3.9v is fine) and checked for charge periodically to make sure they don't drop below 3v. Avoid freezing and high temperatures. Most of us keep ours charged up and ready to go.
Here's my list - starting with Economy Priced: Trustfire 2400mAh http://www.manafont.com/advanced_search_result.php?keywords=trustfire+2400mAh&log=&x=0&y=0 Trustfire 3000mAh http://www.manafont.com/product_info.php/protected-trustfire-18650-37v-3000mah-rechargeable-batteries-2pcsset-p-7941 I would get these over the 2400
Mid-Priced: Xtar 2600mAh http://www.ebay.com/itm/2pcs-XTAR-18700-18650-2600mAh-Lithium-Battery-Fenix-/160708648279?pt=US_Batteries&hash=item256afb5d57 [These are really more like 18700, might not fit all your lights] Hi-Max 2600maH http://www.ebay.com/itm/HIMAX-18650-Batteries-x2-HI-Max-U-S-Seller-Free-Shipping-Fenix-TK15-TK21-/150717077706?pt=US_Batteries&hash=item23177018ca
Expensive (but top quality): IOS Panasonic 3100mAh http://www.intl-outdoor.com/panasonic-ncr18650a-3100mah-protected-battery-p-333.html Redilast various mAh http://www.redilast.com/index.php?option=com_content&view=article&id=56&Itemid=88 AW various mAh http://www.lighthound.com/search.asp?keyword=aw+18650&search=GO Callie's Kustoms 3100 mAh http://callieskustoms.com/CalliesKustoms-Batteries.html